Abstract Book

Last update: 15 June 2012

ATMOS 2012 - Advances in Atmospheric Science and Applications
Table of Contents
Opening Session .....................................................................................................................2
Status Overview of GMES Missions Sentinel-4, Sentinel-5 and Sentinel-5p ....................................... 2
Overview Presentations ..........................................................................................................2
The first Decade of SCIAMACHY, Coupled with GOME and GOME-2, Trace Gas Measurements ............. 2
Highlights of Ten Years of GOMOS Measurements ........................................................................ 3
MIPAS - 10 Years of Spectroscopic Measurements for Investigating Atmospheric Composition ............ 3
Product Quality .......................................................................................................................4
Product Quality of ESA's Atmospheric Chemistry Mission .............................................................. 4
Evaluation of Satellite Total Ozone and NO2 Columns Using the SAOZ UV-Vis Network ....................... 4
Comparison of DOAS Results from the Airborne CARIBIC System with Satellite Observations .............. 5
Valdiation of GOME-2 Ozone Profiles Using Ozonesondes-, LIDAR- and Microwave Data ..................... 5
Results for Operational Limb Data Products Within the SCIAMACHY Long Term Validation 2010
(SCILOV-10) Project ................................................................................................................ 6
Position Error in VMR Profiles Retrieved from MIPAS Observations with a 1-D Algorithm ..................... 6
Stratosphere ...........................................................................................................................7
Odin-OSIRIS: A Summary of the Results from the Past Eleven Years .............................................. 7
Solar Occultation Measurements of Atmospheric Composition: SCISAT/ACE and Beyond .................... 7
Trace Gas Profiles Retrieved from SCIAMACHY Solar Occultation Measurements with an Optimal
Estimation Approach ................................................................................................................ 7
Polar-Night O3, NO2 and NO3 Distributions During Sudden Stratospheric Warmings in 2003-2008 as
Seen by GOMOS/Envisat .......................................................................................................... 8
Denitrification and PSC Formation During the Arctic Winter 2009/2010 and 2010/2011 in Comparison . 8
Measurement of Stratospheric and Mesospheric Wind Fields Using SMILES and with an Outlook to the
Future ................................................................................................................................... 9
Stratosphere (cont.) ............................................................................................................. 11
Progress Towards Generating New Ozone Climate Data Records as Part of the Climate Change Initiative
.......................................................................................................................................... 11
Nadir Ozone Profile Retrieval Within the ESA Ozone-CCI Project ................................................... 11
Variability and Trends in Ozone since 2002 from the GOMOS/ENVISAT IPF V6 Reprocessing ............. 12
Ozone Time Series from GOMOS and SAGE II Measurements ....................................................... 12
Long Term Total Ozone Trend Analysis for the Years 1978 - 2011 from Merged Data Sets of Various
Satellites. ............................................................................................................................. 13
Using 16 Years of European Total Ozone Satellite Observations for Global Trend Analyses ................ 13
Towards a Merged Essential Climate Variable Data Record on Ozone: Stability and Consistency of
Contributing Limb Profilers...................................................................................................... 13
Ozone Losses in the Arctic Winters 2010-12 as Observed by SCIAMACHY ...................................... 14
Evolution and Variability of Water Vapour in the Tropopause Region and Stratosphere Derived from
Satellite Measurements .......................................................................................................... 14
Water Vapor Measurements in the UTLS at 936 nm by Stellar Occultations with GOMOS/ENVISAT ..... 14
Observed Temporal Evolution of Global Mean Age of Stratospheric Air for the 2002 to 2010 Period .... 15
MIPAS2D – 10 Years of MIPAS/ENVISAT Measurements Analyzed with a 2D Tomographic Approach .. 15
The MIPAS NOy Record: A Climatological Analysis and Budget Estimation ...................................... 16
Investigation of the Impact of Horizontal Inhomogeneities on MIPAS/ENVISAT Products .................. 16
MIPAS Climatologies of Atmospheric Trace Gases for the SPARC Data Initiative .............................. 17
I

Troposphere/Air Quality ....................................................................................................... 18
Changes in Tropospheric NO2 as Observed from Space ................................................................ 18
Uncertainties in NOx Lifetimes and their Influence on Top-Down Emission Estimates ....................... 18
Evaluation of NOx Emission Inventories in California Using Multi-Satellite Data Sets During the CalNex
Field Campaign ..................................................................................................................... 19
Retrieval of the Global Water Vapor Distribution from Satellite Observations in the Blue Spectral Range
.......................................................................................................................................... 19
Russian Fires in 2010: Results from the ALANIS Smoke Plume Project .......................................... 20
Troposphere/Air Quality (cont.) ............................................................................................ 22
Analysis of Tropospheric O3 and CO in Continental Outflow Regions Using IASI Satellite Observations
and MOZART-4 Model ............................................................................................................ 22
Upper Tropospheric Pollution Transport Documented with the Metop-A/IASI Sensor ........................ 22
Multi-Spectral Retrieval of Lowermost Tropospheric Ozone Combining IASI and GOME-2 Satellite
Observations ........................................................................................................................ 23
Tropospheric Trace-Gas Column Observations from GOME-2/MetOp .............................................. 23
Biogenic Methanol and Formic Acid Constrained from IASI Measurements ...................................... 24
Variabilities of Chemical Species Over the Mediterranean Basin: Measurements and Models ............. 24
Towards Global Routine Measurements of High-Resolution In-Situ NO2 Profiles - A Project Within ESA's
Innovation Triangle Initiative .................................................................................................. 25
PCW/PHEMOS UV-VIS Spectrometer: Air Quality from a Quasi-Geostationary Orbit ......................... 25
PREMIER - Earth Explorer 7 Candidate Mission ........................................................................... 26
A Satellite Constellation for Observing Global Air Quality: Status of the CEOS Activity ..................... 27
Volcanic Ash and SO2 ............................................................................................................ 28
Advances in Remote Sensing and Forecasting of Volcanic Ash ...................................................... 28
Synergetic Use of Atmosphere and Surface Observations by the Spaceborne European Volcano
Observatory - EVOSS ............................................................................................................. 28
SO2 Plume Height Retrieval from Direct Fitting of GOME-2 Backscattered Radiance Measurements .... 29
Estimating the Lifetime of SO2 from Space: A Case Study for the Kilauea Volcano ........................... 29
Observations of Volcanic Plumes Using Singular Vector Decomposition of MIPAS Spectra ................. 30
Performance Assessment of a Volcanic Ash Transport Model Mini-Ensemble Used for Inverse Modeling
of the 2010 Eyjafjallajökull Eruption ......................................................................................... 30
Upper Atmosphere ................................................................................................................ 32
Measurements of Mesospheric Ozone from MIPAS Spectra ........................................................... 32
Global Determination of Metal and Metal Ion Densities in the MLT Region from SCIAMACHY/Envisat
Data .................................................................................................................................... 32
Chemical Impact of Thunderstorms onto the Upper Atmosphere ................................................... 32
NLC Climatology from GOMOS Observations .............................................................................. 33
MIPAS Kinetic Temperature from the Stratosphere to the Lower Themosphere: Results and Validation
.......................................................................................................................................... 33
Greenhouses Gases ............................................................................................................... 34
The GHG-CCI Project of ESA's Climate Change Initiative: Overview and Status ............................... 34
Model Evaluations of Methane Variability in the Upper Troposphere and Lower Stratosphere ............. 35
Retrieval of Methane Distributions from IASI ............................................................................. 35
Improved Carbon Dioxide and Methane Retrieved from SCIAMACHY Onboard ENVISAT: Validation and
Applications .......................................................................................................................... 36
CarbonSat: ESA's Earth Explorer 8 Candidate Mission ................................................................. 36
Clouds/Aerosols.................................................................................................................... 37
Production of Aerosol Essential Climate Variables Using Satellite Data: Aerosol-CCI......................... 37
II

Retrieval of Saharan Desert Dust Properties from Hyperspectral Thermal Infrared Measurements by
IASI .................................................................................................................................... 37
Pollution Injection Into the Upper Troposphere and Lower Stratosphere: Detection, Plume Transport
and Composition Inference with MIPAS ..................................................................................... 38
Observing Air Quality Degradation by Major Aerosols Outbreaks and Tropospheric Ozone Using IASI
Infrared Sensor ..................................................................................................................... 38
The Collection 6 MODIS Aerosol Data Products .......................................................................... 39
Improving the Synergetic Retrieval Algorithm in the Aerosol_CCI Project ....................................... 39
The Complex Content of Stratospheric Aerosols Better Determined by Balloon-Borne and Satellite
Instruments ......................................................................................................................... 40
Analysis of GOSAT High Spectral Resolution O2 A-Band Measurements ......................................... 40
Satellite Observation of the Daily Variation of Thin Cirrus ............................................................ 41
Long-Term Satellite-Based Cloud Property Datasets Derived Within the EUMETSAT Satellite Application
Facility on Climate Monitoring ................................................................................................. 41
Analysis of Global Time Series of Cloud Properties from GOME/GOME-2 Spectrometers .................... 42
Interpretation of FRESCO Cloud Retrievals in Case of Absorbing Aerosol Events .............................. 42
GMES Services/Data Assimilation .......................................................................................... 44
MACC-II Analyses and Forecasts of Atmospheric Composition and European Air Quality: a Synthesis of
Observations and Models ........................................................................................................ 44
Take a Deep Breath with GMES Downstream Services for Air Quality ............................................ 44
Satellite-Based Particulate Matter Annual Compliance Monitoring for Northern Italy: A PASODOBLE
Downstream Sub-Service ....................................................................................................... 45
Daily Emission Estimates in China Constrained by Satellite Observations ....................................... 45
CO Seasonal Variability and Trend Over Paris Megacity Using Ground-Based QualAir FTS and Satellite
IASI-MetOp Measurements ..................................................................................................... 46
Exploiting Sentinel 5's Synergy with IRS and 3MI on METOP-SG for Protocol Monitoring and Air Quality-
Climate Interaction ................................................................................................................ 46
Simultaneous Assimilation of OMI, TES, MOPITT, MLS Satellite Data for the Analysis of Global
Tropospheric Composition ....................................................................................................... 47
Expected Level 2 Performance of Sentinel 4 UVN and the Impact of Scene Inhomogeneity ............... 47
TROPOMI on the Sentinel-5 Precursor: the Next Generation Shortwave Atmospheric Composition
Spectrometer ....................................................................................................................... 48
Sentinel 5 Precursor: Planned German and Belgian Contribution to the Operational L2 Products ........ 48
III

POSTER SESSION
Atmospheric Sentinels .......................................................................................................... 50
GOME-2 In-Orbit Degradation and its Impact on Level 2 Data (BrO, O3, HCHO, NO2, H2O) .............. 50
Monitoring the South Atlantic Anomaly Using ATSR Instrument Series ........................................... 50
SCIAMACHY: The New Concept of Instrument Performance Monitoring. ......................................... 51
Cross-Calibration of the Satellite Sensors with High Spatial Resolution Using Spectral MERIS Data .... 51
SCIAMACHY Monitoring Factors: Throughput Recovery ................................................................ 52
Sentinel-5 Precursor Payload Data Ground Segment ................................................................... 52
The Use of Airborne Measurements for the Evaluation of Satellite Observations .............................. 52
Remote Sensing of Trace Gases in the Troposphere ............................................................... 53
Cloud Parameter Retrieval in the Oxygen A-Band Using Optimal Estimation for the High-Volume Data
Stream of TROPOMI ............................................................................................................... 53
Intercomparisons of the Distribution of Tropospheric Ozone from SCIAMACHY and Other Satellite
Instruments ......................................................................................................................... 53
Novel Approach to Tropospheric NO2 Retrieval for TROPOMI ........................................................ 54
Global Fire Emission Estimates for 2009-2010 Derived from GOME-2 Formaldehyde Columns ........... 54
Monitoring Emission, Chemistry and Transport of Vegetation Fires from IASI and Comparison with
Simulations .......................................................................................................................... 55
Global and Local Ozone Measurments from the Thermal Infrared IASI/METOP Sounder .................... 55
NO2 VCD Retrieval from Airborne Prism EXperiment (APEX) Data Over the City of Zurich, Switzerland 56
Satellite Observations of Iodine Monoxide and its Relation to Biospheric Variables........................... 56
Tropospheric Emission Monitoring Internet Service ..................................................................... 57
Spectral Signature of Plants for Satellite Remote Sensing ............................................................ 57
Global Tropospheric Ozone Retrievals From OMI Data by Means of Neural Networks ........................ 58
Assessing Sources of Uncertainty in Formaldehyde Air-Mass Factors Over Tropical South America:
Implications for Top-Down Isoprene Emission Estimates ............................................................. 58
Validation of Tropospheric Ozone Columns from SCIAMACHY: First Results .................................... 59
Understanding the Atmospheric Hydrological Cycle Through Isotope Measurements from SCIAMACHY 59
PCW/PHEMOS-WCA: Quasi-Geostationary Viewing of the Arctic and Environs for Weather, Climate and
Air Quality ............................................................................................................................ 60
Simulating the IASI Spectrum Using Radiative Transfer Models .................................................... 60
Intercomparison of 5 Years of Global Formaldehyde Observations from the GOME-2 and OMI Sensors 61
Improving GOME-2 Tropical Formaldehyde Retrievals ................................................................. 61
A Common Approach for the Retrieval of Carbon Monoxide (CO) from TROPOMI's and SCIAMACHY's
SWIR Channel ...................................................................................................................... 62
Water Vapour Column Density Product from GOME, SCIAMACHY and GOME-2 - Validation with
Independent Satellite Observations .......................................................................................... 62
A New Sulphur Dioxide Retrieval Scheme for IASI: Results for Recent Eruptions and Possible Volcanic
Degassing. ........................................................................................................................... 63
Insights Into the Distribution and Role of Volatile Organic Compounds in the Upper Troposphere Using
MIPAS ................................................................................................................................. 63
CO and CH4 from the TROPOMI SWIR Channel on the Sentinel 5 Precursor Mission ......................... 64
Monitoring of Volcanic Eruptions and Determination of SO2 Plume Height from GOME-2 Measurements
.......................................................................................................................................... 64
Development and Maintenance of SCIAMACHY Operational ESA Level 2 Products: from Version 5
Towards Version 6 ................................................................................................................. 65
New Organic Molecules from ACE Satellite Observations .............................................................. 65
IV

Validation of Two Independent Retrievals of SCIAMACHY Water Vapour Columns Using Radiosonde
Data .................................................................................................................................... 66
Development of an FTS for Thermal and Near-Infrared Sounding of Weather, Air Quality and
Greenhouse Gases in the Arctic ............................................................................................... 66
Ozone Profile Retrievals from Metop and Envisat ........................................................................ 67
NH3 from TES: Results on Regional and Global Scales ................................................................ 67
Tropospheric Sulphur Dioxide Retrieval from the ESA SCIAMACHY Observations ............................. 68
IASI Chemistry Data Retrieved at Laboratoire d'Aerologie with the SOFRID .................................... 68
Tropospheric NO2 Trend over the Seoul Metropolitan Area Based on Satellite Remote Sensing and In-
Situ Surface Observations ...................................................................................................... 69
Systematic Investigation of Bromine Monoxide in Volcanic Plumes from Space by Using the GOME-2
Instrument ........................................................................................................................... 69
European Space Agency Campaign Activities in Support of Earth Observation Projects ..................... 70
A Novel Tropospheric NO2 Retrieval Algorithm Optimised for the Compact Air Quality Spectrometer,
CompAQS ............................................................................................................................ 70
Remote Sensing of Trace Gases in the Stratosphere .............................................................. 71
Validation of MIPAS IMK/IAA Ozone Profiles .............................................................................. 71
Vertical Ozone Profiles from GOME-2 on MetOp-A ....................................................................... 71
Global, Long-Term SO2 Measurements from Satellites ................................................................. 72
Detection of Tropical Stratospheric Transport Barriers from the Long Term NO2 Dataset Measured by
SCIAMACHY.......................................................................................................................... 72
The New Operational GOME/ERS-2 Total Ozone Data: GDP Version 5 Direct-Fitting Algorithm ........... 73
Quality Quantifier of Indirect Measurements .............................................................................. 73
Validation of Envisat’s Atmospheric Sensors Using LIDAR – The Valid Project ................................. 74
Precise Tangent Height Determination for SCIAMACHY Solar Occultation Measurements .................. 74
MIPAS/ENVISAT Measurements of the Extreme Depletion of Ozone in the Lower Stratosphere During
the 2010-2011 Arctic Winter Obtained with a 2D Tomographic Approach ....................................... 75
Iterative Approach to Self-Adapting and Altitude-Dependent Regularization for Atmospheric Profile
Retrievals ............................................................................................................................. 75
Stratospheric Composition Measurements Using the MAESTRO Instrument on a Balloon Platform
Launched from Kiruna During Springtime, 2011 ......................................................................... 76
Performance of an Advanced MIPAS Instrument Through the Information Load Analysis .................. 76
JURASSIC2 - A Tomographic Retrieval Processor ........................................................................ 77
Using GOMOS/Envisat Stellar Scintillation Measurements for Studies of Gravity Waves and Turbulence
in the Stratosphere ................................................................................................................ 77
Ten Years of MIPAS Measurements with ESA Operational Processor .............................................. 78
New Perspectives of Gravity Wave Remote Sensing Through ESA's Candidate Mission PREMIER ........ 78
Arctic Ozone in Spring 2011 as Seen by GOMOS and OMI ............................................................ 79
Satellite Observations of OClO from 1995 to 2011 in Comparison to ECMWF Data and EMAC
Simulations .......................................................................................................................... 79
Stratospheric Ozone Profile Trends from a Decade of SCIAMACHY Limb Observations ...................... 80
An Assimilation Study of Ozone Loss in the Arctic Winter 2009/2010 Using SMILES and Odin/SMR Data
.......................................................................................................................................... 80
Retrieval of Stratospheric Trace Gases from FIR/Microwave Limb Sounding Observations ................. 80
Trend Analysis of Stratospheric NO2 Above Jungfraujoch (46.5°E, 8°E) and Harestua (60°N, 11°E)
Using Long-Term Ground-Based UV-Visible, FTIR, and Satellite Observations ................................. 81
Assessment and Geophysical Validation of GOMOS Ozone Data Processed with IPF v.6 .................... 81
SCIAMACHY: New Algorithms for the Operational Level 0-1 Processor ........................................... 82
Inter-Comparison of GOMOS, MIPAS and SCIAMACHY ESA Datasets Using the GECA Validation Tool . 82
V

Time Series of Water Vapor in the Upper Troposphere and Lower Stratosphere from SCIAMACHY Limb
Measurements ...................................................................................................................... 83
MARSCHALS (Millimetre-wave Airborne Receivers for Spectroscopic CHaracterisation in Atmospheric
Limb Sounding) .................................................................................................................... 83
Diurnal Variation of Short-Lived Species in the Tropical Stratosphere and Mesosphere: Model
Comparison with Satellite Measurements .................................................................................. 83
Update to the MIPAS Reference Atmospheres for Infra-Red Active Trace Gases and Implications for
Atmospheric Sounding from Space ........................................................................................... 84
NO2 Seasonal Variation and Vertical Profiles Retrieval with Ground-Based and Satellite Equipment at
Evora Observatory - Portugal during 2010-2011 ........................................................................ 84
The Canadian Led Chemical and Aerosol Sounding Satellite (CASS) .............................................. 85
SPARC Data Initiative ............................................................................................................ 85
GOMOS Bright Limb Ozone Product .......................................................................................... 86
New Method for Radiation Calibration of Satellite Sensors with High Spatial Resolution .................... 86
Retrieval of Temperature and Ozone Profiles in the Upper Troposphere/Lower Stratosphere as
Measured by GLORIA during ESSenCe11 ................................................................................... 86
Remote Sensing of Trace Gases in the Upper Atmosphere ..................................................... 87
MIPAS Measurements of Polar Mesospheric Clouds during the 2005-2011 Period............................. 87
Global Observations of Thermospheric Temperature and Nitric Oxide from MIPAS Spectra at 5.3 µm . 87
Measurements of Water Vapor Distribution in the Middle Atmosphere by MIPAS.............................. 87
Analysis of MIPAS Spectra in the CO2 10 and 4.3 μm Regions in the Mesosphere and Lower
Thermosphere ...................................................................................................................... 88
Overview of MIPAS MA, UA and NLC Data Processing at IMK/IAA .................................................. 88
Remote Sensing of Clouds and Aerosols ................................................................................ 89
Global Multi-Sensor Satellite Monitoring of Volcanic SO2 and Ash Emissions in Support to Aviation
Control ................................................................................................................................ 89
The Validation of Cloud Retrieval Algorithms Using Synthetic Datasets .......................................... 89
Retrieval of Aerosol Optical Tickness and Single Scattering Albedo from MSG2 and Sun Photometer
Observations ........................................................................................................................ 90
Evaluation of the Vertical Distribution of Aerosols Simulated by a CTM (CHIMERE) Using L1 LIDAR
Observations (CALIPSO,EARLINET) .......................................................................................... 90
Aerosol Optical Thickness Retrieval Using Synergy Between MSG/SEVIRI and a Low Earth Orbit Sensor
.......................................................................................................................................... 91
Retrieval and Climatology of Stratospheric Aerosols from SCIAMACHY Limb-Scatter Observations ..... 91
The Airbone Volcanic Object Imaging Detector (AVOID): A New Tool for Atmospheric Airborne Remote
Sensing of Clouds .................................................................................................................. 92
Estimating Aerosol Altitude over Ocean from O2 A-Band Absorption Using MERIS Observations ........ 92
A Six-Year Record of Volcanic Ash Detection with Envisat MIPAS .................................................. 93
Assessing the Performance of the High Resolution MODIS MAIAC AOD Product in the Alpine Region .. 94
The AERGOM Stratospheric Aerosols Dataset: Preliminary Results ................................................ 94
Optical Properties of Volcanic Ash ............................................................................................ 95
Characterizing the Diurnal Cycle of Clouds Using Multiple Satellite Platforms .................................. 95
Impact of Cloud Heterogeneities on the Optical and Microphysical Cirrus Properties Retrieved from
Thermal Infrared Radiometry. ................................................................................................. 96
Synergetic Use of Multiple Data Set for the Derivation of Gridded Stratospheric Aerosol Fields .......... 96
Remote Sensing of Stratospheric and Upper Tropospheric Aerosols by Means of Ground-Based Twilight
Sky Spectral Photometry. ....................................................................................................... 97
LIDAR Climatology of Vertical Aerosol Structure for Space-Based LIDAR Simulation Studies (LIVAS) .. 97
Aerosol Optical Depth and Aerosol Classification by GOCI over East Asia........................................ 97
The MODIS 3 km Product: Algorithm and Global Perspective ........................................................ 98
VI

New and Forthcoming ‘Deep Blue’ Aerosol Datasets from NASA Sensors ........................................ 98
Evaluation of the MODIS 3 km Aerosol Product over an Urban/Suburban Landscape ........................ 99
Atmospheric Composition and Optical Depth Measurements from MAESTRO on the ACE Satellite ....... 99
OMI Simulated Aerosol Index: Initial Results and Verification as Part of the Aerosol-CCI Project ...... 100
Satellite Observations on the Production of Sea Spray Aerosol ................................................... 100
Retrieval over Aerosol Properties Using the AATSR Dual View Algorithm ...................................... 101
Retrieval of Aerosol Height with TROPOMI ............................................................................... 101
Remote sensing of Greehouse Gases ................................................................................... 102
Global Retrievals of CO2 and CH4 and GOSAT .......................................................................... 102
Retrieval of atmospheric CO2 from Satellite near-Infrared Nadir Spectra: Inter-Comparison of Various
Algorithms ......................................................................................................................... 102
Influence of Tropopause Height on Vertical Distribution of Ozone, A Study at low Latitude Using UARS
Data .................................................................................................................................. 102
Improved Retrieval of Methane Profiles from SCIAMACHY Solar Occultation Measurements with Onion
Peeling DOAS ..................................................................................................................... 103
IASI/METOP Sounder Contribution for Atmospheric Composition Monitoring ................................. 103
Retrieval of Methane Line Parameters Around 1.6 Microns from Laboratory Spectra ...................... 103
Impact of Uncertainties in Atmospheric Mixing Representation on Simulated UTLS Composition and
Related Radiative Forcings .................................................................................................... 104
Volcanic Carbon Dioxide Retrieved by Means Hyperspectral Data ................................................ 104
Carbon Gas Retrievals from SCIAMACHY Observations using BIRRA ............................................ 105
Future European Greenhouse Gas Satellite Remote Sensing Capabilities - The Short-Wave Infrared
(SWIR) Perspective ............................................................................................................. 105
Air Quality Monitoring from Space ....................................................................................... 106
Synergisitic LOTOS-EUROS and NO2 Tropospheric Column to Evaluate the NOx Emission Trends over
Europe............................................................................................................................... 106
GlobEmission ...................................................................................................................... 106
Monitoring Particulate Matter in the European Alpine Region from MODIS, SEVIRI, and In-Situ
Measurements .................................................................................................................... 106
Monitoring Air Quality: the Role of OSSEs in Determining the Future Global Observing System ....... 107
NOx Source Category Inferred from the OMI Obs. and Inter-Comparison of SCHAMACHY and OMI
Tropospheric NO2 Columns over India. ................................................................................... 107
Satellite Observations of Air Quality in China’s Megacities .......................................................... 108
Global Trend Analysis of MODIS(Terra), MISR(Terra), SeaWiFS(OrbView-2), and MODIS(Aqua) AOTs
........................................................................................................................................ 108
Atmospheric Ammonia Monitored by IASI ............................................................................... 108
Merging Remote Sensing and In-Situ Data for Detection of Biomass Burning Events ...................... 109
Use of Satellite and Surface Observations of Trace Gases to Evaluate the Impact of Fire Emissions on
Air Quality in Euro-Mediterranean Area ................................................................................... 110
A Global Inventory of Large SO2 Point Sources Derived from OMI Satellite Retrievals .................... 110
Reductions in Nitrogen Oxides over Europe Driven by Environmental Policy and Economic Recession 111
Quantitative Observation of Surface NO2 Variability from Total-Column Measurements .................. 111
Analysis of the Performances of Future Thermal Infrared Geostationary Instruments for Lowermost
Tropospheric Ozone Monitoring ............................................................................................. 112
GMES Services/Data Assimilation ........................................................................................ 113
Assimilation of Surface and Satellite Observations with the Lotos-Euros Air Quality Model Using the
Ensemble Kalman Filter ........................................................................................................ 113
Assimilation of SEVIRI Radiances over Land in the Météo-France Meso-Scale Models ..................... 113
IASI Retrievals over Concordia within the Framework of the Concordiasi Program in Antarctica. ...... 114
VII

Establishing an Infrastructure for Spatial Information in Europe : Insight into INSPIRE Developments
for GMES Atmospheric Data .................................................................................................. 114
Hindcasts of Tropospheric Composition during 2010 Russian Fires Using the MACC System ............ 115
Generic Radiative Transfer Model for the Earth's Surface-Atmosphere System: Towards a Community
Tool .................................................................................................................................. 115
A New Method for the Performance Analysis of a Concentrating Solar Power Energy Plant Using
Remotely Sensed Optical Images ........................................................................................... 116
BEAT - Basic Envisat Atmospheric Toolbox .............................................................................. 116
The Establishment of Atmospheric Essential Climate Variables under the ESA CCI Framework
........................................................................................................................................... 117
The New Operational GOME/ERS-2 Total Ozone Data: GDP Version 5 Direct-Fitting Geophysical
Validation ........................................................................................................................... 117
Towards an Improved Total Ozone Climate Data Record from GOME, SCIAMACHY and GOME-2 as Part
of the ESA Climate Change Initiative ...................................................................................... 117
Essential Climate Variables from Radio Occultation ................................................................... 118
On Merging Data from Satellite Limb Soundings ....................................................................... 118
The ESA Cloud CCI Project: Generation of Multi Sensor Consistent Cloud Properties with an Optimal
Estimation Based Retrieval Algorithm ..................................................................................... 119
Error Characterization of SCIAMACHY Limb Ozone Data ............................................................ 119
VIII

Day 1 , Monday 18 June 2012
1

Opening Session
Status Overview of GMES Missions Sentinel-4, Sentinel-5 and Sentinel-5p
Ingmann, Paul; Meijer, Yasjka; Veihelmann, B.; Koopman, R.; Straume, A.G.
ESA/ESTEC, NETHERLANDS
The space component of GMES (Global Monitoring for Environment and Security) is procured by the
European Space Agency (ESA) and comprises a series of space-borne missions called 'Sentinels'. While
Sentinels-1,-2 and -3 are focusing on ocean and land surface related topics, Sentinels-4, -5 and -5
precursor (S-4, S-5, S-5p) address atmospheric composition, S-4 from a geostationary orbit (GEO),
while S-5 and S-5p fly in a low earth orbit (LEO).
The objective of S-4 is to monitor key air quality trace gases and aerosols over Europe at high spatial
resolution, including the diurnal cycle of NO2. The objective of the LEO missions, S-5 and S-5p, is to
measure daily at global scale and high spatial resolution air quality and climate related trace gases and
aerosols in the Earth’s atmosphere. The target species including O3, NO2, SO2, HCHO and aerosols shall
be observed to support operational services covering air quality near real-time applications, air quality
and climate protocol monitoring. S-4 will fly on the EUMETSAT platforms MTG-S and S-5 is planned to be
embarked on EUMETSAT’s post-EPS series of satellites, respectively, while S-5p will fly on a dedicated
platform.
The development of S-4 and S-5p has entered its implementation phase, while S-5 has advanced into
feasibility study (Phase A/B1). For S-4 supporting studies focusing on retrieval algorithm prototyping and
for S-5p on Level-2 product development are in preparation. For S-5 scientific activities are centred
around requirement consolidation. Recently, a short study on the potential of the S-5 mission to monitor
carbon dioxide was conducted. The main result for the current S-5 baseline configuration is that random
errors meet breakthrough user requirement, while systematic errors are not compliant with threshold
requirements on a global to regional scale. Scattering effects are understood to be the main contributors
to these systematic errors. An optimization of the mission for CO2 monitoring to meet breakthrough
requirements and to perform monitoring on a local scale would require substantial changes to the
baseline such as improvements of the spectral/spatial sampling and/or an additional channel, which are
incompatible with the S-5 UVNS instrument planned to be embarked on EUMETSAT’s post-EPS series of
satellites.
The presentation at the upcoming conference will focus on the status of implementation of the
atmospheric composition related Sentinels, in particular on the preparation of the missions at user level.
Overview Presentations
The first Decade of SCIAMACHY, Coupled with GOME and GOME-2, Trace Gas
Measurements
Burrows, John P.; Bovensmann, Heinrich; Richter, Andreas; SCIAMACHY Team, .
University of Bremen, GERMANY
The SCIAMACHY (Scanning Imaging spectrometer for Atmospheric CHartographY) concept, which is a
national contribution supported initially by Germany and then later also by The Netherlands and Belgium,
was developed between 1985 and 1988 and selected by ESA for flight on POEM-1. This was later
separated into ENVISAT and Metop. SCIAMACHY was descoped and then built and launched on ENVISAT
on the 28th of February 2002. SCIAMACHY has now made over a decade of measurements. A smaller
version of SCIAMACHY initially called SCIA-mini, based on the SCIAMACHY work proposed for flight on
ERS-2. In 1990 ESA selected SCIA-mini for a rapid development as core part of the ERS-2 payload but
descoped it and renamed it GOME (Global Ozone Monitoring Experiment). ERS-2 was launched on the
20th April 1995 and made 16 years of measurements very successfully, prior to ESA switching off as part
of the decommissioning of ERS-2. EUMETSAT and ESA selected GOME-2 as part of the core payload of
Metop series of platforms. The first GOME-2 was launched in 2006 and began its measurements in 2007.
This presentation will describe the measurements and retrieval algorithms briefly and then concentrate
on the research undertaken using the measurements made by GOME, SCIAMACHY and GOME-2 of
relevance for tropospheric and stratospheric chemistry and dynamics. This will address in particular
ozone and its precursors.
2

Highlights of Ten Years of GOMOS Measurements
Tamminen, Johanna 1 ; Kyrölä, E. 1 ; Sofieva, V. 1 ; Hakkarainen, J. 1 ; Verronen, P.T. 1 ; Tukiainen, S. 1 ;
Bertaux, J.-L. 2 ; Hauchecorne, A. 2 ; Dalaudier, F. 2 ; Perrot, K. 2 ; Fussen, D. 3 ; Vanhellemont, F. 3 ; Tetard,
C. 3 ; Fanton d'Andon, O. 4 ; Barrot, G. 4 ; Blanot, L. 4 ; Fehr, T. 5 ; Dehn, A. 5 ; Saavedra de Miguel, L. 5
1 Finnish Meteorological Institute, FINLAND; 2 LATMOS, FRANCE; 3 BIRA-IASB, BELGIUM; 4 ACRI, FRANCE;
5 ESA-ESRIN, ITALY
During the ten years of its operations, Envisat/GOMOS (Global Ozone Monitoring by Occultation of Stars)
instrument has successfully demonstrated the capabilities of stellar occultation technique for atmospheric
profiling.
In this presentation we show highlights of GOMOS measurements: vertical profiles of O3, NO2, NO3 and
aerosols, including polar mesospheric clouds and polar stratospheric clouds, using UV-VIS wavelengths
and O2 and H2O using two near-IR channels. High vertical resolution temperature profiles are obtained
using the time delay of the red and the blue photometers of GOMOS. The two photometers are also used
for studying turbulence and gravity waves. Constituents with weak spectral signatures, such as OClO and
Na, can be detected using temporal averaging.
GOMOS measurements provide global coverage with about 200-400 daily measurements. Vertically the
measurements extend from 10 km to 100 km with varying valid altitude range depending on constituent.
Stellar occultation technique ensures high vertical resolution of 2-4 km, very accurate altitude
registration and relatively simple data retrieval. The self-calibrating feature of the occultation technique
is particularly suitable for long term trend analysis and thus crucial for studying the climate-chemistry
interactions.
MIPAS - 10 Years of Spectroscopic Measurements for Investigating Atmospheric
Composition
Orphal, J.; Fischer, H.
Karlsruhe Institute of Technology, GERMANY
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the European satellite
ENVISAT is a limb sounder measuring the thermal emission (wavelength region from 4.15 to 14.6
microns) of atmospheric trace gases and particles with high spectral resolution. Due to the special limb
viewing geometry, MIPAS has provided global coverage of atmospheric parameters from pole to pole,
day and night, since March 2002. The altitude range detected covers the upper troposphere, the
stratosphere and the mesosphere by using the nominal measurement mode. MIPAS data have been
applied to retrieve operationally vertical profiles of the temperature and of the six key species H2O, O3,
CH4, N2O, HNO3 and NO2. In addition, a huge number of other atmospheric parameters and
constituents have been derived with non-operational research algorithms (H. Fischer et al., ACP, 2008).
Many scientific results from MIPAS have already been published in over 300 papers. In this talk, only an
overview of the most recent results will be presented, including the Arctic “ozone hole” in the winter
2010/2011, the observation of tropical dehydration processes, and the temporal evolution of the age of
stratospheric air.
3

Product Quality
Product Quality of ESA's Atmospheric Chemistry Mission
Dehn, Angelika; Fehr, Thorsten
ESA/ESRIN, ITALY
[Introduction] The operational ESA Atmospheric Chemistry Mission is providing fundamental information
for the understanding of atmospheric chemistry processes. The global datasets are supporting climate
research, air quality assessments, stratospheric ozone monitoring and many other science areas and
operational services. [ESA Missions] With over 16 years in operation, GOME on the ERS-2 platform is
providing the longest single-sensor ESA atmospheric chemistry dataset. ERS-2 was successfully
decommissioned in September 2011. Algorithm development and reprocessing are still continued and
improved datasets will be provided to the users. The ESA’s atmospheric chemistry observations are
continued in the frame of Envisat, which is celebrating its 10th year in operations on 01 March 2012
being operated until 2013 and possibly beyond. It is hosting three chemistry sensors, GOMOS, MIPAS
and SCIAMACHY, complementing and significantly expanding the capabilities of GOME. The SCIAMACHY
instrument performed without any serious problems in one decade of operations. MIPAS operations were
interrupted in 2004 but since its recovery in 2005 it is working basically flawless. GOMOS suffered from
several anomalies related to the mirror steering mechanism. Since August 2011 the operations are
severely impacted by an instrument anomaly. At the time of writing, future operations scenarios are
being investigated. [Products] The quality of the ESA operational Level 1b and Level 2 products is
constantly maintained through the support of expert teams, both for the evolution of the algorithms and
the constant monitoring of individual data files. Upon significant upgrades, ESA is providing a
reprocessed dataset covering the complete mission in order to assure a long time series of homogenous
quality. All atmospheric products have undergone significant improvements. In January 2012 a new
reprocessed MIPAS dataset was provided to the validation teams which among other improvements also
included four new trace gases, CFC-11, CFC-12, ClONO2 and N2O5. In spring 2012, three reprocessed
datasets will become available: SCIAMACHY Level 2, also including new trace gases – SO2, CO, water
vapour (all nadir) and BrO (limb/nadir); the GOMOS Level 1b and Level 2 with greatly improved error
characterisation and water vapour; the GOME reprocessing with GDP5. [Sentinel] In the future, ESA’s
atmospheric composition mission will be continued in frame of the GMES Sentinels. In particular the
Sentinel 5 Precursor will continue the legacy of GOME and SCIAMACHY, but also OMI on NASA’s AURA
mission and GOME-2 on EUMETSAT’s MetOP. The nadir viewing TROPOMI instrument will continue and
enhance the time series for Ozone, NO2 and other UV-VIS products that started with GOME, as well as
for CO and CH4 that started with SCIAMACHY SWIR observations. The launch date is foreseen in 2015.
The presentation will summarise the status of all the issues addresse above with a focus on the ESA
instruments.
Evaluation of Satellite Total Ozone and NO2 Columns Using the SAOZ UV-Vis
Network
Pommereau, Jean-Pierre 1 ; Goutail, Florence 1 ; Pazmino, Andrea 1 ; Ionov, Dmitry 2 ; Hendrick, Francois 3 ;
Van Roozendael, Michel 3
1 LATMOS CNRS, FRANCE; 2 Department of Atmospheric Physics, St. Petersburg State University, RUSSIAN
FEDERATION; 3 Belgian Institute for Space Aeronomy (BIRA-IASB), BELGIUM
The full series of SAOZ network total ozone measurements in the visible Chappuis bands has been
revised according to the spectral analysis and Air Mass Factor (AMF) settings recommended by the
NDACC UV-Vis Working Group (Hendrick et al., 2011). They have been compared to overpass
observations from the TOMS, GOME-GDP4, SCIAMACHY-TOSOMI, SCIAMACHY-OL3, OMI-TOMS, and
OMI-DOAS satellite instruments. Significant improvement is obtained after applying the new O3 AMFs,
although systematic seasonal differences between SAOZ and all other instruments still remain. These are
shown to originate from (i) a stratospheric temperature and solar zenith angle (SZA) dependencies in the
satellites retrievals, (ii) longitudinal modulations and seasonal variations of tropospheric ozone columns
not accounted for in the TOMS V8 ozone profile climatology used for calculating the AMFs, and (iii)
uncertainties on the climatological stratospheric ozone profiles for polar winter conditions. For those
measurements mostly sensitive to stratospheric temperature like TOMS, OMI-TOMS or to SZA like
SCIAMACHY-TOSOMI, the application of temperature and SZA corrections results in the almost complete
removal of the seasonal difference with SAOZ, improving significantly the consistency between satellite
and ground-based total ozone series. However, small but sometimes significant biases remain after
applying those corrections. A similar exercise is in progress with SAOZ NO2 data sets, using AMFs
calculated from a profile climatology based on HALOE, SAGE II, POAM III and SAOZ balloon profiles. The
consistency with GOME/ERS2, SCIAMACHY/ENVISAT and OMI/AURA NO2 total columns is also currently
4

examined. In this presentation, we will focus on the resulting evaluation of ozone and NO2 total columns
biases of the various satellite instruments.
Comparison of DOAS Results from the Airborne CARIBIC System with Satellite
Observations
Heue, Klaus-Peter 1 ; Walter, David 1 ; Brenninkmeijer, Carl 1 ; Wagner, Thomas 1 ; Sihler, Holger 1 ; Hörmann,
Christoph 1 ; Platt, Ulrich 2 ; Krotkov, Nickolay 3 ; Lamsal, Lok 4
1 Max-Planck-Institut für Chemie, GERMANY; 2 Institut für Umweltphysik, GERMANY; 3 NASA, UNITED
STATES; 4 Universities Space Research Association (USRA), UNITED STATES
Comparisons studies between the airborne DOAS instrument on board of CARIBIC and satellite
observations will be presented. CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere
Based on an Instrument Container, www.caribic.de) observes physical and chemical processes in the
Earth's atmosphere using a fully automated measurement container aboard a Lufthansa Airbus 340-600.
A special inlet system is mounted on the aircraft with probes for trace gases, water vapour and aerosol
particles. It also includes three telescopes of a DOAS (Differential Optical Absorption Spectroscopy)
system for remote sensing. Enhanced sulphur dioxide (SO2) column densities were observed by CARIBIC
DOAS after the eruptions of Kasatochi (Alaska, USA) and Eyjafjallajökull (Iceland) as well as downwind of
the nickel smelter in Norilsk (Siberia). For all cases detailed studies were performed and the data were
used for comparisons with products from several satellite instruments. Depending on the time difference
between the CARIBIC observation and the satellite overpass SCIAMACHY, OMI or GOME-2 data were
considered. For the Kasatochi plume wind speeds were relevant for the comparison in view of a
discrepancy in the timing of aircraft and satellite overpass. In the case of a dedicated flight designed to
intercept parts of the Eyjafjallajökull plumes, also BrO was detected. Due to high noise in both CARIBIC
and GOME-2 data a qualitative comparison of the BrO vertical column densities was not performed. For
Norilsk, where NO2 enhancements were also detected, wind data were used to estimate the SO2 flux. The
flux estimate based on CARIBIC data was in a good agreement with independent data including several
satellite based results. In general, good agreement between CARIBIC and the satellite data was
obtained.
Valdiation of GOME-2 Ozone Profiles Using Ozonesondes-, LIDAR- and
Microwave Data
Delcloo, Andy 1 ; Kins, Lucia 2 ; Tuinder, Olaf 3
1
Royal Meteorological Institute of Belgium (RMIB), BELGIUM;
2
Deutscher Wetterdienst (DWD), GERMANY;
3
Royal Netherlands Meteorological Institute (KNMI), NETHERLANDS
More than five years of GOME-2 vertical ozone profile data is available and has been validated against
reference data. GOME-2 vertical ozone profiles are given as partial ozone columns [in DU per layer]
between varying pressure levels (40 levels between surface and 0.01 hPa). The ozonesonde data has a
vertical resolution of about 100 m and is measuring ozone from the surface up to about 30 km.
Differential Absorption LIDARs (DIAL) have a vertical resolution of 1-8 km and an altitude range from
about 12 till 50 km, microwave radiometers measure ozone from about 20 till 70 km with an altitude
resolution of ca. 10 km. To validate the satellite derived ozone layers with the ozonesonde data, we
integrate the ozone measured by the balloon ozone soundings between the corresponding GOME-2
pressure levels. GOME-2 ozone data was made available by KNMI at pre-selected sites. The reference
data includes a global coverage of ozonesonde-, DIAL- and microwave stations. The mean relative
difference between GOME-2 retrieved ozone profiles and mid-latitude ozonesondes as well as with DIAL
is within 10 % in the troposphere and the stratosphere. Between 37 and 45 km GOME-2 has a larger
negative bias (up to -30%) when compared with DIAL and microwave profiles. The high latitude stations
give poorer results: the mean relative difference between GOME-2 and ozonesondes is within 15 % in
the troposphere and the stratosphere. The bias is larger in the UTLS region, especially at high latitudes.
The standard deviation on the mean difference is of the order of 30% in the troposphere and 10 to 15%
in the stratosphere at mid-latitudes and increases to 25% above 55km altitude. In the UTLS region, the
standard deviation on the mean is considerably larger. We take into account the GOME-2 averaging
kernels in our analysis in order to smooth the ozonesonde data towards the resolution of the satellite
data. In preparation of a future processor upgrade, also high-resolution ground pixels (80 km – 40 km)
have been processed and validation results with reprocessed ozone profiles will be presented. The
influence of the degradation of the GOME-2 instrument on the ozone profile product will be discussed.
Also the East-West dependency will be issued.
5

Results for Operational Limb Data Products Within the SCIAMACHY Long Term
Validation 2010 (SCILOV-10) Project
Weigel, Katja; Weber, Mark; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John
University of Bremen, Institute of Environmental Physics (IUP), GERMANY
The SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY) is an
instrument on Envisat which measures scattered solar radiation from the earth atmosphere with different
observation geometries. The ESA project SCILOV-10 (SCIAMACHY long term validation 2010) aims at
documenting the data quality of the operational data products both retrieved from SCIAMACHY in both
limb and nadir observation geometry, respectively. The focus here is on the long-term stability of the
decadal SCIAMACHY data record. Here we present long-term comparisons between operational limb
profiles of O3, BrO and NO2 (ESA/DLR V5.01) to the corresponding scientific SCIAMACHY retrievals at the
Institute of Environmental Physics (IUP) Bremen and other satellite measurements. The limb observation
geometry provides a high vertical resolution in the Stratosphere where all these trace gases play an
important role.
Position Error in VMR Profiles Retrieved from MIPAS Observations with a 1-D
Algorithm
Massimo, Carlotti 1 ; Elisa, Castelli 2 ; Bianca Maria, Dinelli 2 ; Enzo, Papandrea 1
1 2
University of Bologna, ITALY; ISAC, CNR, ITALY
The Information Load (IL) analysis [1] is applied to the inversion of MIPAS observations operated with a
1-Dimensional (1D) retrieval algorithm. We show that the IL analysis, first introduced for the 2dimensional
approach, can also be exploited within a context that makes the assumption of horizontal
homogeneity of the analyzed portion of atmosphere. The IL analysis applied to MIPAS observations
indicates that it is possible to identify a preferential latitude where the retrieved profiles with a 1-D
algorithm should be geo-located. A position error is therefore made when the geo-location is coincident
with the average position of the tangent points of the observations. The IL analysis also provides a tool
to select observations that minimize the position error. The temperature (T) profiles used for the VMR
retrieval of atmospheric constituents can be externally-provided or determined in a previous step of the
retrieval analysis. In the first case, the IL analysis shows that a meaningful fraction of the VMR error
deriving from the 1D approximation is to be attributed to a mismatch between the position assigned to
the external T profiles and the specific IL distributions of the analyzed observations. In the second case
we show that, in general, the T position error is of minor entity and depends on the mismatch between
the IL distribution of the observations analyzed to retrieve T and those analyzed to retrieve the VMR
target. We show that the position error is directly connected to the horizontal T gradients and we provide
an estimate of its contribution to the error budget for the main MIPAS targets. The analysis that we
introduce in this paper can be extended to the 1D inversion of other orbiting limb sounders that, like
MIPAS, continuously measure the atmospheric emission along the orbit track. [1] M. Carlotti and L.
Magnani, “Two-dimensional sensitivity analysis of MIPAS observations”, Optics Express, 17, No. 7, 5340-
5357, (2009)
6

Stratosphere
Odin-OSIRIS: A Summary of the Results from the Past Eleven Years
Degenstein, Doug 1 ; Bourassa, Adam 1 ; Lloyd, Nick 1 ; McLinden, Chris 2 ; Llewellyn, Ted 1
1 University of Saskatchewan, CANADA; 2 Environment Canada, CANADA
The Canadian built OSIRIS instrument has been in operation onboard the Odin spacecraft since the
autumn of 2001. During this time OSIRIS has routinely made measurements of limb scattered sunlight
dispersed with approximately 1 nm resolution over the wavelength range from 280 nm to 810 nm. These
radiance measurements have been used to retrieve vertical number density profiles of ozone, nitrogen
dioxide, sulphate aerosols and bromine oxide. This paper will present the OSIRIS highlights including:
ozone depletion in the arctic spring of 2011; the use of OSIRIS stratospheric aerosol measurements to
determine the impact of volcanoes on climate; the use of OSIRIS data products in various ESA initiatives
related to standardized ozone and aerosol data sets and the role of the Asian monsoon in transport from
the troposphere to the stratosphere.
Solar Occultation Measurements of Atmospheric Composition: SCISAT/ACE and
Beyond
Walker, Kaley A. 1 ; Bernath, Peter F. 2 ; McElroy, C. Thomas 3
1 University of Toronto, CANADA; 2 Old Dominion University, UNITED STATES; 3 York University, CANADA
Reliable chemical composition measurements are essential for monitoring and to understand changes
occurring in the Earth's atmosphere due to ozone recovery, climate change and pollutant emissions.
Altitude-resolved data are a necessary part of this composition data set because many processes occur
at specific altitudes or over limited vertical length scales. Solar occultation has proven to be an effective
technique for measuring profiles of atmospheric trace gases and aerosols, capable of tracking long-term
changes.
This paper will describe the results from the Canadian-led Atmospheric Chemistry Experiment (ACE), a
scientific satellite mission using the solar occultation technique. The SCISAT/ACE satellite uses infrared
and UV-visible spectroscopy to investigate the chemistry and dynamics of the Earth's atmosphere. The
two instruments, ACE-FTS and ACE-MAESTRO, have been making regular solar occultation observations
for more than eight years and, from these measurements, deriving altitude profiles of over 30 different
atmospheric trace-gas species, temperature and pressure. This paper will cover recent scientific and
validation results and will discuss potential missions to continue measurements of this type for
atmospheric monitoring and scientific studies.
Trace Gas Profiles Retrieved from SCIAMACHY Solar Occultation Measurements
with an Optimal Estimation Approach
Bramstedt, Klaus; Azam, Faiza; Noël, Stefan; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John P.
University of Bremen, GERMANY
The spectrometer SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric
CHartographY) on-board ENVISAT is measuring solar irradiances and Earthshine radiances from the UV
to the NIR spectral region in nadir, limb and lunar/solar occultation geometry. Solar occultation
measurements are performed every orbit during sunset at northern latitudes (49°N to 69°N, depending
on season). The radiative transfer and retrieval code SCIATRAN 3.0 is used to derive vertical trace gas
profiles of ozone, NO2 and water vapour. Further trace gases are under investigation. For this dataset,
precise tangent heights are determined from the scans over the solar disk. The retrieval scheme is an
optimal estimation approach with Twomey-Tikhonov regularisation. Here we present an almost complete
10 years dataset of stratospheric profiles from August 2002 onwards. The quality of the data set in the
context of trend investigations will be discussed.
7

Polar-Night O3, NO2 and NO3 Distributions During Sudden Stratospheric
Warmings in 2003-2008 as Seen by GOMOS/Envisat
Sofieva, Viktoria; Kalakoski, Niilo; Verronen, Pekka; Päivärinta, Sanna-Mari; Kyrölä, Erkki; Backman,
Leif; Tamminen, Johanna
Finnish Meteorological Institute, FINLAND
Sudden stratospheric warmings (SSW) are large-scale transient events, which have a profound effect on
the northern hemisphere stratospheric circulation in winter. During the SSW events the temperature in
stratosphere increases by several tens of Kelvins and zonal winds decelerate or reverse in direction.
Changes in temperature and dynamics significantly affect the chemical composition of the middle
atmosphere. In this paper, the response of the middle-atmosphere trace gases during several sudden
stratospheric warmings in 2003-2008 is investigated using measurements from the GOMOS (Global
Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite. We have analyzed
spatial and temporal changes of NO2 and NO3 in the stratosphere, and of ozone in the whole middle
atmosphere. To facilitate our analyses, we have used the temperature profiles data from the MLS
(Microwave Limb Sounder) instrument on board the Aura satellite, as well as simulations by the FinROSE
chemistry-transport model and the Sodankylä Ion and Neutral Chemistry model (SIC). NO3 observations
in the polar winter stratosphere during SSWs are reported for the first time. Changes in chemical
composition are found not to be restricted to the stratosphere, but to extend to mesosphere and lower
thermosphere. They often exhibit a complicated structure, because the distribution of trace gases is
affected by changes in both chemistry and dynamics. The tertiary ozone maximum in the mesosphere
often disappears with the onset of SSW, probably because of strong mixing processes. The strong
horizontal mixing with outside-vortex air is well observed also in NO2 data, especially in cases of
enhanced NO2 inside the polar vortex before SSW. Almost in all of the considered events, ozone near the
secondary maximum decreases with onset of SSW. In both experimental data and FinROSE modelling,
ozone changes are positively correlated with temperature changes in the lower stratosphere in the
dynamically controlled region below ~35 km, and they are negatively correlated with temperature in the
upper stratosphere (altitudes 35-50 km), where chemical processes play a significant role. Large
enhancements of stratospheric NO3, which strongly correlate with temperature enhancements, are
observed for all SSWs, as expected by the current understanding of temperature-dependence of NO3
concentrations and simulations with the CTM.
Denitrification and PSC Formation During the Arctic Winter 2009/2010 and
2010/2011 in Comparison
Khosrawi, Farahnaz 1 ; Urban, Jo 2 ; Pitts, Michael C. 3 ; Voelger, Peter 4 ; Achtert, Peggy 1 ; Santee, Michelle
L. 5 ; Manney, Gloria L. 5 ; Murtagh, Donal 2
1 Stockholm University, SWEDEN; 2 Chalmers Technical University, SWEDEN; 3 NASA Langley Research
Center, UNITED STATES; 4 IRF Kiruna, SWEDEN; 5 California Institute of Technology, UNITED STATES
Polar Stratospheric Clouds (PSCs) and denitrification, the permanent removal of nitric acid (HNO3) by
sedimenting HNO3 containing PSC particles, play a key role in stratospheric ozone depletion. The two
recent Arctic winter 2009/2010 and 2010/2011 were both quite unique. The Arctic winter 2010/2011 was
one of the coldest winter on record leading to the strongest depletion of ozone ever measured. Though
the Arctic winter 2009/2010 was rather warm in the climatological sense it was distinguished by a
exceptionally cold stratosphere from mid December 2009 to mid January 2010 leading to prolonged PSC
formation and strong denitrification. For investigating PSC formation during these two Arctic winter we
apply ground-based measurements performed with the Esrange and the IRF LIDAR in the area of Kiruna,
Northern Sweden (69°N 21° E) and space-borne LIDAR measurements from the CALIPSO (Cloud-Aerosol
LIDAR and Infrared Pathfinder Satellite Observations) Satellite together with microphysical box model
simulations. To investigate denitrification during these two Arctic winter we apply measurements from
the Odin Sub-Millimetre Radiometer (Odin/SMR) as well as measurements from the Microwave Limb
Sounder on Aura (Aura/MLS). Though denitrification in 2009/2010 was until then the strongest in the
entire Odin/SMR measurement period it was excelled by the 2010/2011 winter where denitrification was
nearly as severe as in the Antarctic. PSC occurrance during both winter was also quite different. While
PSCs were present during the Arctic winter 2010/2011 over nearly four months, from mid December to
end of March, they were not as persistent as the ones that occurred during the shorter (one month) cold
period during the Arctic winter 2009/2010.
8

Measurement of Stratospheric and Mesospheric Wind Fields Using SMILES and
with an Outlook to the Future.
Murtagh, Donal 1 ; Baron, Philippe 2 ; Urban, Jo 1 ; Ochiai, Satoshi 2 ; Kasai, Yasuko 2
1 Chalmers tekniska högskola, SWEDEN; 2 NICT, JAPAN
Atmospheric wind field measurements are mostly limited to the troposphere although mesospheric winds
are measured using optical techniques from satellites and by radar systems such as EISCAT and various
meteor radars. In meteorological models stratospheric winds are computed using mass balance
considerations where the pressure and temperature fields are assumed to be in balance with the Coriolis
force. This assumption breaks down in the equatorial regions and the upper stratosphere and
mesosphere where wave effects are important. In the upper stratosphere and mesosphere the
temperature information entering the models is limited and physical processes such as thermal tides are
often badly represented resulting in incorrect wind fields. Considering the importance of the stratospheric
wind pattern, particularly in the tropics, in controlling the seasonal climate and the distribution of trace
gases, observations are essential. The only past stratospheric observations were by HRDI on UARS
covering 10–35 km and 60◦S–60◦N [9]. A gap in the coverage between 30 and 60 km clearly exists. We
report the first global observations of winds in this region using the SMILES sub-mm radiometer that was
launched in September 2009. We have exploited its high frequency resolution to derive the small Doppler
shifts in the atmospheric spectra and thereby line-of-sight wind velocities. Wind information is derived
from 35–80 km and from 40◦S–65◦N with uncertainties

Day2, Tuesday 19 June 2012
10

Stratosphere (cont.)
Progress Towards Generating New Ozone Climate Data Records as Part of the
Climate Change Initiative
Van Roozendael, Michel 1 ; Braesicke, Peter 2 ; Dameris, Martin 3 ; Lambert, Jean-Christopher 1 ; Loyola,
Diego 3 ; van der A, Ronald 4 ; Weber, Mark 5 ; Zehner, Claus 6 ; Kalb, Nathalie 1 ; Wolfmuller, Meinhard 3
1 Belgian Institute for Space Aeronomy, BELGIUM; 2 University of Cambridge, UNITED KINGDOM; 3 German
Aerospace Center, GERMANY; 4 Royal Netherlands Meteorological Institute, NETHERLANDS; 5 University of
Bremen, GERMANY; 6 ESA/ESRIN, ITALY
We report on progress achieved during the first two years of the Ozone_cci project in the framework of
the ESA Climate Change Initiative (CCI) programme. Since September 2010, Ozone_cci scientists have
been working on developing, characterizing and generating improved series of ozone column and vertical
profile products derived from multiple satellite sensors, with a particular emphasis on the exploitation of
ESA European and Third Party Mission (TPM) instruments. Developments are taking place along three
lines of data products: total ozone, ozone profiles from nadir UV sensors (low vertical resolution) and
from limb/occultation-type (high vertical resolution) of instruments. Satellite sensors under investigation
are GOME on ERS-2, SCIAMACHY, MIPAS and GOMOS on ENVISAT, OMI on AURA, GOME-2 on METOP-A
as well as OSIRIS and SMR on ODIN and ACE-FTS on SCISAT-1. Efforts so far have concentrated on
algorithm improvements and on detailed error characterization for the different ozone data products. The
aim is to match as closely as possible the requirements identified by climate users for ozone data records
consistent with those of the Global Climate Observing System (GCOS). We summarize the progress
achieved in terms of level-2 algorithm developments for total ozone and for ozone vertical profile
retrievals from nadir UV sensors. Two major round-robin exercises have taken place with the aim to
define and select reference level-2 ozone profiling algorithms for the MIPAS instrument as well as for the
series of UV nadir sensors GOME, SCIAMACHY, OMI, and GOME-2. These exercises include a number of
activities and involve retrieval experts and independent validation teams. In parallel, data merging
techniques are being developed to properly integrate the information from multiple-sensors in various
level-3 (binned) and level-4 (assimilated) data products. The final aim is to generate new improved data
sets by end of 2012, which will then be available for assessment by the climate user community in the
course of 2013. More information can be found on the project’s web-site (www.esa-ozone-cci.org).
Nadir Ozone Profile Retrieval Within the ESA Ozone-CCI Project.
van Peet, Jacob 1 ; van der A, Ronald 1 ; Miles, Georgina 2 ; Siddans, Richard 2
1 KNMI, NETHERLANDS; 2 RAL, UNITED KINGDOM
Within the Ozone-CCI project an algorithm will be developed for the retrieval of ozone profiles from
nadir-looking UV/VIS spectrometers. Currently, two operational algorithms exist: the OPERA algorithm,
developed at KNMI and used operationally within EUMETSATs O3MSAF and the RAL-scheme, developed
at the Rutherford Appleton Laboratory. It is the intention to merge the best practices of both retrieval
algorithms into a new one, which is dubbed ‘OPERAL’ for the time being. OPERAL will be used to create a
climatological time series of nadir retrieved UV/VIS ozone profiles from the instruments GOME,
SCIAMACHY, GOME-2 and OMI. These retrieved profiles will be assimilated into a global chemistry
transport model to obtain global coverage for the whole period since the launch of GOME. This
assimilated time series will enable research into for example ozone trends and stratosphere-troposphere
exchanges. In the presentation, the differences and similarities of the operational algorithms will be
highlighted. The effect of retrieval pressure grid and the a-priori covariance matrix on the retrieved
profiles will be assessed. The presentation will be concluded with a short demonstration of the proposed
data-assimilation technique.
11

Variability and Trends in Ozone since 2002 from the GOMOS/ENVISAT IPF V6
Reprocessing
Hauchecorne, Alain 1 ; Bertaux, Jean-Loup 2 ; Funatsu, Beatriz 2 ; Dalaudier, Francis 2 ; Barrot, Gilbert 3 ;
Blanot, Laurent 3 ; Sofieva, Voktoria 4 ; Kyrölä, Erkki 4 ; Tamminen, Johanna 4 ; Fussen, Didier 5 ;
Vanhellemont, Filip 5 ; Dehn, Angelika 6 ; Saavedra de Miguel, Lidia 7
1 UVSQ, CNRS-INSU, FRANCE; 2 LATMOS/IPSL,UVSQ, CNRS-INSU, FRANCE; 3 ACRI-ST, FRANCE; 4 Finnish
Meteorological Institute, FINLAND; 5 BIRA-IASB, BELGIUM; 6 ESA/ESRIN, ITALY; 7 SERCO, ITALY
Following the Montreal protocol and its amendments, the concentration of Ozone Depleting Gases (ODP)
is decreasing slowly in the stratosphere. We expect a progressive recovery of the ozone layer during the
next decades. However, due to complex interactions between radiative, dynamical and chemical
processes in the atmosphere, the rate at which the recovery will take place is still very uncertain.
Furthermore, the ozone layer is perturbed by external forcings like solar variability and volcanic
eruptions. Accurate measurements of the 3D distribution of stratospheric ozone are strongly required to
understand all causes of the ozone layer variability in order to better predict its future evolution. The
global coverage can be only obtained from satellite observations and a validation with ground-based
NDACC instruments is needed to assess the quality of the data. The GOMOS instrument on board
ENVISAT (launched in 2002 in a helio-synchronous polar orbit) measures the vertical profiles of
stratospheric and mesospheric constituents using the stellar occultation technique with a UV-visible
spectrometer (250 to 680 nm) for O3, NO2, NO3 and aerosols and two dedicated near IR spectrometers
centred at 760 nm for O2 and 940 nm for H2O. The atmospheric transmission is computed by the ratio
between a star spectrum measured through the atmosphere and a reference star spectrum measured
outside the atmosphere. Vertical profiles of constituents are obtained by a global spectral inversion
followed by a vertical inversion using a Tikhonov regularization. GOMOS is by principle an auto-calibrated
instrument because it does not depend on radiometric calibration. However, due to the ageing of the
CCD detector, creating an increase in the dark charge not perfectly corrected in Version 5 algorithms, a
bias was detected in the difference between GOMOS and NDACC ozone LIDARs during recent years
(Keckhut et al., ACP, 2010). A full reprocessing of GOMOS data since 2002 using V6 algorithms is in
progress. This new version handles correctly the CCD dark charge increase and the bias is expected to
disappear. The GOMOS V6 ozone climatology for the period 2002-2011 from 15 to 100 km will be
presented. A comparison will be made with NDACC ozone LIDARs for the common altitude range (15-40
km). The ozone evolution during this period and the attribution to various forcings (ODP, Brewer-Dobson
circulation, solar cycle, QBO, ENSO, …) will be discussed.
Ozone Time Series from GOMOS and SAGE II Measurements
Kyrölä, Erkki 1 ; Laine, M. 1 ; Tukiainen, S. 1 ; Sofieva, V. 1 ; Tamminen, J. 1 ; Päivärinta, S. 1 ; Zawodny, J. M. 2 ;
Thomason, L. W. 2
1 Finnish Meteorological Institute, FINLAND; 2 NASA Langley Research Center, UNITED STATES
Satellite measurements are essential for monitoring changes in the global stratospheric ozone
distribution. Both the natural variation and anthropogenic change of ozone are strongly dependent on
altitude. Stratospheric ozone profiles have been measured from space in 1984-2005 by the SAGE II solar
occultation instrument. The advantage of the occultation measurement method is self-calibration, which
is essential to ensuring stable time series. SAGE II measurements have been a valuable data set in
investigations of trends in the vertical distribution of ozone. This time series can now be extended by the
GOMOS measurements started in 2002. GOMOS is a stellar occultation instrument and offers, therefore,
a natural continuation of SAGE II measurements.
In this work we present a combined SAGE II - GOMOS ozone profile data set covering 1984-2011. We
show results from the inter-comparison of ozone profiles measured in 2002-2005 when both instruments
were operational. The reasons for observed differences in profiles are studied using simulations by a
chemical transport model and comparing the retrieval schemes of the instruments. The combined ozone
profile set is analyzed using time series methods. Results for the ozone trend and natural variations are
presented.
12

Long Term Total Ozone Trend Analysis for the Years 1978 - 2011 from Merged
Data Sets of Various Satellites.
Chehade, Wissam; Weber, Mark; Burrows, John P.
UNIVERSITÄT BREMEN, GERMANY
The study presents a long term trend analysis of total ozone data sets obtained from various satellites.
The statistical trend analysis is performed using various explanatory variables that represent the
dynamical and chemical processes which modify global ozone distributions in a changing climate. The
total ozone data sets comprise SBUV/TOMS/TOMI merged data (1978 – 2011) and
GOME/SCIAMACHY/GOME-2 (“GSG”) WFDOAS merged data (1995 – 2011). A sensitivity study is carried
out by comparing SBUV/TOMS/OMI merged time series (1978 – 2011) and a merged data set containing
SBUV/TOMS OMI (1978 – 1995) and GOME/SCIAMACHY/GOME-2 (1995 – 2011) in the regression
analysis. The aim of this study is to identify the fingerprint and its statistical significance of the onset of
ozone recovery.
Using 16 Years of European Total Ozone Satellite Observations for Global Trend
Analyses
Coldewey-Egbers, Melanie 1 ; Loyola, Diego 1 ; Zimmer, Walter 1 ; van Roozendael, Michel 2 ; Lerot,
Christophe 2 ; Dameris, Martin 1 ; Garny, Hella 1 ; Braesicke, Peter 3 ; Koukouli, MariLiza 4 ; Balis, Dimitris 4
1 German Aerospace Center, GERMANY; 2 Belgian Institute for Space Aeronomie, BELGIUM; 3 University of
Cambridge, UNITED KINGDOM; 4 University of Thessaloniki, GREECE
Three European satellite sensors GOME/ERS-2 (1995-2011), SCIAMACHY/ENVISAT (launched in 2002),
and GOME-2/METOP (launched in 2006) provide accurate global observations of total ozone columns. We
present a 16 years monthly mean total ozone product by combining all those measurements using an
inter-satellite calibration approach to reduce offsets and temporal drifts among the instruments. Due to
their excellent long-term stability the GOME measurements were taken as the reference data base. The
newly generated consistent and homogeneous time series is called GOME-type Total Ozone - Essential
Climate Variable (GTO-ECV) and covers the period from June 1995 to June 2011. It can now be used for
accurate long-term climate monitoring as well as the evaluation of Chemistry-Climate Models. We will
show results of an intercomparison with the E39C-A model provided by German Aerospace Center, the
UMUKCA-UCAM model provided by University of Cambridge, and a second well-established satellitebased
Merged Ozone Data set (MOD) provided by NASA. Furthermore we present global ozone trend
estimates using a multiple linear least squares regression algorithm applied to satellite and model data,
as well as ground-based observations with Brewer and Dobson spectrophotometers archived at the World
Ozone and UV radiation Data Center.
Towards a Merged Essential Climate Variable Data Record on Ozone: Stability
and Consistency of Contributing Limb Profilers
Hubert, Daan; Verhoelst, Tijl; Keppens, Arno; Granville, José; Pieroux, Didier; Lambert, Jean-Christopher
BIRA-IASB, BELGIUM
The vertical distribution of atmospheric ozone, an Essential Climate Variable (ECV), has been measured
from space for nearly three decades by various instruments, each with their particular measurement and
retrieval technique. The synergistic use of complementary ozone data records from the different satellite
missions should improve our understanding of interactions between changes in ozone, ultraviolet
radiation and climate on the global scale and in the long term. In this context, several international
efforts were recently launched, like ESA's Climate Change Initiative project on ozone (Ozone_cci) and the
SPARC/IO3C/WMO-IGACO Initiative on Past Changes in the Vertical Distribution of Ozone (SI2N). A
prerequisite to build the targeted ECV ozone data record is that the long-term stability, bias and mutual
consistency of the contributing instruments meet the user requirements expressed by, e.g., the climate
research community. Systematic stability and mutual consistency studies were initiated in ESA’s Multi-
TASTE project for Envisat and Third Party Missions (TPMs), which paved the way for network-based,
multi-mission validation assessments.
In this framework of ECV construction, we investigate the suitability of current data versions of seven
ESA and TPM limb/occultation ozone profilers, as well as seven historical data records acquired by
American satellites, namely: ERBS SAGE-II, UARS HALOE and MLS, SPOT-3 POAM-II and SPOT-4 POAM-
III, Odin OSIRIS and SMR, Meteor-3M SAGE-III, Envisat GOMOS, MIPAS and SCIAMACHY, SCISAT-1
ACE-FTS and ACE-MAESTRO, and EOS-Aura MLS. The assessment of biases and drifts and their analysis
with respect to different parameters is based on the data provided by ozonesonde and LIDAR networks
13

affiliated with NDACC and WMO's GAW, used as a reference. For each satellite instrument, we present
the temporal, vertical and meridian structure of the consistency between co-located space- and groundbased
profiles. Our results are further discussed against user requirements, in the context of the
developing an ozone ECV within the SPARC SI2N and Ozone_cci initiatives.
Ozone Losses in the Arctic Winters 2010-12 as Observed by SCIAMACHY
Eichmann, Kai-Uwe; Hommel, R.; von Savigny, C.; Rozanov, A.; Weber, M.; Richter, A.; Bramstedt, K.;
Wittrock, F.; Noel, S.; Aschmann, J.; Bovensmann, H.; Burrows, J.P.
University of Bremen, GERMANY
Stratospheric arctic winter-spring ozone losses for the years 2010 to 2012 were measured using
ENVISAT/SCIAMACHY (Scanning Imaging Absorption spectrometer for Atmospheric CHartographY) limb
spectra in the UV/vis spectral range. The ozone loss calculations were done using a vortex averaging
technique with SCIATRAN V2.6 ozone profiles and the latest UKMO data for the dynamic situation of the
arctic stratosphere. In this work, we present a compilation of SCIAMACHY/ENVISAT stratospheric trace
gas (O3, BrO, NO2, OClO) and PSC observations during these winters. We compare this situation of the
Arctic stratosphere with that during precedent boreal winters within the SCIAMACHY period. An update
on this year’s polar vortex evolution and ozone loss will also be shown. Severe ozone losses over the
Arctic are associated with a characteristic evolution of the planetary wave activity in the stratosphere. A
large inter annual variability was found due to different dynamic situations. Ozone losses of up to 65%
were detected in 2011, when stratospheric vortex temperatures were near the PSC formation point.
Smaller losses were seen in the years before.
Evolution and Variability of Water Vapour in the Tropopause Region and
Stratosphere Derived from Satellite Measurements
Urban, Jo
Chalmers University of Technology, SWEDEN
The evolution and variability of water vapour in the tropical tropopause region and stratosphere is
analyzed using "historical" (SAGE-II, UARS/HALOE) and "recent" (Odin/SMR, ENVISAT/MIPAS, ACE/FTS,
Aura/MLS, TIMED/SABER) satellite measurements along with Boulder frost-point hygrometer balloon
data for the mid-latitude lower stratosphere. In addition, time-series of the water isotopologues HDO,
H2O-17, and H2O-18, observed by Odin/SMR and ACE/FTS since 2001 and 2003, have been evaluated
with regard to their sensitivity to changes of the tropical tropopause temperature.
Water Vapor Measurements in the UTLS at 936 nm by Stellar Occultations with
GOMOS/ENVISAT.
Bertaux, Jean-Loup 1 ; Hauchecorne, Alain 2 ; Dalaudier, Francis 2 ; Blanot, Laurent 3
1 2 3
LATMOS/IPSL/UVSQ/CNRS, FRANCE; LATMOS/IPSL/CNRS/UVSQ, FRANCE; ACRI-ST, Sophia-Antipolis,
FRANCE
The evolution of water vapor in the lower stratosphere is still a case for controversy, though its exact
trend in response to climate change is important. Solomon et al. (2010) have argued that the observed
decrease of about 10% after the year 2000 “acted to slow the rate of increase in global surface
temperature… by about 25%... compared to that which would have occurred due to only CO2…”. The
GOMOS instrument on board ENVISAT (launched 2002 in a helio-synchronous polar orbit) contains a high
resolution spectrometer for the measurement of O2 at 760 nm and H2O at 936 nm, with a resolution of
~0.05 nm per pixel. GOMOS is the first instrument measuring these species by the technique of stellar
occultation, which is protected in principle from long term drift, an essential feature for long term
monitoring of a possible trend. Nine stars are sufficiently bright to provide useful measurements for
stratospheric H2O. However, the data retrieval has been plagued up to now by a severe pixel-to-pixel
non-uniformity of the CCD detector giving a wet bias around 30 km, which is now corrected in the new
reprocessing. Results of this reprocessing will be presented for the first time, in the altitude range 10-50
km with a vertical resolution 3-4 km. A comparison with LIDAR measurements at Mauna Kea allowed the
validation of the new processing. Temporal variations at a constant latitude will be emphasized,
consistent with the motion of the Intertropical Convergence Zone (ITCZ).A trend analysis will be also
presented.
14

Observed Temporal Evolution of Global Mean Age of Stratospheric Air for the
2002 to 2010 Period
Stiller, Gabriele P. 1 ; von Clarmann, Thomas 1 ; Haenel, Florian 1 ; Funke, Bernd 2 ; Glatthor, Norbert 1 ;
Grabowski, Udo 1 ; Kellmann, Sylvia 1 ; Kiefer, Michael 1 ; Linden, Andrea 1 ; Lossow, Stefan 1 ; López-Puertas,
Manuel 2
1 Karlsruhe Institute of Technology, IMK, GERMANY; 2 Instituto de Astrofísica de Andalucía, CSIC, SPAIN
An extensive observational data set, consisting of more than one million SF6 vertical profiles distributed
globally from MIPAS measurements has been condensed into monthly zonal means of mean age of air for
the period September 2002 to January 2010, binned at 10° latitude and 1-2 km altitude. The data were
analysed with respect to their temporal variation by fitting a regression model consisting of: a constant
and a linear increase term, 2 proxies for the QBO variation, sinusoidal terms for the seasonal and semiannual
variation and overtones for the correction of the shapes to the observed data set. The impact of
subsidence of mesospheric SF6-depleted air and in-mixing into non-polar latitudes on mid-latitudinal age
of air and its linear increase was assessed and found to be small.
The linear increase of mean age of stratospheric air was found to be positive and partly larger than the
trend derived by Engel et al. (2009) for most of the Northern mid-latitudes, the middle stratosphere in
the tropics, and parts of the Southern mid-latitudes, as well as for the Southern polar upper
stratosphere. Multi-year decrease of age of air was found for the lowermost and the upper stratospheric
tropics, for parts of Southern mid-latitudes, and for the Northern polar regions. Analyses of the
amplitudes and phases of the seasonal variation shed light on the coupling between different
stratospheric regions. In particular, the Northern mid-latitude stratosphere is well coupled to the tropics,
while the Northern lowermost mid-latitudinal stratosphere is decoupled, confirming the separation of the
shallow branch of the Brewer-Dobson circulation from the deep branch. We suggest an overall increased
tropical upwelling, together with a weakening of mixing barriers, especially in the Northern hemisphere,
as possible explanations for the observed patterns.
Reference: Engel, A., Möbius, T., Bönisch, H., Schmidt, U., Heinz, R., Levin, I., Atlas, E., Aoki, S.,
Nakazawa, T., Sugawara, S., Moore, F., Hurst, D., Elkins, J., Schauffler, S., Andrews, A., and Boering,
K.: Age of stratospheric air unchanged within uncertainties over the past 30 years, Nature Geosci., 2, 28-
-31, doi:10.1038/ngeo388, 2009.
MIPAS2D – 10 Years of MIPAS/ENVISAT Measurements Analyzed with a 2D
Tomographic Approach
Dinelli, Bianca Maria 1 ; Carlotti, Massimo 2 ; Arnone, Enrico 1 ; Castelli, Elisa 1 ; Magnani, Luca 2 ; Papandrea,
Enzo 2 ; Prevedelli, Marco 3
1 ISAC-CNR, ITALY; 2 DCFI - University of Bologna, ITALY; 3 DF - University of Bologna, ITALY
We present the latest version of the MIPAS2D database (Dinelli et al. 2010), a database of physical and
chemical quantities obtained from 10 years of observations made by the Michelson Interferometer for
Passive Atmospheric Sounding (MIPAS) onboard ENVISAT. MIPAS observations have been analysed using
the latest version of the GMTR analysis code (Carlotti et al. (2006)) that uses a full 2D tomographic
retrieval approach that enables to account for the horizontal inhomogeneity of the atmosphere. The new
database includes all MIPAS main targets (pressure, temperature, H2O, O3, HNO3,CH4, N2O, NO2) along
with the minor species N2O5, ClONO2, CFC-11, CFC-12, and ClO. The data have been obtained on a
vertical grid coincident with the nominal vertical grid of MIPAS Full Resolution (FR) measurements (from
6 to 42 km at 3 km steps, and at 47, 52, 60 and 68 km) and on two horizontal (latitudinal) grids: one at
fixed latitudes (one profile every 5 degree of latitude) and one on the average latitudes of MIPAS scans.
FR and Optimised Resolution (OR) measurements have been analysed using personalized spectral
regions (MWs). To avoid possible biases due to the use of different spectroscopic regions at different
spectral resolutions, the FR measurements have also been degraded to the spectral resolution of the OR
measurements and analysed with the same OR set of MWs. Examples of the obtained results will be
presented along with some validation results.
Dinelli, B. M., Arnone, E., Brizzi, G., Carlotti, M., Castelli, E., Magnani, L., Papandrea, E., Prevedelli, M.,
and Ridolfi, M.: The MIPAS2D database of MIPAS/ENVISAT measurements retrieved with a multi-target
2-dimensional tomographic approach, Atmospheric Measurement Techniques, 3, 355–374, 2010
Carlotti, M., Brizzi, G., Papandrea, E., Prevedelli, M., Ridolfi, M., Dinelli, B. M., and Magnani, L.: GMTR:
Two-dimensional multi-target retrieval model for MIPAS-ENVISAT observations, Applied Optics, 45(4),
716-727, (2006).
15

The MIPAS NOy Record: A Climatological Analysis and Budget Estimation
Funke, Bernd 1 ; Lopez-Puertas, Manuel 1 ; Garcia-Comas, Maya 1 ; Stiller, Gabriele 2 ; von Clarmann,
Thomas 2 ; Linden, Andrea 2 ; Grabowski, Udo 2 ; Hoepfner, Michael 2 ; Kiefer, Michael 2 ; Glatthor, Norbert 2 ;
Kellmann, Sylvia 2
1 Instituto de Astrofísica de Andalucía, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut für
Meteorologie und Klimaforschung (IMK-ASF), GERMANY
The MIPAS Fourier transform spectrometer on board Envisat has been measuring limb emission spectra
in the mid-IR since early 2002. We have employed the scientific MIPAS level 2 processor developed and
operated by the Institute of Meteorology and Climate Research (IMK) together with the Instituto de
Astrofisica de Andalucia (IAA) to derive vertically resolved distributions of 6 principal reactive nitrogen
(NOy)compounds (HNO3, NO2, NO, N2O5, ClONO2, and HNO4) with global coverage and independent on
illumination (i.e., including the polar night). The obtained data set provides an unique climatological
record of NOy in the middle atmosphere for a close-to-10 years period. Here, we will discuss the MIPASderived
spatial distributions of NOy and their seasonal and inter-annual variability. Responsible chemical
and dynamical mechanisms will be identified and an estimation of the global middle atmosphere NOy
budget will be presented, including a quantitative analysis of individual sources and sinks.
Investigation of the Impact of Horizontal Inhomogeneities on MIPAS/ENVISAT
Products
Castelli, Elisa 1 ; Carlotti, Massimo 2 ; Dinelli, Bianca Maria 1 ; Papandrea, Enzo 2 ; Arnone, Enrico 1 ; Ridolfi,
Marco 3
1 ISAC-CNR, ITALY; 2 DCFI - University of Bologna, ITALY; 3 DF - University of Bologna, ITALY
Several studies have highlighted the importance of properly account for temperature horizontal
inhomogeneities in the retrieval of atmospheric constituents from limb sounding infrared space-born
instruments. For this reason 2-dimensional (2-D) tomographic retrieval algorithms have been developed
to take into account the inhomogeneity of the atmosphere in the along-track direction of limbmeasurements.
Among these algorithms the Geofit-Multi Target Retrieval (GMTR) by [1]) system was
specifically developed to process Michelson Interferometer for Passive Atmospheric Sounding (MIPAS
/ENVISAT) measurements and was proven to minimize the anomalies observed on MIPAS/ENVISAT
products retrieved with 1-D codes [2]. In this study, we exploit the 2-D Forward Model (FM) of the GMTR
system to evaluate the impact of the horizontal inhomogeneities on ESA MIPAS/ENVISAT level 2 products
retrieved with 1-D approach. The 2-D FM is used to produce synthetic MIPAS/ENVISAT observations
simulated in a realistic horizontal inhomogeneous atmosphere that are analyzed using a 1-D retrieval
system. We also investigate the advantages and disadvantages of the use of an intermediate approach
between the 1-D and 2-D retrieval through the implementation of a temperature gradient along the orbit.
The impact of horizontal Volume Mixing Ratio (VMR) gradients along the orbit is also evaluated.
References: [1]Carlotti, M., Brizzi, G., Papandrea, E., Prevedelli, M., Ridolfi, M., Dinelli, B. M., and
Magnani, L.: GMTR: Two-dimensional geofit multitarget retrieval model for Michelson Interferometer for
Passive Atmospheric Sounding/Environmental Satellite observations, Applied Optics, 45, 716–727,2006.
[2]Kiefer, M., Arnone, E., Dudhia, A., Carlotti, M., Castelli, E., von Clarmann, T., Dinelli, B. M., Kleinert,
A., Linden, A., Milz, M.,Papandrea, E., and Stiller, G.: Impact of temperature field inhomogeneities on the
retrieval of atmospheric species from MIPAS IR limb emission spectra, Atmospheric Measurement
Techniques,3, 1487–1507, 2010.
16

MIPAS Climatologies of Atmospheric Trace Gases for the SPARC Data Initiative
von Clarmann, Thomas 1 ; Funke, Bernd 2 ; Stiller, Gabriele P. 1 ; Kellmann, Sylvia 1 ; Glatthor, Norbert 1 ;
Grabowski, Udo 1 ; Kiefer, Michael 1 ; Linden, Andrea 1 ; Lopez-Puertas, Manuel 2 ; Lossow, Stefan 1 ; Hoepfner,
Michael 1 ; Schieferdecker, Tobias 1 ; Versick, Stefan 3
1 Karlsruhe Institute of Technology, Institut fuer Meteorologie und Klimaforschung (IMK-ASF), GERMANY;
2 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 3 Karlsruhe Institute of Technology, IMK-ASF and
SCC, GERMANY
MIPAS is a limb emission mid-infrared Fourier transform spectrometer designed for altitude-resolved
measurement of temperature and atmospheric trace constituents. Since July 2002 it has provided global
daytime and nighttime measurements. Within the SPARC Data Initiative (Hegglin and Tegtmeier, 2011),
MIPAS data generated by IMK/IAA have been used for generation of monthly zonal averages. These
climatologies include O3, H2O, CH4, N2O, NO, NO2, HNO3, HNO4, N2O5, ClONO2, ClO, CO and other
species for the years 2002-2010 as well as HOCl and H2CO for the years 2002-2004. Furthermore, NOx
(NO + NO2) and NOy (NOx + HNO3 + ClONO2 + 2*N2O5 + HNO4) climatologies are provided. These
climatologies are sampled at 5 degrees latitude resolution and at 28 pressure levels. For species with
pronounced diurnal variation, am and pm measurements are reported separately.
17

Troposphere/Air Quality
Changes in Tropospheric NO2 as Observed from Space
Richter, Andreas; Hilboll, Andreas; Burrows, John P.
University of Bremen, GERMANY
Most human activities involve the use of energy which nowadays is usually provided by the burning of
fossil fuels, either locally in vehicles or heating systems, or centralised in power plants. Emissions of
trace gases and particulates from fossil fuel use have been increasing as energy needs intensified and
economies developed. Implementation of clean air technologies and the switch to cleaner fuels has
helped reducing specific emissions, but in many parts of the world, overall emissions are still on the rise.
Among the trace gases produced by the use of fossil fuels, nitrogen oxides (NOx = NO2 + NO) are of
particular importance as they are a primary pollutant adversely affecting human health, lead to the
acidification of rain and surface waters, and are one of the key factors in ozone smog formation.
Since the first space born observations of tropospheric NO2 by the Global Ozone Monitoring Experiment
(GOME) which was launched in 1995, a long-term record of atmospheric NO2 levels has been
accumulating from measurements by GOME, SCIAMACHY, OMI, and GOME-2. While some instrumental
characteristics such as spatial resolution and overpass time vary between instruments, the resulting data
set can be used to investigate changes in tropospheric NO2 and the underlying changes in emissions.
In this paper, global changes of NO2 in the SCIAMACHY time series are evaluated and discussed. The
data is combined with measurements from GOME, GOME-2 and OMI, and the results are compared to
previous work on satellite observed NO2 changes. Large upward trends are observed in many developing
parts of the world while downward trends can be found over parts of Europe and the US. Many of these
changes are not linear over time, and reasons for this are discussed.
Uncertainties in NOx Lifetimes and their Influence on Top-Down Emission
Estimates
Muller, Jean-Francois 1 ; Stavrakou, Jenny 1 ; Van der A, Ronald 2 ; Boersma, Folkert 2
1 Belgian Institute for Space Aeronomy, BELGIUM; 2 KNMI, NETHERLANDS
NO2 vertical column abundances retrieved from satellite instruments (incl. GOME, SCIAMACHY, GOME-2,
OMI) have been largely used in the last years to infer constraints on regional and global emissions of
nitrogen oxides (NO+NO2=NOx). Furthermore, the temporal variability of the emissions from short-term
(e.g. diurnal/weekly) to long-term (e.g. decadal) scales has also been investigated based on the inverse
modeling technique. The common basic assumption behind these studies is that uncertainties on bottomup
emissions are larger than uncertainties in both the NO2 retrievals and the model operator. Our
contribution aims at verifying the validity of this assumption, in the light of recent studies related to the
main chemical sinks of the NOx family. These sinks include (a) the NO2+OH reaction, (b) the minor
HNO3-forming channel of the HO2+ NO2 reaction, (c) the formation of organic nitrates followed by their
deposition, and (d) the heterogeneous reaction of N2O5 with H2O at the surface of wet aerosols. Our aim
is to investigate the role of uncertainties and the impact of recent advances regarding (1) the
atmospheric abundances of the oxidants (OH and HO2) involved in these reactions, (2) the kinetic rates
and mechanisms of the sink processes. To that effect, the OMI NO2 columns for the year 2007 retrieved
with the version 2 TEMIS algorithm (Boersma et al., ACPD 2011) will be used to infer global NOx
emissions in the IMAGESv2 model run at 2x2.5 degree resolution. As a special focus of this contribution,
the importance of HNO3 formation through the HO2+ NO2 reaction will be stressed.
18

Evaluation of NOx Emission Inventories in California Using Multi-Satellite Data
Sets During the CalNex Field Campaign
Kim, Si-Wan 1 ; Frost, Gregory 1 ; Trainer, Michael 2 ; Boersma, Folkert 3 ; Bucsela, Eric 4 ; Burrows, John 5 ;
Celarier, Edwards 6 ; Krotkov, Nickolay 6 ; Lok, Lamsal 6 ; Richter, Andreas 5 ; Russell, Ashley 7 ; Oetjen, Hilke 8 ;
Baidar, Sunil 8 ; Illana, Pollack 1 ; Ryerson, Tom 2 ; Volkamer, Rainer 8
1 CIRES / NOAA ESRL, UNITED STATES; 2 NOAA ESRL, UNITED STATES; 3 KNMI, NETHERLANDS; 4 SRI
International, UNITED STATES; 5 U. of Bremen, GERMANY; 6 NASA Goddard Space Flight Center, UNITED
STATES; 7 UC Berkeley, UNITED STATES; 8 U. of Colorado, UNITED STATES
Satellite NO2 column measurements indicate large NOx emissions from urban and agricultural sources in
California. In this presentation, we highlight the NOx sources identified in California using the satellite
measurements. Comparison of regional model-simulated NO2 columns with satellite retrievals has proven
useful in evaluating emission inventories for various sectors. We compare the NO2 columns from the
WRF-Chem model with the multi-satellite data sets from different instruments and retrieval groups for a
variety of California sources. Use of multiple satellite data sets help to define the uncertainties in the
satellite retrievals. In addition, the CalNex 2010 intensive field campaign provides a unique opportunity
to independently assess California’s emission inventories. The in-situ airborne observations from CalNex
2010 and fine-resolution model simulations are used to estimate the accuracy of the satellite NO2 column
retrievals.
Retrieval of the Global Water Vapor Distribution from Satellite Observations in
the Blue Spectral Range
Wagner, Thomas; Mies, Kornelia; Beirle, Steffen
MPI for Chemistry, GERMANY
Water vapor is involved in many important chemical reactions in the atmosphere and contributes most to
the natural greenhouse effect. Its atmospheric abundance is highly variable. Thus observations of the
spatio-temporal variation on a global scale are of great importance. Water vapor observations are
possible in different spectral ranges, e.g. in the microwave, thermal IR or near IR and visible spectral
range. Satellite measurements in the red spectral range have the advantage that they are sensitive for
the whole atmospheric column and that they provide global coverage. In this study we exploit the
potential to retrieve the global water vapor distribution from satellite observations in the blue spectral
range. Although the water vapor absorption in this spectral region is rather weak, such retrievals also
have their advantages: First, because of the weak absorption, no corrections for spectral saturation
effects (like in the red spetral region) have to be applied. Second, the surface albedo in the blue spectral
region is very similar for land and ocean. Third, the water vapor distribution can be retrieved also from
satellite instruments, which do not cover the red spectral range (like e.g. OMI or the future Sentinel
missions). Here we show first retrievals of the water vapor column in the blue spectral range from the
GOME-2 instrument on METOP. Since GOME-2 also covers the red spectral region, a direct comparison
with the results of the standard water vapor retrieval is possible. We characterise the accuracy and the
detection limit of the new H2O analysis.
19

Russian Fires in 2010: Results from the ALANIS Smoke Plume Project
Krol, Maarten 1 ; Muller, Jan-Peter 2 ; Peters, Wouter 1 ; Yershov, Vladimir 2 ; Fisher, Daniel 2 ; San-Miguel,
Jesus 3 ; Sedano, Fernando 3 ; George, Maya 4 ; Helbert, Jerome 5 ; Guillaume, Bruno 5 ; El Hajj, Mahmoud 5
1 Wageningen University, NETHERLANDS; 2 University College London, UNITED KINGDOM; 3 Joint Research
Centre, ITALY; 4 Laboratoire Atmospheres, Milieux, Observations Spatiales, FRANCE; 5 Noveltis, FRANCE
The ALANIS (Atmosphere-LANd Integrated Study) Smoke Plume project is a study funded by the ESA’s
Support to Science Element (STSE) dedicated to the monitoring of the fire aerosol and trace gases
dispersion over Eurasia from multi-mission EO-based data, in link with the scientific issues of landatmosphere
processes in the iLEAPS community. The TM5 model is used to ingest several new EOproducts,
derived from MERIS and AATSR. Moreover, the IASI CO product is used to constrain emissions.
New products include burned areas (derived from MERIS), forest fire emissions amounts, and smoke
plume injection heights (SPIH, derived from AATSR). CO emissions and SPIH have been derived for July
and August 2010, a period that includes heavy biomass burning around the Moscow area. Using CO
observations from IASI in the 4D-VAR framework of TM5 allows us to find CO emissions that are
optimally consistent with the available observations. As an example of this procedure, figure 1 shows CO
columns modelled with the optimized emissions in comparison with the IASI observations. We found that
the initial emission estimates that were obtained from the MERIS burned areas (0.6 Tg CO from
25/7/2010 up to 13/8/2010 around Moscow) were insufficient to match the IASI observations. Figure 2
shows the initial and optimized emissions, which are more than 10 times as high (9.3 Tg CO in total). We
also found that taking into account SPIH had only a small effect on the inferred emissions, making them
slightly larger (9.5 Tg CO). Finally, a comparison with independent measurements and other emission
estimates in literature shows that the new optimized emissions are in better correspondence. Moreover,
it is recommended to augment the MERIS burned area with observations from MODIS to obtain a more
realistic initial emission distribution.
20

Day 3, Wednesday 20 June 2012
21

Troposphere/Air Quality (cont.)
Analysis of Tropospheric O3 and CO in Continental Outflow Regions Using IASI
Satellite Observations and MOZART-4 Model
Wespes, Catherine 1 ; Emmons, Louisa 2 ; Edwards, David P. 2 ; Hurtmans, Daniel 3 ; Clerbaux, Cathy 4 ;
Coheur, Pierre-François 5
1 Chimie Quantique et Photophysique, Université Libre de Bruxelles, Brussels, BELGIUM; 2 National Center
for Atmospheric Research, Boulder, CO, UNITED STATES; 3 Chimie Quantique et Photophysique,
Université Libre de Bruxelles, Brus, BELGIUM; 4 UPMC Univ Paris 06, CNR/INSU, LATMOS/IPSL, Paris,
FRANCE; 5 Chimie Quantique et Photophysique, Université Libre de Bruxelles, Brussels, Belgium,
BELGIUM
Tropospheric O3 and CO are two important pollutants and play a major role in determining the oxidizing
capacity of the troposphere. While observed correlations between O3 and CO from surface and aircraft
measurements have been used in many studies to better understand the anthropogenic influence on O3,
there have only been a few studies using global satellite data for this purpose. The correlation patterns
provide also a valuable test for models to predict O3 photochemical production and global anthropogenic
influence on O3. In this study, we propose to take advantage of the high spatio-temporal coverage of the
Infrared Atmospheric Sounding Interferometer (IASI) instrument which provides a unique dataset for
analyzing O3-CO correlations from simultaneous and vertically-resolved O3 and CO measurements. We
examine global distributions of IASI O3-CO correlations in the lower, the middle and the upper
troposphere during the spring (MAM) and the summer (JJA) 2008 to evaluate the continental influence
on tropospheric ozone. Observed O3-CO correlations from IASI are also compared to the correlations
simulated in the MOZART-4 global 3-D chemical transport model in order to test our understanding of
anthropogenic influence on O3 and also to evaluate the photochemistry in the model. The feasibility for
using the ratio dO3/dCO in estimating the O3 production is tested from IASI observations and compared
to the MOZART-4 simulations. We further investigate the different sources of the correlations through
analysis of CO and O3 from each CO and NOx emission sources tagged separately in the MOZART-4
simulations.
Upper Tropospheric Pollution Transport Documented with the Metop-A/IASI
Sensor
Barret, Brice; De Wachter, Evelyn; Le Flochmoën, Eric; Sauvage, Bastien; Cammas, Jean-Pierre
Laboratoire d'Aérologie, OMP, CNRS, Université de Toulouse, FRANCE
The Metop/IASI instrument (launched in 2006) enables characterizing the tropospheric content of ozone
(O3) and carbon monoxide (CO) with an unprecedented spatiotemporal coverage. We will present results
obtained with the Software for a Fast Retrieval of IASI Data (SOFRID) based on the 1D-Var retrieval
module from the UKMO coupled to the RTTOV radiative transfer code. For both O3 and CO, IASI-SOFRID
roughly provides two independent pieces of information in the troposphere: the free tropospheric column
and the upper tropospheric (UT) column. Most of the studies using IASI chemistry data have focused on
the lower troposphere in relation with the topic of Air Quality. We will rather focus on pollution transport
and chemical transformation in the upper troposphere (UT). The global UT O3 and CO distributions will
be presented together with validation results performed with independent in-situ observations (WOUDC,
SHADOZ and MOZAIC). In order to highlight the potential of IASI-SOFRID to document the UT chemical
composition, we will present a case of rapid photochemical pollution transport detected by IASI. This
event, that we have called the “O3 river”, consist in the channelled transport of O3 and CO enriched airmasses
from eastern Africa to northern India during the 2008 post-monsoon season. The O3-CO
relationships based on IASI retrievals and on MOZAIC in-situ observations allowed us to characterize the
photochemical ageing of the air-masses. Lagrangian dispersion modelling further improves our
understanding of the “O3 river” phenomenon, highlighting the sources of O3 precursors responsible for
the increased UT O3 and CO concentrations measured downstream of Africa.
22

Multi-Spectral Retrieval of Lowermost Tropospheric Ozone Combining IASI and
GOME-2 Satellite Observations
Cuesta, Juan 1 ; Eremenko, Maxim 1 ; Liu, Xiong 2 ; Dufour, Gaëlle 1 ; Hoepfner, Michael 3 ; Cai, Zhaonan 4 ; von
Clarmann, Thomas 3 ; Orphal, Johannes 3 ; Chance, Kelly 2 ; Spurr, Robert 5 ; Flaud, Jean-Marie 1
1 LISA / UPEC - IPSL, FRANCE; 2 Harvard-Smithsonian, UNITED STATES; 3 IMK / KIT, GERMANY; 4 LAGEO /
IAP - CAS, CHINA; 5 RT Solutions Inc, UNITED STATES
Lowermost tropospheric ozone is a major factor determining air quality in densely populated megacities.
During pollution events, knowledge on the 3D regional distribution of ozone in and around these urban
areas is key for assessing its impact on health of population and ecosystems damages. Temporal and
spatial coverage of spaceborne observations are particularly fitted for monitoring tropospheric ozone
spatial distribution at the regional scale and offers a great potential for improving air quality forecasting
with numerical regional models. However, current tropospheric ozone retrievals using uncoupled either
UV or thermal IR spaceborne observations show limited sensitivity to lowermost troposphere ozone (up
to 2 km of altitude), which is the major concern for air quality, and are mainly sensitive to ozone at the
free Troposphere (the lowest relative maxima of sensitivity are around 3-4 km of altitude) or above. In
this framework, we are currently developing a new multi-spectral methodology for retrieving the
lowermost tropospheric ozone concentration using the synergy of both atmospheric radiance spectra in
the thermal IR observed by IASI and earth reflectance spectra in the ultraviolet measured by GOME-2.
Both instruments are on-board MetOp satellite since October 2006 and their scanning capability offers
each day an almost global coverage (with pixel resolution of 80 x 40 km2 for GOME-2). Our technique
uses altitude-variable Tikhonov-Philips-type constraints, which optimizes sensitivity to lower troposphere
ozone (formerly used for IASI retrievals [Eremenko et al., 2008, GRL; Dufour et al., 2010 ACP]). It
integrates VLIDORT and KOPRA radiative transfer codes for simulating UV reflectance and thermal IR
radiance, respectively. Meteorological profiles, surface properties (temperature, albedo) and correcting
parameters for UV radiances (degradation, slit function, ring effect e.g. [Liu et al., 2010, ACP; Nowlan et
al., 2011 JGR]) are jointly retrieved for each pixel. Numerical simulations of the present retrieval setup
show a significant improvement in the sensitivity of the multi-spectral retrieval with an increase greater
than 50% in the degrees of freedom for signal in the partial column 0-6 km of altitude, with respect to
single band retrievals. In the current presentation, we will show our first results with real observations
over Europe in July-August 2007 and the performance assessment of the methodology.
Tropospheric Trace-Gas Column Observations from GOME-2/MetOp
Valks, Pieter 1 ; Loyola, Diego 1 ; Zimmer, Walter 1 ; De Smedt, Isabelle 2 ; Pinardi, Gaia 2 ; Lambert, Jean-
Christopher 2 ; Van Roozendael, Michel 2 ; Delcloo, Andy 3
1 DLR, GERMANY; 2 IASB-BIRA, BELGIUM; 3 RMI Royal Meteorological Institute, BELGIUM
This contribution focuses on the operational tropospheric trace gas column products from GOME-2/MetOp
developed in the framework of EUMETSAT’s Satellite Application Facility on Ozone and Atmospheric
Chemistry Monitoring (O3M-SAF). We present an overview of the retrieval algorithms for tropospheric
NO2, SO2, CH2O and (sub)-tropical tropospheric ozone, and we show examples of air quality applications
using GOME-2 observations. These trace gas column products are retrieved from GOME-2 solar
backscattered measurements in the UV and VIS wavelength regions using the GOME Data Processor
(GDP) version 4.5. Tropospheric NO2 is retrieved with the Differential Optical Absorption Spectroscopy
(DOAS) method in the 425-450 nm wavelength region. SO2 emissions from anthropogenic sources can
be measured by GOME-2 using the UV wavelength region around 320 nm. The GOME-2 NO2 and SO2
products are available for the users in near real time, i.e. within two hours after sensing. For CH2O, an
optimal DOAS fitting windows are 335 nm has been determined for GOME-2 in the UV wavelength region.
Tropopsheric ozone columns for sub-tropical areas are derived from GOME-2 observations using a cloud
slicing method. The GOME-2 tropospheric NO2, SO2, and CH2O products have reached the operational
status, and are routinely available to the users. The use of tropospheric trace gas observations from
GOME-2 for air quality applications in Asia and Europe will be presented. Time-series of tropospheric
ozone, NO2, SO2 and HCHO for highly populated sub-tropical area in South East Asia are analysed to
investigate possible trends in air pollutants. These sub-tropical areas frequently suffers severe episodes
of photochemical smog. Furthermore, comparisons of tropospheric ozone and NO2 observations from
GOME-2 with ground-based measurements will be presented for several locations in Europe, Asia and the
(sub)-tropics.
23

Biogenic Methanol and Formic Acid Constrained from IASI Measurements
Stavrakou, Jenny 1 ; Muller, Jean-François 1 ; Guenther, Alex 2 ; Peeters, Jozef 3 ; Razavi, Ariane 4 ; Clarisse,
Lieven 4 ; Clerbaux, Cathy 4 ; Coheur, Pierre-François 4 ; Hurtmans, Daniel 4
1 Belgian Institute for Space Aeronomy, BELGIUM; 2 Atmospheric Chemistry Division, NCAR, Boulder,
Colorado, UNITED STATES; 3 Department of Chemistry, University of Leuven, B-3001, Heverlee,
BELGIUM; 4 Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles, B-1050,
BELGIUM
Methanol and formic acid, the simplest alcohol and carboxylic acid in the atmosphere, are directly
emitted from anthropogenic activities, fire events and vegetation, as well as from photochemical sources.
They are removed from the atmosphere through OH oxidation, and wet and dry deposition, and their
global lifetime is estimated to 6 days for methanol and to 4 days for formic acid.
According to state-of-art estimates, the ocean and terrestrial biosphere account for two thirds of the total
methanol source, whereas the contributions from human activities and biomass burning are minor. Plant
emissions represent the major part of the methanol flux from terrestrial ecosystems, but the uncertainty
regarding the magnitude and localization of this source is very large, ranging between 100 and 300 Tg
on an annual basis. Formic acid is a ubiquitous trace gas in air and precipitation and a major contributor
to rain acidity in remote environments. Its sources, however, are far from being fully understood, as
testify severe underpredictions of observed formic acid concentrations in earlier global modelling studies,
spotting the existence of unaccounted sources.
New insights into our understanding of methanol and formic acid atmospheric cycle are brought forward
by newly acquired measurements of tropospheric columns retrieved from the IASI thermal infrared
satellite sounder. In this communication, we report findings from two source inversion studies of
methanol and formic acid emissions performed using the IMAGESv2 CTM constrained by one complete
year of IASI column measurements. The optimized global methanol source is estimated to about 100 Tg
on a yearly basis, with significant emission decreases, compared to the bottom-up inventory, inferred
over tropical rainforests and unexpectedly high flux strengths in arid environments. The IASI column
data suggest an annual formic acid source about three times higher than estimated from known sources,
with a biogenic contribution of about 90%, mostly from tropical and boreal forests. We investigate the
implications of the large formic source on precipitation acidity on the global scale. The resulting fluxes
are extensively evaluated against previous modelling work, available aircraft and in situ independent
measurements.
Variabilities of Chemical Species Over the Mediterranean Basin: Measurements
and Models
Ricaud, Philippe 1 ; Sic, Bojan 1 ; Attie, Jean-Luc 1 ; El Amraoui, Laaziz 1 ; Teyssedre, Hubert 1 ; Michou,
Martine 1 ; Zbinden, Regina 2 ; August, Thomas 3 ; Warner, Juying 4
1 2 3 4
Meteo-France/CNRS, FRANCE; Laboratoire d'Aerologie, FRANCE; EUMETSAT, GERMANY; University of
Maryland, UNITED STATES
The Mediterranean Basin (MB) is of particular interest in terms of pollution sources as it is at the
confluence of three continents, Europe, Africa and Asia. The impact of these various continental sources
(industrial and populated coastal cities, forest fires, etc.) is still not well understood especially on the O3
and CO budgets. Within the Chemistry-Aerosol Mediterranean EXperiment (CHARMEX) Project, a
particular attention is given to the variabilities and recent trends in chemical species and aerosols over
the MB in order to study the weight of different processes (long-range transport, emissions,
import/export, chemical transformation) on the budgets of these species. The present paper deals with
the time evolution of long-lived species (N2O, CH4 and CO2) and shorter-lived species (O3 and CO) as
measured by space-borne sensors (IASI, AIRS, MOPITT, GOSAT, TES and OMI) over the MB from 2008
to 2010 and how it compares with model outputs from the chemistry-transport model MOCAGE (CO2 not
yet included) and the chemistry-climate model CNRM-CCM. As expected, a great variability is measured
for CO and O3 and eventually CH4, but the N2O and CO2 variabilities are also found to be non negligible.
Furthermore, an Eastern-Western difference is measured within all the observed data sets regarding the
five species, highlighting the different physico-chemical regimes occurring in the Eastern and Western
parts of the MB. Although the two models have some difficulties to mimic the variabilities observed over
the MB, it obviously tracks the seasonal variation of the East-West difference in N2O, CO, O3 and CH4 as
measured by the spaceborne sensors.
24

Towards Global Routine Measurements of High-Resolution In-Situ NO2 Profiles -
A Project Within ESA's Innovation Triangle Initiative
Piters, Ankie; Allaart, Marc; Sluis, Wesley
KNMI, NETHERLANDS
For the validation of tropospheric NO2 retrievals from satellites, regular measurements of NO2 profiles are
needed. Several research groups aim to use these satellite observations within air quality forecast
systems, e.g. in the context of the GMES project MACC. But the uncertainty in the satellite derivations is
large, about 30-40% of the tropospheric amount. One of the major sources of uncertainty is the
assumed vertical NO2 profile shape in the troposphere, which is actually quite variable over a day, due to
chemical and dynamical processes. An accurate profile shape can be obtained by in-situ instruments on
aircrafts and large balloons. An aircraft can take several profiles by ascending and descending through
the troposphere, and, depending on local regulations, sometimes down to the surface. However, both
aircraft and balloon measurements are quite expensive and therefore sparse. What is needed is a global
network of stations where routinely NO2 profiles are measured to verify assumptions used in satellite
retrievals and hence improve the air-quality forecasts. A new instrument, measuring high-resolution NO2
profiles, has recently been developed. This disposable instrument is light in weight and has low power
consumption, which makes it ideal for launch on a weather balloon, similar to the well-known ozone
sondes. The measurement principle is based on the chemiluminescent reaction of NO2 with luminol,
where a photo-diode array is used to detect the light signal. Comparison of the NO2 sonde with a NOx
analyzer with photolyic converter shows that NO2 variations of 1 ppbv are well captured. The design and
calibration of the NO2 sonde are currently optimised and adapted within ESA's Innovation Triangle
Initiative, to allow future serial production. The target precision is 10% or 0.8 ppbv, the vertical
resolution is ~5m, determined by the vertical speed of the sonde. The aim is to have the instrument
available on the market within a few years. Around twenty flights have been performed in the last two
years. The measured NO2 profiles are compared to model output of Air Quality models. The measured
NO2 profiles regularly show enhancements of NO2 above the boundary layer with respect to the models.
Possible reasons for this have been investigated in detail, using auxiliary meteorological measurements
and models. These findings can have an impact on our understanding of the nitrogen cycle, the transport
of air pollution, and the production of tropospheric ozone. Regular measurements of high resolution NO2
profiles are necessary to monitor air pollution above the planetary boundary layer. The new NO2 sonde
can be used for operational measurements, synchronized with satellite overpasses for operational and
long-term satellite validation, in dedicated satellite validation campaigns, and for the calibration of other
validation instruments, like MAX-DOAS.
PCW/PHEMOS UV-VIS Spectrometer: Air Quality from a Quasi-Geostationary
Orbit
McElroy, Tom 1 ; McConnell, John 1 ; O'Neill, Norm 2 ; Nassar, Ray 3 ; Buijs, Henry 4 ; Walker, Kaley 5 ; Martin,
Randall 6 ; Sioris, Chris 1 ; Garand, Louis 3 ; Trichtchenko, Alexander 3 ; Bergeron, Martin 7 ; PHEMOS,
ScienceTeam 8
1 York University, CANADA; 2 University of Sherbrooke, CANADA; 3 Environment Canada, CANADA; 4 ABB
Bomem, CANADA; 5 University of Toronto, CANADA; 6 Dalhousie University, CANADA; 7 Canadian Space
Agency, CANADA; 8 Canada, CANADA
The CSA Polar Communications and Weather mission (PCW) is a two-satellite mission with satellites in
highly eccentric orbits with apogees at approximately 40,000 km altitude and a period in the 12-24 hour
range which can deliver uninterrupted communications and meteorological observations over the Arctic
and middle latitudes. The baseline meteorological instrument is a 21-channel spectral imager similar to
MODIS and ABI. The Polar Highly Elliptical Molniya Orbital Science mission (PHEMOS) is a scientific
complement to the PCW instruments intended to address weather, climate and air quality. The PHEMOS
suite consists of an FTS to cover the NIR and MIR spectral range and a UV-Vis spectrometer (UVS). The
UVS is an imaging spectrometer which covers the spectral range of 280 to 650 nm in the UV and visible
regions. It is intended to measure the tropospheric column densities of the target gases, O3 and NO2,
and also, when accessible, the tropospheric columns of BrO, SO2, HCHO and (HCO)2 as well as
stratospheric columns of O3, NO2 and BrO and the aerosol index (AI). The spatial resolution targeted is 8
× 8 km2 spatial resolution; the spectral resolution will be about 1 nm with 3 samples per resolution
element. The PCW two-satellite system will allow the mapping of air quality parameters on an hourly
basis over most of the circumpolar area 55-90N, and potentially, non-continuously, down to 40N. This
paper presents the current status of the UVS instrument. The presentation will also discuss the
instrument conceptual design, the related analyses and trade-off studies and also the status of species
retrieval studies. PHEMOS WCA study is currently in Phase A and is funded by the Canadian Space
Agency (CSA).
25

PREMIER - Earth Explorer 7 Candidate Mission
Kerridge, Brian 1 ; Siddans, Richard 1 ; Waterfall, Alison 1 ; Latter, Barry 1 ; Miles, Georgina 1 ; Reburn, Jolyon 1 ;
Orphal, Johannes 2 ; Glatthor, Nerbert 2 ; Friedl-Vallon, Felix 2 ; Kleinert, Anne 2 ; Hoffman, Lars 3 ; Preusse,
Peter 3 ; Murtagh, Donal 4 ; Urban, Joachim 4 ; Dudhia, Anu 5 ; van Weele, Michiel 6 ; McConnell, Jack 7 ;
Kaminski, Jacek 7 ; Lupu, Alexander 7 ; Semeniuk, Kirill 7 ; Langen, Joerg 8 ; Riese, Martin 3 ; Eriksson, Patrick 4 ;
Murk, Axel 9 ; Whale, Mark 9 ; Glossow, Stefan 4 ; Hegglin, Michaela 10 ; Peuch, Vincent-Henri 11 ; Forster,
Piers 12 ; Palmer, Paul 13 ; Hogan, Robin 14 ; Coheur, Pierre-Francois 15 ; Bernath, Peter 16 ; Flaud, Jean-Marie 17
1 Rutherford Appleton Laboratory, UNITED KINGDOM; 2 Karlsruhe Institute of Technology, GERMANY;
3 Research Centre Julich, GERMANY; 4 Chalmers University of Technology, SWEDEN; 5 University of Oxford,
UNITED KINGDOM; 6 KNMI, NETHERLANDS; 7 York University, CANADA; 8 ESA - ESTEC, NETHERLANDS;
9 University of Berne, SWITZERLAND; 10 University of Toronto, CANADA; 11 ECMWF, UNITED KINGDOM;
12 University of Leeds, UNITED KINGDOM; 13 University of Edinburgh, UNITED KINGDOM; 14 University of
Reading, UNITED KINGDOM; 15 ULB, BELGIUM; 16 University of York, UNITED KINGDOM; 17 LISA, FRANCE
PREMIER (PRocess Exploration through Measurements of Infrared and millimetre-wave Emitted
Radiation)is one of three candidate missions under Phase A study for ESA’s 7th Earth Explorer. The
mission aims to quantify processes controlling global atmospheric composition in the mid-troposphere to
lower stratosphere (5 – 25 km), a region of particular sensitivity for surface climate, by resolving 3-D
structures in atmospheric constituents and temperature on finer scales than have previously been
accessible from space. In addition, through combination with co-located observations by EPS/EPS-SG,
the mission aims to quantify links with surface emissions and air pollution. To achieve these aims,
PREMIER comprises a limb imaging IR spectrometer and a millimetre-wave limb sounder flying in
formation with EPS/EPS-SG. A number of scientific activities have been undertaken in parallel with Phase
A studies of the system concept by industry. These include simulations with state-of-the-art schemes to
refine sensor specifications and to demonstrate retrieval performance for individual profiles and detailed
structure associated with phenomena such as the SE Asian monsoon circulation, pyroconvective and
volcanic plumes and exchange between the troposphere and stratosphere. They also include studies to
quantify the impact of the retrieved PREMIER data in scientific exploitation studies and assimilation into
operational systems and field campaigns of airborne precursors to demonstrate the new observing
capabilities. This paper will outline these scientific activites, focusing principally on a study to refine
requirements and demonstrate performance through forward modelling and retrieval simulations.
26

A Satellite Constellation for Observing Global Air Quality: Status of the CEOS
Activity
Al-Saadi, Jay 1 ; Zehner, Claus 2
1 NASA HQ, UNITED STATES; 2 ESA ESRIN, ITALY
This talk will summarize activities of the Committee on Earth Observation Satellites (CEOS) Atmospheric
Composition Constellation (ACC) to collaboratively advance the next generation of air quality monitoring
from space. Over the past 2 years, CEOS ACC have developed a position paper describing the benefits to
be derived from such collaboration. The resulting ACC recommendations were endorsed by CEOS in May
2011. We will discuss next steps toward implementing this vision.
Several countries and space agencies are currently planning to launch geostationary Earth orbit (GEO)
missions in 2017-2022 to obtain atmospheric composition measurements for characterizing
anthropogenic and natural distributions of tropospheric ozone, aerosols, and their precursors. These
missions include Europe’s ESA Sentinel-4 with EUMETSAT IRS, the United States’ NASA GEO-CAPE,
Korea’s ME/MEST/KARI GEMS, and Japan’s JAXA GMAP-Asia. GEO observations offer a quantum advance
in air quality monitoring from space by providing measurements many times per day. However, a single
GEO satellite views only a portion of the globe. These satellites, positioned to view Europe, East Asia,
and North America, will collectively provide hourly coverage of the industrialized Northern Hemisphere at
similar spatial resolutions. Planned low Earth orbit (LEO) missions will provide complementary daily
global observations. Observations from a single LEO satellite will overlap those from each GEO satellite
once per day, providing a means for combining the GEO observations and a necessary perspective for
interpreting global impacts of smaller scale processes. The EUMETSAT Metop series, NOAA/NASA JPSS
series, and ESA Sentinel-5 Precursor and Sentinel-5 missions will each provide such daily overlap with
the GEO missions. The Canadian PCW PHEMOS mission will make an additional unique suite of
observations. PCW will provide quasi-geostationary coverage over the Arctic that overlaps with each
geostationary satellite over 30N - 60N, adding opportunities for intercalibration many times per day.
The development of common data products, data distribution protocols, and calibration strategies will
synergistically enable critically needed understanding of the interactions between regional and global
atmospheric composition. Common air quality trace gas products will be tropospheric column O3, NO2,
HCHO, and SO2 nominally at 8 km spatial resolution and 1 hour temporal frequency. Detection of
aerosols in the UV will allow absorbing aerosols to be distinguished from total aerosol optical depth,
providing information on aerosol speciation and particularly relevant to the air quality/climate interface
associated with aerosol radiative forcing. Such activities directly address societal benefit areas of the
Global Earth Observation System of Systems (GEOSS) and are responsive to the requirements of each
mission to provide advanced user services and societal benefits in their own regions.
27

Volcanic Ash and SO2
Advances in Remote Sensing and Forecasting of Volcanic Ash
Prata, Fred 1 ; Buongiorno, Fabrizia 2 ; Richter, Andreas 3 ; Seibert, Petra 4 ; Stohl, Andreas 5 ; Corradini,
Stefano 2 ; Spinetti, Claudia 2 ; Kristiansen, Nina 5 ; Eckhardt, Sabine 5
1 Norwegian Institute for Air Research, NORWAY; 2 INGV, ITALY; 3 University of Bremen, GERMANY;
4 BOKU, AUSTRIA; 5 NILU, NORWAY
Following the recent volcanic eruptions in Iceland, Chile and Eritrea, the science of measuring and
forecasting the movement of hazardous clouds of volcanic particles and gases has received a great deal
of attention. The ESA Support to Aviation for Volcanic Ash Avoidance (SAVAA) project, which began in
2008 provided satellite data products and dispersion model forecasts to assist with mitigation of aviation
hazards from volcanic clouds. The SAVAA project uses space-based assets to determine important
properties of volcanic ash clouds, such as the mass loading and effective particle size. The data are then
used in an inversion scheme based on the FLEXPART dispersion model to determine the most likely
source strength as a function of time. Once the optimum eruption rate and its vertical structure have
been established a new forecast is run that delivers more accurate information on ash concentrations in
the atmosphere.
Here we demonstrate the practical nature of the scheme and assess its accuracy for the Eyjafjallajoekull
and Grìmsvoetn eruptions in Iceland, in April/May 2010 and My 2011, respectively. We also present
validated ash and SO2 gas retrievals for the recent eruptions of Eyjafjallajkull, Grìmsvoetn, Nabro and
Puyehue Cordón-Caulle and compare and contrast the results and their significance to the ash/aviation
hazard. Finally, plans for future projects and the implementation of an operational ash warning service
are described.
Synergetic Use of Atmosphere and Surface Observations by the Spaceborne
European Volcano Observatory - EVOSS
Ferrucci, F. 1 ; Tait, S. 2 ; Tampellini, L. 3 ; Theys, N. 4 ; Clarisse, L. 5 ; Valks, P. 6 ; Hirn, B. 7 ; Laneve, G. 8 ;
Loughlin, S. 9 ; Ratti, R. 3 ; Kenter, P. 10 ; Niemeijer, S. 10 ; Vimercati, M. 3 ; Bianchi, M. 11 ; van der Voet, P. 12 ;
van der A, R. 13
1 Institut de Physique du Globe de Paris, FRANCE; 2 IPGP, FRANCE; 3 CGS, ITALY; 4 BIRA, BELGIUM; 5 ULB,
BELGIUM; 6 DLR, GERMANY; 7 IESC, ITALY; 8 CRPSM, ITALY; 9 BGS, UNITED KINGDOM; 10 S&T,
NETHERLANDS; 11 TRE, ITALY; 12 Terrasphere, NETHERLANDS; 13 KNMI, NETHERLANDS
EVOSS ‘European Volcano Observatory Space Services’ (2010-2013) is a R&D project funded in the
framework of the GMES initiative of the European Commission. The project develops an operational
portfolio of information services exclusively based on space-borne EO data for the timely, multiparameter,
multi-payload, real-time monitoring of major volcanic activity at the global scale. The
system, now running in real-time demonstration mode, is addressed to Volcano Crisis Management: it is
designed to create and distribute real-time EO products from Infra-Red, Ultra-Violet and Synthetic
Aperture Radar data, exploiting the high temporal resolution of SEVIRI and the daily revisits of IASI,
GOME-2, SCHIAMACHY, OMI and MODIS, and generating ground deformation EO strategic products in
delay-time. EVOSS products constrain physical parameters such as properties of aerosols or radiant
power of thermal anomalies on land, relevant for the understanding and the management of any eruptive
crisis occurring in the Region of Interest (the whole of Europe, Africa and the Lesser Antilles). The service
is delivered to, and driven by a group of qualified End Users, responsible for monitoring and/or advising
governments in Ethiopia, Djibouti, Comores, Congo, Tanzania, Uganda, Montserrat, Iceland and overseas
France. The Volcanic Ash Advisory Centers (VAAC) of London and Toulouse are also a part of the User
group. The gas and lava mass rates monitored in EVOSS are being specialized and tuned to serve
primary needs of volcanic hazard management, particularly the precise quantitative characterization of
the volcanic source, ie. the shallow plumbing system of each volcano. A significant example of this is the
service provided by EVOSS during the recent, large eruptions of Nabro (Eritrea, June-July 2011) and
Nyamulagira (Congo, started on November 6, 2011, and still ongoing on January 27, 2012) which both
produced large quantities of SO2. We show how space-borne measured SO2 concentrations in the
atmosphere as a function of time, used in conjunction with the time series of radiant thermal fluxes,
allow constraining the mass flux in the shallow plumbing system at any volcano as a function of time. In
the effusive eruptions that we have studied, both a « lava flow regime » and a « fire-fountaining regime
» are possible. In the latter, a powerful gas jet projects the lava as droplets typically several hundred
metres into the atmosphere: in the former, a hot viscous flow moves over the topography and radiates
from its upper surface. The signatures of these two regimes in terms of thermal and gas fluxes are not
the same, and we show how they can both be identified in different examples that the EVOSS system
28

has followed. EVOSS operations will continue through 2012 on the full set volcanoes having erupted in
2004-2011, with the addition of any newly erupting volcano.
SO2 Plume Height Retrieval from Direct Fitting of GOME-2 Backscattered
Radiance Measurements
van Gent, Jeroen 1 ; Spurr, Robert 2 ; Theys, Nicolas 1 ; Lerot, Christophe 1 ; Brenot, Hugues 1 ; Van
Roozendael, Michel 1
1 2
Belgian Institute for Space Aeronomy, BELGIUM; RT Solutions, Inc., UNITED STATES
The use of satellite measurements for SO2 monitoring has become an important aspect in the support of
aviation control. Satellite measurements are sometimes the only information available on SO2
concentrations from volcanic eruption events. The detection of SO2 can furthermore serve as a proxy for
the presence of volcanic ash that poses a possible hazard to air traffic. In that respect, knowledge of
both the total vertical column amount and the effective altitude of the volcanic SO2 plume is valuable
information to air traffic control. The Belgian Institute for Space Aeronomy (BIRA-IASB) hosts the ESAfunded
Support to Aviation Control Service (SACS). This system provides Volcanic Ash Advisory Centers
(VAACs) worldwide with near real-time SO2 and volcanic ash data, derived from measurements from
space.
We present results from our algorithm for the simultaneous retrieval of total vertical columns of O3 and
SO2and effective SO2 plume height from GOME-2 backscattered radiance measurements. The algorithm
is an extension to the GODFIT direct fitting algorithm, initially developed at BIRA-IASB for the derivation
of improved total ozone columns from satellite data. The algorithm uses parameterized vertical SO2
profiles which allow for the derivation of the peak height of the SO2 plume, along with the trace gas total
column amounts.
To illustrate the applicability of the method, we present three case studies on recent volcanic eruptions:
Merapi (2010), Grimsvoetn (2011), and Nabro (2011). The derived SO2 plume altitude values are
validated with the trajectory model FLEXPART and with aerosol altitude estimations from the CALIOP
instrument on-board the NASA A-train CALIPSO platform. We find that the effective plume height can be
obtained with a precision as fine as 1 km for moderate and strong volcanic events. Since this is valuable
information for air traffic, we aim at incorporating the plume height information in the SACS system.
Estimating the Lifetime of SO2 from Space: A Case Study for the Kilauea Volcano
Beirle, Steffen; Penning de Vries, Marloes; Hörmann, Christoph; Wagner, Thomas
MPI Chemie, GERMANY
Satellite observations of atmospheric trace gases have revolutionized our insights regarding the location
and amount of various pollutants. In addition, it has been demonstrated recently that atmospheric
lifetimes can be derived by analyzing the downwind decay of point sources. Here we present an analysis
of the downwind evolution of the SO2plume from the Kilauea volcano (Hawaii) in 2008. Both the SO2patterns
observed from space (GOME-2) and the wind fields according to ECMWF stay rather stable over
several months, making this an ideal case for lifetime determination. Using a relatively simple
mathematical analysis, an e-folding lifetime of SO2 and the total release of SO2 can be estimated
simultaneously on the basis of monthly mean SO2 maps and wind fields. We estimate the lifetime of
volcanic SO2 to be about 2-3 days. The potential and the limitations of our approach are discussed, and
the consequences for the OH concentrations and the chemistry occurring within the volcanic plume are
investigated.
29

Observations of Volcanic Plumes Using Singular Vector Decomposition of MIPAS
Spectra
Smith, Andrew; Dudhia, Anu; Grainger, Roy
University of Oxford, UNITED KINGDOM
A simple flagging of MIPAS spectra based on ratios of radiances in a narrow section of the A-Band (685–
970 cm-1) can mark suspected volcanic plumes when their signal is strong and uncontaminated, but is
not hugely sensitive to weaker signals. Using singular vector decomposition (SVD) to remove modes of
spectral variability due to normal atmospheric conditions, a more accurate indicator of volcanic ash
plumes in the Oxford MIPAS cloud retrieval can be obtained. As time progresses, the strength of the
signal can fall off, but it is still possible to be tracked. SVD also allows one to obtain information about
the spectral signature of a specific eruption. Since individual events have different signatures, once a
training set has been obtained, signals from different events can be distinguished. Time evolution of the
spectral signals can also be observed. Results from analysis of two eruptions from June 2011, the
Puyehue-Cordon Caulle eruption in Chile, and the Nabro eruption in Eritrea are presented. Geographical
location of the flagged plumes match with local observations.
Performance Assessment of a Volcanic Ash Transport Model Mini-Ensemble Used
for Inverse Modeling of the 2010 Eyjafjallajökull Eruption
Kristiansen, Nina Iren 1 ; Stohl, Andreas 1 ; Prata, Fred 1 ; Eckhardt, Sabine 1 ; Bukowiecki, Nicolas 2 ; Dacre,
Helen 3 ; Henne, Stephan 4 ; Hort, Matt 5 ; Johnson, Ben 5 ; Marenco, Franco 5 ; Thomson, Dave 5 ; Webster,
Helen 5 ; Neininger, Bruno 6 ; Reitebuch, Oliver 7 ; Weinzierl, Bernadett 7 ; Seibert, Petra 8
1 NILU-Norwegian Institute for Air Research, NORWAY; 2 Paul Scherrer Institut (PSI), Laboratory of
Atmospheric Chemistry,, SWITZERLAND; 3 Department of Meteorology, University of Reading, UNITED
KINGDOM; 4 Empa, Swiss Federal Laboratories for Materials Science and Technology, SWITZERLAND;
5 Met Office, Exeter, UNITED KINGDOM; 6 Zurich University of Applied Sciences (ZHAW), Centre for
Aviation, SWITZERLAND; 7 Deutsches Zentrum für Luft- und Raumfahrt, Instituf für Physik der
Atmosphäre, GERMANY; 8 Institute of Meteorology, University of Natural Resources and Life Sciences,
AUSTRIA
The requirement to forecast volcanic ash concentrations was amplified as a response to the 2010
Eyjafjallajökull eruption when ash safety limits for aviation were introduced in the European area. The
ability to provide accurate quantitative forecasts relies to a large extent on the source term which is the
emissions of ash as a function of time and height. This study presents source term estimations of the ash
emissions from the Eyjafjallajökull eruption derived with an inversion algorithm which constrains
modeled ash emissions with satellite observations of volcanic ash. The algorithm is tested with input
from two different dispersion models, run on three different meteorological input data sets. The results
are robust to which dispersion model and meteorological data are used. Modeled ash concentrations are
compared quantitatively to independent measurements from three different research aircraft and one
surface measurement station. These comparisons show that the models perform reasonably well in
simulating the ash concentrations, and simulations using the source term obtained from the inversion are
in overall better agreement with the observations (rank correlation=0.55, Figure of Merit in Time
(FMT)=25-46%) than simulations using simplified source terms (rank correlation=0.21, FMT=20-35%).
The vertical structures of the modeled ash clouds mostly agree with LIDAR observations, and the
modeled ash particle size distributions agree reasonably well with observed size distributions. There are
occasionally large differences between simulations but the model mean usually outperforms any
individual model. The results emphasize the benefits of using an ensemble-based forecast for improved
quantification of uncertainties in future ash crises.
30

Day 4, Thursday 21 June 2012
31

Upper Atmosphere
Measurements of Mesospheric Ozone from MIPAS Spectra
Lopez-Puertas, Manuel 1 ; Garcia-Comas, Maya 1 ; Funke, Bernd 1 ; Gardini, Angela 1 ; Jurado-Navarro,
Aythami 1 ; von Clarmann, Thomas 2 ; Stiller, Gabriele 2 ; Grabowski, Udo 2 ; Glatthor, Norbert 2 ; Smith, Anne 3
1 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut fur
Meteorologie und Klimaforschung (IMK-ASF), GERMANY; 3 Atmospheric Chemistry Division, NCAR,
UNITED STATES
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat (ESA)
observes regularly (1 out of 5 days) the middle and upper atmosphere using three different observational
modes: the Middle Atmosphere (MA) (20-100 km), the Upper Atmosphere (UA) (40-170 km), and the
NLC (39-102 km) modes. These observations are being taken regularly since mid-2007 with the
optimized spectral resolution (0.0625 cm-1). O3 abundances are retrieved routinely from the MIPAS
spectra in the 10 µm region from 20 (or 40 km) up to about 100 km by using the IAA/IMK processor that
account for non-LTE. In this paper we present a characterization of the data in terms of the vertical
resolution and error budget. A validation of the data by its comparison with collocated SABER
measurements is also presented. Finally, the analysis of the variation of the O3 secondary maximum at
high latitudes along the different seasons in recent years are discussed.
Global Determination of Metal and Metal Ion Densities in the MLT Region from
SCIAMACHY/Envisat Data
Langowski, Martin 1 ; von Savigny, C. 1 ; Aikin, A.C. 2 ; Sinnhuber, M. 1 ; Burrows, J.P. 1
1 University of Bremen, GERMANY; 2 The Catholic University of America, Washington, DC, UNITED STATES
Meteroids entering the earth atmosphere ablate in the mesopause region (~90km) . This leads to an
input of metals into this region. The mean global input of meteoric material is still very unknown and
varies between 1 and 200 tons per day.The metals, mostly Mg, Fe and Na and also in smaller quantities
Ca and K, than undergo several chemical and transport processes, like ionisation and/or chemical
reactions into reservoir species and to meteoric dust, what leads to the formation of metal and metal ion
layers in the mesosphere and lower thermosphere (80-110km). This layers have very large horizontal
extensions. but a very sharp peaked vertical profiles of 10 km thickness, or less. Although the density in
this metal layers is very small with less than 100000 particles per cubic centimeter they show strong
dayglow emisssions due to their very large absorption coefficients and oscillator strength, and thus can
be detected by remote sensing. This is crucial as the mesopause region is too high for aircrafts and
balloons and to low for satellite instruments to fly there, and therefore, with exception of rocket borne
instruments, in situ measurements are not possible in this region. The observation of the metals is
therefore e.g. a very good method to track wave motions through this region, coupling the dynamics of
lower and upper atmosphere together. Furthermore the metals and meteoric dust could possibly play a
role as condensation nuclei in the formation of clouds in the middle atmosphere, what might be
interesting to investigate, as e.g. the depletion of ozone is strongly dependent of the presence of clouds.
Ground based measurements in the visible region that are nowadays mostly performed by LIDAR
instruments show very good resolutions in time and space, but they are very bound to local stations.
Global coverage through satellite instruments with long timeseries of data have just become possible in
the last decades. SCIAMACHY on Envisat, a grating spectrometer ranging from UV-VIS-IR launched in
2002, is one of the few spaceborne instruments that scans the MLT region in limb and nadir mode very
regular for a very long time. As it is in space and also operates in UV, it can also detect Mg and Mg+
emission lines that cannot be observed from ground due to the strong absorption of ozone in this range.
Due its very broad wavelength range several metal species can be observed with it. In this paper we will
present latest results for the global density profiles of Mg, Mg+, Na and possibly Fe. We would prefer an
oral presentations, to be able to show animations of the result.
Chemical Impact of Thunderstorms onto the Upper Atmosphere
Arnone, Enrico; Castelli, Elisa; Dinelli, Bianca M.
Istituto di Scienze dell’Atmosfera e del Clima, ISAC-CNR, ITALY
Two decades after their first accidental discovery, sprites, transient luminous events (TLEs) and
terrestrial gamma-ray flashes (TGFs) are drawing the attention of the scientific community to the impact
that thunderstorms exert onto the whole atmosphere, from the troposphere to the upper atmosphere
and lower ionosphere. Thunderstorms are responsible for lightning-NOx, the major source of atmospheric
NOx, for the uplift of tropospheric constituents as high as into the stratosphere driving tropospherestratosphere
exchange, and are likely contributing directly to the upper atmosphere NOx content through
upper atmosphere discharges and ionization. In a changing climate with increasing sea surface
32

temperatures and convection, thunderstorm intensity is likely to increase, as consequently is to increase
the relevance of thunderstorm related processes. We present the first results of the Chemical Impact of
Thunderstorms on Earth's Atmosphere (CHIMTEA) project, focusing on the upper atmosphere. We used
model simulations and observations from MIPAS and GOMOS onboard ENVISAT to study the magnitude
and detectability of TLE chemical perturbations. We present the results of an investigation based on
remote sensing observations and on the first catalogue of over 3500 TLE observations obtained over
Europe during 2009 to 2011 by the Eurosprite network.
NLC Climatology from GOMOS Observations
Pérot, Kristell; Hauchecorne, Alain; Montmessin, Franck
LATMOS, FRANCE
Noctilucent clouds (NLC), also called polar mesospheric clouds when observed from space, are the visible
manifestation of water ice particles persistently present in the polar summer mesopause region, which is
the coldest place on Earth. Because of their extraordinary height of about 83 km, they can become
visible to the naked eye when the sun sinks below the horizon, providing a dazzling display of bluish
light. Since these clouds are extremely sensitive to changes in their environment, their observation
conveys unique information concerning the various processes taking place in the mesosphere. GOMOS is
a stellar occultation instrument combining 4 spectrometers in the spectral range 250 to 950 nm (UV –
visible – near IR) and 2 fast photometers (470-520 nm and 650-700 nm). On the day side, in addition to
star light, GOMOS measures also the solar light scattered by the atmospheric molecules. In the summer
polar days, NLC are clearly detected using the photometers signals. The sun-synchronous orbit of
ENVISAT allows observing them in both hemispheres. The main properties of these clouds (occurrence
frequency, radiance, altitude) have been retrieved from GOMOS data. A very high accuracy is possible
thanks to the stellar occultation technique. Moreover, the observation of these clouds with the
spectrometers provides the spectral dependence of the light scattered by the NLC particles, from which it
is possible to derive their radii. These clouds at the edge of space have been studied using GOMOS data
from 2002 to 2010. After a brief overview of retrieval methods, the climatology obtained for the main
NLC characteristics will be presented, focusing on the seasonal and latitudinal coverage.
MIPAS Kinetic Temperature from the Stratosphere to the Lower Themosphere:
Results and Validation
Garcia-Comas, Maya 1 ; Funke, Bernd 1 ; Lopez-Puertas, Manuel 1 ; Bermejo-Pantaleon, Diego 1 ; Glatthor,
Norbert 2 ; von Clarmann, Thomas 2 ; Stiller, Gabriele 2 ; Grabowski, Udo 2 ; Boone, C. D. 3 ; French, W.J.R. 4 ;
Leblanc, T. 5 ; Lopez-Gonzalez, Maria Jose 1 ; Schwartz, M.J. 6
1 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut fur
Meteorologie und Klimaforschung (IMK-ASF), GERMANY; 3 University of Waterloo, CANADA; 4 Australian
Antarctic Division, AUSTRALIA; 5 California Institute of Technology, Jet Propulsion Laboratory, UNITED
STATES; 6 Jet Propulsion Laboratory, UNITED STATES
The knowledge of kinetic temperature is needed in any study focused in the understanding of the physics
of the atmosphere. MIPAS Middle Atmosphere (MA), Upper Atmosphere (UA) and NoctiLucent-Cloud
(NLC) special modes of limb observations of the CO2 15 µm emission are used to retrieve the kinetic
temperature using the IMK/IAA retrieval algorithm considerinf non-local thermodynamic equilibrium
conditions. The temperature is that way derived from 20 km to 105 km globally and both at daytime and
nighttime. We show results on the quality of the retrieved temperature as a function of latitude and
season: typical random errors ranging from 0.5 K below 50 km to 2-8 K above above 70 km, systematic
errors ranging from 1 K below 70 km to 3-11 K above 85 km, and average vertical resolution ranging
from 3-4 km below 50 km and 6-10 km above 90 km. In order to assess possible biases, we compared
our temperature retrievals for five years with co-located ground-based measurements from the Table
Mountain Facility and Mauna Loa Observatory LIDARs, the SATI spectrograph in Granada and the Davis
station spectrometer, and satellite observations from ACE-FTS, Aura-MLS and TIMED-SABER, from 20 km
to 100 km. The agreement is very good, with differences smaller than 3 K below 85-90 km in midlatitudes.
The differences over the poles are larger but are within biases previously found for the other
instruments. The differences above 90 km increases, MIPAS temperatures being larger than those from
the other measurements.
33

Greenhouses Gases
The GHG-CCI Project of ESA's Climate Change Initiative: Overview and Status
Buchwitz, Michael 1 ; Reuter, Maximilian 1 ; Schneising, Oliver 1 ; Heymann, Jens 1 ; Noel, Stefan 1 ;
Bovensmann, Heinrich 1 ; Notholt, Justus 1 ; Warneke, Thorsten 1 ; Boesch, Hartmut 2 ; Parker, Robert 2 ;
Hasekamp, Otto 3 ; Guerlet, Sandrine 3 ; Aben, Ilse 3 ; Lichtenberg, Guenter 4 ; Crevoisier, Cyril, D. 5 ; Chedin,
Alain 5 ; Laeng, Alexandra 6 ; Stiller, Gabriele P. 6 ; Blumenstock, Thomas 6 ; Orphal, Johannes 6 ; Sussmann,
Ralf 7 ; Dils, Bart 8 ; De Maziere, Martine 8 ; Brunner, Dominik 9 ; Popp, Christoph T. 9 ; Buchmann, Brigitte 9 ;
Chevallier, Frederic 10 ; Bergamaschi, Peter 11 ; Frankenberg, Christian 12 ; Zehner, Claus 13 ; Burrows, John
P. 1
1 University of Bremen FB1, GERMANY; 2 University of Leicester, UNITED KINGDOM; 3 SRON,
NETHERLANDS; 4 DLR, Oberpfaffenhofen, GERMANY; 5 Laboratoire de Meteorologie Dynamique (LMD),
Palaiseau, FRANCE; 6 Karlsruhe Institute of Technology (KIT), Karlsruhe, GERMANY; 7 Karlsruhe Institute
of Technology (KIT), Garmisch-Partenkirchen, GERMANY; 8 Belgian Institute for Space Aeronomy (BIRA),
BELGIUM; 9 Swiss Federal Laboratories for Material Testing and Research (Empa), SWITZERLAND;
10 Laboratoire des Sciences du Climate et de l'Environment (LSCE), Gif-sur-Yvette, FRANCE; 11 European
Commission Joint Research Centre (EC-JRC), Inst. for Environment and Sustainability (IES), ITALY; 12 Jet
Propulsion Laboratory (JPL), Pasadena, CA, UNITED STATES; 13 ESA/ESRIN, Frascati, ITALY
The GHG-CCI project (http://www.esa-ghg-cci.org) is one of several projects of ESA's Climate Change
Initiative (CCI), which will deliver various Essential Climate Variables (ECVs). The goal of GHG-CCI is to
deliver global satellite-derived data sets of the two most important anthropogenic greenhouse gases
(GHGs) carbon dioxide (CO2) and methane (CH4) suitable to obtain information on regional CO2 and
CH4 surface sources and sinks as needed for better climate prediction. The GHG-CCI core ECV data
products are column-averaged mole fractions of CO2 and CH4, XCO2 and XCH4, retrieved from
SCIAMACHY on ENVISAT and TANSO on GOSAT. Other satellite instruments will be used to provide
constraints in upper layers, e.g., IASI, MIPAS, and ACE-FTS. For each of the 4 GHG-CCI core data
products - XCO2 and XCH4 from SCIAMACHY and GOSAT - several algorithms are being further
developed and the corresponding data products are inter-compared to identify which algorithm / data
product is the most appropriate. This includes comparisons with corresponding data products generated
elsewhere, most notably with the operational data products of GOSAT generated at NIES and the
NASA/ACOS GOSAT XCO2 product. This activity, the so-called "Round Robin exercise", is being
performed in the first two years of this project. At the end of the 2 year Round Robin phase (end of
August 2012) a decision will be made which of the algorithms performs best. The selected algorithms will
be used to generate the first version of the ECV GHG. In the last six months of this 3 year project the
resulting data products will be validated and made available to all interested users. In the presentation
and overview about this project will be given focussing on the latest results.
34

Model Evaluations of Methane Variability in the Upper Troposphere and Lower
Stratosphere
van Weele, Michiel 1 ; Williams, Jason 1 ; van Velthoven, Peter 1 ; McConnell, Jack 2 ; Kaminsky, Jacek 2 ; Lupu,
Alex 2 ; Chipperfield, Martyn 3 ; Palmer, Paul 4 ; Kerridge, Brian 5
1 KNMI, NETHERLANDS; 2 York University, CANADA; 3 University of Leeds, UNITED KINGDOM; 4 University
of Edinburgh, UNITED KINGDOM; 5 Rutherford Appleton Laboratory, UNITED KINGDOM
Envisat observations of methane columns (by SCIAMACHY) and profiles (by MIPAS) have provided new
information on the global 3D distribution of methane in the atmosphere. SCIAMACHY total column
observations are used in methane emission inversions and provide important observational constraints in
addition to the surface networks. Limb observations by Envisat/MIPAS, and also by SCISAT-1/ACE-FTS
are used to evaluate methane variability in the upper troposphere/lower stratosphere (UTLS), e.g. in
connection with the Asian monsoon circulation. Recent aircraft methane observations between Frankfurt
and Chennai from the CARIBIC program (Schuck et al., ACP, 2010) provide in-situ evidence of enhanced
methane concentrations during NH summer months in the Asian monsoon upper tropospheric
anticyclone. A model intercomparison has been performed with a group of chemistry-transport models to
evaluate the upper tropospheric methane distribution in the Asian monsoon region. The differences in
between models and between models and the above-mentioned observations will be presented. It will be
shown that convectively uplifted methane emissions from South-Asia during June to August contribute
importantly to the methane concentrations and variability in the UTLS. It will also be shown that the
differences between the models are significant which suggests sensitivity of simulated UTLS methane
concentrations to model formulation. The global importance of regional and seasonal UTLS methane
variations is further assessed using decadal (2000-2009) chemistry simulations that have been
performed with one of models: the global chemistry-transport model TM5 driven by observed
meteorology (ERA-Interim reanalysis). A first simulations is constrained by background surface
observations and a second simulation by methane surface emission distributions following anthropogenic
emission inventories and natural surface fluxes from wetlands varying with the observed meteorology.
The combination of simulations shows the impact of regional seasonal methane emissions variations on
methane concentrations in the UTLS and on the methane total column distribution. The studies have
been performed in the framework of the ESA candidate limb satellite mission PREMIER proposed to fly in
formation with MetOp(-SG) in the 2019+ timeframe.
Retrieval of Methane Distributions from IASI
Waterfall, Alison; Siddans, Richard; Kerridge, Brian; Miles, Georgina; Latter, Barry
RAL Space, STFC, UNITED KINGDOM
In this presentation, we will show results from a scheme being developed at the Rutherford Appleton
Laboratory to retrieve methane distributions from the IASI instrument on METOP. IASI is an infrared
nadir viewing Fourier transform spectrometer, which is capable of providing global information on a
number of atmospheric trace gases, including methane. Methane is an important greenhouse gas, and
knowledge of its distribution, sources and sinks, and trend within the atmosphere are important for our
understanding of the current atmosphere and future climate. The ability to measure information on
methane from space allows global methane distributions to be derived alongside seasonal and even
longer term variations in its concentration. Comparison of such methane distributions against current
models will enable our current understanding of methane sources and sinks to be critically tested.
IASI is predominantly sensitive to the tropospheric distribution of methane, and we will also discuss the
potential for extracting height resolved information on methane alongside global and seasonal
distributions. We will also examine the benefits of combining this data with stratospheric information
from limb sounding instruments, for instance MIPAS on ENVISAT, which should allow a more complete
picture of the vertical methane distribution to be derived.
One critical source of error on the methane retrieval is the presence of clouds. To avoid large errors in
the methane distribution affected pixels must either be rejected or else the cloud must be included in the
retrieval code. Here, we will discuss the impact and possible mitigation of errors due to cloud, through
simulations and the use of collocated imager data.
35

Improved Carbon Dioxide and Methane Retrieved from SCIAMACHY Onboard
ENVISAT: Validation and Applications
Schneising, Oliver; Buchwitz, M.; Heymann, J.; Reuter, M.; Bovensmann, H.; Burrows, J. P.
University of Bremen, GERMANY
Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases
contributing to global climate change. Despite their importance, there are still many gaps in our
understanding of the sources and sinks of these greenhouse gases and their biogeochemical feedbacks
and response in a changing climate. Satellite measurements combined with inverse modelling can
significantly reduce surface flux uncertainties, if the satellite data are accurate and precise enough. The
significant reduction of regional-scale flux uncertainties additionally requires high sensitivity to the lowest
atmospheric layers where the variability is largest. Sensitivity to all altitude levels, including the
boundary layer, can be achieved by using reflected solar radiation in the near-infrared/shortwaveinfrared
(NIR/SWIR) spectral region. SCIAMACHY onboard ENVISAT (launched in 2002) was the first and
is now with TANSO onboard GOSAT (launched in 2009) one of only two satellite instruments currently in
space yielding measurements of the relevant absorption bands of both gases in this spectral range.
Improved global data sets of atmospheric carbon dioxide and methane column-averaged mole fractions -
which are the quantities needed for inverse modelling to get information on the sources and sinks -
retrieved from SCIAMACHY nadir observations are presented upgrading pre-existing greenhouse gas
information derived from European EO data. The multi-year data sets are validated with ground-based
Fourier Transform Spectrometer (FTS) measurements and compared with model results at Total Carbon
Column Observing Network (TCCON) sites providing realistic error estimates of the satellite data which is
a prerequisite to assess the suitability to be used in inverse modelling. These validation results will be
briefly summarised. The presented applications include an analysis of the atmospheric greenhouse gas
variability on a spatial and temporal basis.
CarbonSat: ESA's Earth Explorer 8 Candidate Mission
Meijer, Yasjka; Ingmann, P.; Löscher, A.; CarbonSat, MAG
ESA, NETHERLANDS
The CarbonSat candidate mission is part of ESA's Earth Explorer Programme. In 2010, two candidate
opportunity missions had been selected for feasibility and preliminary definition studies. The missions,
called FLEX and CarbonSat, are now in competition to become ESA's eighth Earth Explorer, both
addressing key climate and environmental change issues.
In this presentation we will provide a mission overview of CarbonSat with a focus on science.
CarbonSat's primary mission objective is the quantification and monitoring of CO2 and CH4 sources and
sinks from the local to the regional scale for i) a better understanding of the processes that control
carbon cycle dynamics and ii) an independent estimate of local greenhouse gas emissions (fossil fuel,
geological CO2 and CH4, etc.) in the context of international treaties. A second priority objective is the
monitoring/derivation of CO2 and CH4 fluxes on regional to global scale. These objectives will be achieved
by a unique combination of frequent, high spatial resolution (2 x 2 km 2 ) observations of XCO2 and XCH4
coupled to inverse modelling schemes. The required random error of a single measurement at groundpixel
resolution is of the order of between 1 and 3 ppm for XCO2 and between 9 and 17 ppb for XCH4.
High spatial resolution is essential in order to maximize the probability for clear-sky observations and to
identify flux hot spots. Ideally, CarbonSat shall have a wide swath allowing a 6-day global repeat cycle.
The CarbonSat observations will enable CO2 emissions from coal-fired power plants, localized industrial
complexes, cities, and other large emitters to be objectively assessed at a global scale. Similarly, the
monitoring of natural gas pipelines and compressor station leakage will become feasible. The detection
and quantification of the substantial geological greenhouse gas emission sources such as seeps,
volcanoes and mud volcanoes will be achieved for the first time.
CarbonSat's Greenhouse Gas instrument will exploit a passive observing technique measuring scattered
solar light with imaging spectrometers. It will perform measurements of CO2 and CH4 in combination with
O2 to yield their dry column amounts. Spectral absorptions of CO2 in the 1.6 ìm and 2 ìm bands, O2 in the
760 nm and CH4 in the 1.65 ìm spectral ranges measured with high spectral resolution of the order of
between 0.03 and 0.3 nm and a high signal-to-noise ratio. The CarbonSat mission concept builds on the
heritage and lessons learned from SCIAMACHY, GOSAT and OCO(-2) to make strategically important
measurements of the amounts and distribution of CO2 and CH4 in the context of Climate Change.
36

Clouds/Aerosols
Production of Aerosol Essential Climate Variables Using Satellite Data: Aerosol-
CCI.
de Leeuw, Gerrit 1 ; Holzer-Popp, Thomas 2 ; Aerosol-cci team, - 3
1 FMI / Univ Helsinki, FINLAND; 2 DLR Oberpfaffenhofen, German Remote Sensing Data Center, GERMANY;
3 -, FINLAND
The European Space Agency (ESA) Climate Change Initiative project Aerosol_cci aims at the production
of aerosol essential climate variables (ECV’s) from European Earth Observation instruments (ATSR-2,
AATSR, MERIS, SCIAMACHY, POLDER, GOMOS and OMI) providing information on column integrated
scattering and absorption properties as well as on stratospheric aerosol. In order to achieve this,
differences between the various algorithms used need to be evaluated to provide the best possible
products. To study the effect of the choice of the aerosol models used in the retrieval, the algorithms
have been used with a variety of aerosol models, using four base models which are combined in several
ways. These models have been used together with an aerosol climatology based on AEROCOM model
results and AERONET observations which was optionally used to provide a priori information on the
occurrence of each aerosol type. The algorithms have been run with either their own cloud mask or with
a prescribed common cloud mask. Based on the tests, the best possible algorithms for each EO sensor or
each algorithm for the same sensor have been used to provide a test data set for a round robin
comparison for 4 months, covering the different seasons, in 2008. The evaluation of the test data sets,
based on a number of different tests including comparison with AERONET and other satellite data, shows
the significant improvement in the performance of each algorithm. An initial ECV data set will be
produced for user evaluation. An overview of the current status of the Aerosol-cci project will be
presented.
Retrieval of Saharan Desert Dust Properties from Hyperspectral Thermal
Infrared Measurements by IASI
Vandenbussche, Sophie 1 ; Kochenova, Svetlana 1 ; Vandaele, Ann Carine 1 ; Kumps, Nicolas 1 ; Dewitte,
Steven 2 ; Nevens, Stijn 2 ; Clerbaux, Nicolas 2 ; De Mazière, Martine 1
1 Belgian Institute for Space Aeronomy, BELGIUM; 2 Royal Meteorological Institute of Belgium, BELGIUM
Saharan dust storms are a major source of desert dust particles in the atmosphere, transporting sand to
Europe, Western Asia or even South America. Desert dust particles are composed of a mixture of
minerals, which absorb and scatter solar radiation, and emit thermal radiation, resulting in (direct)
climate forcing. They also affect climate indirectly, for example by altering cloud microphysics. A better
knowledge of their optical properties, atmospheric aerosol load, sources and sinks may therefore
significantly improve the modeling of climate changes. In particular, desert dust aerosols show strong
spectral features in the thermal infrared (TIR) atmospheric window (800-1200cm -1 ), where they are
therefore a major actor in the amount of thermal energy transmitted to space.
Aerosol properties retrievals from satellite measurements at TIR wavelengths (e.g. by SEVIRI, AIRS or
IASI) are less common than in the visible and near infrared spectral range (e.g. from MODIS, MISR,
SEVIRI, CALIOP or POLDER), but received a growing interest in the recent years. TIR measurements
have the advantage to be performed during both day and night. IASI on METOP has one further
advantage for aerosol retrievals: its large continuous spectral coverage, allowing to better capture the
broadband signature of aerosols. Furthermore, IASI will nominally be in orbit for 15 years and offers a
quasi global Earth coverage twice a day.
Here we will show recently obtained results of desert aerosol properties (e.g. concentration, altitude,
optical depth, refractive index, particle size) retrieved from IASI TIR measurements over ocean and over
the desert. We use a sophisticated radiative transfer (RT) code and the optimal estimation formalism.
The RT code consists of three separate codes: ASIMUT (BIRA-IASB, Belgium), (V)LIDORT (R. Spurr,
RTsolutions Inc, US) and SPHER (M. Mishchenko, NASA GISS, USA), which are linked through a special
interface.
We will show test-case comparisons between our retrievals and measurements from other instruments
like those listed above including an existing MSG SEVIRI retrieval. We will also highlight the challenges
that go along with such retrievals.
37

Pollution Injection Into the Upper Troposphere and Lower Stratosphere:
Detection, Plume Transport and Composition Inference with MIPAS
Sembhi, Harjinder 1 ; Moore, David 1 ; Fromm, Mike 2 ; Trent, Timothy 1 ; Remedios, John 1
1 University of Leicester, UNITED KINGDOM; 2 Naval Research Laboratory, UNITED STATES
In recent years, investigations of wildfire and volcanic pollution influence in the upper troposphere and
lower stratosphere has shown large uncertainties in the determination of vertical injection heights,
“young” plume constituents, tracing plume transport and the evolving plume composition. Not only does
this highlight the need for improved detection/retrievals of such aerosols and their related trace gases
but also improvement of knowledge on the vertical distribution of these pollution injections, the evolving
structure of pollutant clouds and the separation of aerosol, cloud and pollutants within the plumes.
Thermal infrared limb spectrometers can achieve high vertical resolution, between 1 and 3 km, and high
sensitivity to low aerosol particle amounts due to a long horizontal integrated limb path. Furthermore,
the thermal infrared spectrum from 700 to 1200 cm -1 (14 to 8.3 µm) captures the distinct
emission/absorption signatures of aerosols, ice, ash, sulphur dioxide (SO2), sulphuric acid (H2SO4) and
clouds making them ideal to study pollution events by detailing the vertical structure of evolving plumes
and clouds fields, and tracing the transport pathways of pollution across the globe.
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) launched on ESA’s ENVISAT
platform in March 2002 measures atmospheric limb profiles from 6 to 68 km with 1.5 km vertical
sampling and spectral resolution of 0.0625 cm -1 (unapodised) whose emission spectra reveal the detailed
signatures of aerosols and reactive trace gases well into the stratosphere. We highlight the increased
sensitivity of MIPAS to such aerosols (up to 1x10 -5 km -1 at 12 µm) using a particle detection scheme that
successfully identifies wildfire and volcanically influenced MIPAS measurements by accounting for the
strong aerosol, ice and cloud absorption signals. Coincident in-house MIPAS retrievals of volatile organic
compounds (VOCs) also show evidence of significant enhancements in formic acid (HCOOH),
peroxyacetyl nitrate (PAN) and acetylene (C2H2) over wildfire regions.
In particular, we will present two case studies; the Australian Black Saturday bushfires of February 2009
and the Sarychev Peak volcanic eruptions of June 2009 to exemplify a) what MIPAS can reveal about
stratospheric injections in particle and gas composition effects; b) whether we can distinguish fire events
from volcanic events with MIPAS and c) what MIPAS can achieve with its vertical resolution and what are
the implications for future requirements of such instruments.
Observing Air Quality Degradation by Major Aerosols Outbreaks and
Tropospheric Ozone Using IASI Infrared Sensor
Cuesta, Juan 1 ; Eremenko, Maxim 1 ; Dufour, Gaëlle 1 ; Hoepfner, Michael 2 ; Orphal, Johannes 2
1 LISA / UPEC - IPSL, FRANCE; 2 IMK / KIT, FRANCE
Both tropospheric ozone and aerosols significantly affect air quality in megacities during pollution events.
Moreover, living conditions may be seriously aggravated when such agglomerations are affected by
wildfires (e.g. Russian fires over Moscow in 2010), which produce smoke and pollutant precursors, or
even during dense desert dust outbreaks (e.g. recurrently over Beijing or Cairo). Moreover, since
aerosols diffuse and absorb solar radiation, they have a direct impact on the photochemical production of
tropospheric ozone. These interactions during extreme events of high aerosol loads are nowadays poorly
known, even though they may significantly affect the tropospheric photochemical equilibrium. In order to
address these issues, we have developed a new retrieval technique to jointly characterize the 3D
distribution of both tropospheric ozone and coarse aerosols, using spaceborne observations of the
infrared spectrometer IASI onboard MetOp-A satellite. Our methodology is based on the inversion of
Earth radiance spectra in the atmospheric window from 8 to 12 μm measured by IASI and a «Tikhonov-
Philipps»-type regularisation with constraints varying in altitude (as in [Eremenko et al., 2008, GRL;
Dufour et al., 2010 ACP]) to simultaneously retrieve ozone profiles and aerosol optical depths at 10 μm
and aerosol layer effective heights. Such joint retrieval prevents biases in the ozone profile retrieval
during high aerosol load conditions. Aerosol retrievals using thermal infrared radiances mainly account
for desert dust and the coarse fraction of biomass burning aerosols. We use radiances from 15 microwindows
within the 8-12 μm atmospheric window, which were carefully chosen (following [Worden et al.,
2006 JGR]) for extracting the maximum information on aerosols and ozone and minimizing
contamination by other species. We use the radiative transfer code KOPRA, including line-by-line
calculations of gas absorption and single scattering for aerosols [Hoepfner et al., 2006 ACP]. As a priori
inputs, we consider climatological ozone profiles, ECMWF meteorological fields and aerosol refractive
index and size distributions based on desert dust [Hess et al., 1998 AMS] and smoke [Tsay and Stephens
1990] climatologies. We have used our joint ozone/aerosol retrieval to analyse two major events: i) the
Russian fires during the heatwave of summer 2010 in the Moscow area and ii) a desert dust outbreak
reaching Beijing in springtime 2008. We propose to present our results on these two study cases, as well
as the performance assessment of our technique.
38

The Collection 6 MODIS Aerosol Data Products
Levy, Robert 1 ; Mattoo, Shana 2 ; Remer, Lorraine 3 ; Munchak, Leigh 2
1 SSAI / NASA GSFC, UNITED STATES; 2 SSAI/NASA GSFC, UNITED STATES; 3 NASA GSFC, UNITED
STATES
The MODIS Science Team will debut their 6th collection of Atmospheric data products during 2012, which
includes updated MODIS “Dark Target” aerosol parameters over ocean and land. Collection 6 (C006)
represents the result of the five-year evaluation of the Collection 5 (C005) dataset, and includes
modifications to the algorithm, elimination of obsolete parameters and introduction of new products. In
addition to the traditional retrieval at 10 km resolution, C006 includes a parallel product at 3km
resolution – fine enough for regional and urban scale studies. The algorithms include updates for gaseous
and Rayleigh corrections, as well as improved cloud masking. Over ocean, the C006 retrieval accounts
for variable wind speed instead of assuming a global value of 6 m/s, and the logic for assigning data
Quality flags is modified to support the validity of low AOD retrieval. Thus, C006 will significantly reduce
positive bias in comparisons against surface-based sunphotometers measurements over ocean. New
C006 products include additional diagnostic parameters (wind speed, land/sea mask, pixel counts, etc),
and most helpfully, an “integer” Quality flag to help users avoid the tedious practice of decoding
encrypted packed bytes. Finally, the C006 product will provide, at 500 m resolution, the internal cloud
mask that is produced during the aerosol retrieval process. A complementary product will provide
information on how far each cloud-free pixel is from the nearest cloud. Preliminary C006-like data has
been compared and validated compared to global AERONET data. In addition to accounting for
differences in aerosol products that arise from changes in our retrieval algorithms, we also account for
potential changes in calibration of the MODIS spectral “observations” between C005 and C006.
Calibrating the MODIS sensors is a continuing task and the reprocessing of the data with a new
Collection permits adjustments and changes to the calibration. These adjustments are likely to
significantly affect the resulting aerosol products.
Improving the Synergetic Retrieval Algorithm in the Aerosol_CCI Project
Holzer-Popp, Thomas 1 ; Martynenko, Dmytro 1 ; Klüser, Lars 2 ; Kosmale, Miriam 1
1 DLR, GERMANY; 2 DLR and Augsburg University, GERMANY
Within ESA’s Climate Change Initiative project Aerosol_cci the synergetic aerosol retrieval algorithm
(SYNAER) exploiting AATSR and SCIAMACHY onboard ESA participated in the intensive algorithm
experiments and validation efforts together with seven other retrieval algorithms for AATSR, MERIS and
PARASOL. Several algorithm experiments were made to assess the impact of changing critical modules in
the retrieval algorithm. A common definition of aerosol components was agreed with all other algorithms
and implemented into SYNAER. This leads to better representation of some of the major aerosol types
(non-spherical mineral dust, coarse mode dominated sea salt, variable absorption of fine mode). The
APOLLO cloud mask implemented in SYNAER was selected as common cloud mask for all AATSR and
EMRIS retrievals. For cloud masking the size of the safety zone around clouds was shown to be
important. Furthermore, the analysis of different cloud masks showed that the discrimination of heavy
dust plumes and clouds is difficult for all of them, so that a new approach needs to be developed. The
most critical module for SYNAER is the parameterization of surface reflectances of the automatically
selected dark fields. Here, the comparison to reference data is under way. In addition to the critical
modules also filtering and post-processing were shown to be important to optimize all retrievals. A clear
anti-correlation of accuracy and coverage was found. Through the experiments the SYNAER algorithm
was improved substantially and remaining needs for further improvements were identified. First global
monthly datasets were produced and evaluated. The primary focus was on aerosol optical depth (AOD) at
550 nm. Further information content of SYNAER was theoretically proven for variables on aerosol type, if
the AOD is above 0.15. SYNAER provides thus AOD550 distributed to the four components defining the
atmospheric aerosol loading. The results achieved were compared to climatologic model (AEROCOM) and
ground (AERONET) information. SYNAER provides also a pixel level uncertainty value estimated with a
parameterized approach. This approach was extended to cover the most critical retrieval modules. The
paper will show new global SYNAER results achieved within the experiments and demonstrate the
progress made through the collaborative efforts of the entire Aerosol_cci team. Comparison to other
retrieval products (AATSR, PARASOL, MODIS, MISR) and external data (AEROCOM, MACC) will be made.
39

The Complex Content of Stratospheric Aerosols Better Determined by Balloon-
Borne and Satellite Instruments
Renard, Jean-Baptiste 1 ; Jégou, F. 1 ; Berthet, Gwenaël 1 ; Bourgeois, Quentin 2 ; Krysztofiak, Gisèle 1 ;
Catoire, Valéry 1 ; Robert, Claude 1 ; Gaubicher, Bertrand 1 ; Brogniez, Colette 3 ; Della Corte, Vincenzo 4
1 Université d'Orléans, FRANCE; 2 Ecole Polytechnique Fédérale de Lausanne, FRANCE; 3 Laboratoire
d’Optique Atmospheric, FRANCE; 4 University of Partenope, ITALY
Recent works has showed that the stratospheric aerosol content is complex. The lower stratosphere is
frequently refilled by volcanic liquid aerosols. In particular, in June 2009, the Sarychev volcano located in
the Kuril Islands to the northeast of Japan erupted explosively, injected an estimated 1.2 Tg of sulfur
dioxide into the upper troposphere and lower stratosphere. This eruption is one of the 10 largest
stratospheric injections in the last 50 years. Solid particles are present in the whole stratosphere. These
particles seem to be mainly soot, coming from biomass burning but also from the recondensation of
meteoritic disintegrated particles (smokes particles). Finally, some large-size solid aerosols (up to tens of
ƒÝm), coming from meteoritic disintegrations but also from interplanetary medium, are present at all
altitudes. Recently, the stratospheric aerosols have been intensively studded by various kinds of
instruments. The balloon-borne instruments here considered are: the in situ counter STAC, the in situ
infra spectrometer SPIRALE (for chemistry measurements), the MicroRADIBAL radiometer, the DUSTER
aerosols collector; and the satellites instruments are: GOMOS, CALIPSO, OMI, OSIRIS, MAESTRO, IASI.
For liquid aerosols, extensive in-situ measurements in summer 2009 above Kiruna, northern Sweden,
correlated with satellite observations, have allowed us to well document the Sarychev volcano event, and
to evaluate the chemistry-aerosol interactions from aerosol precursors to chemical active species via
heterogeneous reactions. Simultaneous observations of chemical species and aerosols have showed the
perfect anti-correlation between aerosol and NO2 contents. For solid aerosols, remote-sensing balloonborne
measurements have indicated that soot could be the main population of aerosols in the middle
stratosphere. The in situ measurements at various period of the year and at different latitudes has show
the presence of a transient aerosol layer above 30 km, and has confirmed the presence of solid particles
having a large size-range distribution. These detections seem to be confirmed after a re-analysis of the
GOMOS extinction measurements. Finally, an improved version of the STAC counter has showed that the
(solid) aerosols are electrically charged. We will present a synthesis of all these measurements to better
document the complexity of the stratospheric aerosol content. A new strategy of measurements will be
presented, including the future campaigns measurements involving the new light aerosols counter LOAC
Analysis of GOSAT High Spectral Resolution O2 A-Band Measurements
Vieitez, Ofelia; de Haan, Johan; Sanders, Bram; Stammes, Pieter
KNMI, NETHERLANDS
The oxygen absorption band at 760 nm (the O2 A-band) is potentially useful for determining the height
of atmospheric scatterers (clouds and aerosols) from passive remote sensing. The reason is that O2 has
a well-known atmospheric profile, so the depth of the O2 A-band is proportional to the light path in the
atmosphere. In the past 17 years, the European satellite spectrometers GOME on ERS-2, SCIAMACHY on
Envisat and GOME-2 on Metop, all have provided measurements of the O2 A-band at a spectral
resolution of 0.3-0.4 nm. These data have successfully being used for cloud height retrieval purposes.
For aerosol height retrieval, it has been stated that higher spectral resolution would be advantageous,
because of the relatively small optical thickness of aerosols as compared to that of clouds. Therefore, we
have analysed O2 A-band data from the Japanese GOSAT satellite to study its usefulness for aerosol
profile retrieval purposes. GOSAT, launched by JAXA in January 2009, has a Fourier Transform
Spectrometer (FTS) onboard. The spectral resolution in the O2 A-band channel is 0.015 nm, which is
much higher than that of GOME(-2) and SCIAMACHY. We will present results of the analysis, regarding
the information content of the O2 A-band measurements of GOSAT, its noise characteristics, and its
capability for aerosol height retrievals.
40

Satellite Observation of the Daily Variation of Thin Cirrus
Mannstein, Hermann; Kox, Stephan
Deutsches Zentrum für Luft- und Raumfahrt (DLR), GERMANY
Cirrus clouds have a substantial impact on the radiation budget of the earth and therefore on climate.
However, their representation in climate prediction models is still suffering from a lack of validation data.
For a better understanding, especially of thin cirrus clouds, the Cloud-Aerosol LIDAR and Infrared
Pathfinder Satellite Observations (CALIPSO) mission was launched in April 2006 providing global
observations of aerosols and clouds with its Cloud-Aerosol LIDAR with Orthogonal Polarization (CALIOP).
Because of the sparse sampling of a nadir looking LIDAR on a polar orbiting satellite the usefulness of
this excellent sensor for process studies is limited. In this work the results of the COCS algorithm (Cloud
Optical properties derived from CALIOP and SEVIRI during day and night time) are discussed and
validated. The COCS algorithm, based on an Artificial Neural Network, calculates optical and physical
properties of cirrus clouds (e.g. ice optical thickness, cloud top altitude) based on the brightness
temperatures measured by SEVIRI onboard of the operational geostationary satellites of the METEOSAT
series. This Neural Network was trained on a basis of two years temporally and geographically collocated
data of CALIOP and SEVIRI. Hence the algorithm combines the advantages of CALIOP (high vertical and
spatial resolution) and SEVIRI (high temporal resolution, covering an area from around 80°S to 80°N and
80° W to 80° E), which allow for studies of the lifecycle, diurnal cycles and seasonal variations of cirrus
properties and cirrus coverage. We present analyses of the diurnal variation of cirrus coverage and
optical depth for selected regions like the South Atlantic and, North Atlantic region, and continental
regions over Africa and Europe.
Long-Term Satellite-Based Cloud Property Datasets Derived Within the
EUMETSAT Satellite Application Facility on Climate Monitoring
Hollmann, Rainer 1 ; Kaspar, Frank 1 ; Stengel, Martin 1 ; Karlsson, Karl-Goran 2 ; Lockhoff, Maarit 1 ; Meirink,
Jan Fokke 3
1 Deutscher Wetterdienst, GERMANY; 2 SMHI, SWEDEN; 3 KNMI, NETHERLANDS
The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) uses space-based
observations from both geostationary satellites (Meteosat Second Generation, MSG) and polar orbiting
satellites (NOAA, MetOp, DMSP) to provide data sets of geophysical parameters suitable for climate
analysis and monitoring
A substantial part of this initiative is related to clouds and corresponding satellite-derived parameters,
such as cloud fractional coverage, cloud top, cloud optical depth, effective radius, cloud phase, and cloud
water path. Due to recurring efforts of incorporating revised retrieval schemes and new information
about radiance inter-calibration and homogenization, the processing system is periodically maintained
and updated.
Recently, the CM SAF cloud datasets were re-processed using the latest retrieval developments and
homogenized radiances. They span time periods of 28 years for AVHRR GAC, and 6 years for SEVIRI,
respectively. The latter with very high temporal resolution. Besides other existing datasets, e.g. Patmos-
X, ISCCP, and MODIS-, microwave- and IR-sounder-based cloud climatologies, the CM SAF datasets of
cloud properties complement the international effort of analysing and understanding clouds and their
spatiotemporal variations and long-term variability. The CM SAF datasets allow for investigations of
process studies and the general long-term cloud analysis with respect to the time period covered. The
reprocessed and homogenized data will support the assessment of possible occurring global or regional
trends, and of cyclic variations of cloud parameters at different time scales. Among other applications,
these data sets are therefore a proper reference to assess the quality of global climate simulations.
This presentation will give an overview over the cloud products and corresponding datasets, as processed
by the CM SAF. Validation results and examples of applications will be shown. Further, we will give an
outlook on future CM SAF activities which will additionally focus on the generation of cloud properties
derived from TOVS and ATOVS, and derived from multiple generations of geostationary instruments.
41

Analysis of Global Time Series of Cloud Properties from GOME/GOME-2
Spectrometers
Lelli, Luca; Kokhanovsky, A.; Rozanov, V.; Vountas, M.; Burrows, J.P.
University Bremen, GERMANY
Global long term observations of Earth atmospheric components are needed for the study of climate
processes. Among all constituents, clouds play a prominent role also in the assessment of radiation
budget and hydrological cycle. Moreover, potential trends in cloudiness can support models and
forecasting. In order to achieve accurate and homogeneous time series, we analyse global retrievals of
cloud properties (top height, optical thickness and albedo) derived from hyper-spectral measurements of
the GOME sensor family. The retrievals are obtained from top-of-atmosphere backscattered solar light in
the oxygen A-band using the Semi-Analytical CloUd Retrieval Algorithm SACURA. The physical framework
relies on the asymptotic equations of radiative transfer. Moreover, analysis of global and regional
distributions can give insight into both natural and anthropogenic signatures of large scale climate
perturbations.
Interpretation of FRESCO Cloud Retrievals in Case of Absorbing Aerosol Events
Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; Stammes, P.
Royal Netherlands Meteorological Institute (KNMI), NETHERLANDS
The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs
reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud
fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the
FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud
information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading,
aerosols may have a dominant effect, especially for almost cloud-free scenes. We have analysed FRESCO
cloud data and Absorbing Aerosol Index (AAI) data from the Global Ozone Monitoring Experiment
(GOME-2) instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as
volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated
with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressures contain
information on aerosol layer pressure. For cloud-free scenes, the derived FRESCO cloud pressures are
close to those of the aerosol layer for optically thick aerosols. For cloudy scenes, if the strongly absorbing
aerosols are located above the clouds, then the retrieved FRESCO cloud pressures may represent the
height of the aerosol layer rather than the height of the clouds. Combining FRESCO cloud data and AAI,
an estimate for the aerosol layer pressure can be given, which can be beneficial for aviation safety and
operations in case of e.g. volcanic ash plumes.
42

Day 5, Friday 22 June 2012
43

GMES Services/Data Assimilation
MACC-II Analyses and Forecasts of Atmospheric Composition and European Air
Quality: a Synthesis of Observations and Models
Engelen, Richard; Peuch, Vincent-Henri
ECMWF, UNITED KINGDOM
The Monitoring Atmospheric Composition and Climate – Interim Implementation (MACC-II) project is
the current pre-operational atmospheric service of the European GMES programme. MACC-II provides
data records on atmospheric composition for recent years, data for monitoring present conditions and
forecasts of the distribution of key constituents for a few days ahead. MACC-II combines state-of-the-art
atmospheric modelling with Earth observation data to provide information services covering European Air
Quality, Global Atmospheric Composition, Climate, and UV and Solar Energy. MACC-II uses a wide array
of satellite and in-situ data, observing both meteorological and atmospheric composition variables, to
provide a best estimate of the current state of the atmosphere on a daily basis. These analyses are then
used as initial conditions for 5-day global forecasts of atmospheric composition and 4-day European air
quality forecasts. The transformation of a wide array of observational data streams into a comprehensive
monitoring and forecasting capability provides a key element of the full GMES service line. This
presentation will provide an overview of the MACC-II pre-operational monitoring/forecasting system
focusing on the use of current and future satellite data. Both geostationary and low Earth orbit satellite
systems provide input data to constrain the global and European models in MACC-II and we will illustrate
the use of these data with various examples. The presentation will end with an outlook on the use of the
new generation of operational Sentinel satellites. The authors wish to acknowledge the rest of the MACC-
II consortium for all their contributions to the project.
Take a Deep Breath with GMES Downstream Services for Air Quality
Erbertseder, Thilo 1 ; Timmermans, Renske 2 ; Bernonville, Séverine 1 ; Lesne, Olivia 3 ; Sofiev, Mikhail 4 ;
Holzer-Popp, Thomas 1 ; McHugh, Christine 5 ; Blyth, Lisa 6 ; de Rudder, Anne 7 ; Yardley, Rachel 8
1 DLR, GERMANY; 2 TNO, NETHERLANDS; 3 ACRI-ST, FRANCE; 4 FMI, FINLAND; 5 CERC, UNITED KINGDOM;
6 VITO, BELGIUM; 7 IASB, BELGIUM; 8 AEA, UNITED KINGDOM
In the context of Europe's GMES Monitoring system for Environment and Security, PASODOBLE seeks to
provide information and support for the regional and local air quality sectors. Currently PASODOBLE is
developing and demonstrating user-driven services by combining space-based and in-situ data with
models in different thematic service lines. Complementary to MACC, a portfolio of about 30 Myair
services in 17 countries is being developed and evaluated by institutional users (http://www.myaireu.org
).
Results will be presented on health community support services, forecasting and public information
services for regions, cities, the tourist industry and sporting event organizers, compliance monitoring
support services on particulate matter and local forecast model evaluation support.
The developments contribute to establishing satellite-based data as a complementary source of
information on air pollutant levels to in-situ data. Space-borne observations of particulate matter, for
example, are applied to support regional agencies with Air Quality Directive compliance duties. These
services are focussing on different customer needs with regard to annual exceedance monitoring of
particulate matter, understanding of possible natural sources of pollutants and spatial forecasting of
possible exceedances.
By developing a generic and modular service infrastructure, including quality management, PASODOBLE
stimulates the development of quality-assured air quality services and increases the implementation
efficiency for new services in the future addressing new regions, new cities or additional service
providers. The project will aim at integrating and promoting best practice tools for local air quality
services and works towards a harmonized European framework for sustainable services.
44

Satellite-Based Particulate Matter Annual Compliance Monitoring for Northern
Italy: A PASODOBLE Downstream Sub-Service
Cacciari, Alessandra; Di Nicolantonio, Walter
Compagnia Generale per lo Spazio, CGS-OHB SpA, ITALY
The increasing capabilities of Earth Observation satellite in remote sensing retrieval of anthropogenic and
natural aerosols could in fact provide very useful information for improving the estimates of Particulate
Matter (PM) concentration spatial distribution and transport and, thus, estimating population exposure to
aerosols. The importance of these evaluations is linked to the extensive impacts of aerosols on our
climate and, in particular, to the negative effects of anthropogenic aerosol on human health mainly due
to the exposure to fine particulate matter to respiratory problems and cardiovascular and lung diseases.
The European Commission (EC) Directive 2008/50/EC on ambient air quality and cleaner air for Europe,
entered into force on June 2008 and acknowledged by Italian government on August 2010 (DL
155/2010), merges most of existing legislation into a single directive and sets new air quality objectives
for PM2.5 including the limit values and exposure.
In this work, the developments and findings carried out in the satellite-based PM annual compliance
monitoring for Northern Italy sub-service will be reported. This sub-service is part of the GMES -
PASODOBLE Compliance Monitoring Support Downstream Service line.
Satellite remote sensing can allow estimates of air pollutants concentration, characterized by a more
homogeneous spatial distribution and with a more complete coverage of the domain of interest with
respect to those carried out by sparse in-situ samplings.
In particular, this downstream sub-service aims at monitoring the levels of near-surface PM, both PM2.5
and PM10, making use of satellite aerosol observations – i.e. MODIS on board Terra and Aqua platforms
– and meteorological initial and boundary conditions from MACC core service. The data fusion algorithm
allowing to estimate concentration is based on the experience developed in PROMOTE-ESA and QUITSAT-
ASI projects.
Daily maps of concentration of PM2.5 and PM10 at least at the spatial resolution of 10×10 km2 over the
Northern Italy domain are obtained for the whole 2004 – 2010 period. Then, monthly, seasonal, and
annual averaged maps are calculated for the whole domain in order to investigate the spatial patterns of
PM concentrations in this highly polluted area.
Furthermore, for exploring the possibility of a satellite-based monitoring of PM concentration threshold
exceedings also in areas where ground-based measurement sites are not present, relative percentile
maps of exceedances over critical thresholds will be calculated and critically discussed.
Daily Emission Estimates in China Constrained by Satellite Observations
Mijling, Bas; van der A, Ronald
KNMI, NETHERLANDS
Emission inventories of air pollutants are crucial information for policy makers and form important input
data for air quality models. Unfortunately, bottom-up emission inventories, compiled from large
quantities of statistical data, are easily outdated for emerging economies such as China, where rapid
economic growth change emissions accordingly. Top-down emission estimates from satellite observations
of air constituents have important advantages of being spatial consistent, having high temporal
resolution, and enabling updates shortly after the satellite date becomes available. However, constraining
emissions from observations of concentrations is computationally challenging.
We present a new algorithm, DECSO (Daily Emission estimates Constrained by Satellite Observations),
specifically designed for fast daily emission estimates of short-lived atmospheric species on a mesoscopic
scale (~25x25 km2) from satellite observations of column concentrations. The algorithm needs one
forward model run from a chemical transport model to calculate the sensitivity of concentration to
emission, using trajectory analysis to account for transport away from the source. By using a Kalman
filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We
apply the algorithm for NOx emission estimates of East China, using the CHIMERE model on a 0.25
degree resolution together with tropospheric NO2 column retrievals of the OMI and GOME-2 satellite
instruments.
Closed loop tests show that the algorithm assumptions enabling a fast emission estimate are acceptable.
Daily emission analysis errors are 25%-40%, depending on the instrument and the algorithm settings. A
monthly emission time series reveal important emission trends in China, such as the emission reduction
measures during the Olympic Games 2008, and the economic downfall and recovery afterwards. The
algorithm is able to detect emerging sources (e.g. new power plants) and improve emission information
for areas where proxy data are not or badly known (e.g. shipping emissions). A better correlation
45

etween observations and simulations based on the updated emission inventory facilitates improved air
quality forecasts. The algorithm will be used within the ESA GlobEmission project.
CO Seasonal Variability and Trend Over Paris Megacity Using Ground-Based
QualAir FTS and Satellite IASI-MetOp Measurements
TE, Yao 1 ; JESECK, Pascal 1 ; HADJI-LAZARO, Juliette 2
1 LPMAA, FRANCE; 2 LATMOS, FRANCE
In a growing world with more than 7 billion inhabitants and big emerging countries such as China, Brazil
and India, emissions of anthropogenic pollutants are increasing continuously. Monitoring and control of
atmospheric pollutants in megacities have become a major challenge for scientists and public health
authorities in environmental research area. The QualAir platform at University Pierre et Marie Curie
(UPMC), is an innovating experimental research platform dedicated to survey urban atmospheric
pollution and air quality. As one of the major instruments of the QualAir platform, the ground-based
Fourier transform spectrometer (QualAir FTS, IFS 125HR model) analyses the composition of the urban
atmosphere of Paris, which is the third European megacity. The continuous monitoring of atmospheric
pollutants is essential to improve the understanding of urban air pollution processes. Associated with a
sun-tracker, the QualAir remote sensing FTS operates in solar infrared absorption and enables to monitor
many trace gases, and to follow up their variability in the Ile-de-France region. A description of the
QualAir FTS will be given. Concentrations of atmospheric pollutants are retrieved by the radiative transfer
model PROFFIT. Located in the centre of Paris, the QualAir FTS can provide new and complementary
urban measurements as compared to unpolluted ground-based stations of existing networks (NDACC and
TCCON). Ground-based remote sensing measurements from QualAir FTS will be compared to ground insitu
and satellite data like IASI-MetOp (Infrared Atmospheric Sounding Interferometer, a high resolution,
nadir viewing Fourier Transform Spectrometer working in the thermal infrared range extending from 645
to 2760 cm-1 (with no gaps) and flying on a polar orbit on the METOP-A platform since 5 years).
Seasonal variability and trend of carbon monoxide over Paris will be presented.
Exploiting Sentinel 5's Synergy with IRS and 3MI on METOP-SG for Protocol
Monitoring and Air Quality-Climate Interaction
Levelt, Pieternel 1 ; Veefkind, Pepijn 1 ; van Weele, Michiel 2 ; Aben, Ilse 3 ; Clerbaux, Cathy 4 ; Phulpin, Thierry 5
1 2 3 4
KNMI and TUD, NETHERLANDS; KNMI, NETHERLANDS; SRON, NETHERLANDS; LATMOS/IPSL and
CNRS/INSU, FRANCE; 5 CNES, FRANCE
Last Year's unprecedented low ozone episode in the Arctic (March 2011) made again clear that it is
important to continue to monitor the ozone layer in support of the Montreal Protocol. Although scientists
showed that the developments at the Arctic could be fully understood and explained by the same
heterogeneous chemistry as is used for the SP hole (G. Manney et al., Nature, 2011) , an ozone
destruction of that order was not seen before at the NP. Continuation of monitoring the Ozone Layer in
order to detect the expected recovery of the ozone layer is therefore of paramount importance. Both S5-
Precursor (S5P)/TROPOMI as well as Sentinel5 will play a crucial role in that monitoring capacity.
A new capacity of sentinel 5 will be synergistic use of data and synergistic retrievals from Sentinel 5, the
IRS instrument and 3MI, all mounted on the same METOP-SG platform. Combination of CO, O3 and CH4
measurements of the Sentinel 5 and IRS instrument will enable distinction of lower tropospheric, PBL
related, concentrations from free tropospheric amounts. These combined retrievals will largely benefit
from the fact that the same air mass is sensed at the same time. Synergistic analyses of the aerosol
measurements of 3MI and the AQ pollutants measured by Sentinel 5 and IRS will for the first time
provide a co-located and synergistic data base that can be used for studying secondary aerosol
formation. Secondary aerosol formation is the largest unknown contribution to the total aerosol load of
the atmosphere, which is in turn the largest unknown factor in the anthropogenic climate forcing.
Moreover, these co-located trace gas and aerosol measurements are essential for further understanding
of the relation between climate change and air quality (Shindell, Science, 2009). 3MI will be the only
instrument in that timeframe with the needed detailed aerosol detection capacity for this type of
analyses.
The presentation will elaborate on the importance of the monitoring capacity of Sentinel 5 and S5P, and
the new insights the synergistic use of the data sets of Sentinel 5, IRS and 3MI will provide for air quality
and climate change.
46

Simultaneous Assimilation of OMI, TES, MOPITT, MLS Satellite Data for the
Analysis of Global Tropospheric Composition
Miyazaki, Kazuyuki 1 ; Eskes, Henk 1 ; Sudo, Kengo 2
1 Royal Netherlands Meteorological Institute, NETHERLANDS; 2 Nagoya University, JAPAN
We have developed an advanced data assimilation system to combine chemical composition information
obtained from multiple satellite data sets and to reproduce global composition distributions in the
troposphere. NO2, O3, CO, and HNO3 data obtained from OMI, TES, MOPITT, and MLS satellite
measurements are assimilated into the global CTM CHASER during the years 2006-2007 based on the
ensemble Kalman filter approach. The data assimilation provides multiple constraints on tropospheric
compositions and allows us to simultaneously optimizing atmospheric distributions and the emissions of
ozone and its precursors while taking their chemical feedbacks into account. Especially, carbon monoxide
(CO) and nitrogen oxides (NOx) play an important role in tropospheric chemistry through their influences
on the ozone and hydroxyl radical (OH). The simultaneous optimization of these species is expected to
improve both the emission inversion and the concentration through the better description of the chemical
feedbacks in the NOx- and CO-chemistry. The performance of the data assimilation system is evaluated
against independent data from ozone sondes, aircraft measurements during the INTEX-B campaign,
GOME-2, and SCIAMACHY satellite data. The comparison confirms significant improvements by the data
assimilation. For instance, the increase in tropospheric NO2 columns over industrial areas shows much
better agreement with independent data, whereas the negative model ozone bias in the tropical
middle/upper troposphere has been mostly removed by the data assimilation. The chi square diagnostics
and the observation-minus-forecast (OmF) statistics analysis also confirm that the data assimilation
system is properly set up. In comparison to the a priori emissions based on bottom-up inventories, the
optimized emissions of both NOx and CO are higher over most industrial areas especially in the northern
mid-latitudes, suggesting that the anthropogenic emissions are underestimated in the inventories. The
assimilation also increases the surface emissions over several biomass regions (e.g., central Africa) and
lightning NOx sources in the tropical upper troposphere, suggesting that the lightning source predicted
from the model parameterization is underestimated in the tropical upper troposphere. Observing System
Experiments (OSEs) have been conducted to quantify the relative importance of each data set in
constraining the emissions and concentrations. In summary, the combined analysis of multiple data sets
by means of advanced data assimilation system can provide a useful framework for air quality research.
Expected Level 2 Performance of Sentinel 4 UVN and the Impact of Scene
Inhomogeneity
Bovensmann, Heinrich 1 ; Noel, S. 1 ; Bramstedt, K. 1 ; Burrows, J.P. 1 ; Siddans, R. 2 ; Standfuss, C. 3 ; Dufour,
E. 3 ; Veihelmann, B. 4
1 2 3
University of Bremen, GERMANY; Rutherford Appleton Laboratories, UNITED KINGDOM; Noveltis,
FRANCE; 4 ESA ESTEC, NETHERLANDS
The Sentinel 4 UVN instrument is an UV-VIS-NIR spectrometer and part of the geostationary Meteosat
Third Generation (MTG) satellite to be launched in 2019. It builds on the GOME and SCIAMACHY heritage
and the GeoSCIA and GeoTROPE concepts developed between 1997 and 2004. UVN is designed to
measure total and tropospheric columns of several atmospheric constituents relevant in the context of air
pollution, especially O3, NO2, SO2 and HCHO. Furthermore, aerosol information shall be obtained from
high resolution measurements in the Oxygen A-band. During the last years the instrument performance
was consolidated; within an ESA funded activity the impact of instrument performance on the expected
Level 2 quality is currently under assessment. A special area of concern is the impact of scene
inhomogeneity (inhomogeneous slit filling) on Level 2 product quality and potential mitigation options.
This paper will present results on the quantification of this effect and will summarise findings on how to
mitigate the impact of inhomogeneous slit illumination on Level 2 data products derived from
measurements of the Sentinel-4 UVN imaging spectrometer. Furthermore, the paper will present an
updated assessment of the expected Level 2 data quality.
47

TROPOMI on the Sentinel-5 Precursor: the Next Generation Shortwave
Atmospheric Composition Spectrometer
Veefkind, Pepijn 1 ; Aben, Ilse 2 ; Levelt, Pieternel 1
1 Royal Netherlands Meteorological Institute (KNMI), NETHERLANDS; 2 SRON, NETHERLANDS
TROPOMI is a nadir viewing shortwave spectrometer to measure the tropospheric composition for climate
and air quality applications. The TROPOMI instrument, an initiative from the Netherlands and jointly
developed with ESA, will be launched in 2015 as a single payload on the Sentinel 5 Precursor mission.
This mission is a major step forward from the current OMI on NASA EOS Aura and SCIAMACHY on
Envisat. The primary data products of TROPOMI are NO2, carbon monoxide, tropospheric ozone column,
methane and aerosols. In addition, ozone profiles, total ozone, formaldehyde, glyoxal, BrO, and cloud
parameters will be derived. Together, this forms a set of key species for air quality and climate
applications. These applications will include forecasting of the air quality, improving emissions
inventories, and monitoring of the atmospheric composition. TROPOMI will measure the UV-visible
wavelength range from (270-500 nm), the near infrared (675-775 nm) and the shortwave infrared
(2314-2382 nm). In the UV-visible and near infrared the spectral resolution is 0.5 nm, except for the
wavelengths below 308 nm, where the spectral resolution is 1.0 nm. In the shortwave infrared the
spectral resolution is 0.25 nm. TROPOMI will have an unprecedented spatial resolution of about 7x7 km 2
at nadir. The spatial resolution is combined with a wide swath to allow for daily global coverage. The high
spatial resolution serves two goals: (1) emissions sources can be detected with more accuracy and (2)
the number of cloud-free ground pixels will increase substantially. The latter is especially important for
TROPOMI data products that are very sensitive for cloud contamination, such as the methane product. In
addition to an improved spatial resolution, also the signal-to-noise of TROPOMI will be improved as
compared to OMI and SCIAMACHY. The Sentinel 5 Precursor will be launched into a Sun-synchronous
early afternoon orbit. Thus, the TROPOMI data can be used together with the GOME-2 measurements in
the morning to detect diurnal variations. This has already been demonstrated for NO2 using OMI and
SCIAMACHY observations. Over Europe, the diurnal variations will be observed by the geostationary
Sentinel 4 mission after 2018. It is planned to fly the Sentinel 5 Precursor within 5 minutes of the
NPP/JPSS missions. The high spatial resolution imagery of the VIIRS instrument onboard of these
missions can be used for additional information on clouds and aerosols, which is especially important for
the methane, but can also improve the quality of several other data products.
Sentinel 5 Precursor: Planned German and Belgian Contribution to the
Operational L2 Products
Loyola, Diego. 1 ; Van Roozendael, M. 2 ; Richter, A. 3 ; Wagner, T. 4 ; Valks, P. 5 ; Hao, N. 5 ; Zimmer, W. 5 ;
Grossi, M. 5 ; Lerot, C. 2 ; De Smedt, I. 2 ; Theys, N. 2 ; Burrows, J. 3 ; Bovensmann, H. 3 ; Wittrock, F. 3 ; Weber,
M. 3 ; Kokhanovsky, A. 3
1 German Aerospace Center (DLR), GERMANY; 2 Belgian Institute for Space Aeronomy, BELGIUM; 3 Institut
für Umweltphysik, Universität Bremen, GERMANY; 4 Max-Planck-Institut for Chemistry, GERMANY;
5 Deutsches Zentrum für Luft- und Raumfahrt, GERMANY
The ESA Sentinel 5 Precursor (S5P) Mission will provide atmospheric composition products during the
time frame from 2015 to 2022 extending the data record initiated with GOME/ERS-2 and continued with
the SCIAMACHY/ENVISAT, OMI/AURA and GOME-2/MetOp missions. S5P will be the first GMES mission
dedicated to the atmosphere monitoring.
The S5P satellite will embark a single instrument called TROPOMI (TROPOspheric Monitoring Instrument)
that will provide global nadir viewing observations covering the ultra-violet (UV), visible (VIS), nearinfrared
(NIR), and shortwave infrared (SWIR) spectral regions.
The development of the operational S5P Level 2 processors will be jointly performed by a number of
institutes from the Netherlands, Germany, Belgium and the UK following a share of responsibilities
scheme agreed with ESA in June 2011.
In this article we will present the plans for the operational L2 products to be developed by German and
Belgian partners: ozone total and tropospheric column, sulfur dioxide, formaldehyde, cloud information
and optionally water vapour and glyoxal. The state-of-the-art and lessons learned from the
corresponding operational and scientific products from GOME, SCIAMACHY and GOME-2 will be discussed
in detail.
48

POSTER SESSION
49

Atmospheric Sentinels
GOME-2 In-Orbit Degradation and its Impact on Level 2 Data (BrO, O3, HCHO,
NO2, H2O)
Dikty, Sebastian 1 ; Richter, Andreas 1 ; Lang, Rüdiger 2 ; Munro, Rose 2 ; Noel, Stefan 1 ; Weber, Mark 1 ;
Wittrock, Folkard 1 ; Bovensmann, Heinrich 1 ; Burrows, John P. 1
1 University of Bremen, GERMANY; 2 Eumetsat, GERMANY
GOME-2 is a nadir viewing four-channel spectrometer (UV/vis) with a scan-width of 1920 km launched
on MetOp-A in October 2006. It delivers data routinely since January 2007. Its mission is to extend longterm
records of atmospheric trace gas constituents measured by GOME (Oct 1995-today, global coverage
lost in 2003) and SCIAMACHY (Aug 2002-today). The aging of optical components and/or the
introduction of polluting substances is known to let a spectrometer degrade, i.e. the amount of light
reaching the detector decreases (throughput loss). Measured and calibrated earthshine- and sun-spectra
(level 1 data) are being used to retrieve (DOAS approach) information about the amount of trace gases
(level 2 data) in the Earth’s atmosphere. The overall aim of this paper is to provide input on the following
questions. To tackle these questions, different approaches have been selected and have been tested on
selected data sets. 1. What is the effect of GOME-2 degradation on the accuracy (absolute values) of
level 2 products? 2. What is the effect of GOME-2 degradation on the precision (scatter) of level 2
products? 3. Is the degradation dominated by throughput loss or are there also systematic spectral
structures linked to instrument changes or degradation related calibration deficiencies? 4. Are there
possibilities to correct for degradation effects on GOME-2 level 2 products? 5. What happened with
GOME-2 level 2 products during the 2nd throughput test, and what can we learn from these results?
Monitoring the South Atlantic Anomaly Using ATSR Instrument Series
Casadio, Stefano 1 ; Arino, Olivier 2
1 SERCO-IDEAS, ITALY; 2 ESA, FRANCE
The South Atlantic Anomaly (SAA) has been monitored for 20 years using the Along Track Scanning
Radiometer (ATSR) series of instruments onboard the ERS-1, ERS-2 and ENVISAT ESA satellites. The
time evolution of the night-time particle induced noise in the short wavelength infrared (SWIR, 1.6 ìm)
and visible (VIS, 0.55 ìm) channels of the ATSR instrument series have been analysed. The monthly
location and extension of the SAA are inferred by fitting a two-dimensional, elliptical Gaussian function to
the coordinates of the night-time hot spots detected over the SAA region. An alternative approach aiming
at the elimination of the fire signal in the 1.6 ìm channel, allows for a very accurate estimate of the SAA
drift at the cost of loosing information on the SAA area and strength. Results from both approaches will
be discussed. The location of the centre of the SAA is found to drift westwards with an average drift rate
of about 0.24 deg/yr and northward with an average drift rate of about 0.12 deg/yr. Irregularities are
found where the drift speed is inverted and the SAA moves eastward and southward. Results from
Gaussian fitting indicate that the retrieved values of SAA’s strength and extension are anti-correlated
with the solar activity expressed by the solar flux at 10.7 cm (F10.7). Finally, the peak-to-peak
amplitude of the seasonal variation of the SAA strength, estimated from monthly VIS data, is found to be
30 % of the average value with the annual to semiannual amplitude ratio of 1.38.
50

SCIAMACHY: The New Concept of Instrument Performance Monitoring.
Bramstedt, Klaus 1 ; Noël, Stefan 1 ; Liebing, Patricia 1 ; Bovensmann, Heinrich 1 ; Burrows, John P. 1 ;
Lichtenberg, Günter 2 ; Aberle, Bernd 2 ; Krijger, Matthijs 3 ; Snel, Ralph 3 ; Lerot, Christophe 4 ; Tilstra,
Gijsbert 5
1 University of Bremen, GERMANY; 2 German Aerospace Centre (DLR-IMF), GERMANY; 3 SRON Netherlands
Institute for Space Research, NETHERLANDS; 4 Belgian Institute for Space Aeronomy BIRA, BELGIUM;
5 Royal Netherlands Meteorological Institute (KNMI), NETHERLANDS
SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) is a grating
spectrometer in the UV-Vis-NIR spectral range. SCIAMACHY is part of the ENVISAT payload and since
April 2002 in a sun-synchronous orbit, observing Earth's atmosphere in nadir, limb and occultation
geometry. To ensure the SCIAMACHY data quality over the lifetime of the instrument, its performance is
continuously monitored. A new concept of describing the throughput changes over lifetime includes a
sophisticated model of the surfaces (mirrors and diffuser) and their contaminations in the scanner unit of
the instrument. Main advantage of this approach is a scan angle dependent degradation correction,
although the monitoring measurements use only one angle per light path. This new concept is currently
investigated to become the baseline for the next version of SCIAMACHY's Level 0-1b processor. We
describe briefly the new concept, its implementation, the degradation of the instrument in the new
framework and some first results on the impact on L2 products (e.g. AAI and ozone) with a limited
dataset.
Cross-Calibration of the Satellite Sensors with High Spatial Resolution Using
Spectral MERIS Data
Zege, Eleonora; Katsev, Iosif
B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, BELARUS
As known the procedure of the absolute spectral calibration of the satellite sensors places high demands
on the area of the test site (the uniformity of its surface) and on the accuracy of field measurements.
Some of the deserts sites meet these requirements, but they are practically not feasible for sites in
middle latitudes (e.g. in Belarus). In this paper we present the method of cross-calibration of the satellite
spectral sensor with high spatial resolution, which does not require any calibration site and any field
measurements, but uses well-calibrated measurements of other satellite optical instruments, possibly
operating from own platform. As known, multi-zonal systems (MZS) provide the comparatively high
spatial resolution (about a few meters), but have wide spectral channels. Vice versa multi-spectral
satellite instruments like MODIS and MERIS have a relativity poor spatial resolution (about 1 km), but
deliver data in the numerous narrow spectral channels providing information about atmosphere, which is
necessary to carry out the procedure of the atmospheric correction and retrieval the true spectra of
underlying surfaces. As example we will consider below the use of the satellite sensor MERIS as the
source of the multispectral information. The core idea of the considered cross-calibration of satellite
sensors with high spatial resolution is: 1. To find the co-located and practically simultaneous survey of
MERIS and the calibrated instrument; 2. To retrieve the spectral characteristics of the atmosphere and
underlying surface using MERIS data; 3. Using this data to compute the signals in the spectral channels
of the high spatial resolution MZS, averaging over the MERIS pixel; 4. To compare this calculated signal
with the measured MZS signal averaged over the same MERIS pixel. In this paper we will demonstrate
the results of such cross-calibration of the satellite sensors ASTER and ALOS in the spectral channels in
Visible and near IR regions using MERIS data. . In both cases two scenarios (each including 6 pixels)
were used for the cross-calibration. Each MERIS pixel includes about 5000 MZS pixels. The relative
scatter of the calibration factor was the order of 3-5%. The relative scatter of the calibration factor was
the order of 3-5%. Our results of the ASTER calibration are in the good agreement with the conclusions
based on the careful calibration using test sites performed by three research groups from USA and
Japan. It is shown that the following conditions should be ensured in the process of the cross-calibration:
• Direction of the observation is not close to the specular reflection direction; • There are no bright spots
near the edges of the pixel; • The reliable data on the ozone and water vapor in atmosphere is available.
51

SCIAMACHY Monitoring Factors: Throughput Recovery
Krijger, Matthijs 1 ; Snel, R. 1 ; Bramstedt, K. 2 ; Noël, S. 2 ; Liebing, P. 2 ; Bovensmann, H. 2 ; Burrows, J.P. 2
1 SRON Space Research, NETHERLANDS; 2 IUP Bremen, GERMANY
Almost all UV and visible wavelength remote sensing instruments in space show an ever increasing
throughput loss due to effects of the harsh space enviroment. SCIAMACHY (SCanning Imaging
Absorption spectroMeter for Atmospheric CHartographY) is one such instrument, a grating spectrometer
in the UV-Vis-NIR spectral range. SCIAMACHY flies onboard the ENVISAT payload and is since its launch
on the 28th of February 2002 sun-synchronous orbit, in descending node and having an equator crossing
time of 10:00 am observing Earth's atmosphere in various geometries. To ensure the SCIAMACHY data
quality over the life-time of the instrument, its performance is continuously monitored and shows
throughput degradation as expected. Since launch the throughput loss became as large as 80% in some
wavelengths. Yet since March 2011 SCIAMACHY started showing a throughput recovery, never seen
before in similar instruments. The recovery was as high as 10% per month at certain times. We show the
temporal evolution of the throughput recovery and its spectral behaviour. Next we describe the physical
background and most likely causes, concluding with lessons learned for future missions.
Plot of SCIAMACHY UV Throughput, note the strong recent recovery (image from http://www.iup.unibremen.de/sciamachy/mfactors/
)
Sentinel-5 Precursor Payload Data Ground Segment
Kiemle, Stephan; Knispel, Robert; Schwinger, Maximilian; Weiland, Nicolas
DLR, GERMANY
The Payload Data Ground Segment (PDGS) for the Sentinel-5 Precursor mission operating the TROPOMI
instrument is currently being developed at DLR Oberpfaffenhofen. The PDGS covers the functions of
payload data acquisition, level 0 to level 2 near real-time and offline processing, re-processing, short-
and long-term archiving, product quality and service monitoring. A major challenge in the PDGS
development is the handling of high data rates for processing, transmission and archiving, and the
integration of several different processing systems. This contribution describes the Sentinel-5 Precursor
PDGS concept and architecture, gives an overview on the system requirements and presents the current
PDGS development status. The ESA Sentinel-5 Precursor to be launched in March 2015 is an important
mission for the continuous operational remote sensing of the atmosphere filling the gap between the
ENVISAT era and the GMES Sentinel 5 mission.
The Use of Airborne Measurements for the Evaluation of Satellite Observations
Fischer, Jürgen; von Bismarck, Jonas; André, Hollstein; Lindstrot, Rasmus; Ruhtz, Thomas
Institute for Space Science, GERMANY
This abstract is intended for the EUFAR session. Jürgen Fischer, Jonas von Bismarck, André Hollstein,
Rasmus Lindstrot, Thomas Ruhtz Institute for Space Science, Free University Berlin Airborne
observations allow to investigate small scale variabilities of geophysical properties in space and time.
This helps to understand sub-pixel structures of satellite measurements and to validate retrieved satellite
products. Examples on airborne ocean color remote sensing of Baltic Sea waters with an imaging
spectrometer, on a validation of MERIS cloud-top pressure retrievals with an airborne LIDAR, and the
retrieval of aerosol properties with data from an airborne Sun and aureole photometer will be presented
and discussed. Recently the retrieval of the vertical aerosol distribution from passive spaceborne
measurements in the O2 A-band (e.g. from GOSAT), as well as from satellite LIDARs (e.g. from CALIOP
and Earthcare) have gained interest in the remote sensing community. Multi spectral sun photometer
measurements during aircraft ascents and descends provide nearly direct measurements of aerosol
vertical profiles in terms of optical thickness and extinction for validation purposes. A growing fraction of
the next generation of space borne radiance sensors (MSPI, APS, SPEX) will additionally measure
polarization and therefore allow to derive aerosol properties with a higher accuracy than possible in the
past. Multi directional and multi spectral photo polarimeters on airborne platforms (e.g. AMSSP) will
provide a necessary tool to validate products from the new sensors; and can provide the basic
measurements needed to develop future retrieval algorithms.
52

Remote Sensing of Trace Gases in the Troposphere
Cloud Parameter Retrieval in the Oxygen A-Band Using Optimal Estimation for
the High-Volume Data Stream of TROPOMI
Sneep, Maarten; de Haan, Johan F.; Veefkind, J. Pepijn
KNMI, NETHERLANDS
The TROPOspheric Monitoring Instrument (TROPOMI) nadir viewing shortwave spectrometer presents
new challenges for the retrieval of atmospheric constituents. TROPOMI will measure the UV-visible
wavelength range (270 - 500 nm), the near infrared (710 - 770 nm) and the shortwave infrared (2314 -
2382 nm). TROPOMI will have an unprecedented spatial resolution of about 7 by 7 km 2 at nadir. The
spatial resolution is combined with a wide swath to allow for daily global coverage. The high spatial
resolution serves two goals: (1) emissions sources can be detected with more accuracy and (2) the
number of cloud-free ground pixels will increase substantially.
This contribution will focus on the retrieval of cloud parameters from the O2 A-band in the near infrared
part of the spectrum. Apart from improvements to the retrieved parameters, we aim to improve the error
characterization of those parameters across the range of products that will be derived from TROPOMI
spectra. The improved error characterization will make the products easier to use in assimilation systems
and more meaningful for validation. We will use optimal estimation for the retrieval to achieve those
goals. The improved error characterization in the cloud product will allow dependent products to take the
presence of clouds into account in their own error estimates.
The high spatial resolution combined with the broad swath leads to a high data-rate of approximately
260 spectra per second on the day-side of the sun-synchronous early afternoon orbit. To retrieve trace
gas amounts down to the ground, one needs to properly address the presence of clouds within the field
of view. The TROPOMI cloud retrieval algorithm must therefore process all observations, and do so well
within the near real-time requirements to allow other algorithms (notably NO2) to arrive in time. The
combination of these factors poses a serious challenge to the retrieval system in terms of performance.
For the optimal estimation retrieval method we need a forward model to simulate a reflectance spectrum
when given a state-vector. While online radiative transfer will give the highest flexibility, it is also timeconsuming,
especially within the O2 A-band. The performance we require makes it impossible to use
online radiative transfer calculations. We therefore need to use a lookup table based approach. This
contribution will show how we intend to do this for TROPOMI, and discuss the choices we made for the
state vector and atmosphere model.
Intercomparisons of the Distribution of Tropospheric Ozone from SCIAMACHY
and Other Satellite Instruments
Ebojie, Felix; von Savigny, C.; Ladstätter-Weissenmayer, A.; Bötel, S.; Weber, M.; Alexei, R.;
Bovensmann, H.; Burrows, J.
University of Bremen, GERMANY
The limb-nadir-matching technique of the scanning imaging absorption spectrometer for atmospheric
chartography (SCIAMACHY) instrument on-board the ENVISAT satellite has been used to retrieve
tropospheric ozone. This technique is a residual approach that simply involves the subtraction of the
stratospheric ozone columns derived from the limb observations from the total ozone columns derived
from the nadir observations. This novel approach to retrieving tropospheric ozone from one spectrometer
is a state of the art technique that removes the uncertainties that may arise when comparing
measurements made by different instruments probing slightly different air masses in different
observation geometries. Tropospheric ozone has a significant adverse effect on the climate system,
especially of the troposphere. It generally has great impact in the lower, middle and upper troposphere.
In the lower troposphere, during summer, it is a major constituent of photochemical smog and excess of
it are toxic to the ecosystem, animal and man. It is equally known as a major oxidant and also involved
in the production of other oxidant such as hydroxyl (OH) radicals. In the middle and upper troposphere,
ozone acts as a greenhouse gas. A good knowledge of the distribution of tropospheric ozone production
and fluxes on regional and global scale would lead to a better understanding of how it directly affects the
climate as well as its role in atmospheric photochemistry. The tropospheric ozone columns retrieved from
SCIAMACHY compare well with some of the ozonesondes investigated at the tropics and midlatitude to
an average of 1-3 DU but at the higher latitudes the comparison shows an average of 5 - 10 DU. The
comparison on the global distribution plots with Tropospheric Emission Spectrometer (TES) and Ozone
Monitoring Instrument/Microwave Limb Sounder (OMI/MLS) show similar pollution features in some
regions on the global plots.
53

Novel Approach to Tropospheric NO2 Retrieval for TROPOMI
van Geffen, Jos; de haan, Johan; Veefkind, Pepijn
KNMI, NETHERLANDS
For the retrieval of tropospheric NO2 data from measurements of the forthcoming satellite instrument
TROPOMI (Tropospheric Monitoring Intrument, to be launched early 2015 on board of the European
GMES Sentinel-5 Precursor satellite) a new method is proposed, which improves the accuracy of the
retrieved NO2 column, and improves the handling and characterisation of retrieval uncertainties.
The current method at KNMI of tropospheric NO2 retrieval applied to data from instruments such as
SCIAMACHY, OMI and GOME-2 is called DOMINO and it has been favourably evaluated in validation
campaigns. In the DOMINO approach first an NO2 slant column is determined using DOAS (Differential
Optical Absorption Spectroscopy). Then this slant column is converted to an NO2 tropospheric column
using an AMF (air-mass factor) from pre-calculated look-up tables. The selection of the AMF is
determined by external data, notably: a fixed surface albedo (taken from a climatology), cloud cover
information (from a separate cloud retrieval) and a tropospheric NO2 vertical profile (provided by a
chemistry transport / data assimilation system, TM-4). Uncertainties in these components have a large
impact on the final NO2 column value and the associated uncertainty.
The novel approach combines an optimal estimation technique with the idea behind DOAS, by way of a
separation of the differential and the smooth absorption features in the measured spectra. The retrieval
of NO2 is a combined fit of the tropospheric NO2 column, the surface albedo and cloud cover information,
using an NO2 vertical profile provided by a chemistry transport / data assimilation system (TM-4; to be
replaced by TM-5 in the near future). Uncertainties in the quantities are accounted for in the retrieval via
the use of a covariance matrix. This enables the characterisation of uncertainties in the NO2 column in
terms of uncertainties in the surface albedo, cloud cover, and NO2 profile, and improves the accuracy of
the retrieved tropospheric NO2 column.
A sketch of the proposed retrieval scheme will be presented, as well as a study of the sensitivity of the
tropospheric NO2 column to surface albedo, cloud cover, and NO2 profile uncertainties, and the accuracy
of the retrieved NO2 column, illustrating the expected improvements of the new method.
Global Fire Emission Estimates for 2009-2010 Derived from GOME-2
Formaldehyde Columns
Bauwens, Maite 1 ; Stavrakou, Trissevgeni 1 ; Muller, Jean-Francois 1 ; De Smedt, Isabelle 1 ; Van Roozendael,
Michel 1 ; van der Werf, Guido R. 2 ; Wiedinmyer, Christine 3 ; George, Maya 4 ; Cathy, Clerbaux 4 ; Hadji-
Lazaro, Juliette 5 ; Coheur, Pierre-François 6 ; Hurtmans, Daniel 6
1 Belgian Institute for Space Aeronomy, BELGIUM; 2 Faculty of Earth and Life Sciences, Vrije Universiteit
Amsterdam, NETHERLANDS; 3 National Center for Atmospheric Research, UNITED STATES; 4 UPMC Univ.
Paris 06; Université Versailles St-Quentin, FRANCE; 5 Service d’Aéronomie, Institut Pierre-Simon Laplace,
Université Pierre et Marie Curie, FRANCE; 6 Service de Chimie Quantique et Photophysique, Université
Libre de Bruxelles, BELGIUM
To derive updated global biomass burning emission estimates for non-methane volatile organic
compounds (NMVOCs), formaldehyde columns retrieved from the Global Ozone Monitoring Experiment-2
(GOME-2) instrument (launched on MetOp-A in 2006) are used as top-down constraints in an inverse
modeling scheme. Compared to GOME-1 the use of GOME-2 formaldehyde columns are found to be less
sensitive to the South Atlantic Anomaly, offering new perspectives for the study of NMVOC emissions in
the Amazon. Furthermore, the better Earth sampling of GOME-2 allows for a significant reduction of the
noise on the monthly columns leading to a better identification of the emission sources. Furthermore,
two corrections lead to a significant reduction of the scatter in the formaldehyde slant columns: a new
retrieval scheme including a two-step fitting procedure that strongly reduces the interferences between
formaldehyde and bromine oxide spectral structures, and a modified DOAS approach adopted to better
handle the strong ozone absorption effects, improving the fit at large solar zenith angles.
The new version of the Global Fire Emissions Database version 3 (GFEDv3) is used as bottom-up
inventory in IMAGESv2 global chemistry-transport model for biomass burning. The principal updates of
the GFEDv3 inventory with respect to the older GFEDv2 inventory are the use of improved satellite input
data, the explicit inclusion of deforestation and forest degradation fires in the model, the partitioning of
fire emissions into different source categories, and an uncertainty analysis.
The agreement between formaldehyde columns calculated by the IMAGESv2 model and the
formaldehyde columns from GOME-2 is optimized using the adjoint modelling technique. This technique
allows for the optimization of the emission strengths at the model resolution and provides a
differentiation among the emission sources.
Updated biomass burning emissions estimates are obtained monthly for 2009 and 2010 at the model
resolution (2 x 2.5°). They will be evaluated through comparison with the Fire INventory from NCAR
54

(FINN) for the target years. Further, CO columns retrieved from the Infrared Atmospheric Sounding
Interferometer (IASI) abroad on MetOp-A will be compared with CO simulated columns over the fire
affected regions using the a priori and the optimized biomass burning emission inventory.
Monitoring Emission, Chemistry and Transport of Vegetation Fires from IASI
and Comparison with Simulations
R'honi, Yasmina 1 ; Clarisse, L. 1 ; Duflot, V. 1 ; Coheur, P.-F. 1 ; Clerbaux, C. 2 ; Hurtmans, D. 1 ; Ngadi, Y. 1 ;
Messina, P. 3 ; Turquety, S. 3 ; Parrington, M. 4 ; Palmer, P. 4
1 Université Libre de Bruxelles, BELGIUM; 2 UPMC, FRANCE; 3 Ecole Polytechnique, Laboratoire de
Météorologie Dynamique (LMD), Palaiseau, FRANCE; 4 School of GeoSciences, University of Edinburgh,
UNITED KINGDOM
Vegetation fires are a major source of atmospheric trace gases and aerosols. Many studies have been
conducted in the past to characterize locally the composition of biomass burning plumes and the
chemistry that takes place within the vicinity of the source. However, there are fewer analyses of the
plume chemistry during long-range transport and, as a consequence, the impact of fires on e.g. regional
air quality, remains subject to large uncertainties. Remote sounding of atmospheric composition from
satellite instruments offers the possibility to track fire plumes from the source to regions downwind,
sometimes for periods of several days. This work provides an extensive analysis of fire plume
composition, as measured by the Infrared Atmospheric Sounding Interferometer (IASI) on board the
MetOp-A satellite. Different events are considered, including the Greece fires in 2007, the bush fires of
Southern Australia in 2009, and the Russian fires in 2010. For these events, we report and compare
primary (i.e. CO, C2H2, C2H4, NH3…) and secondary (i.e. HCOOH, PAN) trace gas concentrations. Total
masses are calculated. We also derive for the different species enhancement ratios with respect to CO,
which are followed in time to infer in-plume chemistry. To support the interpretation of the data, we
provide for some events a comparison with model simulations.
Global and Local Ozone Measurments from the Thermal Infrared IASI/METOP
Sounder
Safieddine, Sarah 1 ; Clerbaux, Cathy 1 ; Hadji-Lazaro, Juliette 1 ; George, Maya 1 ; Hurtmans, Daniel 2 ;
Coheur, Pierre Francois 2
1 2
UPMC Univ. Paris 6, CNRS/INSU, LATMOS-IPSL, FRANCE; Spectroscopie de l'Atmosphère, Université
Libre de Bruxelles, BELGIUM
Global monitoring of tropospheric ozone is essential as it plays a role in much of the oxidation chemistry
and is a main greenhouse gas and air pollutant. Tropospheric as well as stratospheric ozone are highly
variable in both space and time. It is therefore necessary to perform accurate global measurements in
order to quantify the effect of tropospheric ozone on our environment, and to analyze its spatial
distribution, transport pathways, and trends. The IASI instrument launched onboard the METOP platform
in October 2006 is a nadir looking Fourier transform spectrometer that probes the Earth’s atmosphere in
the thermal infrared spectral range, with a spectral resolution of 0.5 cm-1 (apodized). IASI monitors the
atmospheric composition at any location two times per day, and measures many of the chemical
components which play a key role in the climate system and in several aspects of atmospheric pollution.
In this study, we will present global and regional maps that will show the temporal and seasonal
evolution of the tropospheric and total ozone. We will use the data retrieved from the IASI Level 1
radiance data using a near-real time retrieval algorithm (FORLI) that allows the derivation of global
distributions and profiles of ozone. We will discuss the current performances in terms of vertical
resolution and accuracy and for the first time the maps of the vertical profile of ozone during the year of
2011 will be presented.
55

NO2 VCD Retrieval from Airborne Prism EXperiment (APEX) Data Over the City
of Zurich, Switzerland
Popp, Christoph 1 ; Brunner, Dominik 1 ; Damm, Alexander 2 ; Van Roozendael, Michel 3 ; Fayt, Caroline 3 ;
Buchmann, Brigitte 1
1 Empa, Swiss Federal Laboratories for Materials Science and Technology, SWITZERLAND; 2 Remote
Sensing Laboratories, University of Zurich, SWITZERLAND; 3 Belgian Insitute for Space Aeronomy (BIRA-
IASB), BELGIUM
We present the first application of the Airborne Prism EXperiment (APEX) sensor for high resolution
remote sensing of nitrogen dioxide (NO2). APEX is an airborne dispersive pushbroom imaging
spectrometer for environmental monitoring developed in the framework of the ESA-PRODEX program.
The APEX instrument measures radiances in up to 534 narrow contiguous spectral bands in the range
between 380 and 2500 nm. The spectral sampling interval varies between 0.4 nm and 10 nm. We herein
assess the potential and capability of APEX to retrieve information on the distribution of tropospheric
NO2with high spatial resolution (a few tens of meters). In this study, we use two data sets covering
Zurich and surrounding areas, acquired on the 26 June 2010 in the morning (around 10:00 local time)
and afternoon (17:30 local time). Flight activities took place in frame of an APEX test flight campaign in
Switzerland. Maps of NO2vertical column densities (VCD) are derived with a well-known two-step
approach typically used to derive trace gas columns from satellites. Differential slant column densities
(dSCD) are first computed based on differential optical absorption spectroscopy analysis (DOAS) and the
dSCD are secondly converted to VCD by air mass factors computed with the radiative code LIDORT. First
NO2VCD maps reveal a very plausible spatial distribution with generally high NO2VCD found over the city
and lower NO2VCD found in remote areas outside of Zurich. Additionally, individual NO2sources could be
detected in unprecedented detail, e.g. increased NO2values around Zurich’s international airport and a
waste incinerator. APEX retrieved NO2 maps are also consistent with modeled NO2 surface concentrations.
Further, we found large differences between the results from the morning and afternoon overflights, i.e.
general higher NO2 VCD and higher NO2 variability in the morning than in the afternoon. These
differences can be well explained by a stronger dilution of emissions from the city due to much stronger
winds in the afternoon and increased chemical loss of NO2 caused by reaction with OH. Finally, we
compared APEX derived NO2 VCD with ground-based measurements from eight in-situ sites in the study
region. A very good correlation between the two data sets with a correlation coefficient of 0.83 is found.
It can be concluded that APEX is well capable to retrieve NO2 VCD. These first results also indicate that
APEX NO2 VCD can be used for air pollution assessments, for the identification and quantification of
emission sources, or for the investigation of small-scale NO2 variability on the relation between coarse
scale satellite observations, fine scale in-situ measurements, and (regional) air quality models. In the
meantime, additional APEX flights have been carried out or are in planning. These data will be used to
further refine and improve the APEX NO2 retrievals.
Satellite Observations of Iodine Monoxide and its Relation to Biospheric
Variables
Schoenhardt, Anja 1 ; Wittrock, Folkard 1 ; Richter, Andreas 1 ; Dinter, Tilman 2 ; Bracher, Astrid 2 ; Burrows,
John P. 1
1 University of Bremen, GERMANY; 2 University of Bremen / AWI Bremerhaven, GERMANY
Iodine and its oxides are reactive halogen compounds which affect atmospheric composition. The main
relevance of iodine species lies in the troposphere, including the boundary layer and also the free
troposphere as recent studies suggest. In the presence of iodine, processes such as catalytic ozone
destruction, a change of the HOx and NOx ratios as well as formation of fine particles may occur.
One important source pathway of iodine species is via biogenic emissions of iodine molecules and
halocarbons. Algae and phytoplankton are known to emit iodine compounds, but the overall source
characterization and importance also in comparison to other release mechanisms is not fully understood.
Investigation of iodine abundances is especially interesting above oceanic upwelling regions, where
biological productivity is large and input of biogenic compounds to the atmosphere takes place. Iodine
monoxide (IO) is an indicator of active iodine photochemistry and its column amounts are observed by
satellite instrumentation.
In order to characterize surrounding conditions connected to iodine emissions, satellite observations of
IO are compared to different kinds of biospheric variables of the ocean as well as the atmosphere.
Biogenically active areas in the ocean are associated with enhanced Chlorophyll-a (Chl-a) amounts.
Comparing maps of Chl-a to those of IO, some areas such as the Eastern Pacific upwelling regions and
coastal regions around Antarctica show a positive relation, i.e. similar spatial patterns of enhanced
amounts of IO columns in the atmosphere and Chl-a concentrations in the ocean. Above other regions,
however, no clear relation is found where IO amounts remain below the detection limit while Chl-a
concentrations are strongly enhanced. For the explanation and better understanding of IO distributions,
56

different kinds of phytoplankton species might need to be differentiated. Further information about the
biogenic input of gaseous species into the atmosphere can be obtained by the investigation of short-lived
biogenic trace gases such as formaldehyde, HCHO, or glyoxal, CHOCHO, two species which are also
observed from satellite. Source characteristics of these organic species may reveal similarities as well as
distinctions in comparison to IO distributions above ocean areas. Spatial distributions of trace gases are
always influenced by the basic release intensities and additionally by their photochemical lifetimes and
different surrounding atmospheric conditions.
Maps of the biogenic variables are compared to distributions of IO with a focus on specific ocean areas.
Satellite data sets spanning up to eight years are used. Different regions with their associated relations
between IO abundances and biospheric parameters are identified. The presented satellite investigations
shall improve the understanding of iodine distributions in the atmosphere and the surrounding conditions
connected to the presence of IO.
Tropospheric Emission Monitoring Internet Service
van der A, Ronald 1 ; Van Roozendael, Michel 2 ; De Smedt, Isabelle 2 ; de Leeuw, Gerrit 3 ; Brunner,
Dominik 4 ; Mijling, Bas 1 ; Tilstra, Gijs 1 ; Allaart, Marc 1 ; Boersma, Folkert 1
1 KNMI, NETHERLANDS; 2 BIRA-IASB, BELGIUM; 3 FMI, FINLAND; 4 EMPA, SWITZERLAND
The Tropospheric Emission Monitoring Internet Service (TEMIS), part of the Data User Programme (DUP)
of ESA, is an operational processing and archiving center for tropospheric data sets for targeted user
groups. These data sets consists of global concentrations of tropospheric NO2, tropospheric HCHO,
volcanic SO2, BrO, ozone, aerosols, CO, clouds and UV products derived from observations of nadirviewing
UV-VIS satellite instruments such as GOME, SCIAMACHY, GOME-2 and OMI. The TEMIS data
products are often made available within a few hours after observation. The data is widely used for
monitoring the ozone hole, local UV forecasts, monitoring air pollution, climate change studies and
volcanic plumes.
Spectral Signature of Plants for Satellite Remote Sensing
Tobias, Mahr 1 ; Peper, Eva 2 ; Pöhler, Denis 2 ; Platt, Ulrich 2 ; Wagner, Thomas 1
1 Max-Planck-Institute for Chemistry, GERMANY; 2 Institut für Umweltphysik, Heidelberg, GERMANY
DOAS (Differential Optical Absorbtion Spectroscopy) allows to determine the concentration of trace gases
based on their specific absorptions cross-sections along a light path. Since 1995, this principle is
employed successfully on satellite-based instruments like GOME, GOME-2 and SCIAMACHY for the global
measurement of stratospheric and tropospheric trace gases like ozone and nitrogen oxides. Usually,
spectral signatures from the ground, where a big part of the sunlight is reflected, are neglected in the
evaluation. This can lead to errors in the trace gas determination. However, these structures offer the
opportunity to identify surfaces of the earth and different types of vegetation. To analyse this influence,
high resolved reflection spectra (FWHM 0.29 nm) from plants and other materials were measured
between 350 and 1050 nm. They can serve as a basis for classification studies, e.g. according to the
biological systematics (subdivision, class, order, genus, unranked classification), distribution (continent,
climate zone), photosynthesis mechanism (C3, C4, CAM) and environmental conditions. Results of these
measurements and first applications are presented.
57

Global Tropospheric Ozone Retrievals From OMI Data by Means of Neural
Networks
Di Noia, Antonio 1 ; Sellitto, Pasquale 2 ; Del Frate, Fabio 1
1 Tor Vergata University, ITALY; 2 Laboratoire Interuniversitaire des Systèmes Atmosphériques, FRANCE
Tropospheric ozone is a key player in several chemical and physical processes which take place in the
atmosphere. First, it is harmful for the living beings when it reaches high concentrations near the Earth's
surface. Second, it acts as a precursor of the hydroxyl radical, which is the most important oxidant
species in the upper troposphere. Third, it is one of the most important greenhouse gases in terms of
radiative forcing. Retrieving tropospheric ozone from satellite data is one of the most complex tasks in
the framework of atmospheric remote sensing, due to the difficult task of separating the tropospheric
contribution from an overwhelming stratospheric signal in the measured radiances. High spectral
resolution and a relatively small pixel size are required to measure tropospheric ozone concentrations
from a satellite platform. The Ozone Monitoring Instrument (OMI) meets both these requirements.
Although several methods exist to create global tropospheric ozone maps averaged over extended time
periods (e.g. monthly means), only a limited number of algorithms allow global retrievals to be
performed on a daily basis. Among these, Neural Network (NN) techniques are attractive due to their
processing speed and their robustness to noise and incorrect statistical assumptions on the inverse
problem. A NN algorithm to retrieve the tropospheric column at northern midlatitudes from OMI data –
the OMI-TOC NN – was recently developed, and its results were proven comparable to more established
techniques, like Optimal Estimation (OE) and Trajectory-enhanced Tropospheric Ozone Residual (TTOR).
Here, an adaptation of the OMI-TOC NN to perform tropospheric ozone retrievals on a global scale will be
presented. The new algorithm – called the OMITROPO3 NN – combines OMI UV2 reflectance spectra with
tropopause pressure, temperature profile and climatological information to yield daily global maps of
tropospheric ozone. The algorithm was validated against ozonesonde data over several locations,
encompassing midlatitudes, tropics and polar latitudes, and encouraging results were found.
Furthermore, good generalization capabilities outside the time period covered by the training dataset
were observed. The processing chain of the new algorithm, as well as validation results over an extended
set of locations, will be shown.
Assessing Sources of Uncertainty in Formaldehyde Air-Mass Factors Over
Tropical South America: Implications for Top-Down Isoprene Emission
Estimates
Barkley, Michael
University of Leicester, UNITED KINGDOM
We use a nested-grid version of the GEOS-Chem chemistry transport model, constrained by isoprene
emissions from the Model of Emissions of Gases and Aerosols from Nature (MEGAN), and the Lund-
Potsdam-Jena General Ecosystem Simulator (LPJ-GUESS) bottom-up inventories, to evaluate the impact
that surface isoprene emissions have on formaldehyde (HCHO) air-mass factors (AMFs) and vertical
column densities (VCDs) over tropical South America during 2006, as observed by the SCanning Imaging
Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) and Ozone Monitoring Instrument
(OMI). Although the large-scale seasonal variability of monthly mean HCHO VCDs is typically unaffected
by the choice of bottom-up inventory, large relative differences of up to ±45% in the HCHO VCD can
occur for individual regions and months, but typically most VCD differences are of order ±20%. These
relative changes are comparable to those produced by other sources of uncertainty in the AMF including
aerosols and surface albedo, but less than those from clouds. In a sensitivity test, we fnd that top-down
annual isoprene emissions inferred from SCIAMACHY and OMI HCHO vertical columns can vary by as
much as ±30-50% for each instrument respectively, depending on the region studied and the a priori
isoprene emissions used. Our analysis suggest that the infuence of the a priori isoprene emissions on
HCHO AMFs and VCDs is therefore non-negligible, and must be carefully considered when inferring topdown
isoprene emissions estimates over this, or potentially any other, region.
58

Validation of Tropospheric Ozone Columns from SCIAMACHY: First Results
Ebojie, Felix 1 ; von Savigny, C. 2 ; Ladstätter-Weissenmayer, A. 2 ; Weber, M. 2 ; Bötel, S. 2 ; Alexei, R. 2 ;
Bovensmann, H. 2 ; Burrows, J. P. 2
1 University of Bremen, GERMANY; 2 Institute of Environmental Physics, University of Bremen, GERMANY
The limb-nadir-matching technique of the SCanning Imaging Absorption spectroMeter for Atmospheric
ChartograpHY (SCIAMACHY) instrument on-board the ENVISAT satellite has been used to retrieve
tropospheric ozone. This technique is a residual approach that involves the subtraction of the
stratospheric ozone columns derived from the limb observations from the total ozone columns derived
from the nadir observations. This approach to retrieving tropospheric ozone from one spectrometer helps
to remove the uncertainties that may arise when comparing measurements made by different
instruments probing slightly different air masses in different observation geometries. Tropospheric ozone
has a significant adverse effect on the climate system, especially of the troposphere. It generally has
great impact in the lower, middle and upper troposphere. In the lower troposphere, during summer, it is
a major constituent of photochemical smog and excess of it are toxic to the ecosystem, animal and man.
It is equally known as a major oxidant and also involved in the production of other oxidant such as
hydroxyl (OH) radicals. In the middle and upper troposphere, ozone acts as a greenhouse gas. In this
study we shall focus on the validation of the tropospheric ozone columns retrieved from SCIAMACHY
limb-nadir observations. The retrieval of tropospheric ozone from SCIAMACHY involves the derivation of
the stratospheric ozone columns, the total ozone columns and the tropopause height. The stratospheric
ozone columns was derived by integrating the stratospheric ozone profiles from the tropopause, which
was obtained from the re-analyses data of the European Centre for Medium-Range Weather Forecasts
(ECMWF) in 1.5 ° x 1.5° x 91 levels based on both the thermal definition of tropopause using the WMO
lapse-rate criterion as well as the potential vorticity definition of the tropopause. The total ozone columns
were on the other hand retrieved using the Weighting Function DOAS algorithm (WFDOAS) at the
spectral window of 326.6 – 334.5 nm. Equally of importance to this study is the tropospheric ozone
columns derived from the ozonesondes by integrating the tropospheric ozone profiles from the bottom to
the top of the troposphere, which was determined from the ozonesondes temperature profile
measurements using the WMO lapse rate criterion definition of the thermal tropopause. The tropospheric
ozone columns retrieved from SCIAMACHY compare well with some of the ozonesondes investigated at
the tropics and midlatitude to an average of 1-3 DU but at the higher latitudes the comparison shows an
average of 5 – 8 DU. The comparison on the global distribution plots with Tropospheric Emission
Spectrometer (TES) and Ozone Monitoring Instrument/Microwave Limb Sounder (OMI/MLS) show similar
pollution features in some regions of the globe.
Understanding the Atmospheric Hydrological Cycle Through Isotope
Measurements from SCIAMACHY
Scheepmaker, Remco 1 ; Frankenberg, Christian 2 ; Sutanto, Samuel 3 ; Hoffmann, Georg 3 ; Roeckmann,
Thomas 3 ; Aben, Ilse 1
1 SRON Netherlands Institute for Space Research, NETHERLANDS; 2 Jet Propulsion Laboratory, California
Institute of Technology, UNITED STATES; 3 Utrecht University, NETHERLANDS
The relative abundance of the heavy water isotopologue HDO provides a deeper insight in the
atmospheric hydrological cycle, because evaporation and condensation processes deplete heavy water in
the gas phase. A better understanding of the hydrological cycle is crucial for climate predictions, climate
reconstructions and water resources management. We study the near-surface distribution of water vapor
isotopologues using satellite retrievals of global HDO/H2O abundances. For our satellite retrievals we use
the 2.3 micron (SWIR) channel of the SCanning Imaging Absorption spectroMeter for Atmospheric
CartograpHY (SCIAMACHY) instrument on-board ENVISAT. Our initial 2003-2005 dataset, which is
publicly available, shows expected spatial and temporal gradients and has been compared to various
isotope-enabled atmospheric general circulation models. Here we show the latest results of how the
HDO/H2O dataset compares to the models. We will also give an update of our efforts to improve and
extend the dataset beyond 2005, and validate it against ground-based measurements of atmospheric
HDO/H2O. We also provide an outlook for the new TROPOMI instrument, scheduled for launch in 2014
on-board ESA's Sentinel 5 precursor satellite. With its smaller ground pixels, shorter revisit time and
increased sensitivity, TROPOMI will greatly increase the amount of useful data for retrieving near-surface
water vapor isotopologues in the atmosphere.
59

PCW/PHEMOS-WCA: Quasi-Geostationary Viewing of the Arctic and Environs for
Weather, Climate and Air Quality
McConnell, John 1 ; McElroy, Tom 1 ; O'Neill, Norm 2 ; Nassar, Ray 3 ; Buijs, Henry 4 ; Rahnama, Peyman 5 ;
Walker, Kaley 6 ; Martin, Randall 7 ; Sioris, Chris 1 ; Garand, Louis 3 ; Trichtchenko, Alexander 3 ; Bergeron,
Martin 8 ; Solheim, Brian 1 ; Semeniuk, Kirill 1 ; Chen, Yongsheng 1 ; Lupu, Alexandru 1 ; McDade, ian 1 ; Shan,
Jinjun 1 ; Evans, Wayne 1 ; Jones, Dylan 1 ; Strong, Kim 1 ; Fogal, Pierre 1 ; Drummond, James 7 ; Duck, Tom 7 ;
Royer, Alain 2 ; Hakami, Amir 9 ; Degenstein, Doug 10 ; Bourassa, Adam 10 ; Bernath, Peter 11 ; Boone, Chris 12 ;
Rochon, Yves 3 ; McLinden, Chris 3 ; Menard, Richard 3 ; Turner, David 3 ; Kaminski, Jacek 1 ; Peuch, Vincent-
Henri 13 ; Tamminen, Johanna 14 ; Chance, Kelly 15 ; Clerbaux, Cathy 16 ; Kerridge, Brian 17 ; Moreau, Louis 4 ;
Lantagne, Stephane 4 ; Roux, Michel 4
1 York University, CANADA; 2 U of Sherbrooke, CANADA; 3 Environment Canada, CANADA; 4 ABB Bomen,
CANADA; 5 COM DEV, CANADA; 6 U of Toronto, CANADA; 7 Dalhousie University, CANADA; 8 Canadian
Space Agency, CANADA; 9 U of Carleton, CANADA; 10 U of Saskatchewan, CANADA; 11 Old Dominion
University, UNITED STATES; 12 U of Waterloo, CANADA; 13 ECWMF, UNITED KINGDOM; 14 FMI, FINLAND;
15 HCO/SAO, UNITED STATES; 16 LATMOS, FRANCE; 17 RAL, UNITED KINGDOM
The PCW (Polar Communications and Weather) mission is a dual satellite mission with each satellite in a
highly eccentric orbit with apogee ~ 42,000 km and a period (to be decided) in the 12-24 hour range to
deliver continuous communications and meteorological data over the Arctic and environs. At and near
apogee the viewing is quasi-geostationary due to the slow satellite motion. The operational
meteorological instrument is a 21-channel spectral imager with UV, visible, NIR and MIR channels similar
to MODIS and ABI. The PHEMOS WCA (Weather, Climate and Air quality) mission is an atmospheric
science complement to the operational PCW mission. The PHEMOS WCA instrument package consists of
FTS and UVS imaging sounders with viewing range of ~4.5 degrees or a Field of Regard (FoR) ~
3400x3400 km2 from near apogee. The spatial resolution at apogee of each imaging sounder is targeted
to be 10×10 km2 or better and the image repeat time is targeted at ~ 2 hours or better. The FTS has 4
bands that span the MIR and NIR. The MIR bands cover 700-1500 cm-1 and 1800-2700 cm-1 with a
spectral resolution of 0.25 cm-1 i,e, a similar spectral resolution to IASI. They should provide vertical
tropospheric profiles of temperature and water vapour in addition to partial columns of other gases of
interest for air quality such as O3, CO, HCN, CH3OH, etc and also CO2 and CH4. The two NIR bands
cover 5990-6010 cm-1 (0.25 cm-1) and 13060-13168 cm-1 (0.5 cm-1) and target columns of CO2 and
CH4 and the O2-A band for surface pressure, aerosol OD and albedo. The UVS is an imaging
spectrometer that covers the spectral range of 280 – 650 nm with 0.9 nm resolution and targets the
tropospheric column densities of O3 and NO2. It is also planned to obtain the tropospheric columns of
BrO, SO2, HCHO and (HCO)2 and the aerosol index (AI) as well as stratospheric columns of O3, NO2 and
BrO. The quasi-stationary viewing will provide the ability to measure the diurnal behavior of atmospheric
properties under the satellites and the ability to provide data for weather forecasting and also chemical
data assimilation. Important goals for PHEMOS-WCA include measurement of meteorological and air
quality data and the measurement of changes in CO2 and CH4 throughout the day-lit hours in the NIR
near apogee (see FTS poster). In addition, the imaging design is to be sufficiently flexible so that it can
be directed at special events possibly with the FoR reduced to have more rapid spatial coverage. In this
paper we will outline the scientific objectives, status of retrieval algorithms and also the viewing
geometry necessary with 2 satellites. PHEMOS WCA Phase A study was completed in March 2012. It was
funded by the Canadian Space Agency (CSA).
Simulating the IASI Spectrum Using Radiative Transfer Models
Ventress, Lucy; Dudhia, Anu; Walker, Joanne
AOPP, University of Oxford, UNITED KINGDOM
The Infra Red Atmospheric Sounding Interferometer (IASI) onboard the METOP-A satellite provides data
with high spectral resolution over a large spectral range. It has become a key instrument in providing
temperature and water vapour profiles and its data has been extensively assimilated in Numerical
Weather Prediction (NWP) systems. The ability to simulate accurately the IASI spectra using Radiative
Transfer models is essential within the data assimilation process and in continuing to produce accurate
retrievals. This paper focuses on two Radiative Transfer models used to simulate observations; the RFM
(Reference Forward Model), a line by line radiative transfer model developed at the University of Oxford
and RTTOV (Radiative Transfer model for TOVS), a widely used fast radiative transfer model. The current
ability of the RFM and RTTOV to replicate the IASI spectrum is shown and the sources of discrepancies
between the results are examined. For the simulations, a partial retrieval of the atmospheric profile is
implemented in order to reduce the residuals, and the resulting simulated spectrum is compared to the
average of a number of IASI spectra taken from clear homogeneous scenes.
60

Intercomparison of 5 Years of Global Formaldehyde Observations from the
GOME-2 and OMI Sensors
De Smedt, Isabelle 1 ; Van Roozendael, Michel 1 ; Stavrakou, Trissevgeni 1 ; Müller, Jean-François 1 ; Chance,
Kelly 2 ; Kurosu, Thomas 3
1 Belgian Institute for Space Aeronomy (BIRA-IASB), BELGIUM; 2 Harvard-Smithsonian Center For
Astrophysics, Smithsonian Astrophysical Observatory (CFA-SAO), UNITED STATES; 3 Jet Propulsion
Laboratory (JPL), California Institute of Technology, UNITED STATES
Formaldehyde (H2CO) tropospheric columns have been retrieved since 2007 from backscattered UV
radiance measurements performed by the GOME-2 instrument on the EUMETSAT METOP-A platform. This
data set extends the successful time-series of global H2CO observations established with GOME/ERS-2
(1996-2003), SCIAMACHY/ENVISAT (2003-now), and OMI on the NASA AURA platform (2005-now). In
this work, we perform an intercomparison of the H2CO tropospheric columns retrieved from GOME-2 and
OMI between 2007 and 2011, respectively at BIRA-IASB and at Harvard SAO. We first compare the
global formaldehyde data products that are provided by each retrieval group, respectively via the TEMIS
and NASA/mirador websites (http://www.temis.nl and http://mirador.gsfc.nasa.gov/). We then
investigate each step of the retrieval procedure: the slant column fitting, the reference sector correction
and the air mass factor calculation. Air mass factors are computed for OMI using external parameters
consistent with those used for GOME-2. By doing so, the impacts of the different a priori profiles and
aerosol corrections are quantified. The remaining differences are evaluated in view of the expected
diurnal variations of the formaldehyde concentrations, using simulations performed with the IMAGES
CTM.
Improving GOME-2 Tropical Formaldehyde Retrievals
Hewson, Will; Boesch, Hartmut; Barkley, Michael
University of Leicester, UNITED KINGDOM
Tropical ecosystems are generally thought to be responsible for 70∼90% of the global isoprene budget
(400∼600 Tg C/year). Satellite observations of formaldehyde (HCHO), a high-yield, short lifetime product
of isoprene oxidation, provide top-down constraints on surface isoprene emissions. Differences between
model and measurements during the wet and wet-to-dry seasons highlight major gaps in our current
understanding of isoprene emissions and subsequent atmospheric chemistry.
Significant progress has already been achieved in satellite retrievals of HCHO, but errors in retrieved
Slant Columns (SC – density along the instrument’s line of sight) are typically in the region of 40% for
scenes with no cloud or aerosol contamination. Errors are largely caused by the low signal to noise ratio
frequently encountered with space-borne UV spectrometers, coupled with HCHO’s faint absorption signal.
The essential conversion of SCs to Vertical Columns (VCs – density in a vertical column extending from
the surface), needed for application of retrieved HCHO values to geochemical modelling schemes, is a
further significant contributor to product error (30∼60%), being strongly influenced by aerosol, cloud and
albedo inhomogeneities at sub pixel level. Over tropical landmasses, the above limitations combine to
make satellite retrievals of tropospheric gases particularly difficult due to persistent cloudiness
(especially during the wet season) and high aerosol loading (from biomass burning and to an unknown
extent, secondary organic aerosol).
The launch of GOME-2 (Global Ozone Monitoring Experiment) aboard EUMETSAT’s MetOp-A satellite in
2006 extends the data series of the original GOME instrument (launched 1996), as well as the more
recent SCIAMACHY and OMI instruments. GOME-2’s increased spatial and spectral resolution over GOME-
1 allows for the mitigation of some of the significant error sources highlighted above, enabling
improvements in cloud screening and trace gas derivation, offering a potentially improved HCHO
retrieval. DOAS is applied to infer SCs of HCHO from UV spectra acquired by GOME-2. Extensive
sensitivity testing is conducted on DOAS retrieval parameters, providing a useful tool with which to
derive optimised retrieval settings for subsequent work. Results of these tests are presented along with
updated global HCHO VC retrievals. Our global retrievals are compared with HCHO calculations from the
GEOS-Chem model, as well as retrieval products from other research groups. For the critical, error-prone
conversion of retrieved SCs to vertical columns, Air Mass Factors (AMF) are derived from a combination
of radiative transfer and chemical modelling schemes. Latest results are presented from an in progress
study of AMF sensitivities to cloud, aerosol, albedo and associated influential variables, with the results
being used to inform improvements in the AMF scheme over tropical regions.
61

A Common Approach for the Retrieval of Carbon Monoxide (CO) from
TROPOMI's and SCIAMACHY's SWIR Channel
Borsdorff, Tobias; Landgraf, Jochen; Schrijver, Hans; Aben, Ilse
Netherlands Institute for Space Research (SRON), NETHERLANDS
The Scanning Imaging Absorption Spectrometer for Atmospheric ChartographY (SCIAMACHY) has its 10 th
anniversary working on the ESA ENVISAT satellite and recently this mission got extended until 2013.
Because of the launch of the Tropospheric Monitoring Instrument (TROPOMI) on ESA's Sentinel 5
Precursor in 2015, both instruments will together provide a unique and almost continuous long-term
record of Short Wave Infrared (SWIR) measurements of carbon monoxide (CO) from the 2.36 μm
window from space. For examining long-term changes in the CO concentration it is important that the
retrieval results of both instruments will form a homogeneous datasets. An important step to ensure that
is to use the same CO retrieval method for SCIAMACHY and TROPOMI. SRON is developing a new CO
retrieval approach CORE, which is designed for the upcoming TROPOMI instrument but can be applied
also to SCIAMACHY measurements. By that the SCIAMACHY CO retrievals will benefit from the ongoing
development. In this study we will analysis the retrieval of CO vertically integrated total column using
both the current SCIAMACHY CO level 2 data product and the CORE retrieval algorithm.
Water Vapour Column Density Product from GOME, SCIAMACHY and GOME-2 -
Validation with Independent Satellite Observations
Grossi, Margherita 1 ; Slijkhuis, Sander 1 ; Loyola, Diego 1 ; Aberle, Bernd 1 ; Beirle, Steffen 2 ; Mies, Kornelia 2 ;
Wagner, Thomas 2 ; Gleisner, Hans 3 ; Lauritsen, Kent Bækgaard 3
1 Deutsches Zentrum für Luft- und Raumfahrt, Institut für Methodik der Fernerkundung
(IMF),Oberpfaffenhofen, GERMANY; 2 Max Planck Institute for Chemistry, Mainz, GERMANY; 3 Danish
Meteorological Institute (DMI), Copenhagen, DENMARK
Total column water vapor (TCWV) generated using the satellites GOME/ERS-2, SCIAMACHY/ENVISAT and
GOME-2/MetOp-A, has proved to be a valuable input quantity in climate monitoring, and could also be
useful for numerical weather prediction. However, the absolute accuracy estimate and the long-term
stability of the H2O column needs further investigation. As basis of the analysis we use the TCWV
products from the GOME/SCIAMACHY/GOME-2 family of instruments generated by DLR using the GOME
Data Processor (GDP) version 4.5. The retrieval algorithm is based on a classical DOAS method
(developed by MPI-Mainz) to obtain the trace gas slant column. Subsequently, the vertical column is
derived, making use of the simultaneously measured O2 absorption and radiative transfer calculations.
This ensures consistent H2O and cloud information for all three instruments. This contribution focuses on
the validation of the TCWV from GOME/SCIAMACHY/GOME-2 against global positioning system radio
occultation (GPS RO) measurements from the CHAMP and COSMIC missions. Total column water vapor
estimates are then collocated and compared with ocean passive microwave observations from SSM/I-
USA and over-land, VIS/NIR data obtained using MERIS measurements. Finally, the long-term stability of
the GOME-type H2O products is checked against ECMWF model data. The comparison is done using both
individual measurements and monthly averaged water vapor results, in order to make the selection
effects in the two datasets as similar as possible. With our analysis, we confirm the results of previous
validation studies which showed acceptable bias against the SSM/I instrument (Slijkhuis, 2008) and
obtained differences within 10% over ocean for the GOME-2 instrument. From correlation analysis,
slopes between 0.95 and 1, and biases as small as 1 kg/m2 are found for the combined SSM/I-MERIS
sample. The GOME/SCIAMACHY/GOME-2 retrievals are typically drier than the COSMIC and CHAMP
measurements. For the comparison with GPS RO monthly mean, a positive bias smaller than 2 kg/m2 is
found in the period 2007/2008 for GOME and GOME-2, a bit larger for SCIAMACHY. Also analyzing the
seasonal variation, in general the GOME and GOME-2 data underestimate the GPS RO data, but the
differences, located prevalently in the northern sub-tropical area, are always within the errors associated
to the sample. The comparison with the correlative SCIAMACHY observations allows us to assess internal
consistency between the three sensors.
62

A New Sulphur Dioxide Retrieval Scheme for IASI: Results for Recent Eruptions
and Possible Volcanic Degassing.
Carboni, Elisa 1 ; Grainger, Ray 1 ; Walker, Joanne 1 ; Siddans, Richard 2 ; Dudhia, Anu 1
1 University of Oxford, UNITED KINGDOM; 2 Rutherford Appleton Laboratory, UNITED KINGDOM
It will be presented a new algorithm for the retrieval of sulphur dioxide from IASI data which determines
the amount and effective altitude with high precision (up to 0.3 DU if the plume is in near the
tropopause). The scheme is based on the optimal estimation (OE) method (Rodgers, 2000). It uses the
IASI channels between 1000-1200 and 1300-1410 cm-1. These regions include the two SO2 absorption
band features (the v1 and v3 absorption bands) centred at about 7.3 and 8.7 microns respectively. The
retrieval assumes a Gaussian distribution for the vertical SO2 profile and returns the SO2 column amount
and the altitude of the plume. Radiative transfer computations that generate the forward modelled
spectra (against which the measurements are compared) are based on RTTOV (Saunders et al.,1999)
and ECMWF meteorological data. The retrieval includes a comprehensive error budget for every pixel.
This is derived from an error covariance matrix that is based on the SO2-free climatology of the
differences between the IASI and forward modelled spectra. The IASI forward model includes the
possibility to simulate a cloud or ash layer in the atmosphere, this feature is used to illustrate that: (1)
the SO2 retrieval is not affected by underling cloud; (2) it is possible to discern if ash (or other
atmospheric constituents not considered in the error covariance matrix) affect the retrieval using quality
control based on the fit of the measured spectrum by the forward modelled spectrum. In this work we
present the algorithm itself, results for recent volcanic eruptions, comparison with other satellite data
and the possibility to monitor degassing from some quiescent volcano.
Insights Into the Distribution and Role of Volatile Organic Compounds in the
Upper Troposphere Using MIPAS
Moore, David; Remedios, John; Sembhi, Harjinder; Trent, Tim
University of Leicester, UNITED KINGDOM
Emissions of anthropogenic pollution and natural biomass burning inject of a wide range of carbon
compounds into the atmosphere. Volatile organic compounds (VOCs) are released in significant amounts,
affecting both the oxidation capacity of the troposphere and ozone production. The recent use of satellite
based remote sensing of the atmosphere, with characterised errors, has provided a greater
understanding of the spatial distribution of these compounds in the UT and is beginning to address
questions of the lifetimes of these compounds in this region from a global perspective. A key for testing
the quality of any satellite data-set produced is by validation and inter-comparison to in-situ and other
satellite measurements.
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard Envisat samples
vertically at 1.5 km intervals between 6 km and 21 km (with a vertical resolution around 3 km). We
compare products retrieved from MIPAS (include Peroxyacetyl nitrate (PAN), acetone, formic acid,
acetylene and ethane) to suitable aircraft and satellite data. One such aircraft campaign is the NERCfunded
BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites
(BORTAS) campaign during summer 2011 which was dedicated to studying the impact of local pollution
events over North America and aged plumes originated from Asia and Siberia. The payload included
instruments measuring a large number of VOCs to study plume chemistry, including PAN, acetylene and
formic acid to which we compare. VOC data from the ACE satellite instrument are also available for the
BORTAS measurement period and we inter-compare the recently developed ACE PAN dataset with results
from MIPAS.
The Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container
(CARIBIC) is an innovative scientific project which makes extensive measurements of important chemical
and physical processes in the atmosphere. The automated scientific instrumentation is flown on
commercial aircraft, greatly improving spatial, vertical and temporal coverage, compared to specific
campaigns which focus on a particular region. For acetone and acetylene, we look at a number of
measurements made by CARIBIC between Germany and India, data which cross important regions such
as the summer Indian monsoon and regions affected by biomass burning and agricultural processes. The
MIPAS acetone compares well to the aircraft in most cases. The best comparisons are found where the
CARIBIC data are least variable along-track and so where the acetone within the 500 km x 30 km x 3 km
MIPAS at field-of-view is most homogeneous. We show that the MIPAS is providing unprecedented global
VOC data with good spatial resolution, providing very important new datasets with which to study the
UT. This work on VOCs has the potential to feed into retrieval studies for higher spatial sampling
satellites, such as PREMIER.
63

CO and CH4 from the TROPOMI SWIR Channel on the Sentinel 5 Precursor
Mission
Aben, Ilse 1 ; Hasekamp, Otto 1 ; Tol, Paul 1 ; Snel, Ralph 1 ; Hoogeveen, Ruud 1 ; Vitas, Nikola 1 ; Butz, Andre 2 ;
Galli, Andre 1 ; Borsdorff, Tobias 1 ; Veefkind, Pepijn 3 ; Landgraf, Jochen 3
1 Netherlands Institute for Space Research (SRON), NETHERLANDS; 2 Karlsruhe Institute of Technology,
Institute for Meteorology and Climate Research, GERMANY; 3 Royal Netherlands Meteorological Institute
(KNMI), NETHERLANDS
The Tropospheric Monitoring Instrument (TROPOMI) will be launched on board ESA’s Sentinel-5 Precursor
satellite platform scheduled for launch in late 2014. One of TROPOMI’s goals will be to accurately monitor
methane (CH4) and carbon monoxide (CO) concentrations in the Earth’s atmosphere by measuring
spectra of sunlight backscattered by the Earth’s surface and atmosphere in the shortwave-infrared
spectral range at 4190 – 4340 cm-1 (2.3 µm). TROPOMI is based on heritage from SCIAMACHY and OMI,
employing for the first time a push-broom spectrometer in the SWIR. In this contribution we will discuss
the most important developments and improvements of the SWIR channel of the instrument. The
capabilities of TROPOMI SWIR for CO and CH4 will be illustrated with results from trial ensembles
covering realistic atmospheric conditions.
Monitoring of Volcanic Eruptions and Determination of SO2 Plume Height from
GOME-2 Measurements
Valks, Pieter 1 ; Loyola, Diego 1 ; Van Gent, Jeroen 2 ; Theys, Nicolas 2 ; Van Roozendael, Michel 2 ; Hao, Nan 1 ;
Zimmer, Walter 1
1 DLR, GERMANY; 2 IASB-BIRA, BELGIUM
Volcanic eruptions are a major hazard to local populations near large volcanoes and to aviation, and they
also play an important role in global climate change. Atmospheric SO2 is an important indicator for
volcanic eruptions and volcanic activities such as passive degassing. Space based atmospheric sensors
like GOME-2 on MetOp and OMI on EOS-Aura make it possible to detect the emissions of volcanic SO2 in
near-real time (NRT) and monitor volcanic activity and eruptions on a global scale. This is important as
satellites are often the first, and sometimes the only, source of information on volcanoes in remote
locations, because ground based monitoring is carried out only for a limited number of volcanoes. The
GOME-2 instrument provides near-real time (NRT) measurements of the SO2 columns with a spatial
resolution of 80x40 km² and a global coverage within about one day. Volcanic sulfur dioxide emissions
are routinely derived from solar backscatter measurements in the ultra-violet spectral range around 320
nm, applying the Differential Optical Absorption Spectroscopy (DOAS) method. This retrieval technique
uses the high spectral resolution of the instruments to determine the total column density of SO2.
The operational SO2 column product is retrieved at the German Aerospace Center in the framework of
EUMETSAT’s Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M-SAF).
The SO2 product is available less than two hours after sensing, which makes possible detection and
tracking of volcanic eruption plumes as a valuable tool for aviation warning. For aviation safety the
correct determination of the plume height is also a central issue. Therefore a NRT method has been
developed for the determination of the plume height. Using the DOAS analysis results as input
parameters, spectra are simulated with the radiative transfer model RRS-LIDORT for different plume
heights and matched with the measured spectra. The plume height is then determined using an iterative
approach. Furthermore, the ability to monitor changes in volcanic degassing behavior is of great
importance for early warning of volcanic activity, as large increases in SO2 fluxes are often an indicator
for new episodes of volcanic unrest. As the standard DOAS method is restricted to optically thin
conditions and the use of direct fitting is problematic for NRT applications the use of a modified DOAS
algorithm has been tested. The results have been validated against ground-based measurements of
volcanic SO2. In this contribution, we present examples of results of SO2 retrieved from GOME-2 with
standard and modified DOAS and the direct fitting approach, including analyses and comparisons for
volcanic events. Further we show validation results for GOME-2 SO2 measurements. The NRT plume
height retrieval is presented and compared to results obtained by trajectory matching technique.
64

Development and Maintenance of SCIAMACHY Operational ESA Level 2
Products: from Version 5 Towards Version 6
Bovensmann, Heinrich 1 ; Eichmann, K.U. 1 ; Noel, S. 1 ; Richter, A. 1 ; Wittrock, F. 1 ; Buchwitz, M. 1 ; von
Savigny, C. 1 ; Rozanov, A. 1 ; Kokahnovsky, A. 1 ; Vountas, M. 1 ; Burrows, J.P. 1 ; Lerot, C. 2 ; van Roozendael,
M. 2 ; Tilstra, L.G. 3 ; Snel, R. 4 ; Krijger, J.M. 4 ; Lichtenberg, G. 5 ; Doicu, A. 5 ; Schreier, F. 5 ; Hrechanyy, S. 5 ;
Gimeno-Garcia, S. 5 ; Kretschel, K. 5 ; Meringer, M. 5 ; Hess, M. 5 ; Gottwald, M. 5 ; Dehn, A. 6 ; Fehr, T. 6 ; Brizzi,
G. 7
1 University of Bremen, GERMANY; 2 Belgian Institute for Space Aeronomy, BELGIUM; 3 KNMI,
NETHERLANDS; 4 SRON, NETHERLANDS; 5 Remote Sensing Technology Institute (IMF), German Aerospace
Center (DLR), GERMANY; 6 ESA ESRIN, ITALY; 7 SERCO, ITALY
Since the establishment of the SCIAMACHY Quality Working Group (SQWG) in a joint inter-agency ESA-
DLR-NSO effort in late 2006, the ESA operational Level 2 processor was significantly improved w.r.t. data
quality and the product list was substantially enhanced by new parameters. The version 5 of the
operational Level 2 product is now containing nadir total columns of O3, NO2 , SO2, BrO, OClO (slant
only), H2O, CO as well as the Absorbing Aerosol Index. In limb mode, stratospheric profiles of O3, NO2
and BrO as well as tropospheric cloud flags and top height information is available. The full mission
reprocessing 2002-2011 of this product version is currently on-going and will be provided to the user
community in spring 2012. In addition, the Quality Working Group started to prepare for the next
product version (Version 6). The new version will include for the nadir mode total columns of HCHO,
CHOCHO, CH4, tropospheric columns of NO2 as well as an improved cloud identification over ice/snow
and AAI product. In limb mode main developments are the extension of the O3 profile to the mesosphere
as well as an mesospheric cloud flag. The paper will summarise the key characteristics of the Level 2
version 5 currently under full mission reprocessing. An outlook on the next product version (Version 6)
will also be presented.
New Organic Molecules from ACE Satellite Observations
Harrison, Jeremy 1 ; Boone, Chris 2 ; Bernath, Peter 1
1 University of York, UNITED KINGDOM; 2 University of Waterloo, CANADA
The Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS), onboard the SCISAT-
1 satellite, is a high resolution (0.02 cm -1 ) instrument covering the 750-4400 cm -1 spectral region in
solar occultation mode. ACE, an ESA third-party mission, was launched by NASA in August 2003 and the
FTS performance remains excellent after 8 years in orbit. Although the primary mission goal is the study
of ozone chemistry in the stratosphere, ACE continues to measure the vertical distribution of over 30
trace gases in the atmosphere, more than any other satellite instrument. The transmittance spectra, with
high signal-to-noise ratios, are recorded through long atmospheric pathlengths (~300 km), thus
providing a lower detection threshold for trace species in the atmosphere. A high inclination (74 degrees)
and low earth orbit (650 km) gives ACE coverage of tropical, mid-latitude and polar regions.
Detecting trace molecules in the atmosphere is extremely important because they can contribute to air
pollution and/or climate change, which produce negative effects on human health and ecosystems. For
example, volatile organic compounds, which are released into the atmosphere from both natural and
anthropogenic sources, are oxidised in the troposphere to produce ozone, a toxic and potent greenhouse
gas. On the other hand, hydrofluorocarbons (HFCs), a class of refrigerant used as a replacement for
chlorofluorocarbons, are powerful greenhouse gases, meaning that even small amounts of these gases
contribute significantly to the radiative forcing of climate. In the absence of regulations, the consumption
and emissions of HFCs are projected to increase.
Profiles of new organic molecules continue to be retrieved from the entire catalogue of ACE spectra, often
using new quantitative laboratory spectroscopic data. This presentation will focus on some of the latest
ACE ‘research products’, including acetonitrile and trifluoromethane. Acetonitrile (CH3CN) is principally
emitted into the atmosphere from biomass burning. The lifetime of acetonitrile is of the order of 6
months, making this molecule a useful tracer for biomass burning. Trifluoromethane (CHF3; HFC-23),
which has a very long lifetime of 222 years, is the second most abundant HFC in the atmosphere, and its
atmospheric concentration continues to increase. This work represents the first infrared satellite remotesensing
observations of these molecules.
65

Validation of Two Independent Retrievals of SCIAMACHY Water Vapour Columns
Using Radiosonde Data
du Piesanie, Annelise
Royal Netherlands Meteorological Institute (KNMI), NETHERLANDS
Total water vapour column amounts can be derived from satellite measurements by various techniques.
In this study, two individual water vapour column data sets derived from measurements in the visible
and near-infrared spectral regions performed by SCIAMACHY, are compared with integrated water
vapour derived from radiosonde relative humidity measurements. Firstly, SCIAMACHY water vapour
column amounts derived with the Iterative Maximum Likelihood Method (IMLM) v7.4 developed by the
Netherlands Institute for Space Research (SRON), are compared to two years of radiosonde
measurements. Secondly, water vapour column amounts of the SCIAMACHY level 2 v5.01 operational
product, derived with the Air Mass Corrected Differential Absorption Spectroscopy (AMC-DOAS) method
developed by the University of Bremen, are compared to an 18-month period of collocated radiosonde
measurements. Results indicate that both water vapour column data sets compare relatively well to that
of radiosondes. Comparison results between the operational AMC-DOAS water vapour columns and
radiosondes indicate that the operational SCIAMACHY product measures lower water vapour column
amounts. The water vapour column bias has a clear dependence on the cloud top height, which further
increases with increasing cloud top heights
Development of an FTS for Thermal and Near-Infrared Sounding of Weather, Air
Quality and Greenhouse Gases in the Arctic
McConnell, John C. 1 ; Sioris, Chris 1 ; Walker, Kaley A. 2 ; Buijs, Henry 3 ; Moreau, Louis 3 ; Nassar, Ray 4 ;
Fogal, Pierre 2 ; the PHEMOS Science Team, 1
1 2 3 4
York University, CANADA; University of Toronto, CANADA; ABB Inc., CANADA; Environment Canada,
CANADA
The Canadian Space Agency’s PCW (Polar Communications and Weather) mission is a dual satellite
mission with each satellite in a highly eccentric orbit with apogee ~42,000 km and a period in the 12-24
hour range to deliver continuous (24x7) communications and meteorological data over the Arctic and
northern midlatitudes. The baseline meteorological instrument is a 21-channel spectral imager. The
PHEMOS (Polar Highly Elliptical Molniya Orbital Science) payload is a science complement to the PCW
mission to address weather, climate and air quality issues. One of the proposed PHEMOS instrument
packages, named Weather, Climate and Air Quality, consists of a Fourier transform spectrometer (FTS)
to cover the near-infrared and mid-infrared spectral range and an ultraviolet-visible (UVS) spectrometer.
In a phase A study funded by the Canadian Space Agency, we are developing an FTS instrument for
thermal infrared sounding as well as for greenhouse gas monitoring via near-infrared solar reflection.
Using imaging detectors allows many measurements in parallel with increased observation time up to
100 seconds per view. The field-of-regard (FOR) is subdivided into a number of views such that a full
measurement of the FOR is completed in about 1 hour by utilizing a pointing mirror in a step and stare
mode. The thermal infrared is covered with two optimized bands between 700 and 2500 cm -1 focusing on
temperature and water vapour profiles and air quality species (including CO, O3, HNO3, NH3). The
spectral resolution is 0.3 cm -1 . The near-infrared spectral bands target absorption signatures of CO2, CH4,
and O2. These two spectral ranges are 5990-6450 cm -1 and 13060-13168 cm -1 (O2-A band), measured
with spectral resolutions of 0.3 and 0.6 cm -1 , respectively. The O2-A band is used to determine surface
pressure, albedo, and aerosol optical depth and vertical distribution, the latter of which is critical for CO2
retrieval. The FTS instrument design will be presented as well as design challenges and expected
performance. Retrieval studies examining the feasibility of measuring CO2, CH4, and aerosol properties
will be presented as well.
66

Ozone Profile Retrievals from Metop and Envisat
Siddans, Richard; Miles, Georgina; Waterfall, Alison; Latter, Barry; Kerridge, Brian; Poulsen, Caroline
STFC Rutherford Appleton Laboratory, UNITED KINGDOM
There are a number of satellite instruments currently capable of measuring ozone in the Earth’s
atmosphere. The differing observation methods, in the limb or nadir, and the part of the spectrum in
which measurements are made, provide the potential for an optimal product when used in synergy. Here
work will be presented on the progress of a combined GOME-2 IASI AVHRR ozone retrieval scheme,
which constitutes a comprehensive exploitation of these Metop instruments for ozone, with a principle
focus on tropospheric ozone. The joint scheme has been developed through work funded by the UK
National Centre for Earth Observation, building on continued efforts to develop the RAL GOME scheme
which is also supported by the ESA CCI Ozone project. The GOME-2 scheme has itself benefited from a
number of developments to account for long term changes in the instrument which will be reported.
Cloud retrievals from AVHRR are performed using the ORAC scheme (developed by RAL and Oxford)
which has been selected to provide the core scheme for the CCI cloud project. Performance of the joint
scheme will be illustrated though long-term statistical comparisons to ozone-sondes, as well as global
and regional comparisons to chemical transport models for specific case studies. The potential for further
improvement via joint retrieval with co-located observations from Envisat MIPAS and the proposed
PREMIER limb sounder has also been assessed and results based on MIPAS flight data will be presented.
NH3 from TES: Results on Regional and Global Scales
Cady-Pereira, Karen 1 ; Shephard, Mark 2 ; Luo, Mingzhao 3 ; Henze, Daven 4 ; Pinder, Robert 5 ; Walker, John 5 ;
Bash, Jesse 5
1 AER, Inc., UNITED STATES; 2 Environment Canda, CANADA; 3 JPL, Cal Tech, UNITED STATES; 4 University
of Colorado, Boulder, Colorado, UNITED STATES; 5 US Environmental Protection Agency, UNITED STATES
Ammonia (NH3) is a highly reactive gas emitted principally by animal waste and fertilizer application, and
to a lesser extent by industrial activity, mining and automobiles. Ammonia contributes significantly to
several well-known environmental problems; excess deposition in terrestrial ecosystems can lead to soil
acidification and loss of plant diversity; in coastal ecosystems, it can cause eutrophication, algal blooms,
and loss of fish and shellfish. In the atmosphere NH3 can combine with sulfates and nitric acid to form
ammonium nitrate and ammonium sulfate, which constitute a substantial fraction of fine particulate
matter (PM2.5). Nevertheless the knowledge of the magnitude and seasonal/spatial variability of the
emissions is severely limited, and this limitation impacts the capability of models to predict ammonia
concentrations. Measurements of NH3 from space, such as those now available from METOP IASI or
AURA TES, can provide valuable information. This paper will compare TES NH3 with in situ
measurements from very different regions (China, the Central Valley, North Carolina) to evaluate the
quality of the space based measurements. We will then examine global results and discuss the limits and
capabilities of TES NH3.
67

Tropospheric Sulphur Dioxide Retrieval from the ESA SCIAMACHY Observations
Addabbo, Pia; di Bisceglie, Maurizio; Galdi, Carmela
Università degli studi del Sannio, ITALY
A new approach for the retrieval of the vertical column concentrations of trace gases, from hyperspectral
satellite reflectances, is proposed in this contribution. The method has been previously presented in [1]
with application to the Ozone Monitoring Instrument (OMI) and is here applied to the ESA SCanning
Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) nadir reflectances. This
new approach is quite different from the well-established Differential Optical Absorption Spectroscopy
(DOAS) technique [2] and attempts to exploit more extensively the hyperspectral available information.
The main idea is to consider the trace gas estimation problem as a waveform unmixing problem where
the trace gas absorption cross section is separated by other contributions and its slant column density is
finally retrieved. Statistical unmixing is carried out using the Independent Component Analysis (ICA) [3]
applied to the logarithm of hyperspectral reflectances. The application is the retrieval of sulphur dioxide
concentration, a quite challenging task because of the strong ozone interference in the narrow vibrational
band (from 260 to 340 nm) of the SO2 molecule [4]. Figures 1 and 2 show the SO2 concentration during
the volcanic activity of Kasatochi on August 2008, respectively from SCIAMACHY nadir reflectances and
from OMI reflectances. Red pixels represent areas of high SO2 concentration, while the lowest
concentrations are indicated in light pink colour. Considering the two sensors differences in terms of
spectral and spatial resolution, perspectives and time acquisitions, there is a good agreement between
the two results, proving the applicability of the used method to both. The different lower maximum
concentration value in Figure 1 is probably due to the fact that sulphur dioxide is more spread (the image
is aquired about 40 minutes after the Figure 2). A relevant difference is due to the instrumental artifacts
introduced by the OMI instrument, the vertical violet stripes clearly visible in Figure 2. On the contrary
the SCIAMACHY instrument Figure 1 doesn’t exhibit this kind of artifacts in presence of low SO2
concentrations. Further developments of the study could be the extension of the proposed approach to
limb SCIAMACHY measurements.
References
[1] P. Addabbo, M. di Bisceglie, and C. Galdi, “The unmixing of atmospheric trace gases from
hyperspectral satellite data,” IEEE Transactions on geoscience and remote sensing, vol. 50, no. 1,
January 2012. [2] U. Platt and J. Stutz, Differential Optical Absorption Spectroscopy: Principles and
Applications, Springer, 2008. [3] A. Hyv¨arinen and E. Oja, “Independent component analysis:
Algorithms and applications,” Neural Networks, 2000. [4] C. Lee, A. Richter, M. Weber, and J. P.
Burrows, “SO2 retrieval from SCIAMACHY using the weighting function DOAS (WFDOAS) technique:
comparison with standard DOAS retrieval,” Atmospheric Chemistry & Physics Discussions.
IASI Chemistry Data Retrieved at Laboratoire d'Aerologie with the SOFRID
LE FLOCHMOEN, Eric 1 ; Barret, Brice 2 ; De Wachter, Evelyn 2 ; Matricardi, Marco 3 ; Pavelin, Ed 4 ; Cammas,
Jean-Pierre 2
1 Laboratoire d'Aérologie - CNRS - Université de Toulouse III, FRANCE; 2 Laboratoire d’Aérologie - CNRS -
Université de Toulouse III, FRANCE; 3 ECMWF, UNITED KINGDOM; 4 Met-Office, UNITED KINGDOM
The Infrared Atmospheric Sounding Interferometer (IASI) was launched in October 2006 onboard the
first MetOp satellite. This instrument primarily dedicated to measure meteorological parameters, also
enables to characterize the atmospheric content of chemical species such as ozone (O3) and carbon
monoxide (CO). At Laboratoire d'Aérologie we have developed the SOftware for Fast Retrievals of IASI
Data (SOFRID) to retrieve O3 and CO vertical profiles. This software is based on the 1D-Var module from
the Met-Office (v3.3) coupled to the RTTOV (v9.3) fast radiative transfer code developed within the
EUMETSAT NWP SAF.
We first describe the SOFRID and the retrieved data focusing on their characterization in terms of error
and vertical sensitivity. In particular, we show that both for O3 and CO, the retrievals contain about 2
pieces of information in the troposphere. The SOFRID data have been extensively validated with
radiosoundings (WOUDC and SHADOZ) for O3 and with airborne observations (MOZAIC) for CO. The
validation results will be presented for both the lower and the upper troposphere. The seasonal variations
of global SOFRID-O3 and CO distributions will be discussed in terms of source regions and transport
processes. Finally we will show some events highlighting the ability of IASI to capture fast variations of
the tropospheric composition thanks to its unprecedented spatiotemporal coverage.
68

Tropospheric NO2 Trend over the Seoul Metropolitan Area Based on Satellite
Remote Sensing and In-Situ Surface Observations
Chong, Jihyo 1 ; Kim, Young J. 1 ; Lee, Kwon-ho 2
1 Gwangju Institute of Science and Technology, KOREA, REPUBLIC OF; 2 Kyungil University, KOREA,
REPUBLIC OF
Satellite remote sensing of atmosphere has offered realistic estimation of atmospheric pollution at global,
regional, and even urban scale with improved resolution. Tropospheric vertical column densities (VCDs)
of NO2 can be derived from spectral solar radiance measured by the Global Ozone Monitoring Experiment
(GOME) instrument on board the ERS-2 satellite, the SCanning Imaging Absorption SpectroMeter for
Atmospheric CHartography (SCIAMACHY), the Ozone Monitoring Instrument (OMI), and GOME-2
(Boersma et al., 2007). The aim of this study is to investigate the long-term evolution of atmospheric
pollution over East Asia centered on the Korean peninsular based on satellite measurements. From these
observations, monthly averaged tropospheric NO2 variation has been determined for the period of 1996
to 2010. Satellite data have been also compared with those from ground-based in-situ instrument
network for the study period. The tropospheric VCDs retrieved from OMI data and those determined by
ground-based measurements agree with a correlation coefficient R2 = 0.66. Similar yearly and weekly
cycles of the tropospheric NO2 VCDs were observed for both data sets, with minimum in the summer
months and on weekend days. Since 2005 new air quality management measures has been enforced for
the Seoul metropolitan area through tougher emission control in order to improve its air quality
especially, PM and NO2 pollution. It has been found that in-situ surface NO2 concentration had decreased
by ~0.4% per year since 2005 although it had increased by ~3.2% per year between 1996 and 2005.
Increasing vehicle population might prevent the tropospheric NO2 loading over Seoul from further
reduction. However, satellite-based tropospheric NO2 concentration based on the combined GOME and
SCIAMACHY data sets exhibits ~3.6% increase per year for the study period. OMI data which have daily
coverage over the study area show ~0.7% increase per year since 2005. Satellite remote sensing will
provide independent estimation of the trend of regional NO2 concentration and improve top-down
emission estimation of local industry and transportation for the improvement of chemical transfer
models.
Systematic Investigation of Bromine Monoxide in Volcanic Plumes from Space
by Using the GOME-2 Instrument
Hörmann, Christoph 1 ; Sihler, Holger 1 ; Bobrowski, Nicole 2 ; Platt, Ulrich 2 ; Wagner, Thomas 1
1 Max Planck Institute for Chemistry Mainz, GERMANY; 2 Institute for Environmental Physics, GERMANY
Bromine monoxide (BrO) plays a key role as a catalyst in the depletion of both tropospheric and
stratospheric ozone (O3), e.g. during springtime in polar regions. In addition to sources like salt lakes or
the surface of sea ice in polar regions, it turned out that volcanic emissions are a further natural source
of BrO. The injection of bromine compounds from persistent degassing volcanoes as well as during major
eruptions, might therefore have an important impact on atmospheric chemistry. Since the first
observation of BrO in the volcanic plume of Soufrière Hills in 2002 by ground-based Multi-Axis
Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements, similar observations have been
made at several volcanoes worldwide. While a first systematic investigation with the GOME and
SCIAMACHY satellite instruments failed to detect volcanic BrO also from space for selected volcanic
events, large amounts of BrO were detected for the first time in the plume of the Kasatochi eruption in
August 2008 by GOME-2. This showed the capability of GOME-2 to monitor such events and that satellite
instruments offer in principle the unique opportunity to investigate the behavior of BrO inside volcanic
plumes for large scales, what is usually not possible with ground-based measurements. In order to
detect further events of volcanic unrest, where BrO might be present in the vicinity of the plume, we
systematically investigated the whole dataset of the GOME-2 satellite instrument from the beginning of
the measurements in January 2007 until June 2011. Almost 800 volcanic plumes were automatically
extracted from the data by using sulfur dioxide (SO2) as a proxy and the slant column densities (SCDs)
for BrO were additionally retrieved. While the majority of the captured volcanic plumes showed no signs
for enhanced BrO, several other plumes were found with clear evidence for the coincidentally presence of
volcanic BrO next to SO2, even for minor eruptions. In the latter case, the resulting SCDs for both
species were analyzed for a possible correlation and the BrO/ SO2 ratios are discussed. The results show,
that a close correlation between SO2 and BrO only occurs for some of the observed eruptions or only for
certain parts of the examined volcanic plumes. For some other cases, only a rough spatial correlation can
be found. We discuss possible explanations for the occurrence of different spatial SO2 and BrO
distributions in aged volcanic plumes.
69

European Space Agency Campaign Activities in Support of Earth Observation
Projects
Schuettemeyer, Dirk 1 ; Davidson, Malcolm 1 ; Casal, Tania 2 ; Bianchi, Remo 3 ; Veihelmann, Ben 2 ; Langen,
Joerg 2 ; Straume, Anne-Grete 2 ; Ingmann, Paul 2 ; Meijer, Yasjka 2 ; Kangas, Ville 2 ; Lin, Chung Chi 2 ; Callies,
Joerg 2
1 ESA, NETHERLANDS; 2 ESA-ESTEC, NETHERLANDS; 3 ESA-ESRIN, ITALY
In the framework of its Earth Observation Programmes the European Space Agency (ESA) has been
conducting airborne and ground measurements campaigns since 1981 to support geophysical algorithm
development, calibration/validation, simulation of future spaceborne earth observation missions, and
applications development related to land, oceans and atmosphere. Campaign activities include
experiments related to atmospheric dynamics, atmospheric chemistry, coasts and oceans, ice and land
surfaces by deploying a broad range of active and passive instrumentation in both the optical and
microwave regions of the electromagnetic spectrum The Agency does not normally conduct experiments
in isolation but actively collaborates with national research organizations in the ESA member states as
well as with international organizations. For the different activities a rich variety of datasets has been
recorded, are archived and users can access campaign data through the EOPI web portal
[http://eopi.esa.int]. The first objective of this paper is to highlight the strong link between ESA
spaceborne missions and airborne campaigns through a review of recent campaign activities for the
PREMIER, Carbonsat and ADM/AEOLUS missions, which are part of the Living Planet Programme (Earth
Explorers Core and Opportunity missions). PREMIER’s main objective is to make global high resolution
observations of mid/upper tropospheric and lower stratospheric composition. Related activities address
the need to demonstrate the mission concept by means of different airborne limb-sounding
spectrometers in the infrared and millimetre-wave region. Carbonsat should enhance our current
knowledge about CO2 in the atmosphere. Current activities focus on improving the retrieval of methane
and carbon dioxide concentrations and demonstrating the mission concept by probing CO2 above large
cities including e.g. ground based CO2 and CH4 observations. ADM/AEOLUS the first space mission to
acquire wind profiles on a global scale is approaching its launch and upcoming activities support the
algorithm development and hardware checking during the commissioning and exploitation phase. The
second objective is to highlight ESA activities for airborne instrument development (e.g. sounder,
imager, in situ) which are also a key element in the exploration of new mission concepts and in the endto-end
implementation of spaceborne missions. Here the focus of the paper will be onthe development of
MARSCHALS an airborne millimetre-wave limb sounder, on the upgrade of ISMAR, an airborne
microwave imager for METOP-SG and on Radiosonde development for NO2 measurements in the context
of calibration/validation for Sentinel-5p.
A Novel Tropospheric NO2 Retrieval Algorithm Optimised for the Compact Air
Quality Spectrometer, CompAQS
Jasdeep Anand - University of Leicester, UNITED KINGDOM
Despite efforts to control urban air quality in recent years NO2 emissions from traffic and industry are
still a major pollutant in many cities and have been linked to increased respiratory problems. As in-situ
monitoring is limited by spatial coverage an orbiting satellite instrument capable of measuring NO2
concentrations in the troposphere at a sub-city resolution would provide valuable information to
operational managers and policy makers. Here we present the preliminary results of a novel tropospheric
NO2 retrieval algorithm designed for use with the Compact Air Quality Spectrometer (CompAQS)- an
advanced imaging DOAS spectrometer that could be used in future small satellite payloads. The
algorithm is based on existing satellite DOAS retrievals used for trace gases such as formaldehyde,
where a reference spectrum is taken from a low-polluted area in order to retrieve a purely tropospheric
column.
70

Remote Sensing of Trace Gases in the Stratosphere
Validation of MIPAS IMK/IAA Ozone Profiles
Laeng, A. 1 ; von Clarmann, T. 1 ; Grabowski, U. 1 ; Stiller, G. 1 ; Funke, B. 2 ; Glattor, N. 1 ; Hoepfner, M. 1 ;
Kellmann, S. 1 ; Kiefer, M. 1 ; Linden, A. 1 ; Lossow, S. 1 ; Plieninger, J. 1
1 KIT IMK-ASF, GERMANY; 2 IAA, SPAIN
We present an accomplished part of the validation program of Version V5R_O3_220 of ozone vertical
profiles retrieved with IMK/IAA MIPAS scientific level 2 processor from version 5 of spectral Level 1 files
provided by ESA. The time period covered corresponds to Reduced Resolution period of MIPAS
instrument, i.e. January 2005-present. The comparison with satellite instruments is presented, namely
with ACE-FTS, MLS, GOMOS, SCIA, HALOE and POAM. For each reference dataset, bias determination
and precision validation are performed.
Vertical Ozone Profiles from GOME-2 on MetOp-A
Tuinder, Olaf 1 ; Delcloo, Andy 2 ; Kins, Lucia 3
1 2 3
KNMI, NETHERLANDS; Royal Meteorological Institute of Belgium, BELGIUM; Deutscher Wetterdienst,
GERMANY
Vertical ozone profiles on from GOME-2 (on MetOP-A) are retrieved by KNMI within the framework of the
EUMETSAT Ozone and Atmospheric Monitoring Satellite Application Facility (O3MSAF). The retrieval
algorithm uses GOME-2 radiance measurements in the range from 260 to 330 nm and tries to find the
ozone profile best matching the original radiance measurements. This is done by iteratively adjusting the
knowledge of the state of the model atmosphere via a forward model and the optimal estimation
inversion technique. The ozone profiles are given as partial ozone columns in DU in 40 layers from the
surface up to 0.1 hPa.
In the stratosphere the retrieved GOME-2 profiles are within 15% compared to ozone sondes, LIDAR and
microwave reference instruments up to ~35km. In the UTLS there is a positive bias and a larger RMS. In
the troposphere the accuracy is within 30% compared to balloon ozone sondes.
This poster presents the operational GOME-2 vertical ozone profile and highlights the continuous
validation effort done within the O3MSAF.
71

Global, Long-Term SO2 Measurements from Satellites
Prata, Fred 1 ; Clarisse, Lieven 2 ; Carn, Simon 3 ; Richter, Andreas 4
1 Norwegian Institute for Air Research, NORWAY; 2 Universite Libre de Brussels, BELGIUM; 3 Michigan
Technological University, UNITED STATES; 4 University of Bremen, GERMANY
There is increasing interest in the gaseous composition of the atmosphere, especially with the recognition
that changes are occurring more rapidly than expected and through both anthropogenic and natural
causes. Sulphur dioxide (SO2) has both natural and man-made sources, has a significant effect on the
radiative forcing of the atmosphere and significant vertical structure. In recent years several satellite
instruments have demonstrated that the total column of SO2 can be measured well and it has been
shown that some limited vertical information can be obtained due to the sensitivity of the kernel
functions. Retrievals of total or partial column SO2 can be made using infrared (IR), ultra-violet (UV) and
microwave satellite instruments and here we concentrate on the IR and UV measurements. In the UV,
TOMS, SCIAMACHY, GOME, OMI, GOME-2 and OMPS provide global information on SO2 at differing
spatial and time-scales dating back to 1979. In the IR, HIRS, MODIS, AIRS, SEVIRI, GOES and IASI
provide similar information, also going back to 1979. Many of these sensors can only detect SO2 above a
certain threshold and the IR sensors mostly detect SO2 in the upper-troposphere/lower stratosphere. The
UV sensors have better sensitivity to emissions closer to the surface and are able to measure passively
degassing volcanic emissions as well as emissions from anthropogenic sources. Thus they are well-suited
to assessing the contributions of SO2 from both strong and weak volcanic eruptions. Combining the IR
with the UV measurements offers the possibility to explore the vertical structure of SO2 emissions and
potentially separate out natural from anthropogenic emissions in the upper troposphere. By utilizing the
more accurate modern satellite instruments, such as IASI, AIRS, GOME-2 and OMI to post-calibrate older
measurements (e.g. from TOMS and HIRS) a long time series of volcanic SO2 emissions, dating from
1979 is being developed. The main modern data sources are from IASI, AIRS, GOME-2 and OMI and
historic measurements from TOMS and HIRS permit a reconstructed time-series of measurements back
to 1979. The data set will be described, along with the processing chain, assumptions, limitations and
error characteristics and possible applications of the data. These data may be considered a global
climatology of volcanic SO2 emissions and the data could be used as an SO2 inventory for climate models
or as validation data for hindcast and model sensitivity experiments.
Detection of Tropical Stratospheric Transport Barriers from the Long Term NO2
Dataset Measured by SCIAMACHY
Pukite, Janis; Kuhl, Sven; Dorner, Steffen; Wagner, Thomas
MPI for Chemistry, GERMANY
The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) on the
ENVISAT satellite probes the atmosphere at the day side of Earth in alternating sequences of nadir and
limb measurements. Combining measurements of the same air volume from different viewing positions
allows retrieving stratospheric profiles of various trace gases on a global scale. Also a tomographic
approach can be applied and 2D distribution fields of stratospheric trace gases can be acquired by
combining all measurements of an orbit in one simultaneous inversion. In this presentation, the
SCIAMACHY NO2 dataset will be used to estimate the locations of tropical stratospheric transport barriers
and the associated horizontal gradient strengths. Because of its correlation to the long lived N2O
concentration and processes that are separated by the transport barriers, NO2 distributions are related to
the boundaries of these barriers. For the estimation, the methods of probability density functions (PDFs)
and of the steepest gradient will be applied. The results will be compared with data of long lived proxies
for transport barriers like N2O and methane. Also comparison with aerosol information retrieved from
SCIAMACHY limb observations will be performed.
72

The New Operational GOME/ERS-2 Total Ozone Data: GDP Version 5 Direct-
Fitting Algorithm
Loyola, Diego 1 ; Van Roozendael, M. 2 ; Spurr, R. 3 ; Lerot, C. 2 ; Balis, D. 4 ; Lambert, J-C. 2 ; Zimmer, W. 5 ; van
Gent, J. 2 ; van Geffen, J. 2 ; Koukouli, M. 4 ; Granville, J. 2 ; Doicu, A. 1 ; Fayt, C. 2 ; Zehner, C. 6
1 Deutsches Zentrum für Luft- und Raumfahrt (DLR), GERMANY; 2 Belgian Institute for Space Aeronomy,
BELGIUM; 3 RT Solutions, UNITED STATES; 4 Aristotle University of Thessaloniki, GREECE; 5 Deutsches
Zentrum für Luft- und Raumfahrt, GERMANY; 6 ESA/ESRIN, ITALY
We present the new operational GOME/ERS-2 total ozone data reprocessed with the GOME Data
Processor (GDP) retrieval algorithm version 5.
GDP5 is based on GODFIT, a spectral fitting algorithm that includes direct radiative transfer simulation of
earthshine radiances and Jacobians with respect to total ozone, albedo closure, temperature profile shift,
and amplitudes for undersampling and Ring-effect interferences. The Brion-Daumont-Malicet ozone
absorption cross-sections are used together with a semi-empirical molecular Ring and intra-cloud
correction. Updated versions of the OCRA and ROCINN algorithms are used for the determination of
cloud information.
The reprocessed 16-year GOME data record shows a clear improvement in the accuracy of the ozone
product with reduced solar zenith angle and seasonal dependences compared to GDP4 (based on the
DOAS algorithm).
Improvements of the GDP5 algorithm as well as its adaptation for SCIAMACHY and GOME-2 are being
developed in the framework of the ESA CCI ozone project. Furthermore, GDP5 developments will form
the basis for the operational processing of the next generation of European GMES atmospheric satellite
missions such as Sentinel-5 Precursor, Sentinel-4 and Sentinel-5.
Quality Quantifier of Indirect Measurements
Ceccherini, Simone; Carli, Bruno; Raspollini, Piera
Istituto di Fisica Applicata "Nello Carrara" del Consiglio Nazionale delle Ricerche, ITALY
The quantification of the quality of indirect measurements is an important issue in the design of
atmospheric measurements where a choice among different proposed experiments has to be done with
the purpose of maximizing the information about a target set of parameters. In order to optimize the
design of single and coordinated atmospheric measurements it is essential to have a quality parameter
able to characterize consistently both the single measurements and the result of data fusion of several
measurements.
We consider a quality quantifier, referred to as measurement quality quantifier (MQQ), that satisfies the
additivity property for data fusion, which implies that the MQQ of the data fusion of two or more
independent measurements is the sum of the MQQs of the individual measurements.
The MQQ is derived from the Fisher information matrix and quantifies in absolute way the quality of the
observations with respect to the retrieved parameters independently of any constraint that can be used
in the retrieval. Differently from other information quantifiers, such as the Shannon information content,
it can be also defined in absolute terms for ill-posed inverse problems.
The Fisher information matrix is calculated from the Jacobian matrix of the forward model and from the
covariance matrix of the observations and in the case of an unconstrained retrieval it is equal to the
inverse of the covariance matrix of the retrieved quantities. We demonstrate that for a constrained
retrieval a combination of the covariance matrix and of the averaging kernel matrix of the retrieval is
invariant to the constraint and is equal to the Fisher information matrix. Since the covariance matrix and
the averaging kernel matrix are generally distributed together with the retrieval products, using this
invariant the data user can calculate the Fisher information matrix, and from that the MQQ, quantifying
the information that really comes from the observations and excluding the information coming from the
constraints used to perform the retrieval.
When the measured quantity is a continuous distribution (such as a vertical profile) the MQQ depends on
the sampling grid of the distribution and the need arises of characterizing the observations independently
of the selected grid. To this purpose we introduce the grid normalized MQQ that makes possible the
comparison of quality of measurements represented on different grids.
We use the MQQ to evaluate the quality of the measurements performed by the MIPAS instrument on
board of Envisat. In particular we quantify the quality increase occurred when the measurement mode of
MIPAS was changed from full to optimized resolution.
73

Validation of Envisat’s Atmospheric Sensors Using LIDAR – The Valid Project
van Gijsel, J.A.E. 1 ; Allaart, M.A.F. 1 ; Baray, J.-L. 2 ; Bencherif, H. 2 ; Berkhout, A.J.C. 3 ; Claude, H. 4 ;
Courcoux, Y. 2 ; Fehr, T. 5 ; Gumbel, J. 6 ; Godin-Beekmann, S. 7 ; Keckhut, P. 8 ; Leblanc, T. 9 ; McDermid, I.S. 9 ;
Piters, A.J.M. 1 ; Quel, E.J. 10 ; Steinbrecht, W. 4 ; Swart, D.P.J. 3 ; Wolfram, E.A. 10 ; Dehn, A. 5 ; Stammes, P. 1
1 Royal Netherlands Meteorological Institute (KNMI), NETHERLANDS; 2 University of La Reunión, FRANCE;
3 National Institute for Public Health and the Environment (RIVM), NETHERLANDS; 4 German weather
service (DWD), GERMANY; 5 European space agency (ESA-ESRIN), ITALY; 6 Stockholm University,
Department of meteorology (MISU), SWEDEN; 7 CNRS/UPMC/UVSQ, FRANCE; 8 Laboratoire atmosphères,
milieux, observations spatiales (LATMOS), FRANCE; 9 Jet Propulsion Laboratory, California Institute of
Technology, Table Mountain Facility, UNITED STATES; 10 Laser and applications research centre (CEILAP),
CITEFA-CONICET, ARGENTINA
The Satellite validation with LIDAR (VALID) project supports the long-term multi-mission validation of
ENVISAT’s atmospheric chemistry and physics instruments with ground-based LIDARs. State-of-the-art
LIDAR stations around the globe measure high resolution stratospheric ozone and stratospheric and
mesospheric temperature profiles. All involved sites except one are affiliated with the Network for the
Detection of Atmospheric Composition Change (NDACC) and are therefore dedicated to perform longterm
monitoring and regularly have intercomparisons to ensure high data quality and stability. The
availability of the long time series makes these measurements very suitable for trend studies as well as
validation of satellite retrievals. We will present comparisons with MIPAS, SCIAMACHY and GOMOS ozone
and temperature data of the latest operational versions, with special attention for changes in time,
geographical dependencies and other possible sources of deviation. In addition to ozone and
temperature, the VALID project also has a small part dedicated to studying the validation possibilities of
nitrogen dioxide retrieved from space-borne instruments. A mobile LIDAR system and NO2 sondes have
been developed in the last years and are being operated during campaigns, mostly in the Netherlands.
First results and plans will be outlined.
Precise Tangent Height Determination for SCIAMACHY Solar Occultation
Measurements
Bramstedt, Klaus; Noël, Stefan; von Savigny, Christian; Bovensmann, Heinrich; Burrows, John P.
University of Bremen, GERMANY
The spectrometer SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric
CHartographY) on-board ENVISAT is measuring solar irradiances and Earthshine radiances from the UV
to the NIR spectral region in nadir, limb and lunar/solar occultation geometry. For limb and occultation
measurements from space, good pointing knowledge is necessary to derive atmospheric profiles with
proper altitude information. For SCIAMACHY's solar occultation measurements, we present a method to
derive precise pointing information. The scans over the solar disk are used to determine the elevation
angle of the center of the solar disk, which is then compared to the expected elevation angle at that
time. We describe the method and investigate time series of the mispointing of the instrument. We
observe a stable seasonal cycle with an amplitude of about 160m in tangent height and an overall mean
offset of about 180m. A set of larger tangent height anomalies can be identified in the measurements.
The current knowledge about SCIAMACHY's pointing in limb geometry and the implications for profile
retrieval will be briefly discussed.
74

MIPAS/ENVISAT Measurements of the Extreme Depletion of Ozone in the Lower
Stratosphere During the 2010-2011 Arctic Winter Obtained with a 2D
Tomographic Approach
Arnone, Enrico 1 ; Castelli, Elisa 1 ; Papandrea, Enzo 2 ; Carlotti, Massimo 2 ; Dinelli, Bianca Maria 1
1 ISAC-CNR, ITALY; 2 DCFI - University of Bologna, ITALY
We present the observations of the 2010-2011 Arctic winter stratosphere made by the Michelson
Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT. The observations were
analysed using a full 2D tomographic retrieval approach (GMTR - Carlotti et al. (2006)) that enables to
account for the strong horizontal inhomogeneity of the atmosphere typical of the vortex conditions. Polar
Stratospheric Clouds (PSCs) presence and composition were detected through MIPAS spectra using the
technique developed by Hoepfner et al. (2006). The analysis showed that a well isolated stratospheric
vortex above the Arctic region extended the PSCs season up to middle March, with the consequent
significant activation of heterogeneous chemistry and ozone destruction. Through inspection of MIPAS
spectra, 84% of PSCs were identified as supercooled ternary solution (STS) or STS mixed with nitric acid
trihydrate (NAT), 16% formed mostly by NAT particles, and only a few by ice. In the lower stratosphere,
ozone averaged within the vortex edge showed a daily depletion rate reaching 100 ppbv/day and
absolute values dropping to 0.6 ppmv (corresponding to a chemical loss from early winter greater than
80%). In early April, 10% of vortex measurements at 18 km altitude displayed total depletion of ozone.
The Ozone loss was accompanied by the activation of ClO, associated to the depletion of its reservoir
ClONO2, and by a significant denitrification which further delayed the recovery of ozone in spring.
Carlotti, M., Brizzi, G., Papandrea, E., Prevedelli, M., Ridolfi, M., Dinelli, B. M., and Magnani, L.: GMTR:
Two-dimensional multi-target retrieval model for MIPAS-ENVISAT observations, Applied Optics, 45(4),
716-727, (2006).
Hoepfner, M., Luo, B. P., Massoli, P., Cairo, F., Spang, R., Snels, M., di Donfrancesco, G., Stiller, G., von
Clarmann, T., Fischer, H., and Biermann, U.: Spectroscopic evidence for NAT, STS, and ice in MIPAS
infrared limb emission measurements of polar stratospheric clouds, Atmospheric Chemistry & Physics, 6,
1201-1219, (2006).
Iterative Approach to Self-Adapting and Altitude-Dependent Regularization for
Atmospheric Profile Retrievals
Ridolfi, Marco 1 ; Sgheri, Luca 2
1 University of Bologna, ITALY; 2 IAC-CNR, ITALY
MIPAS is a mid-infrared limb-scanning Fourier transform spectrometer operating since July 2002 onboard
the polar satellite ENVISAT. Profiles of temperature and of volume mixing ratios of some atmospheric
constituents are produced by the retrieval algorithm adopted by the European Space Agency. These
include H2O, O3, HNO3, CH4, N2O and NO2. Oscillations beyond the error bars were observed during the
validation phase in several profiles, particularly in CH4 and N2O. Therefore the algorithm has been
extended with a Tikhonov regularization scheme to damp the oscillations. The strength of the
regularization was chosen to be rather weak in order to preserve the vertical resolution of the profiles.
As an alternative we proposed in 2009 the Variable Strength (VS) regularization method, whose
objective is to smooth out artificial oscillations as much as possible, while preserving the fine detail
features of the profile when related information is detected in the observations. Being based on the
rigorous minimization of a cost function, the VS method has the two drawbacks of depending on the
robustness of a specifically-tuned external optimization routine, and of requiring up to 20% increased
computing time.
Here we illustrate an Iterative approach to the VS method (IVS). While based on the same rationale of
the VS method, the IVS approach does not need a minimization and therefore requires only a marginal
(1.5 %) increase of computing time.
We show the self consistency of the IVS approach using synthetic MIPAS observations. We test its
performance with both synthetic and real MIPAS observations. The results are compared with both the
original VS method and the scalar method currently implemented in the MIPAS on-line processor. In all
the tested cases the IVS method, while sub-optimal with respect to the VS, achieves similar good
performances. In particular, compared to the scalar regularization, thanks to its altitude-dependence, the
IVS shows its capability of smoothing-out profile oscillations associated with large retrieval errors, even
when these are confined in specific altitude ranges.
75

Stratospheric Composition Measurements Using the MAESTRO Instrument on a
Balloon Platform Launched from Kiruna During Springtime, 2011
Lemaître, Cyndie 1 ; Melo, S. M L 1 ; McElroy, C. T. 2 ; Walker, K. A. 3 ; Bourassa, A. 4
1 2 3
Canadian Space Agency, CANADA; York University, CANADA; University of Toronto, CANADA;
4
University of Saskatchewan, CANADA
The Canadian Space Agency (CSA) is developing a high altitude balloon program aimed at enhancing and
sustaining Canadian expertise to fulfill the needs of the space industry, academia and government
institutions. The CSA is entering into national and international collaborations to bring together the
necessary capacity. One such collaboration has been initiated with the Centre National d'Études Spatiales
(CNES). To that effect, the CSA joined efforts with Environment Canada and the Universities of Toronto,
York, and Saskatchewan to provide a scientific instrument to be integrated in a scientific payload
composing the CNES 2011 Kiruna Balloon Campaign. The Canadian MAESTRO-B (Measurement of
Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation from Balloon) is a
replica of the MAESTRO instrument which was developed by Environment Canada in partnership with
COMDEV and University of Toronto to fly as part of the Canadian Atmospheric Chemistry Experiment
(ACE) on the Canadian SCISAT satellite. The instrument measures atmospheric composition, specifically
O3, NO2, BrO, water vapor and aerosol extinction The scientific objectives for the MAESTRO-B flight
during the Kiruna 2011 campaign were to provide satellite validation information and support further
development of the retrieval algorithm to extract stratospheric aerosol particle information and water
vapor concentrations from data collected by the MAESTRO instrument on board SCISAT. The MAESTRO-B
was integrated into the DUSTER payload (Dust in the Upper Stratosphere Tracking Experiment and
Return) and launched on April 2011 during sunset from Esrange (67.9 N, 21.1 E).
The present paper is focused on preparation of the instrument to fly in a non-pointed gondola and
processing of MAESTRO-B dataset in order to retrieve vertical distribution of ozone, NO2, and BrO. We
will discuss those measurements in the context of the large ozone depletion observed in the Arctic during
the spring of 2011.
Performance of an Advanced MIPAS Instrument Through the Information Load
Analysis
Papandrea, Enzo 1 ; Carlotti, Massimo 1 ; Arnone, Enrico 2 ; Castelli, Elisa 2 ; Dinelli, Bianca Maria 2
1 2
Dipartimento di Chimica Fisica e Inorganica, Università di Bologna, ITALY; Istituto di Scienze
dell’Atmosfera e del Clima (ISAC-CNR), ITALY
A novel generation of satellite instruments that sound the atmosphere with advanced techniques is being
developed. In this context, a hypothetical instrument operating in the infrared spectral region as
MIPAS/ENVISAT but having different spectral resolution and observation geometry has been
investigated. This instrument (that we denote here as “advanced MIPAS”) would be an imaging
spectrometer able to sound the atmosphere with a very fine scan-pattern. It indeed would operate about
400 limb-scanning sequences per orbit each sounding the atmosphere at 25 tangent altitudes. We
considered the tangent points separated by 2 km and located in the altitude range 6 - 54 km.
Furthermore, it has been foreseen a challenging signal to noise requirement. All these characteristics
would allow to perform innovative studies (e.g. the structure of the UTLS with high level of detail) that
nowadays are prevented mainly due to spatial resolution limitations. We selected a set of microwindows
for the retrieval of ozone and temperature. The selection has been operated on the basis of a low total
(random and systematic) error and a high and uniformly-distributed “Information Load (IL)” quantifier
[1]. We have then investigated the outcome of the IL analysis getting quantitative estimates about the
performance of the instrument’s observation geometry. This study has been carried out on simulated
retrievals from which it is possible to evaluate precision and spatial resolutions of the retrieved targets.
The results show clearly that the advanced MIPAS would have the capability to extract information in the
UTLS region with a high horizontal and vertical resolutions. Furthermore, the very fine measurement grid
determines also a horizontal and vertical uniformity of the sensitivity. This characteristic is highly
desirable as it makes easier the geo-location of the results. [1] Carlotti M., and Magnani L. (2009). Twodimensional
sensitivity analysis of MIPAS observations, Opt. Express 17, 5340-5357.
76

JURASSIC2 - A Tomographic Retrieval Processor
Ungermann, Joern 1 ; Blank, Joerg 2 ; Tobias, Guggenmoser 2 ; Martin, Kaufmann 2 ; Peter, Preusse 2 ; Riese,
Martin 2 ; Lotz, Johannes 3
1 Forschungszentrum Juelich GmbH, GERMANY; 2 Forschungszentrum Juelich GmbH, GERMANY; 3 RWTH
Aachen, GERMANY
The Juelich Rapid Spectral Simulation Code Version 2 (JURASSIC2) retrieval processor combines a fast
radiative transfer forward model with a suit of inversion techniques. The forward model consists of a core
module implementing the emissivity growth approximation and Curtis-Godson approximation. Using pretabulated,
spectrally averaged values of optical path length already including instrument characteristics
gives a speed-up of already about 1.000 compared to more exact line-by-line models. The C++/Python
based processor is optimised for tomographic 2-D and 3-D retrievals by means of a highly efficient
sparse linear-algebra. A joint MPI/OpenMP parallelisation is implemented for utmost efficiency when
using modern multi-core computing clusters. To calculate Jacobian matrices, the forward model is
enhanced by an algorithmic differentiation tool provided by the RWTH Aachen. This tool allows to
generate an exact derivative of the forward model with respect to all input parameters in the time
required by a few normal evaluations of the fast forward model. It is thereby independent of the number
of unknowns, which makes large-scale tomographic retrievals feasible. The retrieval processor and its
performance are presented with the help of two use-cases: a 2-D tomographic gravity wave sensitivity
study for PREMIER (Process Exploration through Measurements of Infrared and millimetre-wave Emitted
Radiation), one of three candidates for ESA’s 7th Earth Explorer mission that are currently undergoing
feasibility studies, and a study to explore the capabilities of GLORIA (Gimballed Limb Observer for
Radiance Imaging of the Atmosphere) instrument to sound the atmosphere in full 3-D. It is
demonstrated that retrievals involving hundred-thousands of unknowns and measurements are feasible
on small computing clusters.
Using GOMOS/Envisat Stellar Scintillation Measurements for Studies of Gravity
Waves and Turbulence in the Stratosphere
Sofieva, Viktoria 1 ; Gurvich, Alexandre S. 2 ; Kan, Valery 2 ; Dalaudier, Francis 3
1 2
Finnish Meteorological Institute, FINLAND; A.M. Oboukhov Institute of Atmospheric Physics, RUSSIAN
FEDERATION; 3 LATMOS, FRANCE
Stellar scintillations observed through the Earth atmosphere are caused by air density irregularities
generated mainly by internal gravity waves (GW) and turbulence. The strength of scintillation
measurements is that they cover the transition between the saturated part of the gravity wave spectrum
and isotropic turbulence. This allows visualization of gravity wave breaking and of resulting turbulence.
We analyzed the scintillation measurements by GOMOS fast photometers on board the Envisat satellite in
order to quantify GW and turbulence activity in the stratosphere. The analysis is based on reconstruction
of GW and turbulence spectra parameters by fitting the modeled scintillation spectra to the measured
ones. For data interpretation, we use a two-component spectral model of air density irregularities: the
first component corresponds to the gravity wave spectrum, while the second one describes locally
isotropic turbulence resulting from GW breaking and other instabilities. In this presentation, we show
global distributions, seasonal and interannual variations of the GW and turbulence spectra parameters
retrieved from GOMOS data. In our presentation, we pay special attention to gravity wave breaking.
Since other measurements at such small scales are very scarce in this altitude range, the obtained global
distributions provide unique and complementary information about small-scale air density irregularities in
the stratosphere. The obtained information about GW and turbulence activity can be used to
improve/validate parameterization of gravity wave effects in the global circulation models, which are
used in climate change studies.
77

Ten Years of MIPAS Measurements with ESA Operational Processor
Raspollini, Piera 1 ; MIPAS L2, QWG 2
1 IFAC-CNR, ITALY; 2 ESA-ESRIN, ITALY
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a limb-viewing infrared
Fourier transform spectrometer that has been measuring, since July 2002, the three dimension
distribution of atmospheric composition on board the ESA ENVISAT satellite. MIPAS acquired atmospheric
spectra sampled at 0.025 cm -1 from July 2002 to March 2004 (full resolution measurements), and since
January 2005 has been operating at 0.0625 cm -1 sampling (optimized resolution measurements). For the
operations with reduced maximum path difference, a new scenario was adopted that exploits the
reduction in measurement time of each interferometer sweep and uses a finer vertical sampling. We
analyze the performance of the MIPAS operational products (target species) in term of random and
systematic errors, vertical and horizontal resolution, as well as the consistency of the products in the two
phases of MIPAS mission (full resolution and optimized resolution measurements). The performed
analysis proves that for the target species the profiles from optimized resolution measurements are
characterized by an improved horizontal resolution (about 510 km for full resolution measurements,
about 410 km for optimized resolution measurements) and improved vertical resolution (varying, in the
altitude range 10-40 km, between 3 and 5 km for full resolution measurements and between 1.5 and 4
km for optimized resolution measurements). The random and systematic error performances, thanks to
the redundant information on the target species present in MIPAS spectra and the consequent use of
dedicated microwindows in the two phases (larger spectral intervals being used for optimized resolution
measurements), are generally comparable in the two phases. The study on the consistency of the
products in the two phases of the mission (made comparing profiles retrieved from the same
measurements, but using the spectral intervals that have been selected for the analysis respectively of
full resolution and optimized resolution measurements) indicates that, apart from a few exceptions,
generally occurring at the borders of the retrieval range, average differences between optimized
resolution and full resolution measurements are within the estimated systematic errors of the profiles
relative to each phase of the measurements, confirming that the estimation of systematic errors is
appropriate. The long term time series of the target species covering the mission lifetime will also be
addressed, discussing some annual and inter-annual variability of the retrieved profiles and the
correlations between the profiles of different species.
New Perspectives of Gravity Wave Remote Sensing Through ESA's Candidate
Mission PREMIER
Preusse, Peter 1 ; Hoffmann, Lars 1 ; Lehmann, Catrin 1 ; Alexander, M. Joan 2 ; Broutman, Dave 3 ; Chun, Hye-
Yeong 4 ; Dudhia, Anu 5 ; Hertzog, Albert 6 ; Hoepfner, Michael 7 ; Kim, Young-Ha 8 ; Lahoz, William 9 ; Ma, Jun 3 ;
Pulido, Manuel 10 ; Riese, Martin 1 ; Sembhi, Harjinder 11 ; Wuest, Sabine 12 ; Alishahi, Verena 1 ; Bittner,
Michael 12 ; Ern, Manfred 1 ; McConnel, John C. 13 ; Sofieva, Viktoria 14
1 Forschungszentrum Juelich, GERMANY; 2 CoRA, UNITED STATES; 3 CPI, UNITED STATES; 4 Yonsei
University, KOREA, REPUBLIC OF; 5 Oxford University, UNITED KINGDOM; 6 CNRS, FRANCE; 7 KIT,
GERMANY; 8 Jonsei University, KOREA, REPUBLIC OF; 9 NILU, NORWAY; 10 Universidad Nacional del
Nordeste, ARGENTINA; 11 Leicester University, UNITED KINGDOM; 12 DLR, GERMANY; 13 York University,
GERMANY; 14 FNMI, FINLAND
PREMIER is one of three candidates studied in phase A for ESA's Earth Explorer 7 mission. One science
aim are mesoscale atmospheric gravity waves (GWs). Gravity waves are an important dynamical
coupling mechanism and a large source of uncertainty in climate and weather prediction as they are
challenging to measure and to model. For instance, GWs contribute more than 50% of the driving of the
QBO, of the predicted trend of the Brewer-Dobson circulation and of the mesospheric circulation. They
thus have large influence also on radiative forcing and stratosphere-troposphere dynamical coupling. For
instance, European winter temperatures differ up to 2K depending on the phase of the QBO, and NAO
coupling via the stratosphere changes precipitation patterns in future climate predictions.
The PREMIER mission will deploy a 2D infrared limb imager feasible through recent advances in detector
technology. This facilitates the retrieval of high spatial resolution 3D temperature distributions along the
orbital track. A dedicated ESA study ("Observation of Gravity Waves from Space", contract number:
22561/09/NL/AF) was carried out in order to demonstrate that this is a significant step forward for GW
research allowing to infer direction resolved GW momentum flux not accessible from space yet. In
particular, zonal mean zonal net momentum fluxes at different altitudes can be inferred, which makes
PREMIER unparalleled and irreplaceable for GW research.
The study comprises a review of the current state of the art in GW research, a full end-to-end simulation
of the processing, the development of a validation concept and, finally, a demonstration of the scientific
potential. In particular, requirements for the accuracy of GW momentum flux are deduced. The end-toend
simulation is based on simulated radiance measurements through atmospheric model data and
78

encompasses the development of a 2D tomographic retrieval dedicated for mesoscale GWs, the
separation of global scale background and mesoscale GWs and the analysis of the resulting temperature
residuals by a 3D wave analysis. The errors of the inferred momentum flux values are assessed for the
whole processing chain as well as for the contributions of the single steps and compared to the
measurement requirements. Validation of GW momentum flux poses new challenges to validation.
Finally, we will demonstrate the scientific potential by global GW backtracing to different sources. An
illustration for the 3D capabilities (selected measurements from the 3D distribution) and backward raytracing
(purple lines) based on gravity wave analysis is given for an orbit segment at the south tip of
Greenland.
Arctic Ozone in Spring 2011 as Seen by GOMOS and OMI
Tamminen, Johanna; Kyrölä, E.; Hakkarainen, J.; Ialongo, I.; Tukiainen, S.; Sofieva, V.; Kivi, R.; Kyrö,
E.; Backman, L.; Thölix, L.; A., Karpechko; Päivärinta, S.-M.; Andersson, M.
Finnish Meteorological Institute, FINLAND
Exceptionally low ozone concentrations were observed in spring 2011 in the Arctic. The cold stratosphere
and strong vortex that lasted till the end of March created meteorological conditions where the catalytic
ozone loss took place. More than one third of the total ozone was destroyed. In this presentation we
discuss the Envisat/GOMOS O3 and NO2 vertical profile measurements of Arctic ozone during the spring
2011. In addition, Aura/OMI total ozone data is used to get full geographical coverage over the Arctic.
The stellar occultation instrument GOMOS with robust retrieval algorithm and good vertical resolution
turned out to provide reliable measurements in the exceptional conditions. GOMOS measured the ozone
profiles inside and outside the vortex and showed that more than 70 % of the ozone was destroyed at 20
km altitude.
Satellite Observations of OClO from 1995 to 2011 in Comparison to ECMWF Data
and EMAC Simulations
Kühl, Sven 1 ; Pukite, Janis 1 ; Dörner, Steffen 1 ; Jöckel, Patrick 2 ; Kirner, Ole 3 ; Wagner, Thomas 1
1 MPI Chemie, GERMANY; 2 IPA-DLR, Oberpfaffenhofen, GERMANY; 3 KIT, Karlsruhe, GERMANY
Satellite instruments like GOME, GOME-2 and SCIAMACHY measure the spectral intensity of the sunlight,
scattered back from Earths atmosphere, on an almost global and daily scale. By applying the DOAS
method to the spectral measurements, the integrated concentration along the light path, the so called
Slant Column Density (SCD), can be derived for a wide range of absorbers. Chlorine dioxide (OClO) is an
important indicator for stratospheric chlorine activation, the basis for massive ozone depletion in polar
spring. Due to the daily coverage of the Polar regions, the OClO measurements give a good overview of
the intensity and the extension of the chlorine activation. While the observations in nadir geometry (i.e.
perpendicular to Earths surface) provide a (indirect) measurement of the total column, the limb
observations (i.e. tangential view) can be inverted to vertical profiles. We investigated GOME, GOME-2
and SCIAMACHY data from 1995 to 2011, covering Arctic and Antarctic winters with very different
meteorological situations (very cold and very warm winters; early and major warmings). In particular,
the long lasting cold stratospheric temperatures inside the vortex for the Arctic winter 2010/11 led to
large levels of chlorine activation until mid of March, also observed in the OClO data. The derived OClO
columns and vertical profiles are compared to ECMWF analysis data, looking at inter-hemispheric and
inter-annual differences and studying the dependence of the OClO enhancements on meteorological
parameters like stratospheric temperatures, potential vorticity, PSC area and volume. Also, the OClO
observations are compared to correlated ECHAM5/MESSy2 (EMAC) simulations, which were calculated for
the exact time and place of the satellite observations. We investigate the agreement of the observed and
simulated OClO profiles for the dataset from 2003 to 2009 (regarding the magnitude, the altitude of the
profile peak and their evolution throughout the winter).
79

Stratospheric Ozone Profile Trends from a Decade of SCIAMACHY Limb
Observations
Gebhardt, Claus; Rozanov, Alexei; Weber, Mark; Burrows, John P.
IUP, Uni Bremen, GERMANY
This study investigates the long-term changes in stratospheric ozone by analyzing vertically resolved
ozone time series from the SCIAMACHY instrument aboard the European research satellite ENVISAT. The
ozone vertical distributions retrieved from SCIAMACHY limb measurements span the altitudes from 10 to
more than 60 km. SCIAMACHY limb ozone profiles are available since August 2002. In this study we
present long-term ozone trends from SCIAMACHY and show intercomparisons with the results from other
satellite instruments (Odin-OSIRIS, Aura-MLS).
An Assimilation Study of Ozone Loss in the Arctic Winter 2009/2010 Using
SMILES and Odin/SMR Data
Sagi, Kazutoshi 1 ; Murtagh, Donal 1 ; Urban, Joachim 1 ; Kasai, Yasuko 2
1 2
Chalmers University of Technology, SWEDEN; National Institute of Information and Communications
Technology, JAPAN
The objective of this study is to quantify the ozone depletion in the Arctic polar vortex. The
Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space
Station observed ozone profiles in the Stratosphere in the 2009/2010 winter with high accuracy.
Although SMILES measurements normally do not cover high latitudes, the combination of data
assimilation methods and a isentropic advection model allows us to use SMILES measurements to
investigate the ozone depletion even in northern polar vortex due to the instability of the polar vortex in
northern hemisphere. This study was performed using the Dynamical Isentropic Assimilation Model for
OdiN Data (DIAMOND)[Rosevall 2007]. The DIAMOND model is an off-line wind-driven transport model
on isentropic surfaces. By assimilating measurement data sets into the transport model, assimilated
ozone fields can be constructed with less noise than the individual profiles and by also advecting passive
tracer fields the effects of chemistry and transport can be separated. Wind profiles from the European
Centre for Medium- Range Weather Forecasts (ECMWF) were used. Ozone data from both SMILES and
Odin/SMR for the in 2009/2010 arctic winter were assimilated into the DIAMOND model. The assimilated
SMILES ozone fields agree well with the Odin fields despite the limited latitude coverage. Maps of Ozone
depletion have derived by comparing the ozone field acquired by sequential assimilation with on
produced by passively transporting the field as of 1st of January in 2010. Significant ozone loss is seen at
the end of January using both SMILES and Odin/SMR data. Particular attention is paid to the vertical or
cross isentropic transport of the tracer in this study.
Reference : Rosevall, J. D., D. P. Murtagh, and J. Urban (2007), Ozone depletion in the 2006/2007 Arctic
winter, Geophys. Res. Lett., 34, L21809, doi:10.1029/2007GL030620.
Retrieval of Stratospheric Trace Gases from FIR/Microwave Limb Sounding
Observations
Xu, Jian; Schreier, Franz; Doicu, Adrian; Vogt, Peter; Trautmann, Thomas
German Aerospace Center (DLR), GERMANY
The TELIS (TErahertz and submillimeter LImb Sounder) instrument is a new stratospheric balloon-borne
cryogenic heterodyne spectrometer developed by the German Aerospace Center (DLR) in cooperation
with the Netherlands Institute for Space (SRON), and the Rutherford Appleton Laboratory (RAL) in the
United Kingdom. It allows limb sounding of the Earth's atmosphere within the far infrared (FIR) and
microwave spectral range. The ambitious spectral coverage of the TELIS instrument is accomplished by
use of three frequency channels: 500 GHz, 480-650 GHz, 1.8 THz for RAL, SRON and DLR, respectively.
TELIS utilizes state-of-the-art superconducting heterodyne technology and is capable of providing broad
spectral coverage, high spectral resolution and extensive flight duration. These features enable us to
monitor the diurnal variation of key stratospheric constituents associated with ozone depletion and
climate change. The instrument was mounted on a balloon gondola together with the MIPAS-B
(Michelson Interferometer for Passive Atmospheric Sounding - Balloon) instrument, developed by the
Karlsruhe Institute of Technology (KIT), Germany. The combination of TELIS and MIPAS-B covers a wide
range of the electromagnetic spectrum that is used for atmospheric research and offers great synergies
for cross-validating of measured vertical distributions of trace gas species. In addition, TELIS acts as a
technology demonstrator to future spaceborne FIR/microwave limb sounding instruments planned by the
European Space Agency (ESA). The development of FIR/microwave limb sounding techniques contributes
80

to an increased demand in high resolution radiative transfer modelling and efficient inversion strategy for
better understanding of atmospheric environment. The Remote Sensing Technology Institute at DLR has
developed a retrieval code PILS (Profile Inversion for Limb Sounding), whose forward model is built on
GARLIC (General Atmospheric Radiation Line-by-line Infrared Code). The goal of PILS is to solve the
nonlinear inverse problems arising in the analysis of limb sounding measurements obtained by TELIS,
SMILES (Superconducting subMIllimeter-wave Limb-Emission Sounder), or Odin/SMR (Sub-Millimetre
Radiometer) instruments. In this work we present the results of various trace gas retrievals from the
TELIS measurements of the DLR/SRON channels by employing PILS. The error analysis is also conducted
to investigate the retrieval feasibility of key profiles of the data processing. The intercomparison between
TELIS and SMILES is currently ongoing in order to consolidate the performance of the instrument and the
reliability of the retrieval results.
Trend Analysis of Stratospheric NO2 Above Jungfraujoch (46.5°E, 8°E) and
Harestua (60°N, 11°E) Using Long-Term Ground-Based UV-Visible, FTIR, and
Satellite Observations
Hendrick, Francois 1 ; Mahieu, E. 2 ; Rozanov, A. 3 ; Boersma, K. F. 4 ; De Mazière, M. 1 ; Demoulin, P. 2 ; Fayt,
C. 1 ; Hermans, C. 1 ; Pinardi, G. 1 ; Van Roozendael, M. 1
1 Belgian Institute for Space Aeronomy (BIRA-IASB), BELGIUM; 2 Institute of Astrophysics and Geophysics
of the University of Liège, BELGIUM; 3 Institute for Environmental Physics/Remote Sensing, University of
Bremen, GERMANY; 4 Royal Netherlands Meteorological Institute (KNMI), De Bilt/Eindhoven University of
Technology, NETHERLANDS
Nitrogen dioxide (NO2) plays an important role in controlling ozone abundances in the stratosphere,
either directly through the NOx (NO+NO2) catalytic cycle, or indirectly by converting active chlorine,
bromine, and hydrogen into their reservoir forms, reducing their availability for ozone-destroying
catalytic cycles. Ground-based zenith-sky UV-visible measurements of the stratospheric NO2 column
have been conducted at the NDACC (Network for the Detection of Atmospheric Composition Change)
stations of Jungfraujoch (46.5°E, 8°E) and Harestua (60°N, 11°E) since 1990 and 1994, respectively.
Also available at both stations are coincident satellite observations from the ERS-2/GOME,
ENVISAT/SCIAMACHY (nadir and limb), and METOP/GOME-2 instruments, as well as in case of
Jungfraujoch and since the mid-1980s, ground-based Fourier transform infrared (FTIR) solar absorption
measurements. In this presentation, we will perform a trend analysis of stratospheric NO2 by applying a
multiple linear regression model to the ground-based and satellite monthly mean NO2 columns time
series. The regression model includes forcing mechanisms for solar flux, quasi-biennial oscillation, and
aerosol loading, in addition to a linear trend. The aerosols term is essential since both UV-visible and
FTIR observations at Jungfraujoch started before the Mount Pinatubo eruption. The consistency between
inferred NO2 trend values at both stations will be investigated. The observed NO2 trends will be compared
to the increase of nitrous oxide (N2O), usually considered as the main source of NOx in the stratosphere
and which is also monitored by FTIR instruments at the Jungfraujoch and Harestua stations.
Assessment and Geophysical Validation of GOMOS Ozone Data Processed with
IPF v.6
Sofieva, Viktoria 1 ; Kalakoski, Niilo 1 ; Kyrölä, Erkki 1 ; Tamminen, Johanna 1 ; Bertaux, Jean-Loup 2 ;
Hauchecorne, Alain 2 ; Dalaudier, Francis 2 ; Fussen, Didier 3 ; Vanhellemont, Filip 3 ; Barrot, Gilbert 4 ; Blanot,
Laurent 4 ; Fanton d'Andon, Odile 4 ; Saavedra, Lidia 5 ; Angelika, Dehn 5
1 2 3 4
Finnish Meteorological Institute, FINLAND; LATMOS, FRANCE; BIRA, BELGIUM; ACRI-ST, FRANCE;
5
ESA/ESRIN, ITALY
The main features of the GOMOS IPF v.6 processor are the improved instrument calibration and the
accurate characterization of modeling errors implemented in the so-called ”full-covariance-matrix
inversion”. These features are expected to improve the data quality and provide realistic uncertainty
estimates of retrieved profiles. In our presentation, we assess the GOMOS ozone data reprocessed with
IPF v.6, compare them with that processed with IPF v.5, and highlight improvements. The results of
comparison of GOMOS ozone data with that from ozone sondes and from satellite instruments (MIPAS,
SCIAMACHY on board Envisat and OSIRIS on board Odin) are also presented.
81

SCIAMACHY: New Algorithms for the Operational Level 0-1 Processor
Lichtenberg, Günter 1 ; Slijkhuis, Sander 1 ; Aberle, Bernd 1 ; Sherbakov, Denis 1 ; Noel, Stefan 2 ; Bramstedt,
Klaus 2 ; Liebing, Patricia 2 ; Bovensmann, Heinrich 2 ; Snel, Ralph 3 ; Krijger, Mathijs 3 ; van Hees, Richard 3 ;
Lerot, Christophe 4 ; Dehn, Angelika 5
1 DLR (German Aerospace Centre Oberpfaffenhofen), GERMANY; 2 Institute of Environmental Physics /
Remote Sensing (IUP/IFE), University of Bremen, GERMANY; 3 SRON, Netherlands Institute for Space
Research, NETHERLANDS; 4 Belgian Institute for Space Aeronomy (BIRA-IASB), BELGIUM; 5 ESA-ESRIN,
ITALY
SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) is a scanning
nadir and limb spectrometer covering the wavelength range from 212 nm to 2386 nm in 8 channels. It is
a joint project of Germany, the Netherlands and Belgium and was launched in February 2002 on the
ENVISAT platform. Being now well in the second part of the ENVISAT mission extension, SCIAMACHY’s
originally specified in-orbit lifetime has meanwhile doubled with the prospect of adding several more
years. SCIAMACHY was designed to measure column densities and vertical profiles of trace gas species in
the mesosphere, in the stratosphere and in the troposphere (Bovensmann et al., 1999). It can detect O3,
H2CO, SO2, BrO, OClO, NO2, H2O, CO, CO2, CH4, O2, (O2 )2 and can provide information about aerosols
and clouds. The operational processing of SCIAMACHY aims to deliver continuously high quality data
products to the scientific community. It is split into Level 0-1 processing (essentially providing calibrated
radiances) and Level 1-2 processing providing geophysical products.
In this paper we will describe the concept of the Level 0-1 processing and improvement and additions to
the operational Level 0-1 processor planned for the coming version, which include a new concept for the
correction of degradation of the instrument, incorporation of new calibration data, an improved stray
light correction and a better handling and monitoring of calibration data with a dedicated database.
Inter-Comparison of GOMOS, MIPAS and SCIAMACHY ESA Datasets Using the
GECA Validation Tool
Tarchini, Salvatore 1 ; Niro, Fabrizio 1 ; Casadio, Stefano 1 ; Brizzi, Gabriele 1 ; Scarpino, Gabriella 1 ; Saavedra
de Miguel, Lidia 1 ; De Laurentis, Marta 1 ; Dehn, Angelika 2 ; Fehr, Thorsten 2
1 2
Serco SpA, Via Sciadonna, 24, 00044 Frascati, ITALY; European Space Agency (ESA-ESRIN), Via
Galileo Galilei, 00044 Frascati, ITALY
The validation of satellite data is essential to assess precision and accuracy of geo-physical parameters
for use in scientific research and in operational services. Inter-comparison of satellite instruments is
extremely valuable for supporting validation studies as well as for deriving biases and systematic errors.
This paper presents the results of inter-comparison between GOMOS, MIPAS and SCIAMACHY, the three
Atmospheric-Chemistry instruments flying on-board the ENVISAT platform since March 2002. Very few
studies have focused on such comparison and none of them has been based only on official ESA
products. This paper aims to filling this gap, by using the latest re-processed ESA datasets for GOMOS
(V6.01), MIPAS (V6.0) and SCIAMACHY (V5.02). The analysis is performed using a new tool developed
by ESA for validation activities. Such tool, called GECA (Generic Environment for Calibration/Validation
Analysis) allows for an easy reading and processing of satellite data regardless of their different products
format. Furthermore, this tool includes a comprehensive library of functions, specifically developed for
validation studies, such as collocation and interpolation routines. Space- and time-collocated profiles are
inter-compared using the GECA tool. MIPAS data is compared respectively to collocated GOMOS
nighttime and SCIAMACHY daytime measurements. The comparison is focused on those geo-physical
parameters that are commonly retrieved by the three instruments, namely the limb profiles of Ozone
(O3) and Nitrogen dioxide (NO2). Differences in terms of average profiles and median differences with
associated statistics are presented and discussed. Partial column comparison, that allows minimizing the
dependence on the accuracy in the tangent height determination, is also shown. The significant quality
improvements obtained with the latest ESA processor upgrades are underlined with respect to previous
processor versions and the consistency of the three datasets are carefully investigated with estimation of
biases and their variations along the mission lifetime. Finally, this paper demonstrates the capabilities
and the value of the GECA tool in the frame of validation studies.
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Time Series of Water Vapor in the Upper Troposphere and Lower Stratosphere
from SCIAMACHY Limb Measurements
Weigel, Katja 1 ; Rozanov, Alexei 1 ; Azam, Faiza 1 ; Eichmann, Kai-Uwe 1 ; Weber, Mark 1 ; Stiller, Gabriele 2 ;
Bovensmann, Heinrich 1 ; Burrows, John 1
1 University of Bremen, Institute of Environmental Physics (IUP), GERMANY; 2 Karlsruhe Institute of
Technology, Institute for Meteorology and Climate Research, GERMANY
The upper troposphere and lower stratosphere (UTLS) is a region of special interest for a variety of
dynamical and chemical processes. UTLS water vapor plays an important role for the atmospheric
radiative budget, therefore consistent long term measurements are important. The limb viewing
geometry of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY)
allows us to retrieve water vapor in the UTLS from about 12 to 23 km altitude. The latest data version is
validated by comparisons with other satellite data and frost point hygrometer data. SCIAMACHY started
to operate in 2002 and the measurements are ongoing. Water vapor time series from 2002 to 2011 are
presented and their variability during the last decade is investigated.
MARSCHALS (Millimetre-wave Airborne Receivers for Spectroscopic
CHaracterisation in Atmospheric Limb Sounding)
Gerber, Daniel; Moyna, Brian; Oldfield, Matthew; Rea, Simon; Siddans, Richard; Reburn, Jolyon;
Kerridge, Brian
RAL Space, UNITED KINGDOM
The MARSCHALS instrument was built on a ESA contract at the Rutherford Appleton Laboratory in order
to demonstrate the observation capabilities of the PREMIER millimetre-wave limb-sounder (PREMIER
being a candidate mission for the 7th generation ESA Earth Explorer Mission). The instrument is deployed
from the M55 "Geophysica" high altitude airplane in conjunction with the infra-red limb-sounder MIAPS
and - as of this year - the novel infra-red imager GLORIA. MARSCHALS has taken part in the PremierEx
campaign in March 2010 and the ESSENCE campaign in December 2011, both of which were ESA funded
flight campaigns based at the Arena Arctica in Kiruna, Sweden. We report on the latest stage of
instrument updates and present scientific results from both campaigns, obtained using the RAL Space inhouse
data processor. We also address the synergies between the millimetre-wave and the infra-red
techniques.
Diurnal Variation of Short-Lived Species in the Tropical Stratosphere and
Mesosphere: Model Comparison with Satellite Measurements
Khosravi, Maryam 1 ; Urban, Joachim 1 ; Murtagh, Donal 1 ; Baron, Philippe 2 ; Kasai, Yasuko 2
1 2
Chalmers University of Technology, SWEDEN; National Institute of Information and Communications
Technology, JAPAN
The diurnal variation of HOCl, ClO, HO2 and HCl measured by satellites has been compared with the
results of a 1D photochemical model. This study aims to compare the data from various limb instruments
with model simulations of the species diurnal variation in the middle stratosphere (35 km) to lower
mesosphere (55km) altitude region. Data from three sub-millimeter instruments and two thermal
infrared spectrometer are used, namely from the Sub-Millimeter Radiometer (SMR) on board Odin, the
Microwave Limb Sounder (MLS) on board AURA, the Superconducting Sub-millimeter wave Limb-
Emission Sounder (SMILES) on the International Space Station, the Michelson Interferometer for Passive
Atmospheric Sounding (MIPAS) on board Envisat, and the Atmospheric Chemistry Experiment Fourier
transform Spectrometer (ACE-FTS) on board SCISAT. Comparisons of the measurements by sunsynchronous
satellites (Odin, MLS, MIPAS) and solar occultation instruments (ACE-FTS) are rather
difficult since measurements correspond to different solar zenith angles (or local times). The comparison
with a model which covers all solar zenith angles and the new SMILES instrument which measures at all
local times over a period of several months provide the possibility to indirectly compare the diurnally
variable species. The satellite data were averaged for latitudes of 20 o S to 20 o N for the SMILES
observation period from November 2009 to April 2010. The satellite data then were compared at three
altitudes: 35, 45 and 55 km. HOCl data are gathered from SMILES, MLS and MIPAS. HO2 is taken from
SMILES, MLS, and SMR. ClO observations were performed by SMR, MLS and SMILES, whilst HCl data are
available from SMILES, MLS and ACE-FTS. The simulations have been done using the MISU1d model for
conditions and locations of the observations. Generally a good agreement is achieved from the diurnal
cycle comparison, as the model reproduces very similar features as the observations. The presentation
will focus on the detailed results of the study.
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Update to the MIPAS Reference Atmospheres for Infra-Red Active Trace Gases
and Implications for Atmospheric Sounding from Space
Remedios, John; Sembhi, Harjinder; Moore, David; Trent, Tim
University of Leicester, UNITED KINGDOM
Reliable reference profiles and estimates of variability are a necessity for a variety of processes related to
the use of satellite data for atmospheric sounding. By their very nature, they also encapsulate the most
significant information available on atmospheric composition. Hence they implicitly identify where our
knowledge of atmosphere composition is very good and where there are some key challenges in our
understanding which need to be addressed in the future. The present study addresses more than 36
species which are active in the infra-red. These are particularly relevant to the MIPAS instrument on
ENVISAT where they are used in radiative transfer calculations to identify the spectral windows for
retrievals and to estimate retrieval errors, as a priori profile information in retrievals, as contaminant gas
profiles in the operational retrieval processor, and to provide (diagonal) covariance information. The
nature of these operations has resulted in the derivation of two forms: five standard atmospheres
covering tropical, mid-latitude and polar situations, and the IG2 seasonal climatologies covering four
seasons in six latitude bands. The trace gas profiles in the present study are developed on a common
altitude, pressure, and temperature grid from 0 to 120 km, and include both means and estimates of
variability (maximum, minimum and one sigma values). The latest developments in the reference
atmosphere will be described, in particular the inclusion of diurnally variation information in the
stratosphere for MIPAS local times, time varying CFC and HCFC profiles, and organic compounds in the
troposphere. The diurnal updates are based on a long time series of SLIMCAT model runs (over 15 years)
covering Mt. Pinatubo and the ENVISAT decade and are important for gases such as O3, NO2, N2O5,
ClONO2 and HNO3. Developments of CFC and HCFC profiles include use of surface estimates updated to
the stratosphere using age of air, and comparisons with ATMOS and ACE data. Organic compound
updates are based on MIPAS retrievals and on knowledge gained from operational aircraft and campaign
data. Finally, these results will be used to draw conclusions and suggest future work in two areas at the
heart of atmospheric sounding from space. Firstly, the characterisation of knowledge in the reference
atmosphere profiles will be used to suggest possible science objectives for future science missions.
Secondly, the results of the study will be employed to illustrate the impact of profile and variability
knowledge on the retrieval of atmospheric products, their characterisation and error propagation.
NO2 Seasonal Variation and Vertical Profiles Retrieval with Ground-Based and
Satellite Equipment at Evora Observatory - Portugal during 2010-2011
Domingues, Ana Filipa 1 ; Bortoli, Daniele 1 ; Silva, Ana Maria 2 ; Anton, Manuel 3 ; Kulkarni, Pavan 1
1 Geophysics Centre of Evora, PORTUGAL; 2 Department of Physics, University of Evora, PORTUGAL;
3 Departamento de Fisica Aplicada, Universidad de Granada, SPAIN
The Remote Sensing Techniques (RST) are intensely used in geophysics researches. For example, the
RST have been used in the study of land surfaces like forests, for urban or land use, geology (floods,
landslide, rock types, etc.) and for cartography. In the last 30 years the application of RST for
atmospheric studies became more important particularly in the monitoring of air pollution and trace
species like ozone (O3), nitrogen dioxide (NO2), and halogen oxides (BrO, OClO, etc). In the 70s, Alan
Brewer used the spectroscopy technique for the ground based measurement of NO2 column density. The
development of satellite instruments capable of retrieving atmospheric compound information from
Earth's backscatter radiation began in the 60s and only in the late 70s, the first satellite equipment for
the ozone monitoring (TOMS - Total Ozone monitoring Experiment) was launched and became
operational. In 2002 the SCIAMACHY instrument was launched onboard ENVISAT satellite providing the
global measurement of various trace gases in the troposphere and stratosphere, aerosols and clouds.
This paper presents the retrieval and analysis of NO2 total columns ( daily and seasonal variations) and
NO2 vertical profiles over the Évora Observatory for the period 2010-2011 obtained from spectral
measurements carried out with the multi purpose UV-Vis. Spectrometer for Atmospheric Tracers
Monitoring (SPATRAM) installed at the Observatory of the Geophysics Centre of Evora (CGE) (38,5º N;
7,9ºW) since 2004. In addition, the comparison of the ground-based measurements with data derived
from satellite equipments –SCIAMACHY instrument onboard ENVISAT is also discussed. The SPATRAM
instrument, developed by CGE and Institute of Atmospheric Sciences and Climate (ISAC-CNR), carries
out zenith scattered light intensity observations in the spectral range of 300-900 nm, in automatic mode
since 2004. The application of the Differential Optical Absorption Spectroscopy (DOAS) algorithms to the
SPATRAM spectral measurements allows for the retrieval of the total columns of NO2, O3, BrO, CHOCHO.
With the inversion schemes based on the optimal estimation method, it is also possible the determination
of the vertical profiles for NO2 and O3. The retrieved total column of NO2 show a pronounced daily course
and a seasonal variation. In general the daily course of NO2 concentration exhibits higher values during
the afternoon and lower at sunrise. As to the seasonal pattern the NO2 total column density increases till
the summer months (June), when the maximum is reached, decreasing till January when the minimum is
84

obtained. Satellite data give the same average NO2 total column density and show a seasonal cycle that
is similar to the ground data.
The Canadian Led Chemical and Aerosol Sounding Satellite (CASS)
Degenstein, Doug 1 ; Walker, Kaley 2 ; Melo, Stella 3 ; Perron, Gaetan 4 ; Moreau, Louis 4 ; Thibault, Jean-
Francois 5
1 University of Saskatchewan, CANADA; 2 University of Toronto, CANADA; 3 The Canadian Space Agency,
CANADA; 4 ABB-Bomem, CANADA; 5 Bristol Aerospace, CANADA
The Chemical and Aerosol Sounding Satellite (CASS) is a proposed Canadian Space Agency (CSA)
mission to address the Committee on Earth Observation Satellites (CEOS) recommendation for continuity
in climate-quality profile measurements of stratospheric and upper tropospheric composition. The
mission includes two instruments: an infrared Fourier transform spectrometer and a limb scatter
spectrograph. Both of these instruments are next generation technology building upon the currently
operational ACE-FTS and Odin-OSIRIS respectively. There is also power, mass and volume budget for a
guest instrument with one possibility a Total Solar Irradiance (TSI) radiometer. The two baseline CASS
sensors focus primarily on trace gas and aerosol measurements using standard techniques and retrieval
processes to produce climate quality data products in order to continue the data sets collected by their
predecessors. These global measurements are aimed at understanding the changes that are occurring in
our atmosphere including changes in climate due to increasing greenhouse gases and recovery of the
stratospheric ozone layer. This presentation will describe the mission as it currently stands and the
progress that has been made by the Canadian definition team.
SPARC Data Initiative
Kyrölä, Erkki 1 ; Hegglin, Michaela I. 2 ; Tegtmeier, Susann 3 ; Anderson, John 4 ; Brohede, Samuel 5 ;
Froidevaux, Lucien 6 ; Funke, Bernd 7 ; Jones, Ashley 2 ; Neu, Jessica 6 ; Rozanov, Alexei 8 ; Toohey, Matthew 3 ;
Urban, Joachim 5 ; von Clarmann, Thomas 9 ; Walker, Kaley A. 2
1 Finnish Meteorological Institute, FINLAND; 2 University of Toronto, CANADA; 3 IFM-GEOMAR, GERMANY;
4 Hampton University, UNITED STATES; 5 Chalmers University, SWEDEN; 6 Jet Propulsion Laboratory,
UNITED STATES; 7 Instituto de Astrofísica de Andalucía, SPAIN; 8 University of Bremen, GERMANY;
9 Karlsruhe Institute of Technology, GERMANY
In this contribution we will present an overview on the SPARC Data Initiative started in 2010
(http://www.issibern.ch/teams/atmosgas/index.html/Welcome.html). The initiative’s main objective is to
compile vertically resolved tracer climatologies from satellite measurements and make a detailed intercomparison
of these climatologies. The study involves data from 19 satellite instruments capable of
measuring vertical profiles of trace gases. Climatologies will be collected using a monthly, 5 degree
latitude grid (data are zonally averaged). In the vertical direction climatologies are given on 28 pressure
levels from 300 hPa up to 0.1 hPa. Climatologies include all major long-lived trace gases (e.g., O3, H2O,
N2O, CH4), shorter-lived trace gases important to stratospheric chemistry (e.g., BrO, ClO, NO2), and
aerosols. The evaluations will include comparisons of the latitudinal and vertical structure of the various
longer-lived and shorter-lived trace gases. Analysis of seasonal cycles and interannual variability will be
based on comparisons of trace gas time series. The initiative will assess the quality of the available
chemical data sets and highlight differences between the observational data sets taking full account of
sampling differences and biases.
The results will be published in a SPARC report in 2012. The report is intended to provide a guide for
users of satellite data sets in order to facilitate use of data for model-measurement comparisons and
other data analyses. The initiative will help to capture and summarize existing knowledge on current and
recent instruments, measurements and retrieval techniques, and validation activities. The climatological
data sets will be made publicly available through the SPARC website.
85

GOMOS Bright Limb Ozone Product
Tukiainen, Simo; Kyrola, Erkki; Jukka, Kujanpaa; Johanna, Tamminen
Finnish Meteorological Institute, FINLAND
GOMOS on Envisat measures the middle atmosphere using the stellar occultation technique. Trace gas
retrievals from the daytime occultations are challenging due to weak stellar signal and strong scattered
sunlight. Thus, only the few brightest stars have provided good daytime ozone profiles. To improve the
daytime coverage, we developed a retrieval method using the limb scattered signal. This bright limb
retrieval method can produce homogeneous ozone profiles, doubling the amount of usable GOMOS ozone
data. During 2012, the whole 10 years of GOMOS daytime data will be processed using the bright limb
retrieval method. This work is part of the so called SPIN project funded by ESA. In this paper we present
the bright limb retrieval method and show how the ozone profiles compare with the high quality GOMOS
nighttime profiles.
New Method for Radiation Calibration of Satellite Sensors with High Spatial
Resolution
Katsev, Iosif; Prikhach, Alexander; Zege, Eleonora
B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, BELARUS
The traditional method to perform the radiation calibration of satellite sensors using the test site includes
the measurements of the signal at the input of the calibrating satellite sensor and simultaneous field
measurements of the atmosphere and surface parameters (albedo and radiance reflection coefficients of
the underlying surface). The characteristics of atmosphere and underlying surface are used to compute
the spectral density of the solar radiation at the input of the satellite sensor. For these calculations the
altitude structure of aerosol-gaseous atmosphere is assumed to be known a priori. Beside the
computations of the radiative transfer in the coupled system atmosphere-underlying surface are
supposed to be performed with regards to the influence of the adjusted pixels contribution into the
registered satellite signal from the test pixel. This influence exists because of molecular and aerosol
scattering in atmosphere and as known is essential at the distances up to 5km. We propose the new
method to calibrate the satellite sensors of high spatial resolution. This method requires the registration
of signals from two closely located test pixels and enables significantly simplify and improve the accuracy
of the radiation calibration of satellite sensors. To implement this method one needs to measure the
atmosphere optical thickness and albedo and radiance coefficients of two test sites. Compared with
traditional calibration process, new method eliminates the need of a priori knowledge of the vertical
structure of atmosphere, the necessity to calculate radiative transfer in the coupled system atmosphereunderlying
surface and an additional allowance for the influence of the neighboring pixels in the signal
registered by the satellite sensor. The simulation performed showed the use of this new technique
provides noticeable improvement of radiation calibration of satellite sensors with high spatial resolution.
Retrieval of Temperature and Ozone Profiles in the Upper Troposphere/Lower
Stratosphere as Measured by GLORIA during ESSenCe11
Joerg Blank; for the GLORIA Team
Bergische University, Wuppertal, Germany
The Gimballed Limb Observer for Radiance Imaging in the Atmosphere (GLORIA) is a new remote
sensing instrument combining a Fourier transform infrared spectrometer with a highly flexible gimbal
mount. Measurements are made with uniquely high spatial and spectral resolution by a 2-D detector
array. The gimbal frame allows to turn the instrument's line of sight horizontally by 45° forward and
backward, so that air masses can be observed from different directions.
We developed the JUTIL toolkit (Juelich Tomographic Inversion Library) and the JURASSIC2 forward
model to calculate atmospheric profiles from measurement data. JUTIL provides general methods to
solve large scale inverse problems, JURASSIC2 is a fast radiative transport model based on the
Emissivity Growth Approximation (EGA).
During December 2011 the instrument flew for the first time on the Russian Geophysica M-55 research
plane over Kiruna (Sweden). At that time, there was a very strong and cold polar vortex with several
filamentary structures at its boundary and within the operation radius of the aircraft. Preliminary fields of
temperature and ozone abundance obtained during the ESSenCe campaign will be presented and
compared to 3-D model calculations.
86

Remote Sensing of Trace Gases in the Upper Atmosphere
MIPAS Measurements of Polar Mesospheric Clouds during the 2005-2011 Period
Lopez-Puertas, Manuel 1 ; Garcia-Comas, Maya 1 ; Funke, Bernd 1 ; Jurado-Navarro, Aythami 1 ; Gardini,
Angela 1 ; Stiller, Gabriele 2 ; von Clarmann, Thomas 2 ; Hoepfner, Michael 2 ; Lossow, Stefan 2
1 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut fur
Meteorologie und Klimaforschung (IMK-ASF), GERMANY
Polar mesospheric clouds (PMCs) occur at the coldest regions of the atmosphere near the summer high
latitude mesopause where they form a layer of a few kilometers wide, peaking near 83 km and located at
latitudes poleward of 50 degrees. They are being discussed as potential early indicators of global change
since they are very sensitive to temperature and water vapour concentration in that region. PMCs have
been intensively studied by observations from ground, rockets (in situ), and space, as well as by
sophisticated models. The observations of PMCs in emission in the infrared are, however, very difficult
because of the low icy particle volume concentration and the very cold mesopause temperatures, thus
requiring very sensitive instruments for their detection. In this paper we report on the polar mesospheric
clouds measured by MIPAS in emission in the infrared (10-12 μm). We analyze the measurements taken
by MIPAS in its NLC (39-102 km, vertical sampling of 1.5 km), and its Middle Atmosphere (MA) (20-100
km) and Upper Atmosphere (UA) (40-170 km) modes, the latter two with a vertical sampling of 3 km.
We analyze the period since July 2005 until December 2011. We show results on the volume ice density,
mean vertical altitude of the clouds and their latitudinal distribution of the PMCs for that period for the
2005-2011 period for the Northern and Southern seasons.
Global Observations of Thermospheric Temperature and Nitric Oxide from
MIPAS Spectra at 5.3 µm
Lopez-Puertas, Manuel 1 ; Funke, Bernd 1 ; Bermejo-Pantaleon, Diego 1 ; Garcia-Comas, Maya 1 ; Stiller,
Gabriele 2 ; von Clarmann, Thomas 2 ; Linden, Andrea 2 ; Grabowski, Udo 2 ; Hoepfner, Michael 2 ; Kiefer,
Michael 2 ; Glatthor, Norbert 2 ; Kellmann, Sylvia 2 ; Friederich, Felix 2 ; Lu, Gang 3
1 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut fur
Meteorologie und Klimaforschung (IMK-ASF), GERMANY; 3 High Altitude Observatory, NCAR, UNITED
STATES
Nitric oxide is an important species in the upper mesosphere and lower thermosphere for several
reasons: first, it is the major infrared cooling species; second, it is transported downwards into the
mesosphere and stratosphere during polar night, participating in the catalytic destruction of ozone; third,
the rotational structure of its emission spectrum can be used to determine kinetic temperature in the
thermosphere; and fourth, its low ionization potential makes NO an important source of ionization in D
and E regions in the ionosphere at all latitudes. The Michelson Interferometer for Passive Atmospheric
Sounding (MIPAS) on board Envisat (ESA) observes regularly (1 out of 10 days) the upper atmosphere
up to 170 km since 2007, providing rotationally resolved 5.3 μm emission from the NO fundamental
band. These emissions have been used to retrieve simultaneously thermospheric NO abundances and
kinetic temperature. Vibrational, as well as rotational and spin non-LTE have been taken into account in
the inversion of the spectra. In this talk we give an overview of the quality of the data and present a
solar minimum climatology of thermospheric temperature and NO corresponding to the 2007-2009
period. Comparisons with previous models (NRLMSISE†00, NOEM) and a previous climatology based
on HALOE and SME data are also presented. The effects of SPE on the thermospheric temperature and
NO and its comparison with TIME-GCM model simulations for the SPE in Jan 2005 are also discussed.
Measurements of Water Vapor Distribution in the Middle Atmosphere by MIPAS
Garcia-Comas, Maya 1 ; Funke, Bernd 1 ; Lopez-Puertas, Manuel 1 ; Lossow, Stefan 2 ; Stiller, Gabriele 2 ; von
Clarmann, Thomas 2 ; Glatthor, Norbert 2 ; Grabowski, Udo 2
1 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut fur
Meteorologie und Klimaforschung (IMK-ASF), GERMANY
Water vapor is a key constituent of the middle atmosphere. It is involved in the ozone chemistry, it is the
precursor of PSCs and PMCs, and it is an infrared cooler in the stratosphere. The Michelson
Interferometer for Passive Atmospheric Sounding (MIPAS) onboard Envisat observes the H2O infrared
emissions with high resolution up to the mesopause. We have derived water vapor abundance from
MIPAS spectra using the IMK/IAA data processor, which includes the GRANADA non-LTE algorithm. That
87

allows for accurate H2O retrievals in the atmospheric regions where its emissions are affected by non-
LTE, i.e., above 50 km and particularly in the polar summer. We describe the information gained from
MIPAS spectra about the non-LTE processes affecting the H2O infrared emissions, discuss its
uncertainties and present MIPAS pole-to-pole distributions of water vapor retrieved from the
stratosphere to the upper mesosphere. We pay special attention to its behavior in the polar summer
mesosphere, where the presence of PMCs and particular dynamical events may perturb the H2O vertical
distribution. We also compare our results with those from global circulation models and other
independent measurements.
Analysis of MIPAS Spectra in the CO2 10 and 4.3 μm Regions in the Mesosphere
and Lower Thermosphere
Jurado-Navarro, Aythami 1 ; Lopez-Puertas, Manuel 1 ; Funke, Bernd 1 ; Garcia-Comas, Maya 1 ; Gardini,
Angela 1 ; Stiller, Gabriele 2 ; von Clarmann, Thomas 2 ; Grabowski, Udo 2 ; Glatthor, Norbert 2
1 Instituto de Astrofisica de Andalucia, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut fur
Meteorologie und Klimaforschung (IMK-ASF), GERMANY
The MIPAS instrument on Envisat has a large spectral coverage (15-4.3 μm) measuring the most
important IR emission of CO2, i.e., the 15 μm, 10 μm and 4.3 μm bands. Additionally, it has a very high
spectral resolution (0.0625 cm -1 ). These characteristics makes it an ideal instrument for studying the
non-LTE processes of CO2 emissions and measuring the CO2 vmr, as well as the temperature retrieval.
In this paper we focus on the analysis of the CO2 non-LTE emission at 10 and 4.3 μm and the retrieval of
the CO2 vmr in the mesosphere and lower thermosphere. The unprecedented spectral coverage and
spectral resolution of MIPAS allow us to study in depth the non-LTE mission of CO2 in the 4.3 μm,
discerning the individial contributions to the limb emission of several tens of bands, including optically
thick and thin bands in this altitude range. These measurements thus allow us to acquire unique
information of the non-LTE processes driving the populations of the CO2 vibrational levels. We present
here new information about the non-LTE collisional processes derived from MIPAS spectra. Once
established the non-LTE populations we have inverted the CO2 vmr in the mesosphere and lower
thermosphere. Preliminary results on the inverted CO2 vmr profiles from the daytime spectra are also
presented.
Overview of MIPAS MA, UA and NLC Data Processing at IMK/IAA
Gardini, Angela 1 ; Funke, Bernd 1 ; García-Comas, Maya 1 ; López-Puertas, Manuel 1 ; Jurado-Navarro,
Aythami 1 ; von Clarmann, Thomas 2 ; Stiller, Gabriele 2 ; Friederich, Felix 2 ; Grabowski, Udo 3 ; Glatthor,
Norbert 2 ; Kiefer, Michael 2 ; Kellmann, Sylvia 2 ; Linden, Andrea 2
1 Instituto de Astrofísica de Andalucía, CSIC, SPAIN; 2 Karlsruhe Institute of Technology, Institut für
Meteorologie und Klimaforschung (IMK-ASF), GERMANY; 3 Karlsruhe Institute of Technology, Institut für
Meteorologie und Klimaforschung (IMK-ASF), SPAIN
The Michelson Interferometer for Passive Atmosphere Sounding (MIPAS) is a mid- IR high-resolution limb
sounder onboard of the polar orbiter ENVISAT, successfully launched on March 1st, 2002. Since January
2005, MIPAS has been operating at a resumed optimized spectral resolution of 0.0625 cm-1, with a
variety of scan patterns providing different altitude coverage as well as horizontal and vertical sampling.
Operational data processing by the European Space Agency (ESA) covers the retrieval of pressure,
temperature, and the mixing ratios of various trace species under assumption of local thermodynamic
equilibrium (LTE). Complementary to the operational processing, there are other off-line data processors;
One of them is the IMK/IAA retrieval processor, developed and operated at the Institut für Meteorologie
und Klimaforschung (IMK) and Instituto de Astrofísica de Andalucía (IAA). Because it considers non-LTE,
it allows to derive atmospheric parameters beyond the ESA operational products in an extended altitude
range. Specifically, it is particularly suitable for the data analysis of the special MIPAS observation modes
“Middle Atmosphere” (MA, 18-102 Km), “Upper Atmosphere” (UA, 42-172 Km) and “Noctilucent Clouds
(NLC, 42-102 Km)”. In this work, we present an overview of MIPAS MA, UA and NLC data processing of
temperature and H2O, CH4, N2O, O3, NO2, NO and CO at IMK/IAA and a characterization of these data
product in terms of zonal mean distributions, vertical resolution and accuracy.
88

Remote Sensing of Clouds and Aerosols
Global Multi-Sensor Satellite Monitoring of Volcanic SO2 and Ash Emissions in
Support to Aviation Control
Brenot, Hugues 1 ; Theys, Nicolas 1 ; van Gent, Jeroen 1 ; Van Roosendael, Michel 1 ; van der A, Ronald 2 ;
Clarisse, Lieven 3 ; Hurtmans, Daniel 3 ; Ngadi, Yasmine 3 ; Coheur, Pierre-François 3 ; Clerbaux, Cathy 3
1 BIRA-IASB, BELGIUM; 2 KNMI, NETHERLANDS; 3 ULB, BELGIUM
The "Support to Aviation Control Service" (SACS; http://sacs.aeronomie.be) is an ESA-funded project
hosted by the Belgian Institute for Space Aeronomy. The service provides near real-time (NRT) global
SO2 and volcanic ash data, as well as alerts in case of volcanic eruptions. The SACS service is primarily
designed to support the Volcanic Ash Advisory Centers (VAACs) in their mandate to gather information
on volcanic clouds and give advice to airline and air traffic control organisations. SACS also serves other
users that subscribe to the service, in particular local volcano observatories and research scientists.
SACS is based on the combined use of UV-visible (SCIAMACHY, OMI, GOME-2) and infrared (AIRS, IASI)
satellite instruments. When a volcanic eruption is detected, SACS issues an alert that takes the form of a
notification sent by e-mail to users. This notification points to a dedicated web page where all relevant
information is available and can be visualized with user-friendly tools. The strength of a multi-sensor
approach relies in the use of satellite data with different overpasses times, minimizing the time-lag for
detection and enhancing the reliability of such alerts.
This paper will give a general presentation of the SACS service, different techniques used to detect
volcanic plumes. It will also highlight the strengths and limitations of the service and measurements.
The Validation of Cloud Retrieval Algorithms Using Synthetic Datasets
Kokhanovsky, Alexander 1 ; Lindstrot, Rasmus 2 ; Meirink, Jan 3 ; Poulsen, Caroline 4 ; Siddans, Richard 4 ;
Thomas, Gareth 5 ; Arnold, Chris 5 ; Grainger, Don 5 ; Lelli, Luca 1 ; Rozanov, Vladimir 1
1 University of Bremen, GERMANY; 2 Free University of Berlin, GERMANY; 3 KNMI, NETHERLANDS; 4 RAL,
UNITED KINGDOM; 5 Oxford University, UNITED KINGDOM
The inter-comparison of various cloud retrieval algorithms using synthetic datasets is of great importance
for understanding weak and strong points of various algorithms and also for further improvements of the
retrieval techniques. With this in mind, we have performed the inter-comparison study of cloud property
retrievals using algorithm initially developed for AATSR (ORAC, RAL-Oxford University), AVHRR(CPP,
KNMI), SCIAMACHY/GOME(SACURA, University of Bremen), MERIS(ANNA, Free University of Berlin). The
results of retrievals of cloud optical thickness(COT), effective radius(ER) of droplets, and cloud top
height(CTH) have been inter-compared in the framework of ESA Cloud CCI Project. Generally, the codes
produced similar results. They are based on different methods to solve the inverse problem. In
particular, ORAC is based on optimal estimation approach using fitting for all AATSR channels
simultaneously. CPP uses the iteration approach, where COT is determined from a visible channel for an
assumed ER and then ER is retrieved the near IR channel using derived COT. The process is stopped if
the convergence is reached. The cloud top height is found using measurements at 11 microns. SACURA
is based on the asymptotic solutions of the radiative transfer equation and parameterizations of results
derived from Mie theory. It makes it possible to derive the cloud optical thickness from the visible
channel analytically (for arbitrary surface reflectance). The derived value of COT is used in the analytical
expression for the reflectance in the near-infrared to derive the value of ER from the solution of a
corresponding transcendent equation using Brent's method. Artificial Neural Network Algorithm (ANNA)
developed at Free University of Bremen is aimed at determination of CTH and COT using MERIS
observations. Neural networks are able to reduce the size of required database, which is of particular
importance for the calculation inside gaseous absorption bands (e.g., in the oxygen A-band as used in
ESA MERIS operational cloud retrieval). The determination of CTH is based on the fact that high clouds
screen larger amounts of tropospheric oxygen as compared to low clouds, leading to shallow absorption
bands seen in the reflectance spectra around 760nm. In synthetic calculations, the CTH was varied in the
range 2-12km, ER was changed from 4 to 20 microns, COT was in the range 1-100 for various viewing
and illumination conditions and underlying surface albedo. It was found that errors in COT and ER are
below 20% in most of cases for all codes except ANNA. The failure of COT retrievals using ANNA in some
cases (generally, the overestimation of COT) is due to the absence of near IR channels in MERIS setup.
The error of CTH retrieval is in the range 0.5-1.0 both for TIR and A-band retrievals with general
tendency for the underestimation of CTH.
89

Retrieval of Aerosol Optical Tickness and Single Scattering Albedo from MSG2
and Sun Photometer Observations
Zawadzka, Olga; Markowicz, Krzysztof
Institute of Geophysics, Faculty of Physics, University of Warsaw, POLAND
The Spinning Enhanced Visible Infrared Radiometer (SEVIRI) instrument on board Meteosat Second
Generation (MSG) offers new capabilities to monitor aerosol loading over land at high temporal and
spatial resolution. We propose algorithm to derived aerosol optical properties from synergy of the
satellite and ground-based observations.
In order to retrieve aerosol optical thickness and single scattering albedo we apply inverse methods. For
simulations of satellite observations we use 6S (Second Simulation of a Satellite Signal in the Solar
Spectrum) radiative transfer model, based on successive orders of scattering (SOS) approximations. The
6S model is used to define and scalar cost function. This function is described by following vectors:
observation, retrieved quantities, a priori information, and covariance matrix for uncertainties of
measurements and model disparity and uncertainties of a priori information, respectively.
Retrieval algorithm consists of three parts. The first step is to remove cloud-contaminated pixels using
spatial variability of the top of the atmosphere reflectance at 1.64 µm. The next step provide surface
reflectance based on the cost function minimization. Surface reflectance is the main difficulty in
determination of aerosol optical properties over land. To estimate this parameter we use surface
observations of aerosol optical thickness from sun photometer during a day with low aerosol content in
the atmosphere. Assuming that surface reflectance at SEVIRI resolution change slowly with time we can
use previous result to calculate aerosol optical thickness and single scattering albedo for next’s or
previous days. The last part of algorithm is related to aerosol optical properties estimation based on
minimization of the respectively defined cost function.
Described method has been tested for data collected in April 2009 and April and May 2010. Preliminary
results were obtained for pixels located in the Kampinos Forest, a large forest complex located near to
Warsaw in Poland. We found good consistency between the retrieved and measured at the surface the
aerosol optical thickness. The calculated values differ from those measured by sun photometer by 0.7%-
17%. Estimated single scattering albedo varies between 0.90 and 0.99.
Evaluation of the Vertical Distribution of Aerosols Simulated by a CTM
(CHIMERE) Using L1 LIDAR Observations (CALIPSO,EARLINET)
Stromatas, Stavros 1 ; Turquety, Solene 1 ; Menut, Laurent 1 ; Valari, Myrto 1 ; Chepfer, Hélène 1 ; Péré, Jean-
Christophe 2 ; Césana, Gregory 1 ; Bessagnet, Bertrand 2 ; Tanré, Didier 3
1 2 3
Laboratoire de Météorologie Dynamique (LMD), FRANCE; INERIS, FRANCE; Laboratoire d’Optique
Atmosphérique (LOA), FRANCE
Aerosols have significant radiative and environmental impacts, affecting human health, visibility and
climate. A key element in modeling aerosols, especially for studying long-range transport and a usual
point of divergence between the chemical transport models (CTM) is the representation of the vertical
distribution of aerosols. In this context, active remote sensing offers precious information on the vertical
distribution of the atmospheric components.
The classic approach for comparing model simulations and satellite observations is using the level 2 (L2)
processing products (e.g. particle backscatter and extinction coefficients profiles) issued from the Level 1
(L1) observations. In this presentation we introduce an adaptable simulator of LIDAR backscattering
profiles from CTM concentration outputs. Our objective is to evaluate the model aerosol vertical
distributions with a direct comparison between simulation outputs and LIDAR L1 observations. By using
the L1 products, we assure that the differences between the model and the observations reveal the bias
of the model in simulating the aerosols rather than the hypotheses made during the restitution of the
inversion products (L2 processing).
Firstly, the principle and the structure of the LIDAR simulator will be presented. We will then show
applications of this simulator for the evaluation of the CHIMERE CTM :
• A complete evaluation of the vertical distribution of aerosols over Europe based on the observations of
the EARLINET network for the period 2007-2009.
• An analysis of specific transport events (fire and dust plumes) based on the CALIPSO satellite-based
LIDAR CALIOP.
90

Aerosol Optical Thickness Retrieval Using Synergy Between MSG/SEVIRI and a
Low Earth Orbit Sensor
Jolivet, Dominique 1 ; Ramon, Didier 1 ; Lifermann, Anne 2 ; Descloitres, Jacques 3 ; Riedi, Jerome 4
1 HYGEOS, FRANCE; 2 CNES, FRANCE; 3 CGTD ICARE, FRANCE; 4 Laboratoire d Optique Atmopsherique,
Lille, FRANCE
An algorithm has been developed for the daily monitoring of aerosol optical thickness over land from
geostationary MSG/SEVIRI measurements (GEO) using high-quality information from a sensor on a polar
and low Earth orbit (LEO) such as MODIS.
This algorithm, so called SMAOL-GEOLEOS (Seviri to Monitor Aerosol Over Land using GEO and LEO
Synergy), is based on an original method composed of three steps : correction of clear sky reflectance
from atmospheric absorption and scattering, determination of the surface reflectance and retrieval of the
aerosol optical thickness.
In a first step, SEVIRI clear sky reflectances in the solar spectrum are corrected from Rayleigh scattering
and gaseous absorption. Then they are corrected from aerosol effects using MODIS/AQUA aerosols
products (MYD04) in coincidence to derive the instantaneous surface reflectance. Because of the lack of
coincident measurement between SEVIRI and MODIS, at least 1 or 2 maximum per day, a relation on the
spectral dependence of the surface reflectance is assumed between VIS06 (630nm) and NIR16 (1610
nm) to determine surface reflectance for SEVIRI measurements in the day not in coincidence with
MODIS.
In a second step, to maximize the spatial coverage of the surface reflectance data, synthesis over 15
days is composed for each slot or time of acquisition. The diurnal variation of the synthesis is finally
fitted with a BRDF model to minimize noise and remaining erroneous values (shadow, clouds, etc ...).
In the last step, using derived surface reflectance values and aerosol model given by MODIS, the Aerosol
Optical Thickness is retrieved at pixel resolution and every 15 minutes.
To illustrate the potentialities of such a synergy between geostationary and low Earth's orbit sensor, first
results of validation versus AERONET are shown. Finally, advantages and limitations of the method are
discussed and future improvements, such as use of different exogenous source of information, are
presented.
Retrieval and Climatology of Stratospheric Aerosols from SCIAMACHY Limb-
Scatter Observations
Brinkhoff, Lena A. 1 ; Ernst, Florian 2 ; Rozanov, Alexei 2 ; von Savigny, Christian 2 ; Bovensmann, Heinrich 2 ;
Burrows, John P. 2
1 2
Institude of Environmental Physics, University of Bremen, GERMANY; Institute of Environmental
Physics, University of Bremen, GERMANY
Stratospheric aerosols belong to the so-called essential climate variables (ECVs). The permanent aerosol
background in the stratosphere is due to tropical injection of tropospheric air containing SO2, OCS and
sulphate particles which are precursors for stratospheric aerosols. An additional contribution is
sporadically caused by an uplift of SO2 after a strong volcanic eruption. Aerosols scatter and absorb solar
and terrestrial radiation. As scattering of solar radiation is the dominating process here, stratospheric
aerosols generally lead to an increasing planetary albedo and thus to tropospheric cooling. According to
the IPCC report 2007 the radiative forcing based on stratospheric aerosols shows the highest
uncertainties in comparison to all other ECVs. To improve this, further investigation of stratospheric
aerosols is necessary. Moreover, stratospheric aerosols are of scientific interest, as they influence the
destruction of ozone being precursors for polar stratospheric clouds and they are hence important for
chlorine activation outside polar vortices. We perform retrievals of stratospheric aerosol extinction
profiles from SCIAMACHY limb-scatter observations. The retrieval algorithm, which is a combination of an
optimal estimation scheme and the radiative transfer model SCIATRAN, uses normalized limb-radiance
profiles at 470 nm and 750 nm wavelength. The goal is on the one hand to study temporal and spatial
variability in stratospheric aerosol extinction as well as the impact of volcanic eruptions and distribution
of volcanic aerosol plumes across the globe, and on the other hand to improve the current retrieval
algorithm. A first analysis of the entire SCIAMACHY stratospheric aerosol data set from 2002 to the
present will be presented and with this also first results on possible long-term trends in background
aerosol loading. Another field of interest is the potential to determine aerosol particle size information
from multi-wavelength observations with SCIAMACHY.
91

The Airbone Volcanic Object Imaging Detector (AVOID): A New Tool for
Atmospheric Airborne Remote Sensing of Clouds
Durant, Adam; Prata, Fred; Kylling, Arve
Norsk institutt for luftforskning, NORWAY
A new on-board dual thermal imaging infrared camera system has been developed to identify water and
volcanic ash clouds during aircraft operation. The system, AVOID, uses interference filters to discriminate
clouds of water and ice from volcanic particles (silicates) through utilisation of the spectral features of
these substances between wavelengths of 8–12 µm. Using a radiative transfer model and information on
the spectral refractive indices of water, ice and silicate ash, a retrieval scheme has been devised to
determine the mass loading and effective particle radius of these substances. Through utilisation of a
narrow band-pass filter centred on 8.6 µm, AVOID can also detect sulphur dioxide (SO2) gas. Proof-ofconcept
tests were recently conducted in Sicily, in the vicinity of Mt Etna volcano and at Stromboli
volcano, during emission of ash and SO2. These data were acquired over altitudes up to ~3.5 km (12000
ft), sampling at frequencies of ~1 Hz. Corrections for the aircraft attitude were made using a fast
response sampling attitude sensor (up to 50 Hz), collocated with the imaging system. During the
campaign 18 flights were achieved and ~30 hours of data were acquired; some preliminary results and
illustrative examples will be presented. Over 90% of these measurements were focussed on
meteorological clouds of water droplets and ice in order to eliminate “false-positive” detection of volcanic
emissions. In parallel, we have developed a sophisticated simulation tool to model the 3D structure of
atmospheric clouds based on Monte Carlo radiative transfer. During March 2012 the AVOID system will
be flown on an AIRBUS A340 at altitudes up to 11.5 km (38000 ft) and initial results will be presented.
This campaign will target measurement of different water cloud types, in addition to dispersing clouds of
volcanic origin (containing volcanic ash, and/or SO2 gas and sulphate aerosol).
Estimating Aerosol Altitude over Ocean from O2 A-Band Absorption Using
MERIS Observations
Dubuisson, Philippe 1 ; Riedi, Jerome 2 ; Ramon, Didier 3 ; Monsterleet, Bruno 3 ; Pascal, Nicolas 4 ; Matusiak,
Stanislaw 4 ; Lifermann, Anne 5
1 2 3 4
Laboratoire d'Optique Atmosphérique, FRANCE; LOA, FRANCE; HYGEOS, FRANCE; ICARE, FRANCE;
5
CNES, FRANCE
Aerosol vertical distribution is a key parameter for radiative forcing studies, for remote sensing
applications, or for air quality forecasts. As an example, scattering by mineral particles can affect the
direct aerosol forcing in the longwave spectral region during dust events, but the effect is dependent on
the altitude of the particles. Knowledge of aerosol vertical structure is also important for inversion of
satellite data since it affects the reflectance measured at the top of the atmosphere. In this respect,
several studies have shown the impact of aerosol vertical structure on the performance of standard
atmospheric correction algorithms in ocean-color remote sensing, especially in presence of absorbing
particles. This study reports on the potential of MERIS measurements for estimating the aerosol layer
altitude over ocean. Characteristics of the MERIS instrument onboard ENVISAT allow aerosol altitude
retrievals using a two-band ratio method. Reflectance ratio measurements in the O2 absorption A-band,
i.e., in spectral bands centred on 760 nm, are sensitive to aerosol altitude. The proposed methodology is
based on simple parameterizations and LUTs, and is easily applicable to MERIS data. LUT coefficients are
calculated as a function of sun-satellite geometrical conditions and aerosol characteristics: altitude,
optical thickness and type (fine and coarse mode). A two-band ratio approach is, however, limited
because only the mean altitude of particles in the total atmospheric column can be retrieved. In addition,
simulations indicate that the methods are only accurate for large aerosol optical thicknesses over dark
surfaces and very sensitive to the spectral position of O2 bands. Altitude retrievals are presented using
MERIS data at global scale over the ocean. This altitude retrieval module is a part of the ALAMO
algorithm, developed by HYGEOS for the characterization of aerosols over ocean using MERIS. Necessary
inputs for altitude retrievals, such as aerosol optical properties, are therefore derived from ALAMO.
MERIS data have been processed by ICARE. Results and accuracy are discussed as a function of the
aerosol optical thickness, especially over aerosol plumes over Atlantic Ocean or polluted areas. Some
comparisons between MERIS retrievals and altitudes derived from the Cloud-Aerosol LIDAR CALIOP (Atrain)
are presented for quasi-simultaneous observations. In addition, impact of the spectral calibration
of MERIS oxygen bands is also discussed. A perspective is given on the operational applicability of this
algorithm.
92

A Six-Year Record of Volcanic Ash Detection with Envisat MIPAS
Griessbach, Sabine 1 ; Hoffmann, Lars 2 ; von Hobe, Marc 3 ; Mueller, Rolf 3 ; Spang, Reinhold 3
1 Forschungszentrum Juelich, GERMANY; 2 Forschunszentrum Juelich, JSC, GERMANY; 3 Forschungszentrum
Juelich, IEK-7, GERMANY
Volcanic ash particles have an impact on the Earth's radiation budget and pose a severe danger to air
traffic. Therefore, the ability to detect and characterize volcanic ash layers on a global and altitudedependent
scale is essential. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)
on-board ESA's Envisat is mainly used for measurements of vertical profiles of atmospheric trace gases.
The instrument is also very sensitive to cloud and aerosol particles. We have developed a fast, simple,
and reliable method to detect volcanic ash in the stratosphere and troposphere using MIPAS spectra.
From calculations of volcanic ash and ice particle optical properties, such as extinction coefficients and
single scattering albedos as well as simulated MIPAS radiance spectra, we derived two optimal micro
windows at 10.5 and 12.1 µm to detect volcanic ash. The calculations were performed with the JUelich
RApid Spectral Simulation Code (JURASSIC), which includes a scattering module. Our method applies
two radiance thresholds to distinguish volcanic ash from ice particles. The first threshold is derived from
a statistical analysis of six years of measured MIPAS radiances in the selected spectral windows. This
statistical threshold accounts only for pure volcanic ash detections. The second threshold is derived from
simulations of MIPAS radiances with JURASSIC for a broad range of atmospheric conditions and tangent
altitudes for volcanic ash and ice particles. The second threshold allows more volcanic ash detections,
because it accounts also for mixtures of ice and volcanic ash particles within the instrument's field of
view. From the JURASSIC calculations we also derive the particle radius and cloud optical depth ranges
for which ash detections are feasible. With the new method major eruptions (from e.g. Chaiten, Okmok,
Kasatochi, Sarychev, Eyafjallajokull, Merapi, Grimsvotn, Puyehue-Cordon Caulle, Nabro) as well as
several smaller eruptions in mid-latitudes and in polar regions between 2006 - 2011 were clearly
identified in the MIPAS data. Trajectory calculations using the Chemical Lagrangian Model of the
Stratosphere (CLaMS) are used to locate a volcanic eruption for each detection. For the time span of May
to August 2011 we show detections of the volcanic ash emitted by the Icelandic Grimsvotn, the Eritrean
Nabro, and the Chilean Puyehue-Cordon Caulle volcanos. As MIPAS measures vertical profiles we
estimate the ash cloud top altitudes. Short time after the eruptions the highest ash cloud altitudes can be
observed. Later on, the ash is diluted and slowly descends with time. The volcanic ash of Grimsvotn is
observed over the Arctic and northern mid-latitudes and remains detectable for about one month. The
Puyehue-Cordon Caulle emitted much more ash so that it is detected up to two month after the first
eruption. The data show that the ash spreads over the entire southern hemisphere mid-latitudes.
93

Assessing the Performance of the High Resolution MODIS MAIAC AOD Product
in the Alpine Region
Petitta, Marcello 1 ; Emili, Emanuele 2 ; Lyapustin, Alexei 3 ; Wang, Y. 4 ; Popp, Christoph 5 ; Korkin, S. 6 ;
Wunderle, Stefan 7 ; Zebisch, Marc 1
1 EURAC, ITALY; 2 Institute for Applied Remote Sensing, European Academy, Bolzano, Italy, and 3
Institute of Geography, University of Bern, Bern., ITALY; 3 Goddard Space Flight Center, Greenbelt,
Maryland., UNITED STATES; 4 Goddard Space Flight Center, Greenbelt, Maryland and GEST, University of
Maryland Baltimore County, Baltimore, Maryland, UNITED STATES; 5 Empa, Swiss Federal Laboratories
for Materials Science and Technology, Dubendorf, SWITZERLAND; 6 Goddard Space Flight Center,
Greenbelt, Maryland and GESTAR, Universities Space Research Association, Columbia, Maryland.,
UNITED STATES; 7 Institute of Geography, University of Bern, Bern, SWITZERLAND
The MODIS standard Aerosol Optical Depth (AOD) product (MOD04) has a horizontal resolution of 10km
which is sufficient for most application such as global aerosol monitoring. Conversely, the observation of
aerosols in complex mountain regions like Alps, where aerosol abundance vary at scales of a few
kilometers, is often difficult or impossible with MOD04 or similar products from other space borne
instrument. For this reason, satellite high resolution products are required to detect small scale aerosol
features in mountain regions. Recently, the Multi-Angle Implementation of Atmospheric Correction
(MAIAC) algorithm developed for MODIS performs a simultaneous retrieval of surface bidirectional
reflection and aerosol properties at a resolution of 1km. This algorithm has a global scope and works
over both dark and bright surfaces; it has an internal cloud mask and snow detection, and provides an
enhanced data coverage with respect to the MODIS standard product which all together is very appealing
for the Alpine region. In this study, we analyze MAIAC AOD in the European Alpine region for the years
2008-2009. We developed a filter to correct the AOD noise due to unresolved clouds and snow pixel
contamination which are characteristic of our study region. The filtering approach is divided in three
steps: a coarse and fine mode fraction filter, a proximity-cloud filter and an AOD standard deviation
filter. This methodology preserves the spatial resolution and enhances the accuracy of MAIAC AOD for
air-quality and climatological applications. We validated MAIAC AOD with AERONET measurements in the
alpine region and we compared it with MODIS product MOD04. In our results we found similar accuracies
for both products (RMSE=0.05) but with MAIAC providing about 50% more observations in the area,
because of its higher spatial resolution and less restrictive filtering. We also compared MAIAC with
ground measurements of aerosol mass (PM10), the results show that MAIAC AOD can be used to detect
the fine scales of aerosol variability (2-3 km) in the mountains. Evidence of AOD variability in the
mountains (up to 0.1−0.2) at scales of several km (width of valleys) is confirmed by the satellite
retrieval. Finally, AOD maps for the Alpine region demonstrate that topography is correlated with the
average aerosol spatial distribution. We conclude that 1km retrieval gives valuable insights for mapping
aerosols in a topographically complex terrain, provided that some care is used with cloud/snow related
artifacts. Sampling frequency have been quantified in the region and is everywhere lower than 50%, but
the product of AOD accuracy and sampling frequency with MAIAC is higher than the one achievable with
other polar orbiting sensors or MODIS global AOD algorithm.
The AERGOM Stratospheric Aerosols Dataset: Preliminary Results
Robert, Charles; Vanhellemont, Filip; Bingen, Christine; Mateshvili, Nina; Fussen, Didier
Belgian Institute for Space Aeronomy, BELGIUM
In the framework of the ESA AERGOM project, a new stratospheric aerosol retrieval algorithm dedicated
to the GOMOS experiment has been developed. This new algorithm greatly enhances the quality of the
retrieval mainly due to the extension of the spectral range used, a refinement of the aerosol spectral
parameterisation, the simultaneous inversion of all atmospheric species as well as an improvement of the
Rayleigh scattering correction. The retrieval algorithm now allows for a proper characterisation of the
stratospheric aerosol extinction at various wavelengths, which can then be used to derive the particle
size distribution without any particular assumption on its functional form. In this work, stratospheric
aerosol extinction, AOD, particle size and other derived properties will be presented, based on the new
aerosol dataset processed using the AERGOM retrieval algorithm and GOMOS version 5.0 official data
product. Singular profiles as well as gridded data will be presented, with the gridded dataset derived on a
grid of 2.5° in latitude, 10° in longitude and 1 km in the vertical direction. A comparison with the official
GOMOS aerosol data product will also be shown, and the various features of the data set will be
analysed. This aerosol dataset is used in the framework of Aerosol_CCI, one of the 11 ESA Climate
Change Initiative projects. The objective of Aerosol_CCI is to realize the full potential of ESA Earth's
Observation archives by better understanding the differences between various aerosol algorithms, and by
developing further innovative retrieval approaches to take maximum benefit of the combined information
content of the different instruments. In this respect, the GOMOS dataset enables the computation of
suitable corrections to take into account the perturbations of tropospheric satellite measurements by the
stratospheric compound.
94

Optical Properties of Volcanic Ash
Peters, Daniel 1 ; McPheat, Robert 2 ; Grainger, Don 1
1 University of Oxford, UNITED KINGDOM; 2 RAL, UNITED KINGDOM
The recent eruption of Eyjafjallajökull volcano has emphasized the importance measuring volcanic ash
clouds remotely. Current methods of detection use wavelengths from the UV to infra-red both actively
(LIDAR) and passively (radiometers and spectrometers) on both ground and satellite platforms.
Underpinning these remote measurements is the requirement to know the optical properties of the ash.
As ash composition varies from eruption to eruption the refractive index also differs; our aim is to derive
the refractive index of a range of ashes including Eyjafjallajökull. The refractive index data are required
and will underpin remote measurements and further work. This poster shows our latest findings.
Characterizing the Diurnal Cycle of Clouds Using Multiple Satellite Platforms
Maddux, Brent 1 ; Maddux, Brent 2 ; Meirink, Jan Fokke 2
1 Koninklijk Nederlands Meteorologisch Instituut (KNMI), NETHERLANDS; 2 KNMI, NETHERLANDS
The diurnal cycle of clouds represents a major source of uncertainty in the assessment of satellite cloud
data records. In some regions and clouds types it is larger than the seasonal cycle. Its full
characterization will enable scientists to account for uncertainties among satellite data records from
instruments in polar orbit with different equatorial overpass times, interpret differences among satellite
data records and models with more confidence, and better characterize the role clouds play in the earth
radiation budget.
We use data from the Spinning Enhanced Visible Infra-Red Imager (SEVIRI) to tie multiple polar orbiter
cloud data records(e.g., AATSR, MODIS, AVHRR) to a common time in the diurnal cycle. Our technique
characterizes the diurnal cycle independently for disparate cloud types using various cloud properties and
ancillary data sets at Level-2 and Level-3 scales. We provide two distinct statistical measures of the
magnitude and variability for the diurnal cycle of clouds. The first is tied to a specific time and location
within each data record. The second is the statistical relationship between cloud types and the diurnal
cycle that is based on all available polar and geostationary data. This project is part of the Cloud CCI
project to establish a cloud data record.
95

Impact of Cloud Heterogeneities on the Optical and Microphysical Cirrus
Properties Retrieved from Thermal Infrared Radiometry.
Fauchez, T. 1 ; Dubuisson, P. 1 ; Cornet, C. 1 ; Szczap, F. 2
1 LOA Université de Lille 1, FRANCE; 2 LaMP Clermont-Ferrand, FRANCE
Clouds are key parameters in the climate and radiative budget of the Earth. They are however difficult to
handle due to temporal and spatial variabilities on their microphysical (size, shape) and macrophysical
properties (optical thickness, fractional coverage, cloud top variation..). In the atmosphere, clouds are
three-dimensional structures but classical retrieval algorithms of cloud parameters are based on the IPA
(Independent Pixel Approximation) assumption because of operational constraints. This approximation
assumes clouds as plane-parallel homogeneous and infinite layer, introduces errors in the computation of
the thermal brightness temperature and thus in the optical and microphysical retrieved parameters. Lot
of studies were conducted on the effects of cloud heterogeneities on the cloud products obtained by
visible measurements. These studies were done mainly for strato-cumulus clouds. Heterogeneity effects
on cirrus cloud parameters have yet not been a lot studied especially from thermal infrared bands, even
if it is an important information to characterize optical and microphysical properties of cirrus clouds (ex :
size particles, water and ice contain etc ..). Many spatial atmospheric sensors are dedicated to the study
of cloud in the infrared, for example, the instruments AATSR (Advanced Along Track Scanning
Radiometer) on board the ENVISAT satellite, MODIS (Moderate Resolution Imaging Spectroradiometer)
on board TERRA and AQUA and IIR (Infrared Imager Radiometer) on board Calipso. They observe the
atmosphere in two or three different wavelengths: 8.65 μm, 10.60 μm and 12.05 μm and with a spatial
resolution of 1x1 kilometer. The goal of this study is to quantify the importance of cirrus heterogeneities
in the thermal infrared radiative transfer. To realize this objective, it is necessary to use accurate cloud
and radiative transfer models. In this work, the generation of a three-dimensional uncinus cirrus clouds
is made by a stochastic model named 3DCLOUD (LaMP) in respect to realistic atmospheric conditions and
the 3DMCPOL (LOA) code is used to simulate infrared radiometer measurements (brightness
temperatures) of a cirrus cloud. The radiative transfer (RT) simulations are done at the wavelengths and
the spatial resolution of the sensors described previously. For each cloud field, two types of simulation
are realized: a 3D RT simulation at a high spatial resolution of 100m, which is next averaged at 1km and
a IPA RT simulation where the cloud properties are first degraded at 1km. Then, an inversion algorithm is
applied to the 3D and IPA brightness temperature fields to retrieve cirrus optical thickness and effective
diameter. In this poster, we analyze differences between parameters (effective diameter, optical
thickness) retrieved with the 3D and IPA simulations and give conclusions on the impact of cirrus
heterogeneities in the inversion process.
Synergetic Use of Multiple Data Set for the Derivation of Gridded Stratospheric
Aerosol Fields
Bingen, Christine; Robert, Charles; Vanhellemont, Filip; Mateshvili, Nina; Fussen, Didier
BIRA-IASB, Brussels, BELGIUM
Nowadays, satellite, ground-based and in situ measurements are able to provide very rich information
about stratospheric aerosols. Satellite experiences (SAGE II, GOMOS, OSIRIS, etc.) provide extinctions
at instrument-specific wavelengths with a large, often global or near global coverage, as the result of a
retrieval of which the methodology has to be adapted to the experimental technique. Size information
has been derived from SAGE II extinctions, in some case combined with other satellite data set (CLAES),
whereas in the case of the most recent limb sounders OSIRIS and SCIAMACHY, a particle size
distribution has to be assumed to build up a forward model for radiative transfer calculations in the
extinction retrieval algorithm. In all cases, aerosol satellite measurements suffer from a theoretical
limitation: they are unable to discriminate very thin particles in the Rayleigh limit of diffraction and
mainly sensitive for large particles. On the other hand, in situ measurements by optical particle counting
provide direct, local and detailed information on the particle size distribution. They are particularly wellsuited
to detect thin particles but less performing for large particles. All these sources of information
provide a wide range of diverse data sets that can be used to feed models, but combining all of them in a
coherent whole and taking into account the limitations and specificities of each of them to derive the
most accurate gridded fields is challenging. The present work investigates a way to develop a
methodology for the derivation, from multiple measurement data sets, of a gridded field reflecting in an
optimal way the real distribution of stratospheric aerosols.
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Remote Sensing of Stratospheric and Upper Tropospheric Aerosols by Means of
Ground-Based Twilight Sky Spectral Photometry.
Mateshvili, Nina
Belgian Institute for Space Aeronomy, BELGIUM
The presence of aerosol in the stratosphere – upper troposphere essentially disturbs twilight sky
brightness, especially in red – near infrared wavelengths. In this wavelength domain, the stratospheric
aerosol layer causes a prominent “hump” on a curve of the twilight sky spectral brightness as a function
of the solar zenith angle. Stratospheric and upper tropospheric aerosol extinction profiles over Caucasus
region were retrieved at the measurement wavelength 780 nm. The twilight sky brightnesses were
modeled in spherical atmosphere approximation using Monte-Carlo technique to represent correctly
multiple scattering. The retrieved stratospheric aerosol was in a background condition from October 2009
to June 2011 with the optical depth varying in the range 0.01 - 0.02. A sharp increase (up to 0.08-0.1)
in July-August 2011 was observed after the Nabro eruption (June 2011, Eritrea).
LIDAR Climatology of Vertical Aerosol Structure for Space-Based LIDAR
Simulation Studies (LIVAS)
Amiridis, Vasilis 1 ; Kazadzis, Stelios 2 ; Marinou, Eleni 1 ; Giannakaki, Eleni 3 ; Mamouri, Rodelise 4 ; Kokkalis,
Panagiotis 4 ; Tsekeri, Alexandra 1 ; Herekakis, Themistoklis 1 ; Ulla, Wandinger 5 ; Gelsomina, Pappalardo 6 ;
Alexandros, Papayannis 4 ; Dimitrios, Balis 7
1 ISARS / National Observatory of Athens, Greece, GREECE; 2 IERSD / National Observatory of Athens,
Greece, GREECE; 3 Aristotle University of Thessaloniki, Thessaloniki, GREECE; 4 National Technical
University of Athens, Athens, GREECE; 5 Institute for Tropospheric Research, Leipzig, GERMANY; 6 Istituto
di Metodologie per l'Analisi Ambientale, Potenza, ITALY; 7 Aristotle University of Thessaloniki, GREECE
LIVAS (LIDAR climatology of Vertical Aerosol Structure for space-based LIDAR simulation studies) is an
ESA project that will provide a global multi-wavelength (355-2050 nm) aerosol and cloud profile
climatology for use in current and future ESA¢s LIDAR end-to-end simulations of realistic atmospheric
scenarios as well as retrieval algorithm testing activities. The climatology is based on CALIPSO
observations at 532/1064 nm and aerosol-type dependent spectral conversion factors, derived from
EARLINET database and ancillary ground-based measurements or suitable selected optical models.
Specifically, the extinction- and backscatter-related aerosol-type-dependent conversion factors from UV
to infrared is extracted from multi-year, ground-based aerosol measurements of the EARLINET aerosol
network, as well as experimental campaigns focusing on specific aerosol types (e.g. SAMUM). The exact
methodology followed for LIVAS is presented in this study along with examples of the climatological
profiles. The vertical distributions of the retrieved optical parameters are provided at high spatial and
vertical resolution in order to ensure realistic simulations of the atmospheric variability in LIDAR end-toend
simulators.
Aerosol Optical Depth and Aerosol Classification by GOCI over East Asia
Kim, Kwan Chul 1 ; Lee, Kwon-Ho 2 ; Kim, Young J. 1
1 2
Gwangju Institute of Science and Technology, REPUBLIC OF KOREA; Kyungil university, REPUBLIC OF
KOREA
The first Geostationary Ocean Color Imager (GOCI) instrument on board the Communication Ocean and
Meteorological Satellite (COMS) platform developed by Korea Aerospace Research Institute (KARI)
measures reflected solar radiation at 8 narrowband channels (412, 443, 490, 550, 660, 680, 745, 865
nm) with much higher spatial resolution (500m at nadir). In this study, we have developed the aerosol
retrieval algorithm for COMS/GOCI, which is a modified version of the SaTellite Aerosol Retrieval (STAR)
algorithm (Lee and Kim, 2010) for off-line aerosol retrieval over East Asia. The 500m resolution GOCI
Level 1B calibrated radiance data obtained from Korea Ocean Satellite Center have been used. Optical
properties of aerosol over target areas of GOCI were also analyzed from extensive observations of
AERONET sunphotometer network to generate look-up tables. The STAR algorithm uses a separation
technique that can distinguish aerosol reflectance from the top-of-atmosphere (TOA) reflectance. Aerosol
classification method has separated the contribution of each aerosol type over East Asia based on the
spectral aerosol optical properties. The comparison of the retrieved GOCI AOD with those by ARONET
sunphotometer and LIDAR observations shows good correlation coefficient (R>0.8). Especially, the
application of STAR algorithm has improved the accuracy of retrieving GOCI AOD with fine temporal
resolution which can provide information on the diurnal variation of aerosol loading over the area of
interest
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The MODIS 3 km Product: Algorithm and Global Perspective
Mattoo, Shana 1 ; Remer, Lorraine 2 ; Levy, Robert C 1 ; Munchak, Leigh 1
1 SSAI/GSFC/NASA, UNITED STATES; 2 GSFC\NASA, UNITED STATES
The Moderate resolution Imaging Spectroradiometer (MODIS) has been producing a global aerosol
product at a nominal 10 km spatial resolution since early 2000, using the standard Dark Target
procedures. Recently a finer resolution product at a nominal 3 km resolution has been developed and will
become part of the standard publicly available MODIS data archive. The only differences between the
algorithm that produces the Dark Target 3 km product and the one that produces the 10 km product are
the way the input pixels are organized and the number of pixels required to proceed with a retrieval. The
3 km product is more conservative in that it requires a higher percentage of non-cloudy pixels to survive
the masking before making a retrieval. The 3 km product does not include some of the diagnostics
available at 10 km, but otherwise outputs almost identical parameters at the finer resolution. The 3 km
algorithm applied to a set of 6 months of MODIS data allows us to test the new product in a global sense.
Overall the 3 km product closely mirrors the results of the 10 km product, but it is able to better resolve
smoke plumes, fine details of aerosol distributions imposed by geographic features and producing
products in some areas where the 10 km product is missing. On the other hand, the 3 km product does
introduce greater noise. Over land the 3 km product appears to be biased high against the 10 km
product by roughly 0.01. Over ocean there is no overall bias, but day to day variation depending on the
aerosol situation each day. Preliminary validation against AERONET shows that the 3 km product is at
least as accurate as the 10 km product, and perhaps even exhibiting a higher correlation and regression
slope closer to 1.
New and Forthcoming ‘Deep Blue’ Aerosol Datasets from NASA Sensors
Sayer, Andrew; Hsu, Christina; Jeong, Myeong; Bettenhausen, Corey
NASA GSFC, UNITED STATES
The ‘Deep Blue’ retrieval approach extended the coverage of aerosol optical depth (AOD) retrievals from
the NASA Moderate Resolution Imaging Spectrometer (MODIS) Collection 5 data to bright reflecting
source regions, such as the Sahara and Asian deserts. Recently, the approach was updated and used to
generate a new 13-year record of AOD from the Sea-Viewing Wide Field-Of-View Sensor (SeaWiFS),
covering deserts, vegetated land, and oceans. The refined Deep Blue algorithm will be applied in the
forthcoming MODIS Collection 6 dataset, where coverage will be expanded to vegetated surfaces,
providing a second retrieval to complement the existing ‘Dark Target’ algorithm. Finally, Deep Blue will
be applied to data from the recently-launched Visible and Infrared Radiometer (VIIRS) aboard the
National Polar-orbiting Partnership (NPP) satellite ‘Suomi’. This presentation will provide an introduction
into these new and forthcoming aerosol datasets, including developments in Deep Blue between MODIS
Collections 5 and 6; an overview and some results from the SeaWiFS dataset; and a look at the
capabilities of the new VIIRS sensor.
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Evaluation of the MODIS 3 km Aerosol Product over an Urban/Suburban
Landscape
Munchak, Leigh 1 ; Levy, Robert 1 ; Mattoo, Shana 1 ; Remer, Lorraine 2 ; Holben, Brent 3 ; Schafer, Joel 4 ;
Smirnov, Alexander 4 ; Ferrare, Richard 5 ; Burton, Sharon 6 ; Hostetler, Chris 5
1 NASA-GSFC/SSAI, UNITED STATES; 2 NASA-GSFC, UNITED STATES; 3 NASA, UNITED STATES; 4 NASA-
GSFC/Sigma Space, UNITED STATES; 5 NASA-LaRC, UNITED STATES; 6 NASA-LaRC/SSAI, UNITED
STATES
The MODIS sensors aboard the Terra and Aqua satellites have provided a rich dataset of aerosol optical
depth global distributions at a nominal 10 km spatial scale with the intended purpose of understanding
aerosols in the climate system. The air quality community quickly became interested in using satellite
data for air-quality applications; however, the 10 km resolution is not sufficient to resolve some smallscale
features including biomass burning plumes and point anthropogenic aerosol sources. With this in
mind, MODIS Collection 6 is including a 3 km resolution global aerosol product. This product is evaluated
against airborne sensors such as the High Spectral Resolution LIDAR (HSRL) and ~40 ground and ship
based sun photometers (AERONET/MAN), all deployed over the Baltimore/Washington DC corridor over
the summer of 2011 under the auspices of the DISCOVER-AQ campaign. Throughout the campaign, both
the 10 km and 3 km products compare well to AERONET/MAN. As compared to the 10 km product, the 3
km product is better able to resolve aerosol distributions during events that create strong aerosol spatial
gradients (e.g., frontal passage and convective outflow). The 3 km product is also able to retrieve over
the Chesapeake Bay, an estuary with width of ~10 km in the region of study. However, the 3 km product
is noisier than the 10 km product. Despite this limitation, the 3 km MODIS aerosol product provides a
novel look at aerosols on a regional scale.
Atmospheric Composition and Optical Depth Measurements from MAESTRO on
the ACE Satellite
McElroy, Tom 1 ; Zou, Jason 2 ; Drummond, James 3 ; Bernath, Peter 4
1 2 3 4
York University, CANADA; University of Toronto, CANADA; Dalhousie University, CANADA; University
of York, UNITED KINGDOM
The Canadian Atmospheric Chemistry Experiment (ACE) has now been operating on orbit since August,
2003. The satellite, called Scisat by the Canadian Space Agency which funded its development, was
launched under a cooperative agreement with NASA which provided the Pegasus launch. The primary
instrument on ACE is the ABB Bomem infrared, Fourier transform spectrometer. MAESTRO
(Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) is a
UV-Visible-Near-IR dual spectrophotometer included primarily to extend the wavelength range (280 to
1000 nm) over which aerosol extinction information could be obtained. Occultation measurements are
very important because of their high vertical resolution, large altitude range and the long-term stability
of the measurements which can be achieved. The instrument performance, data analysis methodology
and some measurement results will be presented.
99

OMI Simulated Aerosol Index: Initial Results and Verification as Part of the
Aerosol-CCI Project
Stein Zweers, Deborah
KNMI Royal Netherlands Meteorological Institute, NETHERLANDS
As part of the ESA Aerosol-Climate Change Initiative (CCI) work has been carried out using the Ozone
Mon- itoring Instrument (OMI) aerosol index to address two Aerosol-CCI objectives: 1) to create a longterm
record of aerosol index data and 2) to evaluate the feasibility of creating a simulated aerosol index.
The latter objective is designed to facilitate comparisons between satellite measured aerosol index
datasets and information from atmospheric chemical (transport) models or climate models about the
presence of aerosols. The simulation of the aerosol index also facilitates the creation of necessary
correction and offset factors needed to create a long-term aerosol index dataset based on differences
which arise from combining multiple data sources (ie. OMI, GOME, TOMS) which have differing
wavelength pairs and overpass times. A wide range of simulations have been carried out using aerosol
properties defined by the Aerosol-CCI group in a common set of aerosol models including strongly and
weakly absorbing particles, sea salt and desert dust. The common aerosol model properties for these
four aerosol types have been used to carry out radiative transfer simulations using optimal estimation
based DISAMAR (Determining Instrument Specifications and Analyzing Methods for Atmospheric
Retrieval). This software is used to retrieve surface albedo to calculate the aerosol index based on
variations in aerosol layer height, optical thickness, viewing geometry and wavelength pair. The results
of these simulations are used to establish dependencies of the aerosol index in these properties including
variations in solar zenith angle or wavelength pair. These simulated dependencies are then evaluated
using OMI and GOME-2 data. Monthly means have been analyzed for several different seasons and years
to test just how realistic the simulation-derived dependencies are. The results from these simulations are
also used to build a look-up table for determining aerosol index based on typical aerosol model output
parameters. The initial results of the simulations and the OMI to GOME-2 data comparison is presented
and discussed.
Satellite Observations on the Production of Sea Spray Aerosol
de Leeuw, Gerrit 1 ; Korhonen, Hannele 2 ; Ovadnevaite, Jurgita 3 ; Manders-Groot, Astrid 4 ; Sogacheva,
Larisa 2 ; Lappalainen, Hanna 5 ; Schaap, Martijn 4 ; O'Dowd, Colin 3 ; Pinnock, Simon 6
1 2 3 4 5
FMI / Univ Helsinki, FINLAND; FMI, FINLAND; NUIG, IRELAND; TNO, NETHERLANDS; Dep of Physics,
Univ. of Helsinki, FINLAND; 6 ESA, ITALY
The amount of sea spray aerosol (SSA) produced per area of sea surface and per unit of time is
described by the sea spray source function which can be formulated in terms of meteorological and
oceanographic parameters. The most common of these parameters is the wind speed, and in some
formulations also use sea surface temperature is used, to provide quantitative information on the
production of SSA. In addition, information on enrichment in organic matter is obtained from satellitederived
ocean chlorophyll data which is used as a proxy. The scientific objective of the ESA Oceanflux
Sea Spray Aerosol (OSSA) project is to further explore the use of satellite data to obtain information on
the production of SSA and, based on the results, develop an improved source function. Satellite data
provide information on a global scale, with a repeat time varying with the satellite platform and
instrument and sampling strategy, of a variety of geo-physical quantities which often are only available
as local point measurements, or through campaigns with a limited duration. The strategy of the OSSA
project is to use these EO data in addition to already available information rather than replace it. For
instance, excellent information on wind speed is available to the modelers through the ECMWF data with
known and sufficient (in view of other uncertainties in the SSSF formulation) accuracy. Hence it will not
be useful to replace this data with satellite observations. However, other information which may be
important for the production of SSA, such as chlorophyll, sea surface temperature or wave information,
is generally not available except from satellites and the use of such information has only been explored
through few laboratory experiments and verified indirectly in the field. Satellites have thus far little been
used for this purpose and the exploration of the use of such data may further develop the scientific
understanding of the production of SSA and the role of SSA in atmospheric processes. In particular,
OSSA sea spray source function results will be implemented in climate models to determine the SSA
radiative effects, direct and indirect through aerosol cloud interaction.
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Retrieval over Aerosol Properties Using the AATSR Dual View Algorithm
de Leeuw, Gerrit 1 ; Kolmonen, Pekka 2 ; Sogacheva, Larisa 2 ; Virtanen, Timo H. 2 ; Rodriguez, Edith 2 ;
Sundstrom, Anu-Maija 3 ; Atlaskina, Ksenia 3 ; Hannukalainen, Meri 3 ; Saponaro, Giulia 1
1 FMI / Univ Helsinki, FINLAND; 2 FMI, FINLAND; 3 Dep of Physics, Univ. of Helsinki, FINLAND
The Advanced Along Track Radiometer (AATSR) flying on the Environmental satellite (ENVISAT)
combines 7 wavebands from the visible to the thermal infrared with two views, one at nadir and one
forward. This renders the instrument very suitable for the retrieval of aerosol properties over both land
and water. Over water each of the two views are used in the single view algorithm (ASV) and over the
land the two views are used together to eliminate the surface contribution from the radiance measured
at the top of the atmosphere. After cloud screening the path radiance contains contributions due to
scattering by gases and aerosols. The AATSR dual view (ADV) algorithm is used to retrieve the aerosol
optical density (AOD) over land at 3 wavelengths by minimizing the difference between calculated and
observed radiances. ADV and ASV build on the algorithms developed by Veefkind et al. (1998) and
Veefkind and de Leeuw (1998) and have been continuously improved based on studies over areas with
widely different aerosol composition and surface characteristics. Significant improvement has been
achieved from experiments made as part of the ESA Aerosol-cci project, including the use of different
combinations of aerosol models, a model/measurement based aerosol climatology and the analysis of the
results using AERONET data. Stringent post-processing and debugging of the code has led to further
improvement. Global AOD maps show the features in different parts of the world such as production and
transport by anthropogenic and natural (desert dust) processes. Examples of the use of the AATSR
algorithms in various studies will be presented. Veefkind, J.P., G. de Leeuw and P.A. Durkee (1998).
Retrieval of aerosol optical depth over land using two-angle view satellite radiometry during TARFOX.
Geophys. Res. Letters. 25(16), 3135-3138. Veefkind, J.P. and de Leeuw, G., 1998b, A new algorithm to
determine the spectral aerosol optical depth from satellite radiometer measurements. Journal of Aerosol
Sciences, 29, 1237-1248.
Retrieval of Aerosol Height with TROPOMI
Sanders, A.F.J.; de Haan, Johan F.; Veefkind, J. Pepijn
KNMI, NETHERLANDS
The Tropospheric Monitoring Instrument (TROPOMI), to be launched in 2015, will feature a new aerosol
product that is specifically dedicated to retrieval of the height of aerosol layers. The Aerosol Layer Height
product will be based on absorption by oxygen in the A-band (759-770 nm). Algorithm development for
the aerosol height product is currently underway at KNMI. In this presentation we will introduce the
product, highlight the algorithm and some of its development issues and discuss possible applications
and example aerosol cases. TROPOMI is a hyperspectral imager with channels in the ultraviolet, visible,
near-infrared and shortwave infrared wavelength ranges, dedicated to remote sensing of the
troposphere. It will have daily global coverage with small 7 x 7 km ground pixels. It is the successor to
OMI and the precursor to ESA's Sentinel-5 mission. Aerosol Layer Height and the Absorbing Aerosol
Index will be TROPOMI's main aerosol products. Aerosol height observations from the near-infrared
wavelength range will help to interpret the Absorbing Aerosol Index. Furthermore, they will improve
retrieval of other aerosol properties, particularly retrieval of absorption optical thickness in the ultraviolet
wavelength range. An increase in absorption can be due to a higher imaginary part of the refractive
index or to the aerosol layer being at a higher altitude. Independent height observations will therefore
further constrain retrieval of the single scattering albedo. In addition, aerosol height information is an
important parameter when estimating radiative forcings and climate impacts of aerosol, it is a significant
source of uncertainty in trace gas retrieval and it helps in understanding atmospheric transport
mechanisms. Finally, timely available, global observations of aerosol height will be of interest to aviation
safety agencies. The retrieval algorithm will be based on a spectral fit of reflectance (resolution 0.5 nm)
across the O2 A absorption band. Aerosols are assumed to be confined to a single layer. The retrieval
method will be optimal estimation to ensure a proper error analysis. The retrieval algorithm will be
particularly sensitive to elevated, optically quite thick aerosol layers. Sensitivity studies have indicated
that accuracy and precision of retrieved height for cloud-free scenes will be well below the TROPOMI
science requirements (1 km). They have also shown that retrieval is robust against inaccurate knowledge
of the single scattering albedo and that precise knowledge of the phase function or the surface albedo is
not needed. Thus, specific knowledge of the aerosol type is not needed for a reliable height retrieval.
101

Remote sensing of Greehouse Gases
Global Retrievals of CO2 and CH4 and GOSAT
Byckling, Kristiina 1 ; Boesch, Hartmut 1 ; Cogan, Austin 1 ; Parker, Robert 1 ; Palmer, Paul 2 ; Feng, Liang 2 ;
Fraser, Annemarie 2
1 University of Leicester, UNITED KINGDOM; 2 University of Edinburgh, UNITED KINGDOM
The first observations of greenhouse gases from a dedicated satellite sensor are now available with the
launch of the Japanese Greenhouse gas Observing SATellite (GOSAT) on 23 January 2009. GOSAT
provides global measurements of total column CO2 and CH4 from its shortwave infrared (SWIR) bands,
which are well suited to improve our knowledge of greenhouse gas surface fluxes, specifically for regions,
which are poorly sampled by surface sites. However, the requirements on precision and accuracy of the
retrieved columns are stringent, representing a major challenge for trace gas retrieval algorithms, and
potential biases introduced by spectral interference from atmospheric aerosols and clouds as well as
uncertainties in spectroscopy and instrument calibration need to be minimized and characterized.
In this presentation we will give an overview over the retrievals of the CO2 and CH4 columns using an
optimal estimation retrieval algorithm and the validation activities against ground-based column
retrievals from the Total Carbon Column Observing Network. We will also present detailed discussion of
the comparison between our global CO2 retrievals from GOSAT with model calculations from the GEOS-
Chem global 3-D transport model to test the consistency between model and observations and we will
show some first results of a surface flux inversion from the global GOSAT CO2 retrievals using an
ensemble Kalman filter.
Retrieval of atmospheric CO2 from Satellite near-Infrared Nadir Spectra: Inter-
Comparison of Various Algorithms
Reuter, Maximilian; Buchwitz, M.; Schneising, O.; Heymann, J.; Bovensmann, H.; Burrows, J.P.
University of Bremen, GERMANY
Carbon dioxide is the most important anthropogenic greenhouse gas. Its global increasing concentration
in the Earth's atmosphere is the main driver for global warming. However, in spite of its importance,
there are still large uncertainties on its global sources and sinks. Satellite measurements, if accurate and
precise enough, have the potential to reduce these surface flux uncertainties. At present, there are only
two satellite instruments orbiting the Earth which are able to measure the CO2 mixing ratio (XCO2) with
large sensitivity also in the boundary layer. These are SCIAMACHY (launched in 2002) and GOSAT
(launched in 2009). Worldwide, several teams of scientists are developing algorithms aiming to meet the
challenging user requirements. The majority of these groups take part in ESA's climate change initiative
(CCI) on greenhouse gases (GHG) where their algorithms stand into competition. Within the
presentation, recent inter-comparison results will be shown focusing on global SCIAMACHY nadir
observations.
Influence of Tropopause Height on Vertical Distribution of Ozone, A Study at
low Latitude Using UARS Data
Patel, Shailesh
St xavier's college, INDIA
The Halogen Occultation Experiment (HALOE) has been collecting profiles of middle atmosphere
composition and temperature on board the Upper Atmosphere Research Satellite (UARS). In present
study we have used ozone and temperature profiles at five different heights 20 km, 25 km, 30 km, 35
km and 40 km for the period Nov 1991 to Dec 2005 at low latitude (23 o N, 75 o E) of UARS satellite.
Volume Mixing Ratio (VMR) of O3 at 25 km and 30 km are ~5x10 -6 and ~6.9x10 -6 in winter respectively.
Tropopause height(TH) during winter is around 17 km and during summer around 17.5 km. Sometimes
tropopause is also seen above 18 km. However no signature of double tropopause is seen. Regression
analysis shows that tropopause height increases about 0.3 km/decade. Influence of tropopause height on
ozone at above mentioned five different heights has been studied. We found positive correlation between
two parameters at tropopause. Results will be presented.
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Improved Retrieval of Methane Profiles from SCIAMACHY Solar Occultation
Measurements with Onion Peeling DOAS
Noël, Stefan; Bramstedt, Klaus; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John P.
University of Bremen, GERMANY
Recently, first stratospheric methane profiles have been derived from solar occultation measurements of
the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) using the
so-called "Onion Peeling DOAS" (ONPD) method. The ONPD method is based on a combination of an
onion peeling approach with a modified DOAS (Differential Optical Absorption Spectroscopy) fit. First
comparisons of the SCIAMACHY methane profiles with data provided by the Atmospheric Chemistry
Explorer Fourier Transform Spectrometer (ACE-FTS) showed a good agreement within about 10% in the
altitude region between 20 to 40 km (see Noël et al., AMT, 2011).
Meanwhile, the ONPD retrieval method has been further improved by e.g. taking into account various
pointing effects and pressure and temperature profiles also derived from SCIAMACHY solar occultation
measurements. As a consequence, the vertical range in which reasonable methane data can be obtained
from SCIAMACHY occultation measurements could be extended to altitudes below 20 km.
In this presentation we will show first results of this improved ONPD methane retrieval.
IASI/METOP Sounder Contribution for Atmospheric Composition Monitoring
Oudot, Charlotte 1 ; Clerbaux, Cathy 1 ; Hadji-Lazaro, Juliette 1 ; George, Maya 1 ; Safieddine, Sarah 1 ; Lieven,
Clarisse 2 ; Hurtmans, Daniel 2 ; Coheur, Pierre 1
1 UPMC Univ Paris 6, CNRS/INSU, LATMOS-IPSL, FRANCE; 2 Spectroscopie de l'atmosphère, Chimie
Quantique et Photophysique, Université Libre de Bruxelles, BELGIUM
During the last decade, remote sensing sounders have demonstrated their capability for monitoring
atmospheric composition and pollution. The Infrared Atmospheric Sounding Interferometer (IASI)
instrument is a high resolution, nadir viewing Fourier Transform Spectrometer working in the thermal
infrared range extending from 645 to 2760 cm -1 (with no gaps). Flying on a polar orbit on the METOP-A
platform since 5 years, IASI delivers more than 1.3.10 6 spectra per day and provides global coverage
twice a day. It is characterized by an apodized resolution of 0.5 cm -1 and a low radiometric noise. From
the IASI spectra concentrations for several atmospheric key species can be retrieved. These include
strong absorbers such as CH4 or O3 and also weakly absorbing molecules detected during extraordinary
events, like SO2 during volcanic eruption or reactive species in fire plumes.
With now 5 years of atmospheric monitoring available from the IASI mission, long term variations for key
species can also be analyzed from the observations. A detailed analysis based on Level 1 (spectra) and
Level 2 data (concentrations) will be provided. Special events such as volcanic eruptions, fires plume or
pollution episodes are studied from the comparison of fully resolved IASI spectra along with
reconstructed spectra using principal component analysis.
Retrieval of Methane Line Parameters Around 1.6 Microns from Laboratory
Spectra
Humpage, Neil 1 ; Serdyuchenko, Anna 2 ; Gorshelev, Victor 2 ; Buchwitz, Michael 2 ; Remedios, John J. 1 ;
Burrows, John P. 2
1 2
Earth Observation Science, University of Leicester, UNITED KINGDOM; Institute of Environmental
Physics, University of Bremen, GERMANY
Atmospheric methane makes a significant contribution towards the greenhouse effect, and its abundance
in the atmosphere is related to anthropogenic activity. There is consequently much interest in monitoring
the global distribution of methane from space over long time periods to a high level of accuracy. The
successful retrieval of methane concentrations from near-infrared spectral radiances, as measured by
satellite instruments such as SCIAMACHY on board ENVISAT and TANSO-FTS on board GOSAT, relies on
an accurate knowledge of methane spectroscopic line parameters. Whilst a significant amount of
methane spectroscopic data is already available at near-infrared wavelengths, there is still a need for
improved line parameters if the space-borne spectral observations of the Earth’s atmosphere are to be
used to their full potential.
The line parameter database used in SCIAMACHY and GOSAT retrievals of methane is HITRAN 2008. The
methane line parameters around 1.6 microns in HITRAN 2008 are based on the analysis of laboratory
spectra measured at the University of Bremen (Frankenberg et al, 2008). However, only a limited range
of measurements were used in the analysis, covering only room temperature samples and using only
nitrogen (rather than air) as a buffer gas. This work describes further laboratory measurements
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(performed at the Molecular Spectroscopy Laboratory at the University of Bremen, Germany, and the
Molecular Spectroscopy Facility at the Rutherford Appleton Laboratory in the UK) which extend the range
of sample temperatures to those more representative of atmospheric temperatures, and consider dry air
and oxygen as alternative buffer gases.
The analysis of these new spectra is carried out using a line parameter calculation technique, developed
at the University of Leicester, which is described here. The technique makes use of an optimal estimation
approach (more commonly used in the retrieval of atmospheric composition from satellite
measurements), which aims to minimise the difference between measured and simulated radiance
spectra by iteratively adjusting a state vector. The retrieval of atmospheric composition from satellite
measurements assumes that the line parameters are fixed, whilst the atmospheric profiles used to
forward model the measured spectra are optimised to reduce the model-observation residual. Here, we
employ the opposite approach; we fix the sample cell conditions (composition, pressure, temperature),
and create a state vector from the line parameters, which is then iteratively adjusted until the optimal
parameters minimising the model-observation residual are obtained. We compare the retrieved line
parameters with those previously published (Frankenberg et al, 2008; Lyulin et al, 2009) to demonstrate
the suitability of this technique for analysing laboratory spectra. Future work will focus on the testing of
our new line parameter dataset in SCIAMACHY and GOSAT retrieval schemes as part of the ESA
ADVANSE-II project.
Impact of Uncertainties in Atmospheric Mixing Representation on Simulated
UTLS Composition and Related Radiative Forcings
Riese, Martin 1 ; Plöger, Felix 1 ; Vogel, Bärbel 1 ; Konopka, Paul 1 ; Dameris, Martin 2 ; Forster, Piers 3
1 Forschungszentrum Jülich, GERMANY; 2 DLR, GERMANY; 3 University of Leeds, UNITED KINGDOM
The upper troposphere / lower stratosphere (UTLS) region plays an important role in the climate system.
Changes in the structure and chemical composition of this region result in particulary large changes in
radiative forcings (RF) of the atmosphere. Quantifying the processes that control UTLS composition (e. g.
stratosphere-troposphere exchange) therefore represents a crucial task. We assess the influence of
uncertainties in the representation of transport (irreversible mixing) in model simulations on the global
UTLS distributions of greenhouse gases (water vapor, ozone, methane, nitrous oxide) and associated
radiative forcings. The study is based on multi-annual simulations with the Lagrangian chemical transport
model CLaMS driven by ERA-Interim meteorological data and a state of the art radiance code. The
results show that simulated radiative forcing values of water vapor and ozone, both with steep gradients
in the UTLS, are very sensitive to the atmospheric mixing strength. Current uncertainties in the model
representation of irreversible mixing result in globally averaged radiative forcing differences of 0.6 and
0.2 Watt/m2 for water vapor and ozone, respectively. For ozone, the largest impact of mixing
uncertainties is observed in the lower stratosphere. In our presentation, illustrate the potential of
PREMIER (PRocess Exploration through Measurements of Infrared and millimetre-wave Emitted
Radiation), one of three candidates for ESA’s 7th Earth Explorer Core Mission, to considerably narrow
down theses uncertainties. The results were obtained in the framework of the PREMIER science impact
study by ESA (phase-A).
Volcanic Carbon Dioxide Retrieved by Means Hyperspectral Data
Spinetti, Claudia; Buongiorno, Maria Fabrizia
INGV, ITALY
Volcanoes represents a natural source of carbon dioxide. Several studies estimate about 34 milions
tons/day global flux of effusive volcanic emissions, such as tropospheric volcanic plume. Absorbing
electromagnetic radiation in several regions of solar spectrum, CO2 plays an important role on the earth
radiation budget, although his concentration is low compared to other atmospheric gases (N2, O2).
Ground networks for measuring atmospheric carbon dioxide has been developed, as the most long-lived
is located at Mauna Loa. While the first spatial mission dedicated to mapping CO2 at global level is the
JAXA GOSAT, starting in 2008. The volcanic contribution of CO2 is important not only for the knowledge
of the atmospheric variations but also to understand the volcano behavior. Indeed, CO2 is directly
implicated in the eruptive mechanism of all volcanoes. However, measurements of volcanic carbon
dioxide are difficult and often hazardous, due to the high background of atmospheric CO2 and to the
inaccessibility of volcanic sites. The hyperspectral remote sensing gives a large and fast view of volcanic
plumes and permits to detect volatiles components exolving from craters if they are abundant and
absorption bands are in the sensor spectral range. In the present study the developed algorithm to
calculate CO2 columnar abundance in tropospheric volcanic plume will be presented. It relies on the
assumption that there is a relationship between the dip in the atmospheric spectrum curve, due to the
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gas absorption, and the gas concentration in the atmospheric column. The algorithm is based on
CIBR ’Continuum Interpolated Band Ratio’ remote sensing technique initially developed to calculate water
vapor columnar abundance. The algorithm has been firstly applied to the digital remote sensing images
acquired by AVIRIS hyperspectral sensor over the Hawaiian Pu’u’O’o Vent cone of the Kilauea volcano
(Hawaii). Then has been adapted to MIVIS data acquired over Stromboli volcano (Italy) and to Hyperion
data over Mt. Etna. The atmosphere has been simulated using Modtran radiative transfer model in the
spectral range between 1,9 to 2,1 microns, where the CO2 absorption band is present. The results are
spatial distributions of CO2 columnar abundance of the volcanic plumes. The obtained results in terms of
CO2 columnar abundance over the Pu’u’O’o Vent has been has been compared to the CO2 flux rate
deduced by the SO2/CO2 ratio measured at ground.
Carbon Gas Retrievals from SCIAMACHY Observations using BIRRA
Gimeno Garcia, Sebastian; Schreier, Franz; Meringer, Markus; Lichtenberg, Günter
DLR, GERMANY
The near infrared (NIR) region of the spectrum contains valuable information about atmospheric
greenhouse gases such as CO2, CH4 or H2O. Moreover, down-looking NIR atmospheric spectra are
sensitive to variations of molecular concentrations over the whole atmosphere, including the lower layers
of troposphere, what makes this spectral region especially suitable for the analysis of emission sources
and sinks. SCIAMACHY aboard the ENVISAT satellite is equipped with 3 channels (6, 7, and 8) on the NIR
region. Channel 8 (2259--2386 nm) is mainly used for CO retrievals, whereas channel 6 (971--1773 nm)
is exploited by most of the existing retrieval algorithms to obtain information on CH4 and CO2. For the
processing of SCIAMACHY NIR data, the BIRRA (Beer InfraRed Retrieval Algorithm) has been
implemented in the operational processor. In order to estimate the actual atmospheric state, BIRRA
performs a separable least squares fit of the measured radiance where the atmospheric parameters are
scaled to fit the observed spectra. The current version of the processor includes CO vertical column
densities among the official products, whereas a new CH4 column-averaged mixing ratio product is
planned for the next release. In this study, we present some representative results of CO and CH4 from
SCIAMACHY NIR spectra using BIRRA.
Future European Greenhouse Gas Satellite Remote Sensing Capabilities - The
Short-Wave Infrared (SWIR) Perspective
Bovensmann, Heinrich 1 ; Buchwitz, M. 1 ; Burrows, J.P. 1 ; Bréon, François-Marie 2 ; Ehret, G. 3 ; Flamant, P. 4 ;
Landgraf, J. 5 ; Bösch, H. 6
1 2 3
University of Bremen, GERMANY; CEA/DSM/LSCE, FRANCE; DLR IPA, Oberpfaffenhofen, GERMANY;
4 5 6
LPSL, École Polytechnique, Palaiseau, FRANCE; SRON, NETHERLANDS; University of Leicester, UNITED
KINGDOM
Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases
causing global climate change. A better understanding of the surface sources and sinks of those
greenhouse gases, the underlying processes, as well as their role in climate feedbacks is important in
order to reliably predict the future climate of our planet. Such applications require highly precise and
accurate satellite CO2 and CH4 data and high sensitivity to near-surface greenhouse gas concentration
changes. With satellite remote sensing this is coming into reach using reflected solar radiation in the
near-infrared/shortwave-infrared (NIR/SWIR) spectral range or using active remote sensing with space
based LIDARs. The usage of SCIAMACHY and GOSAT data of CO2 and CH4 is beginning to demonstrate
that global satellite observations can provide new information on global to regional CO2 and CH4 large
scale surface fluxes and/or on current model deficits. Upcoming future European missions will have some
capabilities to continue the data series currently established by SCIAMACHY and GOSAT. Sentinel 5
Precursor (launch 2015) has - even if not fully optimised for it - CH4 measurement capabilities in the 2.3
µm spectral region. Sentinel 5 (launch 2020) will have good CH4 and potential for some CO2
measurement capabilities with its 1.6 µm channel. Both Sentinels will provide data with daily global
coverage and 7 to 10 km spatial resolution. In addition to those firmly planned ESA missions, on ESA
side the Earth Explorer Opportunity Candidate Mission CarbonSat is aiming for accurate CO2 und CH4
data down to the sub-urban scale (2 km spatial resolution), thereby opening the way to apply the data
down to the local scale. Two national missions currently under preparation in Europe, namely the French
MicroCarb (CO2 passive) and the French-German climate mission MERLIN (CH4-LIDAR) missions need
also to be considered in this context. In this paper the different characteristics of future European
missions will be compared and confronted with user requirements established over the last few years.
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Air Quality Monitoring from Space
Synergisitic LOTOS-EUROS and NO2 Tropospheric Column to Evaluate the NOx
Emission Trends over Europe.
Curier, Lyana 1 ; Segers, Arjo 1 ; Timmermans, Renske 1 ; Eskes, Henk 2 ; Schaap, Martijn 1
1 TNO, NETHERLANDS; 2 KNMI, NETHERLANDS
The quality of available information about sources (emissions) of atmospheric pollutants is a key
parameter in any attempt to represent the current state or predict the future changes of the atmospheric
composition. Besides natural sources and biomass burning, current estimates show that fossil fuel
combustion is responsible for about 50% of the total NOx production. In situ measurements in polluted
areas have shown that the boundary layer contains more than two third of the tropospheric NO2. Hence,
satellite remote sensing providing tropospheric NO2 columns is a suitable answer for the monitoring of
urban pollution. Indeed, recent studies using spaceborne instruments have illustrated that the
tropospheric column of nitrogen dioxide contains valuable information about its sources, transport and
sinks. NO2 timeseries derived from satellites instruments have also been used to study long-term
changes in anthropogenic emissions of NOx. The goal of this study is to estimate the trends in NOx
emissions in Europe and subsequently identify the source of the pollution over Europe. To this end a pilot
is performed using data-assimilation of tropospheric NO2 columns from OMI satellite measurements in
the LOTOS-EUROS chemistry transport model. In this presentation, we will discuss the added value of
the synergistic use of remote sensing data and regional air quality models to infer information on NOx
emissions.
GlobEmission
van der A, Ronald 1 ; Mijling, Bas 1 ; Eskes, Henk 1 ; Van Roozendael, Michel 2 ; Stavrakou, Jenny 2 ; De Smedt,
Isabelle 2 ; Muller, Jean-Francois 2 ; Bauwens, Maite 2 ; Schaap, Martijn 1 ; Curier, Lyana 1 ; Denier van der
Gon, Hugo 1 ; de Leeuw, Gerrit 3 ; Rodriquez, Edith 3 ; Sofiev, Mikhail 3 ; Vira, Julius 3 ; Veldeman, Nele 4 ;
Deutsch, Felix 4
1 KNMI, NETHERLANDS; 2 BIRA-IASB, BELGIUM; 3 FMI, FINLAND; 4 VITO, BELGIUM
Emissions of pollutants are at the origin of atmospheric pollution issues and climate change. Emission
inventories provide important information on magnitude, type of activity, time evolution and the spatial
coverage of the estimated emissions. These inventories are developed for use in scientific applications as
input in urban, regional or global scale models, and for use by the policy makers in order to evaluate
progress towards emission abatement measures, and decide on future strategies. Within the ESA
GlobEmission project, emission estimates are being developed based on satellite observations of air
constituents. The main advantages of these emission estimates are the spatial consistency, high
temporal resolution and the rapid availability of these estimates. Project partners from Belgium, Finland,
and the Netherlands are focusing on 4 distinct services: global biogenic emissions, regional emissions of
NOx and SO2 (East Asia, South Africa, India), European emission estimates of NOx, SO2 and CO, and
aerosol-related emissions.
Monitoring Particulate Matter in the European Alpine Region from MODIS,
SEVIRI, and In-Situ Measurements
Emili, Emanuele 1 ; Popp, Christoph 2 ; Zebisch, Marc 1 ; Wunderle, Stefan 3 ; Petitta, Marcello 1
1 2
Eurac, ITALY; Empa, Swiss Federal Laboratories for Materials Science and Technology, SWITZERLAND;
3
University of Bern, SWITZERLAND
We investigate the monitoring of particulate matter (PM10) over the complex terrain of the European
Alps by satellite remote sensing and ground-based point measurements in Italy and Switzerland.
Knowledge about the spatial and temporal characteristics of particulate matter is of great interest
because higher PM concentrations affect human health and activities (e.g. reduced visibility). For this
reason, such information might potentially be used by authorities to take counteractions like e.g. traffic
restrictions. Our study area is frequently influenced by high PM concentrations especially under situations
of atmospheric inversions which severely decreases air quality. The study is divided into three parts.
First, we apply a linear model which relates aerosol optical depth (AOD) from the geostationary Spinning
Enhanced Visible and InfraRed Imager (SEVIRI) and the polar orbiting Moderate Resolution Imaging
Spectroradiometer (MODIS) together with boundary layer height information to surface concentrations of
PM10 to derive maps of the two dimensional surface PM10 distribution for the years 2008-2010. Second,
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we compute spatially complete maps of PM10 by inverse distance interpolation of ground-based in-situ
measurements. Both, SEVIRI and MODIS PM10 estimates reveal a moderate performance with a
correlation coefficient (R) of around 0.6 and a RMSE of around 10 µg m -3 . In contrast, the interpolation of
the in-situ data alone lead to more accurate PM10 maps (R~0.8, RMSE < 6 µg m -3 ). Third, we
subsequently combined the satellite and in-situ PM10 distribution through an assimilation scheme where
the interpolated maps as background field are updated by the satellite estimates. However, this step led
to minor improvements only in the case where most of the in-situ sites are excluded from the
interpolation (simulating a much sparser network). We therefore conclude that satellite based PM
estimates in the European Alpine region are of limited additional value due to the dense coverage of the
already existing in-situ network and difficult terrain for remote sensing applications (topography, snow
and cloud coverage). On the other side, remote sensing of PM is of great interest in regions which have a
much sparser in-situ network (> 100km) and the presented approach can generally be applied to test
the additional information provided by remotely sensed PM estimates.
Monitoring Air Quality: the Role of OSSEs in Determining the Future Global
Observing System
Lahoz, William 1 ; Attie, Jean-Luc 2 ; El Amraoui, Laaziz 3 ; Hache, Emeric 3 ; Ricaud, Philippe 3 ; Dupont,
Richard 3 ; Jamouille, E 3 ; Orphal, Johannes 4 ; Flaud, Jean-Marie 5 ; Peuch, Vincent-Henri 6
1 NILU (also at CNRM), NORWAY; 2 CNRM and Laboratoire d'Aerologie, U. Toulouse, FRANCE; 3 CNRM,
FRANCE; 4 KIT, GERMANY; 5 LISA, FRANCE; 6 ECMWF, UNITED KINGDOM
The need to monitor air quality is recognized world-wide. This involves, inter alia, measurements of key
pollutants (e.g. ozone and carbon monoxide) in the lowermost troposphere at spatio-temporal scales
relevant to monitor, forecast and manage air quality on a daily basis (temporal frequencies less than 1
hour; spatial scales less than 10 km). This presentation identifies the role of data assimilation observing
system simulation experiments (OSSEs) in determining the future observing system to monitor air
quality, with focus on lower troposphere measurements of ozone and carbon monoxide. Caveats
associated with setting up and interpreting OSSEs are discussed. OSSEs performed to assess the added
value of the proposed geostationary satellite platform MAGEAQ (Monitoring the Atmosphere from
Geostationary orbit for European Air Quality), as well as the added value of other observing platforms of
the global observing system for monitoring air quality (low earth orbit satellites; ground-based data) are
presented to illustrate the concept.
NOx Source Category Inferred from the OMI Obs. and Inter-Comparison of
SCHAMACHY and OMI Tropospheric NO2 Columns over India.
Jena, Chinmay Kumar; Ghude, Sachin D.; Kulkarni, Santosh H.
Indian Institute of Tropical Meteorology,Pune, INDIA
Here we report on the systematic analysis of the distribution of dominant NOx sources from the Indian
region using OMI observations of tropospheric NO2 columns, following up on our earlier work on detection
of NOx emission hotspots from India. Using the characteristics of the seasonal variability of source
categories (anthropogenic, biomass burning and soil), the dominant source of NOx emissions has been
partitioned. We show that OMI captures the soil emission from the less populated areas during the onset
of monsoon. It is also observed that soil emission occurs in strong pulses lasting 1–3 weeks following the
onset of rain during Asian summer monsoon. Relating OMI tropospheric NO2 column to surface NOx
emission, soil emission account for an average emission flux of ~21 - 25 ng N m-1 s-1 from the study
region. OMI observations also detects the emission from the biomass burring during the peak biomass
burning season, particularly from the Northeastern region of India, and well correlate with the MODIS fire
counts. Evidence of increase in tropospheric CO and subsequent photochemical ozone formation is also
detected during this brief burning period. We estimated an emission of about 54 ng N m-1 s-1 from the
Northeastern region during April. Inter-comparison of SCIAMACHY and OMI tropospheric NO2 columns
shows that SCIAMACHY NO2 is generally higher that the OMI over fossil fuel region, which is particularly
pronounced our large urban areas and metro cities in India. Using SCIAMACHY observation and inversion
technique we further present top-down estimate for NOx emission from India and compare with the
bottom-up inventory.
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Satellite Observations of Air Quality in China’s Megacities
Hao, Nan 1 ; Valks, Pieter 1 ; Smedt, I. De. 2 ; Loyola, Diego 1 ; Van. Roozendael, M. 2 ; Zhou, Bin 3 ; Zimmer,
Walter 1
1 Deutsches Zentrum für Luft- und Raumfahrt (DLR), GERMANY; 2 Belgian Institute for Space Aeronomy,
BELGIUM; 3 Fudan University, CHINA
In the last three decades, air pollution has become a major environmental issue in metropolitan areas of
China as a consequence of fast industrialization and urbanization, and the rapid increase of the vehicle
ownership. Now in China there are 3 megacities (Beijing, Shanghai and Guangzhou) in existence. A
recent study of Asian megacities showed that they cover less than 2% of the land area, hold more than
30% of the population and produce about 10% of the anthropogenic gas and aerosol emissions.
Therefore, it is important to qualify and understand current air pollution distribution and development in
and around the megacities of China. Satellite observations provide unique insight into the regional air
quality around megacities and air pollution transport from surrounding areas. In this work, we present an
investigation of air quality over Beijing, Shanghai and Guangzhou combining satellite and ground-based
measurements. Aerosol optical thickness (AOT), precursors of ozone (notably NO2 and CH2O), and SO2
are observed from space. The operational GOME-2 trace gases products developed at German Aerospace
Center and SCIAMACHY trace gases products will be used. To observe the characteristics of aerosol over
megacities, AOT acquired from the MODIS instruments onboard NASA’s Terra and Aqua satellite are
analyzed. Moreover, near surface concentrations of particular matter (PM), NO2 and SO2 in Beijing,
Shanghai and Guangzhou are investigated. The effect of air pollution transport from neighboring areas to
megacities will be researched using satellite measurements. Long-term NO2, SO2 and CH2O data
recorded from GOME, SCIAMACHY and GOME-2 are analyzed to investigate possible trends in air
pollutants for China’s megacites. Initial comparison between satellite and ground-based measurements
of air pollutants in Beijing, Shanghai and Guangzhou will be shown. We will present the relationship
between AOT and PM concentrations in megacities. The use of AOT, tropospheric NO2 and CH2O columns
for air quality applications will also be shown.
Global Trend Analysis of MODIS(Terra), MISR(Terra), SeaWiFS(OrbView-2), and
MODIS(Aqua) AOTs
Yoon, J. 1 ; Vountas, M. 1 ; von Hoyningen-Huene, W. 1 ; Chang, D. Y. 2 ; Burrows, J. P. 1
1 University of Bremen, GERMANY; 2 Max-Planck-Institute for Chemistry, GERMANY
The present study investigates global AOT trends derived from MODIS-Terra (MOD) from 2000/03 to
2009/12, MISR-Terra (MIS) from 2000/03 to 2010/12, SeaWiFS-OrbView-2 (SEA) from 1998/01 to
2007/12, and MODIS-Aqua (MYD) from 2003/01 to 2008/12 in order to minimize incomplete sampling
caused by restricted temporal coverage (i.e., different local equatorial crossing time and revisit cycle). By
using a weighted least squares regression and a bootstrap method (aka, Monte Carlo error bars
analysis), it is possible to estimate significant trends of global cloud-free AOTs. The weighted trends of
MOD AOT (550 nm), MIS AOT (558 nm), SEA AOT (510 nm), and MYD AOT (550 nm) over OECD Europe
show a significant decrease (-0.00274±0.00126, -0.00303±0.00169, -0.00077±0.00044, and -
0.00530±0.00304 per year respectively) while increasing over East Asia (+0.00727±0.00385,
+0.00673±0.00401, +0.00342±0.00171, and +0.01939±0.00986 per year respectively) and South Asia
(+0.00777±0.00306, +0.00675±0.00321, +0.00313±0.00128, +0.01452±0.00615 per year
respectively).
Atmospheric Ammonia Monitored by IASI
Van Damme, Martin 1 ; Ngadi, Yasmine 2 ; Clarisse, Lieven 2 ; Clerbaux, Cathy 3 ; Hurtmans, Daniel 2 ; Schaap,
Martijn 4 ; Wichink Kruit, Roy 4 ; Erisman, Jan Willem 5 ; Coheur, Pierre-François 2
1 Spectroscopie de l’Atmosphère, SCQP, Université Libre de Bruxelles (ULB) (& Free University (VU)),
BELGIUM; 2 Spectroscopie de l’Atmosphère, SCQP, Université Libre de Bruxelles (ULB), BELGIUM; 3 UPMC
Univ. Paris 06, CNRS/INSU, LATMOS-IPSL & Spectroscopie de l’Atmosphère, SCQP, ULB, BELGIUM;
4 Dept. of Air Quality and Climate, TNO Environment and Geosciences, NETHERLANDS; 5 Dept. of
Hydrology and Geo-environmental Sciences, Free University (VU), NETHERLANDS
The natural nitrogen cycle is significantly perturbed by anthropogenic atmospheric emissions of reactive
nitrogen compounds resulting from our production of energy and food. Ammonia (NH3) is one of the
largest contributors to reactive nitrogen and the principal alkaline component in our atmosphere. In the
last century global ammonia emissions have doubled and are expected to further increase in the coming
decades, with huge implications on Earth’s environment, climate and human health. In the atmosphere
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NH3 rapidly forms aerosols and is therefore a species of high relevance for air quality. In Europe, it is
expected to become the single most important contributor of tropospheric aerosol by 2020.
As a short-lived species, ammonia is highly variable in time and space, and while ground based
measurements are possible, they are sparse and not representative for larger scales. Consequently, the
ammonia budget is poorly understood and accounts for the largest uncertainty in the global nitrogen
cycle.
The Infrared Atmospheric Sounding Interferometer (IASI), an infrared sounder onboard the MetOp
platform, has demonstrated its capabilities for probing atmospheric ammonia, down to the boundary
layer. We recently developed an Optimal Estimation Method on Spectral Ensemble (OEMSE) to obtain
global distributions of NH3 total columns with much improved sensitivity than in previous studies, and
which also allows assessing retrievals errors.
This new method and daily-based global ammonia products will be presented. Comparisons with groundbased
in situ measurements and model data will be provided as a first validation of the product.Based on
the results, we will further assess the capabilities of IASI to monitor local sources (in terms of seasonal
and inter annual variations) and transport, and to contribute, by also using model simulations, in refining
emission inventories. Finally we will provide the first results of an empirical analysis of NH3 volatilization,
performed by correlating the retrieved total columns to soil parameters (temperature, soil pH, relative
humidity,…) and anthropological activity indicators (livestock density, intensity of fertilization, population
density,…).
Merging Remote Sensing and In-Situ Data for Detection of Biomass Burning
Events
Ulevicius, Vidmantas 1 ; Bycenkiene, Steigvile 1 ; Kecorius, Simonas 2 ; Plauskaite-Sukiene, Kristina 1
1 2
Center for Physical Sciences and Technology, LITHUANIA; Center for Physicsl Sciences and Technology,
LITHUANIA
Atmospheric aerosols have significant influence on the radiative forcing and climate change, which has
become an important research field on a global change. The long-range transported smoke emitted by
biomass burning had a strong impact on the black carbon concentrations in Lithuania during 2008 and
2009 spring periods. An investigation of the source types of pollutants, their locality, chemical
composition and quantitative contribution to the particulate concentration enhancement using suitable
methodologies to make initial estimations was conducted. To identify possible episodes of regional and
long-range transport hotspot/fire the location of a thermal anomaly was detected by MODIS using data
from the middle infrared and thermal infrared bands. Each MODIS sensor achieves global coverage once
per day and once per night every 24 h. Therefore, most fires detectable at a 1-km spatial resolution have
the potential to have their FRP (Fire Radiative Power) measured four times a day, except when covered
by thick meteorological cloud. The MODIS monthly fire maps, available since 2001, showed that these
episodes of biomass burning in March-April occur annually. However, the duration, geographical extent
and emission of the smoke from these fires differ year by year. The results of The Navy Aerosol Analysis
and Prediction System (NAAPS) model were used to determine the distribution of smoke aerosols from
fires (model description and results are available from the web pages of the Naval Research Laboratory,
Monterey, CA, USA; http://www.nrlmry.navy.mil/aerosol/). The NAAPS model has recently been modified
to incorporate real-time observations of biomass burning based on the joint Navy/NASA/NOAA Fire
Locating and Modeling of Burning Emissions system (FLAMBE) The method has proven helpful in previous
studies of long-range and regional transport of smoke. The results from NAAPS analyses suggested that
the source of the episodes was dual-long-range and regional transport. Analysis of BC and PM2.5 levels
to those of other typical anthropogenic pollutant species (as NOx, SO2) also demonstrates that levels of
other pollutants generally remained high during the two incidents, again suggesting a predominantly
anthropogenic source. This could explain the increased sulphate concentration during a regional episode,
compared with LRT, since the source area for regional transport also included areas from Southern
Russia and Ukraine.
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Use of Satellite and Surface Observations of Trace Gases to Evaluate the Impact
of Fire Emissions on Air Quality in Euro-Mediterranean Area
Messina, Palmira 1 ; Turquety, Solene 2 ; Stromatas, Stavros 1 ; Menut, Laurent 1 ; Anav, Alessandro 3 ; Coheur,
Pierre-François 4 ; R'honi, Yasmina 4 ; Bessagnet, Bertrand 5 ; Clerbaux, Cathy 6
1 École Polytechnique, Centre national de la recherche scientifique, FRANCE; 2 École Polytechnique,
Laboratoire de Météorologie Dynamique, FRANCE; 3 Exeter University, UNITED KINGDOM; 4 Université
Libre de Bruxelles, BELGIUM; 5 Institut National de l’Environnement Industriel et des riSques, FRANCE;
6 CNRS/INSU, LATMOS-IPSL, FRANCE
Wildfires are one of the main sources of trace gases and aerosols. However, their impact remains poorly
quantified due to large uncertainties especially on the emissions, as well as on the transport processes
and chemical evolution of the pollution plumes. Satellite data, due to their high spatial coverage, can be
a powerful tool for monitoring pollution plumes transport, although the information remains vertically
integrated (implying limited vertical resolution). Here we present an evaluation of the effects, provided
by fire emissions, on atmospheric trace gases composition. Therefore simulations by the regional
chemistry-transport model CHIMERE are performed using high resolution fire emissions scenarios and
subsequently a comprehensive comparison between satellite observations and model output is
conducted. In particular, simulations in fire plumes are compared with CO, NH3 and C2H4 observations
from the IASI instrument, NO2 and CH2O from GOME2 (both on MetOp-A satellite) and NO2 from OMI (on
Aura). In the present work we focus on strong biomass burning episodes that occurred in Euro-
Mediterranean area in summer 2007. Fire plume characteristics are analyzed to constrain emission
scenarios, that will then be corrected in a bottom-up method. In order to evaluated the impact of fires on
surface air quality, complementary comparisons to ground measurements from the AirBase database
(i.e. CO, O3 and NO2 concentrations) are carried out. These allow an evaluation at high temporal
resolution, but at specific locations and, in general for our case study, quite far away from the location
where wildfires occur. The same fire simulation setup is used for both reanalysis and near-real time
analysis. The first evaluation of an experimental air quality forecasting system including fires will be
presented.
A Global Inventory of Large SO2 Point Sources Derived from OMI Satellite
Retrievals
Fioletov, Vitali 1 ; McLinden, Chris 1 ; Krotkov, Nickolay 2 ; Moran, Mike 1 ; Yang, Kai 2
1 Environment Canada, CANADA; 2 NASA Goddard Space Flight Center, UNITED STATES
Multi-year averages of SO2 measurements from the Ozone Monitoring Instrument (OMI) on board the
NASA Aura satellite have been used to detect SO2 emissions from large point sources such as volcanoes,
coal-fired power plants, base-metal smelters, oil refineries, etc., many of which were not previously
observed from satellites. Low- and high-frequency spatial filtering were applied to the satellite data to
reduce the noise and bias and reveal weak SO2 signals that are otherwise not readily apparent.
Averaging a large number of individual observations also yields SO2 spatial distributions near SO2 point
sources that have an effective resolution superior to that of individual satellite observations. By applying
this technique to the OMI archived SO2 data set, it was possible to identify about 200 SO2 point sources
around the globe. Moreover, approximate SO2 emissions levels from these sources were also estimated
from the OMI data. To do this, averaged OMI SO2 measurements were compared with known
measurement-based “bottom-up” emissions inventories over the US in order to obtain an empirical
relationship between point-source emissions and OMI signals. This relationship was then applied to
obtain estimates of the emissions level from locations where emissions information is not well-known.
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Reductions in Nitrogen Oxides over Europe Driven by Environmental Policy and
Economic Recession
Castellanos, Patricia; Boersma, K. Folkert
KNMI - Royal Netherlands Meteorological Institute, NETHERLANDS
We present a trend analysis of tropospheric NO2 for the time period of 2004-2010 over Europe.
Necessary for monitoring pollution abatement strategies, NO2 trends analyses are often based on surface
networks, which suffer from poorly quantified NO2 biases and spatial representativity issues inherent to
the standard monitoring method. Space based NO2 trends are unbiased and self-consistent, but over
Europe they have not been as obvious as those observed over North America and East Asia. In this work
we exploit the daily NO2 column observations from the Ozone Monitoring Instrument (OMI) in order to
isolate long-term (timescales greater than one year) variability in NO2 over Europe using a time-series
separation technique. In general, we find between 2005 and 2008, 1-5% per year declines in NO2
concentration in many polluted regions (e.g. Germany, Netherlands, Belgium, Italy, Spain). In 2009, NO2
almost exclusively decreased over Europe at a rate of 5-10% per year, coinciding with the abrupt
decrease in industrial production and construction prompted by the global economic crisis. Thus by the
end of 2010, we find substantial reductions in NO2 concentrations of at least 20% throughout Europe.
These reductions are as much the result of temporary reductions prompted by the 2008-2009 global
economic recession, as of European NOx emission controls. Our results demonstrate that realistic
concentration pathways of NO2 do not follow simple linear trends, but reflect a compilation of
environmental policy and economic activity.
Quantitative Observation of Surface NO2 Variability from Total-Column
Measurements
Knepp, Travis N. 1 ; Pippin, M. 1 ; Neil, D. 1 ; Crawford, J. 1 ; Herman, J. 1 ; Fishman, J. 2 ; Szykman, J. 3 ; Long,
R. 3
1 2 3
NASA, UNITED STATES; NASA & Saint Louis University, UNITED STATES; U.S. Environmental
Protection Agency, UNITED STATES
The Chemistry And Physics of the Atmospheric Boundary Layer Experiment (CAPABLE) site located at
NASA’s Langley Research Center in Hampton, VA was established to provide continuous monitoring of
atmospheric species relevant to climate change and local air quality. Key to this is our ability to
understand how surface-chemical variability influences column observations, and how incoming radiation
influences climate-relevant pollutants and air quality climatologies. A ground-based sun-tracking
spectrometer system (Pandora) is used to retrieve high time and spatial resolution total-column nitrogen
dioxide. These column observations are compared with data from a surface NOx instrument that employs
a photolytic converter, as opposed to the traditional molybdenum-converter instrumentation that are
incapable of distinguishing between NO2 and NOy. The column data are inverted (via the EDAS-40 model)
to yield surface mole fractions (i.e. ppb) that have typically high coefficients of correlation (e.g. R =
0.80), thereby displaying both Pandora’s sensitivity to surface variability and the potential for
quantitatively estimating surface NO2 from space-based instruments. Sensitivity of this inversion method
to boundary-layer dynamics is briefly explored. The upcoming GEO-CAPE mission will be in geostationary
orbit over the United States with improved resolution allowing hourly city-scale NO2
observations. Translating these column observations into boundary-layer mole fractions provides a direct
NO2 data set that can significantly improve the understanding of emission, chemical transportation,
effectiveness of control strategies, and predictive capabilities. Data from the 2011 DISCOVER-AQ field
campaign are also presented as case-study days, and act as validation of the current method.
Preliminary results regarding the relation of surface and column NO2 will be presented.
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Analysis of the Performances of Future Thermal Infrared Geostationary
Instruments for Lowermost Tropospheric Ozone Monitoring
Sellitto, Pasquale; Dauphin, Pierre; Dufour, Gaelle; Eremenko, Maxim; Cuesta, Juan; Coman, Adriana;
Foret, Gilles; Beekmann, Matthias; Gaubert, Benjamin; Jean-Marie, Flaud
Laboratoire Inter-universitaire des Systèmes Atmosphériques, FRANCE
Monitoring air quality (AQ) from space is crucial to gather a more thorough comprehension of pollution
processes that can have a relevant impact on the biosphere. In recent years, reliable observations of
several pollutants, including the lowermost tropospheric (LmT) ozone, have been obtained from low
Earth orbit (LEO), proving the feasibility of monitoring the tropospheric composition from space. In this
sense, thermal infrared (TIR) LEO instruments are widely regarded as a useful tool to observe targeted
AQ parameters like tropospheric ozone concentrations. However, LEO instruments are not well adapted
to monitor small scale and short term phenomena, owing to their unsatisfactory revisit time. From this
point of view, a more satisfactory concept might be based on geostationary (GEO) platforms. Current
and planned GEO missions are mainly tailored on meteorological parameters retrieval and do not have
sufficient spectral resolutions and signal to noise ratios (SNR) to infer information on trace gases in the
LmT. New satellite missions are currently proposed that can partly overcome these limitations. Here we
present a group of simulation exercises and sensitivity analyses to set-up future TIR GEO missions
adapted to monitor and forecast AQ over Europe, and to evaluate their technical requirements. At this
aim, we have developed a general simulator to produce pseudo-observations for different
platform/instrument configurations. The core of this simulator is the KOPRA radiative transfer model,
including the KOPRAfit inversion module. Using our simulator, we have produced pseudo-observations for
targeted sensors including some potential and planned future GEO instruments like MTG-IRS [1] and
MAGEAQ [2]. In order to achieve the best performances that can be obtained from TIR instruments, we
applied an altitude-dependent Tikhonov-Philips retrieval algorithm optimized to maximize the information
retrieved from the lower troposphere. This algorithm has already demonstrated powerful performances
to retrieve LmT ozone and to detect pollution events. Finally, a detailed analysis of the pseudoobservations
has allowed quantifying the added-value brought by the MAGEAQ TIR instrument to resolve
LmT geographical patterns and temporal trends of ozone. The results are critically discussed.
REFERENCES [1] Stuhlmann, R., A. Rodriguez, S. Tjemkes, J. Grandell, A. Arriaga, J.-L. Bézy, D.
Aminou, and P. Bensi: Plans for EUMETSAT’s Third Generation Meteosat (MTG) geostationary satellite
program, Advances in Space Research, 36, 975–981, 2005. [2] Peuch, V.-H., J. Orphal, and the MAGEAQ
consortium: MAGEAQ: Monitoring the Atmosphere from Geostationary orbit for European Air Quality,
Proposal submitted to ESA for Earth Explorer opportunity mission EE-8, Tech. rep., 2010
112

GMES Services/Data Assimilation
Assimilation of Surface and Satellite Observations with the Lotos-Euros Air
Quality Model Using the Ensemble Kalman Filter
Eskes, Henk 1 ; Curier, Lyana 2 ; Segers, Arjo 2
1 KNMI, NETHERLANDS; 2 TNO, NETHERLANDS
LOTOS-EUROS is a chemistry transport model developed in the Netherlands, and is used for air quality
assessments and forecasts. Operational air quality forecasts for the Netherlands concerning ozone and
PM10 are made available on the RIVM webpage (http://www.lml.rivm.nl/) and are used to warn the
population in case of predicted exceedances of air quality standards. Lotos-Euros is also contributing to
the model-ensemble based air quality forecasts for Europe (MACC project, http://macc-raq.gmesatmosphere.eu/index.php?op=get).
Currently, the system is expanded to assimilate routine observations
from European networks for ozone and PM10, as well as OMI NO2 satellite observations, based on the
ensemble Kalman filter technique. This work is done in the context of the MACC project and contributes
to the MACC air quality reanalyses for the years 2008 and 2009. The Ozone Monitoring Instrument (OMI)
is a Dutch-Finnish instrument on the NASA EOS-Aura mission, and has a capability to detect boundarylayer
NO2 with a unique resolution of about 20 km. In our contribution we will discuss the assimilation of
NO2 tropospheric columns from the OMI instrument, and the derivation of NOx emissions in Europe based
on OMI.
Assimilation of SEVIRI Radiances over Land in the Météo-France Meso-Scale
Models
GUEDJ, Stephanie 1 ; KARBOU, Fatima 2 ; RABIER, Florence 2 ; GUIDARD, Vincent 2
1 Fellowship EUMETSAT/METEO-FRANCE, FRANCE; 2 METEO-FRANCE, FRANCE
This work aims to improve the assimilation of low-level SEVIRI (Spinning Enhanced Visible and Infra Red
Imager) IR (Infra-red) observations over land to better constrain atmospheric analyses in meso scale
models operated at Météo-France. To date, only high-peaking Water Vapour channels are operationally
assimilated over land and IR channels are entirely rejected over land surfaces. The assimilation of IR
observations over land is possible only if several limitations are accounted for: a reliable description of
the surface emissivity, an accurate estimation of the surface temperature and an effective bias correction
scheme. Some feasibility studies have been undertaken in order to assimilate more SEVIRI observations
in the ALADIN and AROME French mesoscale systems. The land surface emissivity was described using
climatologies from the EUMETSAT Land-SAF (Satellite Application Facilities). The land surface emissivity
and SEVIRI Tb were used as input parameter in the radiative transfer model to retrieve the surface
temperature (Ts) over Europe. The retrieved Ts was compared with independent Ts estimates (MODIS,
Land-SAF products, etc.) and was then used within the assimilation process to constrain the analysis of
surface temperature. Several assimilation experiments were run during both summer and winter periods
on the basis of the operational versions of ALADIN and AROME. We show that the impact on forecast
quality is generally neutral to positive, especially during summer. In particular, SEVIRI data point to
positive impact on humidity fields over Southern Europe. SEVIRI data are also shown to improve the
quality of analyses, particularly those of Total Column Water Vapour (TCWV), and this is substantiated
through comparisons with independent GPS measurements. With regard to the Spanish synoptic station
measurements, forecast of temperature and geopotential are improved. A description of the methods for
temperature retrievals will be given. An evaluation of the retrieved Ts against independent
measurements will be briefly presented. Finally, we will give an overview of assimilation and forecast
experiment results when SEVIRI IR observations are assimilated over Europe.
113

IASI Retrievals over Concordia within the Framework of the Concordiasi
Program in Antarctica.
Vincensini, Anais; Bouchard, Aurelie; Rabier, Florence; Guidard, Vincent; Fourrie, Nadia; Traulle, Olivier
CNRM-GAME, Meteo-France and CNRS, FRANCE
The Concordiasi project was designed in the framework of the fourth International Polar Year. This field
experiment occurred during Austral springs 2008–2010. Radiosoundings and stratospheric balloons were
launched in order to gather additional in situ measurements over Antarctica. One of the main goals of the
Concordiasi campaign is the improvement of satellite data assimilation at high latitudes and, particularly,
the assimilation of the Infrared Atmospheric Sounding Interferometer (IASI) radiances over the southern
polar regions. The use of satellite radiances in data assimilation is impeded by the presence of clouds,
which curtail the amount of information received from infrared sounders, and by inaccurate estimations
of both surface temperature and surface emissivity. This study focuses on the IASI data retrieval using a
1-D variational data assimilation system, which was carried out at the Concordia station and within the
framework of Concordiasi. The study period lasted from November 20 to December 12, 2009. Only clear
sky cases are considered. Radiosonde measurements are utilized to validate temperature and water
vapor retrieved profiles. Baseline Surface Radiation Network data and manned measurements in
Concordia are used to verify skin temperature retrievals and derive information about cloudy conditions.
This study assesses the impact of several parameters on the retrieved profile quality. In particular, the
background error specification is crucial. The background error covariance matrix is optimally tuned to
provide the best possible retrievals, modifying the shape of these covariances for stratospheric
temperatures, computing and maximizing the degree of freedom for signal (DFS). The DFS characterizes
how the assimilation system uses the observation to pull the signal from the background. The
improvement due to the background error modification is measured quantitatively by improvement in the
analyses fit to collocated radiosonde data. For the study period, the humidity and temperature retrieved
profiles are optimally improved compared with background profiles, with the largest reduction in error for
the skin temperature. Indeed, retrieved skin temperatures reproduce measured surface data (BSRN and
manned measurements) with good fidelity. Thus IASI is also found to be very informative for surface
conditions.
Establishing an Infrastructure for Spatial Information in Europe : Insight into
INSPIRE Developments for GMES Atmospheric Data
De Rudder, Anne; Lambert, Jean-Christopher
Belgian Institute for Space Aeronomy (IASB-BIRA), BELGIUM
The INSPIRE Directive was adopted by the European Parliament and Council in March 2007. This
legislative text and its related subsequent Regulations aim at shaping a common framework for the
communication of spatial information throughout Europe. Together with GMES and GALILEO, they
constitute a major contribution of the EU to the Global Earth Observation System of Systems (GEOSS),
and the relationship between INSPIRE and GMES is explicitly established in the first lines of the Directive.
Earth Observation and modeling data on atmospheric composition and associated parameters typically
belong to the INSPIRE scope. Moreover, complying with INSPIRE rules has become a contractual
requirement for scientific projects funded under the EU FP7, and is expected from projects funded by
ESA, EUMETSAT and national space agencies. In the context of projects directly related to the GMES
Atmospheric Service (GAS) and the GMES Space Component (GSC), and aware of the importance of data
and service harmonization not only for communication but also to meet the requirements of international
legislation - e.g. about adverse effects of climate change and air pollution -, the atmospheric community
has liaised with the INSPIRE drafting teams during the shaping phase of several Implementing Rules, in
an effort to convey key notions of geophysical science and data to be integrated into the INSPIRE
scheme, as well as to arouse awareness of already existing international standards and practices in use.
Major interactions were related to the Directive scope, the notion of quality, the concepts of dataset and
dimensionality, the prevalence of the information content on metadata formal aspects, etc. This paper
will provide an account of the progress achieved on the INSPIRE scene, will screen the current status of
its Implementing Rules and will outline some remaining issues for the atmospheric thematic domain.
114

Hindcasts of Tropospheric Composition during 2010 Russian Fires Using the
MACC System
Huijnen, Vincent 1 ; Flemming, Johannes 2 ; Kaiser, Johannes 2
1 KNMI, NETHERLANDS; 2 ECMWF, UNITED KINGDOM
In summer 2010, western Russia experienced a strong heat wave, accompanied by severe wildfires over
this region. This extreme event is used to evaluate the ability of the global MACC (Monitoring
Atmospheric Composition and Climate) atmospheric composition forecasting system to model large-scale
pollution episodes. Daily 4-day hindcasts were conducted using assimilated aerosol optical depth, carbon
monoxide, nitrogen dioxide and ozone data from a range of satellite instruments. Daily fire emissions
were used from the Global Fire Assimilation System (GFAS) version 1.0, derived from satellite fire
radiative power retrievals. The respective influence of a priori emission information and data assimilation
on the forecast accuracy is evaluated. We show that the impact of accurate wildfire emissions is
dominant on the composition in the boundary layer, whereas the assimilation system influences
concentrations throughout the troposphere, reflecting the vertical sensitivity of the satellite instruments.
Therefore this information is complementary and best results in terms of mean biases are achieved using
both assimilation and GFASv1.0 emissions. Nevertheless, we find that the forecast accuracy on a local
scale is strongly depending on the assumptions made for forecasted fire emissions.
Generic Radiative Transfer Model for the Earth's Surface-Atmosphere System:
Towards a Community Tool
Emde Claudia
Institution/Company Ludwig-Maximilians-Universität, GERMANY
Radiative transfer modeling plays a key role for remote sensing because it is central for the development
and testing of inversion algorithms as well as for the design of new remote sensing instruments: Remote
sensing of planetary atmospheres and surfaces uses radiation covering a wide range of wavelengths,
coming either from the sun or from the atmosphere (passive remote sensing), or from an artificial
radiation source (active remote sensing). Radiation is affected by interaction with the atmosphere and
surface – the observed radiation therefore contains information about the atmosphere and surface which
can be retrieved.
The libRadtran software package (Mayer and Kylling, 2005) is freely available and covers the complete
solar and thermal spectral range, concentrating but not necessarily restricting itself on the Earth’s
specific requirements. One of the most relevant features of libRadtran is that it includes a selection of
about ten different radiative transfer solvers, including the widely-used DISORT code, a fast two-stream
code, a polarization-dependent code, and the fully three-dimensional Monte Carlo code for the physically
correct tracing of photons in cloudy atmospheres, MYSTIC.
Within the ESA project ESASLight the libRadtran package is improved and extended based on an initial
phase of user requirement consolidation. The overarching objective of ESASLight is to provide a radiative
transfer toolbox for the Earth observation remote sensing community which can be used for forward
simulations of the Earth surface-atmosphere system.
References:
- B. Mayer and A. Kylling, Technical Note: The libRadtran software package for radiative transfer
calculations: Description and examples of use. Atmos. Chem. Phys., 5:1855-1877, 2005.
- libRadtran website: www.libradtran.org
- ESASLightI project website: http://esaslight.libradtran.org/internal/Wiki/doku.php
115

A New Method for the Performance Analysis of a Concentrating Solar Power
Energy Plant Using Remotely Sensed Optical Images
Morelli, Marco 1 ; Masini, Andrea 2 ; Potenza, Marco Carlo Alberto 1
1 University of Milan, ITALY; 2 Flyby S.r.l., ITALY
We present a new method, developed under the GMES ENDORSE (ENergy DOwnstream SErvices)
project, for the performance analysis of a Concentrating Solar Power (CSP) energy plant that combines a
detailed model of each part of a CSP plant (solar filed, thermal storage system, electrical power system
and inverters) and the near real-time remote sensing of the direct component of solar irradiance incident
on the plane normal to sun rays (DNI) at ground level. Starting from temporal series of satellite Meteosat
Second Generation (MSG) optical images, we use the Heliosat algorithm to retrieve firstly the solar global
horizontal irradiance (GHI) and then the DNI using a model to derive irradiance on tilted planes from
GHI. Combining that with the model and the technical features of a CSP plant, using also air temperature
values (measured in-situ), we can monitor near-real-time the daily behavior of the alternate current
power yield by the plant and then, using a temporal integration, we can finally retrieve the expected
daily energy yield by the CSP plant. We are therefore able to compare the energy yield retrieved from
satellite measurements with the measured one and, consequently, to readily detect eventual
malfunctions and to evaluate the performances of the plant. This method has been successfully applied
for the performances analysis of some CSP plants located in Sicily (Italy), showing always a precision
less than 10% respect to the measured values of energy yield by well-functioning plants. We present the
results of these test cases in the final part of the paper.
BEAT - Basic Envisat Atmospheric Toolbox
Niemeijer, Sander 1 ; Zehner, Claus 2
1 S[&]T, NETHERLANDS; 2 ESA/ESRIN, ITALY
The Basic Envisat Atmospheric Toolbox project (BEAT) aims to provide scientists with tools for ingesting,
processing, and analyzing atmospheric remote sensing data. The primary instruments supported by BEAT
are GOMOS, MIPAS, and SCIAMACHY (ENVISAT), GOME (ERS-2), OMI, TES, MLS, and HIRDLS (Aura),
and GOME-2 and IASI (MetOp), but several other missions are supported as well. The toolbox consists of
several software components.
The CODA software allows direct access to product data, supporting a wide range of products (including
also many non-atmospheric earth observation data products). All product file data is accessible via the
CODA C library. On top of this C library there are several interfaces available to directly ingest product
data using Fortran, IDL, MATLAB, Python, and Java. Furthermore, CODA also comes with a set of
command line tools (codacheck, codacmp, codadump, codafind, and codaeval). All CODA functionality
can be found in the BEAT package but is also available as a standalone package that can be downloaded
from the CODA website.
The BEAT software also comes with a second layer of data access, called BEAT-II, that is build on top of
CODA. This data access layer provides an abstraction to the product data to make it easier for the user
to get the most important data from a product. Using only a single command you will be able to ingest
atmospheric product data (from one or more files) into one of a set of flexible data types for spectral
readout data, profile data, total column swath data, or L3/4 gridded data. These predefined data types
make it easier to compare and combine similar data coming from different instruments and also simplify
the creation of general visualisation routines. All BEAT-II functionality is accessible via the BEAT-II C
library that is included in the BEAT package. In addition the BEAT package contains interfaces of BEAT-II
for Fortran, IDL, MATLAB, Python, and Java, and a command line tool (beatl2dump).
The final component of BEAT is VISAN. VISAN is a cross-platform visualization and analysis application
for atmospheric data. The application uses the Python language as the means through which you provide
commands to the application. The Python interfaces for CODA and BEAT-II are included so you can
directly ingest product data from within VISAN. Using the Python language and some additional included
mathematical packages you will be able to perform analysis on your data. Finally, VISAN provides some
very powerful visualization functionality for 2D plots and worldplots.
116

The Establishment of Atmospheric Essential Climate
Variables under the ESA CCI Framework
The New Operational GOME/ERS-2 Total Ozone Data: GDP Version 5 Direct-
Fitting Geophysical Validation
Koukouli, MariLiza 1 ; Balis, Dimitris 1 ; Loyola, Diego 2 ; Zimmer, Walter 2 ; Van Roozendael, Michel 3 ; Lambert,
Jean-Christopher 3 ; Lerot, Christophe 3 ; Kazadzis, Stylianos 4 ; Zerefos, Christos 5 ; Zehner, Claus 6
1 Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, GREECE; 2 German Aerospace
Center (DLR), GERMANY; 3 Belgian Institute for Space Aeronomy, BELGIUM; 4 IERSD, National
Observatory of Athens, GREECE; 5 Navarino Environmental Observatory, Biomedical Research Foundation,
Academy of Athens, GREECE; 6 European Space Agency, ITALY
In the frame of the ESA-funded project “GDP 5.0 - Upgrade of the GOME Data Processor for Improved
Total Ozone Columns”, total ozone estimates from different GOME GDP4.x (based on the DOAS
algorithm) configurations were compared with the latest developments in the GOME GDP5 (based on the
GODFIT algorithm) data products and with ground based total ozone data from quality controlled Brewer,
Dobson and SAOZ measurements available at WOUDC and NDACC. The different configurations of the
GDP 5.0 total ozone retrieval algorithms include the study of the effects of: I. An Internal Closure [IC]
technique where the effective surface albedo is retrieved from the GOME radiances against an External
Closure [EC] technique where the surface albedo from a climatology database is used as input. The IC
technique requires as input L1 products corrected for degradation effects. II. The usage of an Intra-Cloud
Correction [VIC] scheme similar to the one introduced for the DOAS retrievals. The long term behavior of
the GDP 5.0 dataset is examined closely, with special focus in the final years of GOME’s lifetime where
the degradation effects become more prominent. Dependencies in solar zenith angle, latitude, cloud
retrieval parameters and total ozone columns are also investigated and discussed. The target accuracy at
the 1% level is shown to be achieved for most observational geometries and total ozone column
characteristics.
Towards an Improved Total Ozone Climate Data Record from GOME, SCIAMACHY
and GOME-2 as Part of the ESA Climate Change Initiative
Lerot, Christophe 1 ; Van Roozendael, Michel 1 ; Spurr, Robert 2 ; Loyola, Diego 3 ; Natraj, Vijay 4 ; van Gent,
Jeroen 1 ; Lambert, Jean-Christopher 1 ; Balis, Dimitris 5 ; Koukouli, MariLiza 5 ; Zehner, Claus 6
1 Belgian Institute for Space Aeronomy (BIRA-IASB), BELGIUM; 2 RT Solutions, Inc., UNITED STATES;
3 German Aerospace Center (DLR-IMF), GERMANY; 4 Jet Propulsion Laboratory, California Institute of
Technology, UNITED STATES; 5 Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki,
GREECE; 6 ESA/ESRIN, ITALY
The ESA Ozone Climate Change Initiative project (Ozone_cci) aims at producing and characterizing a
number of high quality ozone data products generated from multiple satellite sensors. To facilitate the
merging of data from different sensors while minimizing error sources and biases, it is essential to work
on improving and harmonizing the data sets from individual sensors. One way to facilitate such a
harmonisation is to apply common retrieval algorithms to all level-1 data sets.
In this study, we concentrate on total ozone retrieval from the European sensors GOME, SCIAMACHY and
GOME-2 using the GODFIT algorithm. The GOME-type Direct FITting (GODFIT) algorithm has been
developed by the consortium BIRA-IASB/RT-Solutions/DLR-IMF and forms the basis of the current
operational GOME Data processor version 5. For the Ozone_cci project, it has been selected as the
baseline for total ozone ECV (Essential Climate Variable) production. GODFIT uses a direct-fitting
approach where backscattered spectral radiances are simulated on-the-fly at about 100 wavelengths
from 325 to 335 nm using the radiative transfer model LIDORT v3.3. The algorithm is consistently
applied to the GOME, SCIAMACHY and GOME-2 data sets which altogether span a time period of more
than 16 years, to be extended in the future with the launches of the METOP-B and -C platforms, as well
as the ESA Sentinels 4, 5 and 5-P.
We present the latest algorithmic developments realized within the Ozone_cci project. These include
improved treatment of the Ring effect and explicit corrections for polarization effects that have been
neglected in past versions of the algorithm. To speed up the algorithm and make it suitable for
processing large data sets, radiative transport calculations have been accelerated by about one order of
magnitude without significant loss of accuracy using a new 2-stream model coupled to a principal
component analysis correction scheme. In addition, a new reflectance correction approach has been
designed that minimizes the impact of instrument degradation and inter-sensor level-1 inconsistencies on
117

total ozone retrievals in the Huggins bands. We illustrate the impact of each of these improvements and
give a flavour of the resulting multi-sensor total ozone data to be produced by the end of 2012.
Essential Climate Variables from Radio Occultation
Foelsche, Ulrich; Scherllin-Pirscher, Barbara; Ladstädter, Florian; Danzer, Julia; Steiner, Andrea K.;
Fritzer, Johannes; Kirchengast, Gottfried
University of Graz, AUSTRIA
The Radio Occultation (RO) technique has originally been developed in the 1960s for the study of
planetary atmospheres and ionospheres. Accurate RO measurements of the Earth’s atmosphere became
feasible in the 1990s, with the precise radio signals of the GPS satellite system (guaranteed by on-board
atomic clocks). A few hundred times per day, a satellite in low Earth orbit (LEO) sees one of the GPS
satellites setting or rising behind the Earth’s horizon. In this “occultation” geometry, the GPS signals
have to pass through the Earth’s atmosphere and they are characteristically influenced (slowed and
bent), depending on the density of the atmosphere. The respective motion of the satellites provides a
scan through the atmosphere. Accurate measurements of the change in the GPS signal (onboard the LEO
satellite) therefore allow to reconstruct the atmospheric density and, subsequently, profiles of pressure
as well as temperature. RO measurements can be performed during day and night, over oceans and
land, and even inside clouds. During the last few years, RO measurements have been increasingly used
by weather centers around the globe, and they a surprisingly large positive impact on the quality of
atmospheric analyses (which are used as starting points for weather forecasts). RO data a very well
suited for climate applications, since they do not require external calibration and only short-term
measurement stability over the occultation event duration (1 – 2 min), which is provided by the atomic
clocks onboard the GPS satellites. With this “self-calibration”, it is possible to combine data from different
sensors and different occultation missions without need for inter-calibration and overlap (which is
extremely hard to achieve for conventional satellite data). The comparison of RO climatologies from
different receiving satellites of the COSMIC constellation shows a remarkable consistency of about 0.01
K, when RO data are globally averaged. Even though the RO record is still comparatively short, its high
quality already allows to see statistically significant temperature trends in the lower stratosphere.
On Merging Data from Satellite Limb Soundings
Sofieva, Viktoria; Tamminen, Johanna; Laine, Marko; Kyrölä, Erkki
Finnish Meteorological Institute, FINLAND
The use of combined data from different limb sensors is of high interest, because they provide much
better spatio-temporal coverage than each of the instruments separately. However, the data from
different instruments can be biased with respect to each other, have different vertical resolution, are
attributed to different local times, and might use different a priori information in the inversion process.
Therefore, the datasets need to be homogenized before the merge. The creation of homogenized ozone
dataset based on limb measurements from GOMOS, MIPAS, SCIAMACHY and OSIRIS is one of the
objectives of the on-going ozone-CCI project. In this presentation, we discuss approaches to the data
merging. Selection of optimal spatio-temporal grid, methods for bias detection and its correction, and
characterization of the related uncertainties are presented. We discuss different approaches for merging
the data in the selected spatio-temporal bins: the use of generalized weighted mean (which takes into
account different vertical resolution), and the use of geostatistical analysis to account for the spatial
correlation structure. The proposed methods are illustrated by examples of using GOMOS, MIPAS,
SCIAMACHY and OSIRIS data.
118

The ESA Cloud CCI Project: Generation of Multi Sensor Consistent Cloud
Properties with an Optimal Estimation Based Retrieval Algorithm
Hollmann, Rainer 1 ; Stengel, Martin 1 ; Lindstrot, Rasmus 2 ; Poulsen, Caroline 3 ; Jerg, Matthias 1
1 Deutscher Wetterdienst, GERMANY; 2 Free University Berlin, GERMANY; 3 RAL, UNITED KINGDOM
The ultimate objective of the ESA Climate Change Initiative (CCI) Cloud project is to provide long-term
coherent cloud property data sets exploiting and improving on the synergetic capabilities of past,
existing, and upcoming European and American satellite missions. The synergetic approach allows not
only for improved accuracy and extended temporal and spatial sampling of retrieved cloud properties
better than those provided by single instruments alone but potentially also for improved (inter-
)calibration and enhanced homogeneity and stability of the derived time series. Such advances are
required by the scientific community to facilitate further progress in satellite-based climate monitoring,
which leads to a better understanding of climate. Some of the primary objectives of ESA Cloud CCI Cloud
are
• the development of inter-calibrated radiance data sets, so called Fundamental Climate Data Records –
for ESA and non ESA instruments through an international collaboration,
• the development of an optimal estimation based retrieval framework for cloud related essential
climate variables like cloud cover, cloud top height and temperature, liquid and ice water path, and
• the development of two multi-annual global data sets for the mentioned cloud properties including
uncertainty estimates.
These two data sets are characterized by different combinations of satellite systems: the AVHRR heritage
product comprising (A)ATSR, AVHRR and MODIS and the novel (A)ATSR – MERIS product which is based
on a synergetic retrieval using both instruments. Both datasets cover the years 2007-2009 in the first
project phase. ESA Cloud CCI will also carry out a comprehensive validation of the cloud property
products and provide a common data base as in the framework of the Global Energy and Water Cycle
Experiment (GEWEX).
The presentation will give an overview of the ESA Cloud CCI project and its goals and approaches and
then continue with results from the Round Robin algorithm comparison exercise carried out at the
beginning of the project which included three algorithms. The purpose of the exercise was to assess and
compare existing cloud retrieval algorithms in order to chose one of them as backbone of the retrieval
system and also identify areas of potential improvement and general strengths and weaknesses of the
algorithm. Furthermore the presentation will elaborate on the optimal estimation algorithm subsequently
chosen to derive the heritage product and which is presently further developed and will be employed for
the AVHRR heritage product. The algorithm’s capabilities to coherently and simultaneously process all
radiative input and yield retrieval parameters together with associated uncertainty estimates will be
presented together with first results for the heritage product. In the course of the project the algorithm is
being developed into a freely and publicly available community retrieval system for interested scientists.
Error Characterization of SCIAMACHY Limb Ozone Data
Rahpoe, Nabiz 1 ; Weber, Mark 1 ; von Savigny, Christian 1 ; Rozanov, Alexei 1 ; Bovensman, Heinrich 2 ;
Burrows, John P. 2
1 IUP Bremen, GERMANY; 2 IUP Brmen, GERMANY
The SCIATRAN code has been used to simulate synthetic ozone profiles and to estimate the impact of
different geometrical and physical parameters on the retrieved ozone profiles. A detailed error budget
has been established for the SCIAMACHY data. The systematic and random errors calculated can be used
for the validation of the SCIAMACHY limb ozone data with other instruments.
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