2011 - Cooperative Institute for Research in Environmental Sciences ...

CLIMATESYSTEMVARIABILITY
CSV-01 Detection of Climate Models,
Trends and Variability
n GMD-03 Climate Trend Analysis
n PSD-04 Decadal Climate and Global Change Research
n NGDC-04 Paleoclimatology: Understanding Decadal- to
Millennial-Scale Climate Variability
GMD-03ClimateTrendAnalysis
FEDERAL LEAD: SAMUEL OLTMANS
CIRES LEAD: IRINA PETROPAVLOVSKIKH
NOAA Goal 2: Climate
Project Goal: Interpret operational data (ozone column,
ozone profile, aerosol extinction, broadband spectral radiation
and other environmental parameters) collected by NOAA
ground-based and National Center for Atmospheric Research
(NCAR) aircraft-based instruments. Assess data for long-term
quality. Evaluate stability and interannual variability in the
ground-based and aircraft-based data sets. Provide the scientific
community with information relevant to climate research
and evaluate usefulness of data for validation of other independent
measurements, including satellite observations.
Milestone 1: Analyze ground-based, balloon and aircraft
in situ ozone measurements for long-term trends in the
troposphere and at the surface.
The 35-year record of surface ozone measurements
at four of the NOAA Baseline Observatories (Barrow,
Alaska; Mauna Loa, Hawaii; American Samoa; and South
Pole) represents some of the longest continuous records
of tropospheric ozone at background locations. At these
sites, less than 5 percent of the data are influenced by
nearby (less than 100 km) anthropogenic ozone precursor
emissions. This data record is investigated for longerterm
changes with an emphasis on the 30-year period
1980-2009. The three 10-year periods are compared with
particular emphasis on possible changes in the seasonal
pattern over this time. At each of these sites, strong
seasonally dependent processes, such as the springtime
boundary layer ozone depletion at Barrow, influence the
year-to-year variability and can influence the longerterm
changes. At several other regionally representative
locations (Bermuda; Barbados; Iceland; and Niwot Ridge,
Colo.), there are 20-plus years of observations, although
in all cases there are multi-year gaps in the record. Earlier
and more recent portions of the record are compared,
again with emphasis on possible changes in the seasonal
pattern over this time. Significant longer-term changes
have taken place at Barrow and Mauna Loa. At Barrow
this has been during the summer and winter months,
while in Hawaii the change has been primarily during the
seasonal minimum in the autumn and early winter. There
is some suggestion of an increase over the Atlantic from
the discontinuous records in Bermuda and Iceland that
encompasses the entire year.
Product: Douglass, A, V Fioletov, S Godin-Beekmann,
106 CIRES Annual Report 2011
R Müller, RS Stolarski, A Webb, A Arola, JB Burkholder,
P Burrows, MP Chipperfiel, R Cordero, C David, PN
den Outer, SB Diaz, LE Flynn, M Hegglin, JR Herman, P
Huck, S Janjaim, IM Jánosi, JW Krzyścin, Y Liu, J Logan,
K Matthes, RL McKenzie, NJ Muthama, I Petropavlovskikh,
M Pitts, S Ramachandran, M Rex, RJ Salawitch, BM
Sinnhuber, J Staehelin, S Strahan, K Tourpali, J Valverde-
Canossa, C Vigouroux (2010), Stratospheric ozone and
surface ultraviolet radiation, Scientific Assessment of Ozone
Depletion: 2010, World Meteorological Organization, 2011.
Milestone 2: Continue to assess and improve quality of
column and profile ozone measurements for climate
trend analysis and satellite validation.
The improvement of the Dobson and Brewer ozone
profile retrieval algorithm has continued. The Umkehr
data acquired in 2009-2010 by the NOAA Dobson and
NEUBrew Brewer ozone ground-based network have
been processed and archived. The new level 300 total
ozone data are corrected for long-term drifts in instrumental
degradation and are now used in the Umkehr
ozone profile retrievals. The largest effect (about 5 percent)
is in the lowermost tropospheric layers, and it reduces
the previously found bias with respect to the co-located
ozone-sounding data. Verification/quantification of the
instrumental changes (caused 5 percent error in retrieved
ozone at 40 km) found in the Dobson Umkehr retrieved
ozone data at Mauna Loa (MLO), Hawaii, in 2005 were
performed through the comparisons against the climatological
data, and long-term time-series of co-incident
measurements taken by lidar and microwave instruments
at MLO, and ozone-sounding at Hilo, Hawaii. The work
to apply corrections is underway. The study to assess the
sensitivity of Dobson and Brewer Umkehr retrieved ozone
profiles to the choice of the ozone absorption cross-section
(Bass and Paur, 1985; Daumont, 1992), the out-of-band
stray light (OOB) error and stratospheric temperature
variability were assessed. It was found that ozone crosssection
choice and its temperature dependence only minimally
(within the retrieval accuracy) affect the Dobson
and the Brewer Umkehr retrievals. Significantly larger
errors are found when the OOB stray light contribution to
the Umkehr measurement is not taken into account in the
retrieval algorithm, but produces no statistically significant
effect on long-term trends.
PSD-04DecadalClimate
andGlobalChangeResearch
FEDERAL LEAD: RANDALL DOLE
CIRES LEAD: PRASHANT SARDESHMUKH
NOAA Goal 2: Climate
Project Goal: Improve understanding of long-term climate
variations through analysis of observations and hierarchies of
General Circulation Model (GCM) experiments. Seek dynamical
explanations of oceanic variability and changes through
observational analysis and GCM experiments. Provide attribution
for long-term regional climate changes.
Milestone 1: Investigate the relative contributions of El
Niño Southern Oscillation (ENSO)-related and ENSO-unrelated
tropical sea surface temperature (SST) variations on
global climate changes over the last 130 years.
An important question in assessing 20th-century climate