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

Figure 1: Simplified schematic showing a broadband cavity enhanced absorption spectrometer.
single scattering albedo with better sensitivity, higher accuracy,
and fewer artifacts than previous instrumentation.
Major development of the new 3-wavelength, 5-channel
photo-acoustic aerosol absorption spectrometer has been
completed. The instrument was successfully deployed onboard
the NOAA P-3 research aircraft during the CalNex
field campaign in 2010. Sensitive multi-wavelength aerosol
absorption measurements, in addition to multi-wavelength
thermally denuded aerosol absorption measurements,
were accomplished from a selection of the CalNex
flights. This is seen as a major milestone in the measurement
of aerosol absorption, as the acoustic technique was
shown to provide sensitive measurements despite deployment
onboard the noisy aircraft environment. Further
development of instrument electronics, optical components
and calibration procedures will be necessary based
on lessons learned from the CalNex campaign. Laboratory
and field experiments and manuscript preparation based
on the CalNex data set will continue.
Product: Langridge, J, M Richardson, D Law, D Lack,
and DM Murphy, Aircraft instrument for comprehensive
characterisation of aerosol optical properties, part 1:
Wavelength dependent optical extinction and its relative
humidity dependence measured using cavity ringdown
spectroscopy, submitted to Aerosol Sci. Technol.
Langridge, JM, DA Lack, et al., Evolution of aerosol optical
properties with transport in the Los Angeles basin, in
preparation.
Lack, DA, CD Cappa, JM Langridge, M Richardson, D
Law, R McLaughlin, and DM Murphy, Aircraft instrument
for comprehensive characterisation of aerosol optical
properties, part 2: Black and brown carbon absorption and
absorption enhancement measured with photo acoustic
spectroscopy, submitted to Aerosol Sci. Technol.
Lack, DA, JM Langridge, R Bahreini, CA Brock, AM
Middlebrook, and JP Schwarz, Black and brown carbon
absorption attribution within biomass burning particles,
in preparation.
Milestone 3. Develop and test cavity enhanced absorbtion
spectroscopy (CEAS) instruments for glyoxal, nitrous acid
and nitrogen dioxide. Impact: Both glyoxal (C2H2O2) and nitrous
acid (HONO) are reactive intermediates in atmospheric
chemistry that serve as photochemical radical sources and,
in the case of glyoxal, may participate in secondary organic
aerosol formation. Understanding their abundances is important
to both regional air quality and climate.
A new CEAS field instrument (Figure 1) was designed and
constructed during 2010. The instrument consists of two
CEAS channels, which are centered at 365 nm for nitrous
acid (HONO) and nitrogen dioxide (NO2), and 455 nm for
glyoxal (CHOCHO) and NO2. The optical components are
installed in a weatherproof case for installation outdoors.
The instrument was successfully deployed at the ground site
84 CIRES Annual Report 2011
in Pasadena, Calif., during the CalNex campaign in 2010.
Sensitive measurements of HONO, CHOCHO and NO2
were acquired during the field campaign. Analysis of these
data sets are underway, with a scientific focus on CHOCHO
contribution to secondary organic aerosol, radical budgets
and daytime HONO concentrations. Further development of
the optics and electronics is planned to improve the precision
and sensitivity of the CEAS instrument for future field
deployments.
Product: Washenfelder, RA, CJ Young, SS Brown, W
Angevine, EL Atlas, DR Blake, DM Bon, MJ Cubison, JA de
Gouw, S Dusanter, J Flynn, JB Gilman, M Graus, S Griffith,
N Grossberg, PL Hayes, JL Jimenez, WC Kuster, BL Lefer, IB
Pollack, TB Ryerson, H Stark, PS Stevens, and MK Trainer,
(2011), The glyoxal budget and its contribution to secondary
organic aerosol for Los Angeles during CalNex 2010, in
preparation.
Washenfelder, RA, C Young, and SS Brown, (2011), A field
instrument for NO2, HONO, and CHOCHO using incoherent
broadband cavity enhanced absorption spectroscopy, in
preparation.
Young, CJ, RA Washenfelder, SS Brown, JB Gilman, WC
Kuster, J Flynn, N Grossberg, B Lefer, S Alvarez, B Rappenglueck,
J Stutz, C Tsai, O Pikelnaya, LH Mielke, HD Osthoff,
JM Roberts, S Griffith, S Dusanter, and PS Stevens (2011),
Contribution of nitrous acid to the radical budget in urban
Los Angeles, in preparation.
Young, CJ, RA Washenfelder, SS Brown, P Veres, AK
Cochran, TC VandenBoer, JM Roberts, O Pikelnaya, C Tsai, J
Stutz, C Afif, V Michoud, and A Borbon (2011), Intercomparison
of nitrous acid measurements in urban Los Angeles, in
preparation.
PSD-08SensorandTechniqueDevelopment
FEDERAL LEAD: JIM JORDAN
CIRES LEAD: ANDREY GRACHEV
NOAA Goal 3: Weather and Water
Project Goal: Design, develop, enhance and evaluate remote and
in situ sensing systems for use from surface and other platforms
of opportunity in order to measure critical atmospheric, surface
and oceanic parameters.
Milestone 1. Write reports on the use of roving calibration
standard for ship flux measurements on two University-National
Oceanographic Laboratory System (UNOLS) ships.
Reports were written for the Research Vessel (R/V) Kilo
Moana (Bariteau, et al., Intercomparison of meteorological
observation systems on the R/V Kilo Moana and WHOTS
buoys) and the R/V Knorr (Wolfe, et al., Shipboard meteorological
sensor comparison: ICEALOT 2008).
Milestone 2. Perform laboratory study on crosstalk and sensitivity
of new fast carbon dioxide (CO2) sensor.