HR: 10:20h
AN: A12A-01    [Abstracts]
TI: Comparison of Airborne Sunphotometer and Satellite Retrievals of Aerosol Optical Depth during MILAGRO/INTEX-B
AU: * Livingston, J M
EM: jlivingston@mail.arc.nasa.gov
AF: SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025, United States
AU: Torres, O
AF: Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County (UMBC), NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
AU: Russell, P B
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000, United States
AU: Redemann, J
AF: Bay Area Environmental Research Institute, 560 Third Street, Sonoma, CA 95476, United States
AU: Johnson, R R
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035-1000, United States
AU: Bergstrom, R W
AF: Bay Area Environmental Research Institute, 560 Third Street, Sonoma, CA 95476, United States
AU: Veheilmann, B
AF: Royal Netherlands Meteorological Institute (KNMI), 3730 AE, De Bilt, 201, Netherlands
AU: Smirnov, A
AF: Goddard Earth Sciences and Technology Center, University of Maryland, Baltimore County (UMBC), NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
AU: Holben, B N
AF: NASA Goddard Space Flight Center, Building 33, Greenbelt, MD 20771, United States
AU: Remer, L
AF: NASA Goddard Space Flight Center, Building 33, Greenbelt, MD 20771, United States
AU: Schmidt, K S
AF: Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Duane Physics, Boulder, CO 80309, United States
AU: Coddington, O
AF: Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Duane Physics, Boulder, CO 80309, United States
AU: Pilewskie, P
AF: Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Duane Physics, Boulder, CO 80309, United States
AB: In March 2006 the 14-channel Ames Airborne Tracking Sunphotometer (AATS) was operated on a Jetstream 31 (J31) aircraft based in Veracruz, Mexico during MILAGRO/INTEX-B (Megacity Initiative-Local And Global Research Observations /Phase B of the Intercontinental Chemical Transport Experiment). AATS measured total extinction aerosol optical depth (AOD) at 13 wavelengths (354-2139 nm) and water vapor column content in 13 flights that sampled clean and polluted airmasses over the Gulf of Mexico and Mexico City. Vertical differentiation of AOD and columnar water vapor data obtained during J31 vertical profiles yields vertical profiles of multiwavelength aerosol extinction and water vapor density, respectively. J31 flights were coordinated with overflights of several satellites, including Aqua, Aura, Terra, and Parasol, plus other aircraft, including the NASA DC-8 and King Air and the NCAR C-130. Data obtained by the Ozone Monitoring Instrument (OMI) aboard Aura are routinely inverted using two different inversion schemes, a near UV algorithm and a multiwavelength (MW) algorithm, to yield retrievals of AOD and absorption AOD (AAOD). We have identified four Aura overpasses for which OMI retrievals have been performed and AATS AOD spectra have been calculated at coincident or near-coincident times and locations. Three of these (3, 10 and 17 March) were over the Gulf of Mexico, and one (19 March) was over the Mexico City area. In this presentation we will compare the AATS and OMI AOD retrievals. For the 10 and 17 March comparisons, MODIS (aboard Aqua) AOD retrievals are available, and these agree well with the AATS AOD spectra. AOD values resulting from application of both the OMI UV and MW retrieval algorithms on 3, 10, and 17 March significantly overestimate the AATS and MODIS values. The suborbital data set for the 19 March comparison is particularly rich, including ground-based AERONET retrievals of aerosol properties from the T2 site NNE of Mexico City and the T0 site in the heart of the city, additional aerosol retrievals from radiometers on the J31, and lidar and in situ measurements from the DC-8. AERONET data at T0 yield AOD spectra that are consistent with AATS AOD spectra calculated from measurements acquired ~ 450 m above the T0 site. OMI UV and MW AOD retrievals significantly exceed the AATS and AERONET values. However, when the comparison is performed in AAOD after conversion of AATS AOD to AAOD using realistic single scattering albedos obtained from other measurements during previous field campaigns, the OMI UV AAOD retrievals (which are less sensitive to surface albedo uncertainties than the OMI MW retrievals) agree well with the corresponding AATS values. We intend to examine possible reasons for these observed differences and explore plausible approaches to bring the retrievals into agreement. In particular we will explore using different assumptions about the nature of the absorbing particles.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0520 Data analysis: algorithms and implementation
DE: 3311 Clouds and aerosols
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting