HR: 1340h
AN: A33C-0912    [Abstracts]
TI: Sensitivity of Multiangle Imaging to Optical and Microphysical Properties of Biomass Burning Aerosols
AU: * Chen, W
EM: annechen@caltech.edu
AF: Department of Environmental Science and Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Kahn, R A
EM: ralph.kahn@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Li, W
EM: wen-hao.li@ngc.com
AF: Jet Propulsion Laboratory, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Li, W
EM: wen-hao.li@ngc.com
AF: Now at Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA 90278 United States
AU: Seinfeld, J H
EM: seinfeld@caltech.edu
AF: Departments of Chemical Engineering and Environmental Science and Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125
AB: The Multiangle Imaging Spectroradiometer (MISR) provides unique multiangle, multi-spectral global tropospheric aerosol data. To improve the retrieval algorithm of MISR for biomass burning (BB) aerosols, the microphysical and optical properties of BB particles are summarized from the literature of past field experiments, and variations with vegetation type, plume age, and fire phase are identified. Based on the review, a theoretical sensitivity study is carried out to examine the MISR retrieval algorithm's ability to discriminate among component particles in the two-dimensional space of spherical particles covering the observed range of BB size distribution (mean volume-weighted geometric diameter, D_pg,V, from 0.15 to 0.63 μm) and Single Scattering Albedo (SSA at 550 nm, ω_0,550, from 0.83 to 0.93). For a column Aerosol Optical Depth (AOD) of 0.5, over a dark, uniform surface, MISR can distinguish two to three groups in size and SSA, except when the atmospheric particles are very absorbing (ω_0,550~0.74) and have D_pg,V smaller then 0.36 μm. In BB field case studies over Alta Floresta, Brazil and Mongu, Zambia, our analysis indicates that, in retrievals having AOD ≥ 0.4 over a relatively uniform land surface, MISR can separate small, absorbing particles from ones in other size and SSA categories. The uncertainty and interpretation of the retrieval depends on AOD as well as surface properties, which in our field study are derived using a forward radiative transfer model constrained by AERONET aerosol inversion products on clean days before and after the hazy day. The scarcity of good cases indicates the importance of aerosol measurements with coordinated BB field campaigns and long-tem monitoring networks to help refine satellite aerosol retrievals, which, in turn, will benefit future aerosol research.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 1640 Remote sensing (1855)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005