HR: 0800h
AN: A31C-0069    [Abstracts]
TI: Modeling the Vertically Stratified Atmosphere of Southern Africa During the Biomass Burning Season
AU: * Magi, B I
EM: magi@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington, Box 351640, Seattle, WA 98195-1640 United States
AU: Hobbs, P V
EM: phobbs@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington, Box 351640, Seattle, WA 98195-1640 United States
AB: The University of Washington Convair-580 research aircraft measured in situ aerosol properties during the biomass burning season of southern Africa in August and September, 2000. During the burning season, the atmosphere in southern Africa consists of persistent regional haze reaching as high as 5 km. The regional haze is often stratified into distinct layers with particle concentrations varying by an order of magnitude. Above the regional haze, particle concentrations decrease significantly. The haze consists primarily of aged biomass burning aerosol, the concentration of which depends on local fire intensities and meteorology. Detailed in situ measurements from near the surface to about 5 km were obtained from the Convair-580. The measurements most relevant to this study are the dry particle size distribution (for particle diameters of 0.10-3.0 microns) and the aerosol single-scattering albedo, which is derived from measurements of the aerosol scattering and absorption coefficients. Regional scale models generally use an averaged particle size distribution and a column-averaged single-scattering albedo based on studies made in the region of interest. However, the vertical stratification of polluted layers found in southern Africa is unaccounted for in such models. In this study, we describe the aerosol properties of polluted layers with a vertical resolution of about 10 m for two cases. We use those data as input to a radiative transfer code. The outgoing radiances from the radiative transfer code will be compared with those measured by the MODIS sensor aboard the Terra satellite, which was correlated both spatially and temporally with the cases explored here. Uncertainties and assumptions in the input will be discussed. We will explore the effects on the outgoing radiances of increasing the vertical resolution in the polluted aerosol layers. Finally, we examine the effects of parameter averaging with respect to the dry particle size distribution and the single-scattering albedo.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0360 Transmission and scattering of radiation
DE: 0365 Troposphere--composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting