HR: 0800h
AN: A31A-0819    [Abstracts]
TI: Modeling Aerosol Direct Radiative Forcing With Observed Properties of Southern African Biomass Burning Aerosol
AU: * Magi, B I
EM: magi@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences, Box 351640, Seattle, WA 98195 United States
AU: Fu, Q
EM: qfu@atmos.washington.edu
AF: University of Washington, Department of Atmospheric Sciences, Box 351640, Seattle, WA 98195 United States
AU: Hobbs, P V
EM: none
AF: University of Washington, Department of Atmospheric Sciences, Box 351640, Seattle, WA 98195 United States
AB: Measurements of aerosol physical, chemical, and optical properties obtained from the University of Washington Convair-580 research aircraft and other platforms are used to constrain a retrieval algorithm to obtain aerosol extinction coefficient, single scattering albedo, and asymmetry parameter in the solar spectrum. Using in situ measurements of aerosol scattering and absorption at visible wavelength along with Mie theory, we derive an aerosol size distribution that is consistent with these measurements. Using this size distribution and independently observed aerosol extinction from a sun photometer, we then retrieve single scattering albedo and the asymmetry parameter over the entire solar spectrum. We examine two detailed cases from the biomass burning season of southern Africa. In both cases, we have vertical profiles of the in situ measurements required for the retrieval algorithm. The vertical profiles of the meteorological properties and the measured and retrieved wavelength-dependent aerosol optical properties are then used as input to an atmospheric column radiative transfer model to calculate radiative fluxes and heating rates at multiple layers in the atmosphere. We will investigate the aerosol direct radiative forcing related to biomass burning aerosols, as well as assessing the level of accuracy required in the retrieved aerosol properties to reduce the uncertainties in biomass burning aerosol direct radiative forcing evaluations. Finally, the simulated outgoing fluxes will be compared to available remote sensing platforms. The ground-based Aerosol Robotic Network (AERONET) measures aerosol optical depth as well as offering a set of retrieved aerosol parameters, all at wavelengths in the solar spectrum. The CERES (Clouds and the Earth's Radiant Energy System) instrument aboard the Terra satellite estimates broadband flux from the top of the atmosphere and our column radiative transfer model output will be compared to measurements from CERES.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005