HR: 1340h
AN: A43C-1432    [Abstracts]
TI: Aerosol Optical Effects on Deep Convective Clouds and Radiative Forcing
AU: * Fan, J
EM: jiwen.fan@pnl.gov
AF: Department of Atmospheric Sciences, Texas A&M University, 3150 TAMU, College Station, TX 77843-3150, United States
AU: Zhang, R
EM: zhang@ariel.met.tamu.edu
AF: Department of Atmospheric Sciences, Texas A&M University, 3150 TAMU, College Station, TX 77843-3150, United States
AU: Tao, W
EM: tao@agnes.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Code 613.1, Greenbelt, MD 20771, United States
AU: Mohr, K I
EM: mohr@atmos.albany.edu
AF: University at Albany, SUNY, Department of Earth and Atmospheric Sciences, Albany, NY 12222,
AB: Aerosols interact directly and indirectly with the Earth's radiation budget and climate. For the direct effect, aerosols scatter and absorb solar radiation. Light scattering by aerosols changes the radiative fluxes at the top-of- atmosphere (TOA), at the surface, and within the atmospheric column, while aerosol absorption modifies the atmospheric temperature structure, decreases the solar radiation at the surface, and lowers surface sensible and latent fluxes, suppressing convection and reducing cloud fraction. Using a two-dimensional cloud-resolving Goddard Cloud Ensemble (GCE) model coupled with radiative transfer processes and the land-atmosphere interaction processes, we investigate aerosol radiative effects on deep convective clouds in an urban atmospheric environment, focussing on the radiative effects of anthropogenic aerosols containing BC. An aerosol radiative module is developed to calculate the wavelength-dependent aerosol radiative properties based on the aerosol composition, size distribution, mixing state, and ambient relative humidity. The significance of the aerosol radiative effects (ARE) is investigated by comparing with the cases excluding the ARE. The associated aerosol direct, semi-direct and indirect radiative forcing for deep convective clouds are estimated, and the sensitivity of cloud properties and radiative forcing to aerosol single-scattering albedo (SSA) are examined. The results provide insight on the coupling between the aerosol direct, semi-direct, and indirect effects on clouds.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting