HR: 1340h
AN: A53A-0160    [Abstracts]
TI: Impact Of Chemical Compositions And Size Distributions Of Anthropogenic Aerosols On Their Radiative Forcings: A Modeling Study Using An Interactive Aerosol-Climate Model Based On NCAR CAM3
AU: * Kim, D
EM: dckim@mit.edu
AF: Massachusetts Institute of Technology, EAPS Bldg.54-1726 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Wang, C
A53A-0160 AF: Massachusetts Institute of Technology, EAPS Bldg.54-1726 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Ekman, A M
A53A-0160 AF: Stockholm University, Frescativägen 54, Stockholm, 10691 Sweden
AU: Barth, M C
A53A-0160 AF: National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305 United States
AU: Rasch, P J
A53A-0160 AF: National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305 United States
AB: Aerosols are known to influence global climate by reflecting or absorbing solar radiation (direct effect) and by changing cloud properties and precipitation (indirect effect). In spite of their importance, the current scientific understanding of aerosols is still low. The prediction of atmospheric evolution and the climate effects of aerosols in many global models are mainly done by using simplified aerosol modules often ignoring the size distributions of aerosols. To better understand the role of aerosols in the climate system, an interactive aerosol-climate model has been developed by incorporating a chemistry and size-dependent aerosol model into the National Center for Atmospheric Research Community Atmospheric Model, version 3 (CAM3). For the present study four different aerosol species of black carbon (BC), organic carbon (OC), sulfate (SO₄), and mixed aerosols are included in the model as six aerosol modes (3 for sulfate aerosols). The aerosol model thus provides prognostic number and mass concentrations of various modes of aerosols by including emissions, transport, dry/wet deposition, and aerosol chemical and physical processes in the model. The global radiative forcings of various aerosols are then examined using predicted information of aerosol size distributions. The modeled aerosol distributions are compared with satellite and surface observations and discrepancies between modeled and observed results have been analyzed. The impact of modeled aerosols evolution on their radiative forcings will be discussed.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0321 Cloud/radiation interaction
DE: 0325 Evolution of the atmosphere (1610, 8125)
DE: 1626 Global climate models (3337, 4928)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005