89th American Meteorological Society Annual Meeting

Wednesday, 14 January 2009
Examining the impact of radiative absorption and scattering by atmospheric aerosols on WRF/Chem forecasts
Hall 5 (Phoenix Convention Center)
Steven E. Peckham, NOAA/ESRL/GSD and CIRES-Univ. of Colorado, Boulder, CO; and G. A. Grell, S. A. McKeen, J. D. Fast, W. I. Gustafson Jr., J. C. Barnard, and R. Zaveri
The increase in atmospheric aerosols since the preindustrial period has perturbed the radiative balance of the Earth-atmosphere system and may be contributing significantly to the anthropogenic forcing of climate change. The radiative energy perturbation, referred to as direct radiative forcing, is due to aerosols' ability to scatter and absorb radiation. Light-absorbing aerosols such as soot, often called black carbon (BC), exerts a warming influence that may be second only to that of carbon dioxide and is considered an important factor in the perturbation of regional climate.

Atmospheric heating due to the absorption of solar radiation by aerosols is coincident with a reduction of solar radiation reaching the surface. This vertical redistribution of radiation directly affects static stability and boundary layer dynamics, which are important factors in the transport and atmospheric distribution of aerosols and other chemical species, resulting in complex feedbacks that occur at spatial scales smaller than typical resolutions of global climate models.

This study examines the impact of radiative absorption and scattering by atmospheric aerosols on meteorology. The mesoscale Weather Research and Forecast/Chemistry model (WRF/Chem) is used to simulate meteorology and air quality in the eastern United States for July 2004. The Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) is coupled to WRF/Chem so that all aerosol processes and radiative calculations are simulated online with meteorological calculations. The differences on temperature, water budget, and boundary layer dynamics with and without absorption and scattering of solar radiation are analyzed.

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