HR: 1340h
AN: A33E-1647    [Abstracts]
TI: A regional climate model study of how biomass burning aerosol impacts the land- atmosphere interactions over the Amazon
AU: * Zhang, Y
EM: gtg674c@mail.gatech.edu
AF: Earth and Atmospheric Science Georgia Institute of Technology, 311 Ferst Dr. Atlanta, GA 30332, U.S.A., Atlanta, GA 30332,
AU: Fu, R
EM: rf66@mail.gatech.edu
AF: Earth and Atmospheric Science Georgia Institute of Technology, 311 Ferst Dr. Atlanta, GA 30332, U.S.A., Atlanta, GA 30332,
AU: Yu, H
EM: hyu@climate.gsfc.nasa.gov
AF: Goddard Earth Science and Technology Center, NASA/GSFC/Code 613.2 Greenbelt, MD 20771, U.S.A., Greenbelt, MD 20771,
AU: Dickinson, R E
EM: robted@eas.gatech.edu
AF: Earth and Atmospheric Science Georgia Institute of Technology, 311 Ferst Dr. Atlanta, GA 30332, U.S.A., Atlanta, GA 30332,
AU: Juarez, R
EM: rjuarez@tulane.edu
AF: Ecology and Evolutionary Biology Tulane University, 6823 St. Charles Ave. Rm# 400 Boggs Center New Orleans, LA 70118-5698, New Orleans, LA 70118,
AU: Chin, M
EM: mian.chin@nasa.gov
AF: Goddard Earth Science and Technology Center, NASA/GSFC/Code 613.2 Greenbelt, MD 20771, U.S.A., Greenbelt, MD 20771,
AB: A regional climate model is applied to examine the smoke aerosol direct and semi-direct effects during a dry to wet transition season in South America. By modified the soil and plants root parameters and by adding soil water to mitigate a dry bias of soil moisture, a realistic diurnal cycle of the surface sensibles and latent fluxes are obtained. Model results suggest that the decrease of cloudiness in early afternoon partially compensates the direct effects of smoke aerosols, so that the strongest changes of surface flux and PBL occur in later morning instead of in early afternoon. cloudiness decrease occurs right above the daytime PBL in the smoke area, while outside of the smoke center in equatorial Amazonia, cloudiness increases with its maximum occurring within the daytime PBL. An increase of lower-level moisture convergence in this region appears to be responsible for the increase of both specific and relative humidity in the PBL. Smoke aerosols, probably through their surface cooling, cause an increase of low-level moisture divergence in the smoke center, and compensational moisture convergence in the equatorial Amazonia. Such regional circulation changes can weaken the normal circulation transition from dry season to monsoon onset.
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting