The influence of a Soil-Vegetation-Atmosphere Transfer scheme on the simulated climate of LLNL/UCLA AGCM

The sensitivity of the Lawrence Livermore National Laboratory (LLNL)/Univer sity of California, Los Angeles (UCLA) Atmospheric General Circulation Mode l (AGCM) to coupling with a Soil-Vegetation-Atmosphere Transfer (SVAT) sche me is investigated in this paper. The SVAT leads to general warming of the climate over continents in association with enhanced sensible heat fluxes. The wetness bias of AGCM is reduced drastically with reductions in latent h eat fluxes and precipitation. There is reduction in cloudiness when the SVA T is coupled which results in increased solar radiation at the surface. Upw ard long wave radiation increases in association with increases in land sur face temperature. Although the coupling of SVAT improves surface fluxes of heat and water vapor, these changes are mainly offset by changes in solar a nd infrared radiative fluxes. Global mean energy balance at the surface and the top of atmosphere is improved marginally. (C) 1999 Elsevier Science B. V. All rights reserved.