Abstract: The effects of sulfate aerosols over China on East Asian summer monsoon and precipitation were investigated using the latest version of general circulation model (GCM) CAM3.0 developed by NCAR/UCAR, coupled with an off-line aerosol assimilation system. The model results show that sulfate aerosols over China could bring about an extra global radiative force of -0.25 W/m². In most of China ( about the north of 25°N), the surface temperature universally drops while sea surface temperature increases, which drops the temperature difference between sea and land so that it weakens the East Asian summer monsoon and the precipitation in China. Especially, the cumulus cloud precipitation decreases greatly since sulfate aerosols mainly suppress the convection and cumulus cloud precipitation over China.

Key words: GCM CAM3.0, sulfate aerosols, direct climate effect, East Asian summer monsoon