The First Indirect Radiative Forcing of Black Carbon Aerosol and Its Effect on Regional Climate of China

The regional climate model(RegCM3) and a tropospheric atmosphere chemistry model(TACM) was coupled,thus a regional climate chemistry model system(RegCCMS) was constructed,which was applied to investigate the spatial distribution,the indirect radiaitive forcing and the climatic effect of black carbon aerosol over China in January and July 2003.The simulated results show that there is high concentration of black carbon aerosol in Sichuan,Hebei and Shandong Provinces.The maximum value of the concentration reaches to 4 μg·m-3 in Sichuan Province in January,and 3.5 μg·m-3 in Central China in July,respectively.The average indirect radiative forcing at the tropopause due to black carbon aerosol is-0.389 W·m-2 in January and-1.18 W·m-2 in July over China,respectively.In some areas,indirect radiative forcing reaches-4~-4.5 W·m-2.Sensitivity test shows that the black carbon aerosol makes the surface air temperature drop and precipitation reduce.Mean changes in surface air temperature and precipitation are 0.025K and 0.0027 mm·d-1 in January and 0.16K and 0.095 mm·d-1 in July,respectively.There are significant differences of the reduction of the surface air temperature and precipitation in different seasons and areas.