Direct Radiative Forcing and Climatic Effects of Aerosols over East Asia by RegCM3

The authors used a high-resolution regional climate model (RegCM3) coupled with a chemistry/ aerosol module to simulate East Asian climate in 2006 and to test the climatic impacts of aerosols on regional-scale climate. The direct radiative forcing and climatic effects of aerosols (dust, sulfate, black carbon, and organic carbon) were discussed. The results indicated that aerosols generally produced negative radiative forcing at the top-of-the-atmosphere (TOA) over most areas of East Asia. The radiative forcing induced by aerosols exhibited significant seasonal and regional variations, with the strongest forcing occurring in summer. The aerosol feedbacks on surface air temperature and precipitation were clear. Surface cooling dominated features over the East Asian continental areas, which varied in the approximate range of -0.5 to -2°C with the maximum up to -3°C in summer over the deserts of West China. The aerosols induced complicated variations of precipitation. Except in summer, the rainfall generally varied in the range of -1 to 1 mm d-1 over most areas of China.