Numerical Simulations of the Effect of Organic Carbon on Regional Climate in East Asia

The Regional Climate Model version 3 (RegCM3) is used to investigate the effect of organic carbon (OC) and sulfate aerosol on radiation forcing and regional climate in East Asia. The simulation results show that OC aerosol produces a negative radiation forcing at the whole atmosphere column and at the surface in this region. The negative radiation forcing becomes less significant from south to north China in Winter and Spring, and an extreme value center in central China both in the whole atmosphere radiation and surface radiation. Mixed with sulfate aerosol, the whole atmosphere radiation is reduced and surface radiation is increased due to OC. OC aerosol makes the surface temperature in high latitude higher and in middle latitude lower. Furthermore, the rainfall in south and north China is decreased and that in middle China increased. Mixed with sulfate, OC also reduces rainfall in the region.