Effects of anthropogenic aerosols over Asia on east Asian winter monsoon
A regional climate model RegCM4.0 coupled with a chemistry module is employed to investigate the effects of three anthropogenic aerosols (sulfate,black carbon and organic carbon) over Asia on east Asian winter monsoon.Moreover the correlation analysis as well as composite analysis are used to analyze the effects of the change of anthropogenic aerosols concentration in the main anthropogenic aerosols distribution area in east Asia on east Asian winter monsoon.The results show that anthropogenic aerosols intensify both east Asian tropical and subtropical winter monsoon.Anthropogenic aerosols lead to the reduction of winter precipitation in the east of South China.Anthropogenic aerosols in the main distribution area of east Asia showed a decreasing trend in autumn and winter from 2000 to 2007,which separately led to the delaying of the establishment and the weakening of east Asian winter monsoon.Correlation analysis as well as composite analysis also show that an increasing trend of anthropogenic aerosols column burden in the main distribution area in east Asia in autumn and winter may make east Asian winter monsoon strengthen and cause its onset in advance,and vice versa.The reasons for the strengthening of east Asian winter monsoon induced by anthropogenic aerosols may be explained as follows:the anthropogenic aerosols induce the decrease of land surface temperature,but almost have no effect on sea surface temperature,so they induce the increase of low-level temperature difference between sea and land and lead to the increase of low-level pressure difference between sea and land.
Anthropogenic aerosolEast Asian winter monsoonDirect climate effectRegCM4.0Correlation analysis