Direct Climate Effect Of Anthropogenic Aerosols On Asian Summer Monsoon

This paper consists of two main contents as follows:Firstly, the anthropogenic aerosols (sulfate, black carbon and organic carbon) have been simulated by using a regional climate model RegCM3coupled with a chemistry aerosol model. Using this coupled Aerosol-Climate model, we have compared the model results in Asia from the different anthropogenic aerosols. At last, according to above comparing, the transported characterizations of anthropogenic aerosols in Asia have been described. Secondly, this coupled Aerosol-Climate model is also employed to numerically simulate the direct climate effects of the anthropogenic aerosols discharging in Asian summer monsoon. The correlation analysis as well as composite analysis are used to conduct on the relationship between summer aerosol column burden and Asian summer monsoon based on the data of the numerical simulation. This kind of climate effect of aerosols is a forefront scientific problem in the world, so it is very significant to probe. Through above researsh, we have gained these conclusions as follows:Firstly, in East Asian summer monsoon region, results show that the aerosol can change summer850-hPa wind over East Asia. A cyclone appears on the estuary of the Yangtze River and its north air flow will weaken East Asian summer monsoon. Investigation has been conducted on the relationship between spring as well as summer aerosol column burden over China and summer850-hPa meridional wind in East Asia. Evidence shows that the aerosol column burden, both in spring and summer, bears a close negative correlation with summer850-hPa meridional wind in East Asia, East Asian summer monsoon weakened when the spring aerosol column burden over northern region of China as well as summer aerosol column burden over southern region of China increases. The reasons for these maybe that aerosol effects the short wave radiative forcing at both the top of the atmosphere and the surface, while the air pressure and potential height between sea and land have changed.Secondly, in South Asian summer monsoon region, evidence shows that aerosol can change summer zonal wind over South Asia both in200-hPa and850-hPa, and will weaken South Asian summer monsoon. When aerosol column burden increases, summer500-hPa potential height will increase as well as850-hPa monsoon trough will weak in South Asia. So results show that the aerosol column burden bears a close positive correlation with South Asian summer monsoon rainfall. It will decrease when the summer aerosol column burden over India increases.