Study on the role of Short-lived climate pollutants in East Asian climate system

Abstract

Recent studies have suggested that the Short Lived Climate Pollutants (SLCPs) such as Sulfate aerosols, Black carbon, Seasalt play a role to influence the weather and climate variability by changing radiative forcings. Therefore, it is useful to examine the relationship between atmospheric variability and SLCPs. Particularly, the concentration of SLCPs is significant in east Asia, which is mostly due to a rapid industrialization. It is known that both the atmospheric circulation and cloud variability is closely associated with the variations of SLCPs in east Asia. We use for each analysis using GEOS-Chem model and the MODIS(Moderate Resolution Imaging Spectroradiometer) Terra AOD observational data. Using the global chemical transport model (GEOS-Chem) simulation for 1985-2010, we examine the inter-annual variability of and the its effect on atmospheric variability. The composite analysis reveals that the high and low concentration year of in east Asia is differently associated with the spatial pattern of atmospheric anomalies. In addition, the changes in the concentration in east Asia may lead the changes in the amount of high and low cloud in the downstream region of the North Pacific. And we examine the inter-annual variability of observational MODIS Terra AOD for 2000-2014 and its effect on early East Asia summer monsoon. We find a significant correlation between Land-Sea thermal contrast in June and aerosol loading in spring, indicative of strong concentration of aerosols transported from Eastern China. Composite analyses based on AOD show that high concentration of aerosol over Eastern China in spring is associated with increased cloud fraction, enhanced dynamically reflected downward short wave radiation over the ocean, and reduced ocean surface temperature over similar area. Land-Sea thermal contrast increased during June, followed by a subsequent enhanced Early East Asian summer monsoon.