The Spatial And Temporal Characteristics And Interactions Of Aerosol-Cloud-Radiation-Monsoon During Summer In East Asia

Aerosol-cloud-precipitation have an effect on east asian summer monsoon,it is of great importance to analyze the relationship among them.In this paper, we mainly use the aerosol optical depth and cloud data from MODIS on board Terra, the reanalysis data from NCEP/NCAR, the precipitation data from TRMM, radiation data at top-of-atmosphere(TOA) from CERES and at surface from CMSAF to study the spatial and temporal characteristics. We also analyze the interaction of aerosol-cloud-precipitation and aerosol-radiation-temperature with statistical methods. The results are as follows.Aerosol affects cloud and precipitation but differs in different areas. Aerosol optical depth(AOD) is about 0.4 to 0.68 with a decreasing trend in Pearl River Delta. The highest annual cloud optical depth is 23.6 and lowest 18.7.Cloud effective radius is about 20.2 to 25.6 μm for ice cloud and 12.9 to 15.3 μm for liquid cloud.Cloud water path has a range from 222.2 to 243.3 g/m’.The precipitation rate is 3.6 to 8.6 mm/d. The aerosol optical depth has a positive correlation with cloud optical depth(highest in YRD) and change the cloud effective radius(CER).It also has a positive correlation with cloud water path(highest in YRD). Heavy rains occur much more frequently under polluted conditions compared to light polluted case, with light rains conversely. The composition and vertical distribution of aerosol have an important effect on the interactions of aerosol-cloud-precipitation and need more research.The spatial distribution of incoming shortwave radiation(ISW) is opposite to AOD. Recent years incoming shortwave radiation of four areas have a decreasing trend, with outgoing long-wave radiation increasing at surface and dropping at top-of-atmosphere. The aerosol optical depth has a negative correlation with direct radiative forcing at surface and TOA. The highest direct radiative forcing at TOA is-36.27 W/m2 and-42.10 W/m2 in Beijing area at surface. Aerosols cause a cooling effect at surface and increase temperature at middle level of troposphere.The spatial distribution of AOD is induced by east asian summer monsoon(EASM), with an decreasing after the onset of monsoon. The streamlines in 850 hPa can changes the distribution of AOD, but the precipitation amount has little effect. The increasing AOD may influence EASM index and changes the date, which is obvious in 20N and 30N. It causes the monsoon in PRD later and in YRD opposite. The downdraft in 35N increase AOD. In the same time, AOD may influence downdraft which is linked to EASMI.The result shows that aerosol may affect EASM for cloud and radiation, EASM has a great influence on aerosol. Increasing AOD may cause CER decreasing, less light rains, dropping in SW and surface cooling. The intensity and onset date of EASM have great influence on the distribution of AOD, otherwise AOD may influence onset date in East China and downdraft in 35N, which is important for EASM.