Statistical Analysis of Aerosol Optical Property and Cloud Microphysical Characteristics over China Region during Winters of 2006–2016

To investigate the climate effects of aerosol in East Asia, the temporal and spatial variation of aerosol-cloud-precipitation physical characteristics were analyzed, by comparing the monthly average data of MODIS and TRMM measurements in winter during the years of 2006-2016. By choosing winter as the research background, there are more frequent haze pollution, less convective precipitation, and lower relative humidity. The initial analysis of aerosol optical depth (AOD) shows that aerosols mainly concentrate in the middle and eastern regions of China (including the Yangtze River Delta, Pearl River Delta, Beijing-Tianjing-Hebei region and Sichuan Basin), within the mean values ranging from 0.6 to 1.2. To further understand the aerosol-cloud-precipitation interactions (ACPI), cloud micro-physical parameters were analyzed, including cloud optical thickness (COT), cloud effective radius of liquid cloud (CER_Liquid), liquid water path (LWP) and ice water path.

It is found that in winter COT and LWP are basically negatively correlated with AOD. However, CER_Liquid has a positive correlation with AOD over southeast China in 67% cases, and a negative correlation for other areas in 92% cases. Along the southeast coast of China, there is a positive correlation between AOD and precipitation, compared to the negative correlation in other areas. For Yangtze River Delta region, AOD of lower level has a positive correlation with cloud micro-physical parameters, and AOD of high level shows an obvious negative correlation. For cases of high AOD in this area, the negative correlation between AOD and COT of middle clouds is significant, and the relativity between AOD and LWP increases according to the decrease of cloud height.

Keywords: Aerosol Optical Depth, Cloud Micro-physical Characteristics, MODIS, TRMM, Spatial and Temporal Variation