Trends in the Different Grades of Precipitation over South China during 1960-2010 and the Possible Link with Anthropogenic Aerosols

Using observed daily precipitation data to classify five levels of rainy days by strength in South China (SC), with an emphasis on the Pearl River Delta (PRD) region, the spatiotemporal variation of different grades of precipitation during the period 1960-2010 was analyzed and the possible link with anthropogenic aerosols examined. Statistical analysis showed that drizzle and small precipitation has significantly decreased, whereas medium to heavy precipitation has increased slightly over the past 50 years (although not statistically significant). Further data analysis suggested that the decline in drizzle and small precipitation probably has a strong link to increased concentrations of anthropogenic aerosols produced by large-scale human activities related to the rapid socioeconomic development of the PRD region. These aerosols may also have led to the obvious decreasing trend in horizontal visibility and sunshine duration in SC, which is statistically significant according to the t-test.