基于IMERG卫星遥感数据的华南地区近20年汛期强降雨气候特征分析OA北大核心CSTPCD

This study analyzed the regional climate variations in heavy rainfall across South China by using the IMERG precipitation data during 2001-2020.The research focused on the spatiotemporal distribution characteristics of heavy rainfall and the diurnal variations of extreme heavy rainfall before,during,and after the onset of the South China Sea summer monsoon.The results showed that:(1)The rainfall center in South China was influenced by diverse weather systems at different times of the year.The ratios of rainfall during the two rainy seasons to the annual precipitation were inversely distributed,and the proportion of heavy rainfall along the coast of Guangdong and Guangxi was significantly higher than those of other regions.Heavy rainfall contributed the most to the overall precipitation in the rainfall center of South China.(2)The coastal areas of Guangdong experienced two peaks of heavy rainfall in June and August,while Hainan Island observed a single peak in October.Other regions of Guangdong and Guangxi exhibited a single peak in June,which was closely related to the onset of the South China Sea summer monsoon.During the onset of the summer monsoon,the strong summer monsoon intensified the heavy rainfall in Zone I(Beibu Gulf),Zone II(area near Yangjiang),and Zone III(Pearl River Delta)along the coastal land areas of Guangdong and Guangxi.In the second rainy season,the summer monsoon continued to contribute to increased heavy rainfall across the entire coastal area and Hainan Island.In early June,Zone III and Zone IV(Shanwei and its eastern region)experienced a high frequency of heavy rainfall,primarily due to warm-sector heavy rainfall induced by the southwest summer monsoon.(3)Hainan Island exhibited the highest occurrence of extreme heavy rainfall in South China,predominantly in the afternoon.Guangdong followed with a lower occurrence,while Guangxi experienced the lowest occurrence.The diurnal variation of extreme heavy rainfall was most pronounced in the morning along the coastal area of Guangdong and Guangxi,especially from early morning to forenoon(5-11 am),which corresponded to the peak period in Zone II and Zone III.Inland areas of Guangdong only exhibited a peak period in the evening during the onset of summer monsoon.