Abstract:

Based on the daily precipitation data of 44 stations in Xiangjiang River Basin during last 48 years,the 95th percentile is defined as the threshold of extreme precipitation for each station.At the same time,the changing feature and temporal and spatial characteristics of the different grade rain events were analyzed by using the methods of Line Regression，Abrupt Changing Analysis and Similarity Coefficients.The result showed that every index (precipitation quantity,precipitation days,precipitation intensity,precipitation index and daily maximum precipitation)of extreme precipitation increased in last 48 years.But in different times,the extreme precipitation shows a different changing trend.The heavy rain events were more frequent before 1970s.During the 1970s and 1980s,each grade rain event was in a relatively weak stage.Since the 1990s,all precipitation obviously increased,especially the rainstorm and heavy rainstorm events.Besides,regional difference was revealed by analyzing the distribution of extreme precipitation in Xiangjiang River Basin.Rainstorm events were mainly in the upper reaches;heavy rain events were more in the middle reaches;heavy rainstorm events were in the lower reaches.