Abstract: In recent years, the trend of global warming has been more and more serious, and extreme precipitation contributed to the risk of drought and flood disaster in the Yangtze River basin. Daily precipitation data of 34 automatic meteorological stations in the Yangtze River delta region from 1960-2012 were used to investigate the features of spatial and temporal variations of extreme precipitation using methods of the trend analysis, Mann-Kendall test and GIS spatial analysis. The main conclusions are as follows: 1) the extreme precipitation threshold limit value was in the range between 30.7mm and 46.7mm, all are heavy rainfall, and some close to rainstorm. The extreme precipitation threshold value presents zonal distribution features, large in north Jiangsu, southwest and southeast Zhejiang, and small in south Jiangsu, north Zhejiang, and Shanghai; 2) the frequency and intensity of extreme precipitation has obvious interdecadal differences, characterized by trends of decreasing obviously in early stage and slowly rising in late stage. The precipitation in the Yangtze River delta was more abnormal, and the extreme precipitation mutations mainly occurred in 1987; 3) the frequency and total amount of extreme precipitation were high in the southwest and southeast coastal islands of Zhejiang, and the value of R_95T was large mainly in north Jiangsu and Zhejiang's southeast coastal areas; 4) the seasonal change of extreme precipitation frequency reflected the north-south movement of the rain belt in a year, and also reflected the precipitation differences between the coast and the inland. The study also found that the precipitation events in Ganyu station of north Jiangsu, and stations on eastern Zhejiang's coast and island had become extreme, with rainstorm and flooding likely to happen in the future. The probability of drought in Sheyang and its surrounding areas will increase.

Key words: Yangtze River Delta region, extreme rainfall, trend analysis, Mann-Kendall test, GIS spatial analysis, spatial and temporal variations