Spatial-temporal evolution characteristics and trend of annual precipitation in Jiangsu Province under the background of climate change

The spatial and temporal evolution characteristics and development trend of precipitation are important basis for regional flood and drought disaster analysis, water resources planning and agricultural water management. According to the long annual precipitation data of 22 stations in Jiangsu and neighboring provinces from 1961 to 2020, the distribution characteristics and trends of annual precipitation at different spatial and temporal scales under the background of climate change were analyzed by several methods of spatial interpolation, cumulative anomaly, hydrological statistics, moving average and Mann-Kendall test, with station, regional and provincial domains as spatial scales and 10 years, 30 years and 60 years as time scales. The results show that the multi-year average precipitation contour maps of different time scales indicate that the spatial distribution of precipitation in Jiangsu Province is uneven, which is basically in line with the distribution law of more in the south and less in the north, more in the east and less in the west, and the three cities in Central Jiangsu are closer to the five cities in South Jiangsu. The annual precipitation in the northern part of North Jiangsu showed an insignificant decreasing trend; the southern part of North Jiangsu, Central Jiangsu and South Jiangsu overall showed an increasing trend. From the average precipitation of all stations, the annual precipitation from 1961 to 2020 showed an overall upward trend; the occurrence time of annual precipitation mutation point is regional. In addition, compared with the previous 30-year series, the statistical parameters of the latter 30-year series are closer and more representative to the 60-year series. The research conclusions have guiding significance for hydrological year patterns analysis, flood and drought disaster prediction, water resources planning and water management in Jiangsu Province under the background of climate change.