1961-2020年中国降水等级的变化特征OA北大核心CSTPCD

[Objective]The aims of this study are to explore the spatial and temporal distribution characteristics and seasonal change patterns of precipitation of various grades across China,enhance the knowledge of the occurrence patterns of different grades of precipitation in China,and then provide scientific and technological support for enhancing the national disaster prevention and mitigation capacity.[Methods]Based on the daily surface precipitation data from 681 meteorological stations in China during 1961-2020,the temporal and spatial distribution characteristics and seasonal variation of the days and intensity of precipitation of different grades(light rain,moderate rain,large rain and heavy rain)across China were analyzes.[Results](1)From 1961 to 2020,the number of light rain days showed a decreasing trend,while the number of moderate rain,large rain and heavy rain days showed an increasing trend,and no significant changes in the intensity of light,moderate and large rain except for great changes in the intensity of heavy rain were found.The number of light rain days decreased the most in autumn,large and heavy rain days increased the fastest in summer,and the slowest in autumn.The intensity of heavy rain fluctuated greatly in each season.(2)There was some variability in the spatial distribution of different precipitation levels,the high number of light rain days mainly distributed in the southwest river basins,the number of days with moderate rain and above and the intensity of precipitation at each level gradually decreased from southeast to northwest,and the number of days and intensity of precipitation in the Inland River basins were the smallest.(3)Precipitation in spring,autumn and winter mainly concentrated in the southeastern River Basins and the Pearl River Basin,where light rainfall predominated,and in summer precipitation mainly concentrated in the southwestern Rivers Basin,the southeastern Rivers Basin and the Pearl River Basin.The areas with higher intensity of precipitation at all levels in spring were mainly located in the southeastern Rivers Basin,the Yangtze River Basin and the Pearl River Basin,and the areas with higher intensity of precipitation in winter were mainly located in the southeastern Rivers Basin and the Huaihe River Basin.(4)The decrease in the number of light rain days was more obvious in spring and winter,and the southeastern River Basins and the Pearl River Basin contributed greatly to the decrease in the number of light rain days.The number of precipitation days above the moderate rain level was generally on an upward trend in all seasons.The intensity of large rain strengthens in spring and weakened in autumn,and the intensity of heavy rain in all basins was on an increasing trend in spring.[Conclusion]There are obvious differences in the spatial and temporal distribution and seasonal scales of precipitation levels across China,and the contribution of the nine major river basins to the different levels of precipitation across the China varies,so future research on the influence of the major circulation systems and the water cycle in each river basin on the different levels of precipitation should be strengthened.