云南省1961-2020年降水结构时空变化特征OA北大核心CSTPCD

[Objective]The aims of this study are to reveal the changes of precipitation structure in Yunnan Province in the last 60 years,to strengthen the monitoring and early warning of precipitation in Yunnan Province,and to provide scientific reference basis for the risk assessment of water and drought disasters in Yunnan Province.[Methods]Based on daily precipitation observation data from 32 meteorological stations in Yunnan Province,two indicators of precipitation occurrence and precipitation contribution were introduced,and the characteristics of spatial and temporal variation of precipitation structure under different precipitation durations and precipitation grades were explored by using innovative trend analysis(ITA),Mann-Kendall test and inverse distance weighting(IDW)method.[Results](1)The precipitation occurrence rate tended to decrease with the increase of precipitation calendar time,and the precipitation contribution rate tended to increase and then decrease,with short calendar time precipitation dominating in Yunnan Province.Spatially,the precipitation occurrence rate and contribution rate of short calendar period showed an overall decreasing trend from northeast to southwest,while the opposite was true for long calendar period.(2)As the precipi-tation level increased,the precipitation occurrence rate tended to increase and the precipitation contribution rate tended to increase and then decrease,with light rainfall dominating in Yunnan Province.Spatially,the occurrence rate of light rain was decreasing from north to south,while the occurrence rate of medium rain,heavy rain and heavy rain was the opposite trend.The contribution rate of light and moderate rainfall showed a decreasing trend from northwest to southeast,and the contribution rate of heavy and torrential rainfall showed the opposite trend compared with that of the light and moderate rainfall.The occurrence and contri-bution rate of heavy and torrential rainfall were higher in central,southern and southwestern Yunnan,which might cause higher risk of flooding.(3)Under different precipitation durations,the occurrence and contribu-tion rate of precipitation at most stations in short durations were increasing with the increase of more than 5%,and in long durations were decreasing with a trend of more than 5% .Under different precipitation grades,the occurrence and contribution rate of light rainfall at most stations showed the decreasing trend within 10%,and the occurrence and contribution rate of heavy rainfall and storms showed the increasing trend above 5% .[Conclusion]In Yunnan Province,the probability of short-calendar-time heavy rainfall and storms had risen,and the chance of flooding and soil erosion in the region had increased,so the precipitation structure should be continuously monitored and researched in the future.