乌东德水电站蓄水前后降水变化特征OA

The characteristics of precipitation changes before and after the impoundment of Wudongde Hydropower Station are analyzed by using mathematical statistics,linear fitting,Theil-Sen slope and SPI drought index methods.Since 2014,five fixed observation points of automatic weather stations in the dam area of Wudongde Hydropower Station have been built,but there is a lack of long-term observation data,making it impossible to directly calculate SPI.The monthly precipitation data from 1994 to 2024 of seven national meteorological stations within a 100-kilometer radius of Wudongde Hydropower Station are used to construct a gamma distribution parameter interpolation method to fit the relevant parameters of the drought index SPI of Wudongde Hydropower Station,thereby calculating the drought index SPI.The results show that:(a)the precipitation in Wudongde Hydropower Station has generally decreased over past 11 years,however,the trend rate before impoundment is negative,while it is positive after impoundment,indicating an upward trend in precipitation after impoundment;(b)based on the spatial distribution of drought and flood frequencies of SPI12,the hydropower station is prone to flooding before impoundment,and after impoundment,the frequency of drought is lower than that of the surrounding areas in the regional drought environment;and(c)the SPI3 slopes of the five automatic weather stations in the hydropower station are generally stable,a negative center of drought occurred before impoundment,while a positive center of flooding emerged after impoundment,and to the south of the dam area,the flooding trend is more obvious.