新疆伊犁河流域近30年极端降水时空动态OA

Based on daily precipitation data from 11 national surface meteorological stations(1991-2020),this study utilized the RClimDex model to calculate six precipitation indices and five precipitation-day indices,systematically investigating the evolution of extreme precipitation in the Ili River Basin,Xinjiang.Using linear trend analysis,the Mann-Kendall abrupt change test,and Morlet wavelet analysis,we systematically examined the spatiotemporal variation characteristics of extreme precipitation in the Ili River Basin,Xinjiang.The results showed that,with the exception of consecutive dry days and consecutive wet days(which decreased at rates of 0.86 and 0.12 d·(10 a)-1,espectively),all other precipitation indices exhibited an upward trend.There were multiple mutation points in each index,and the mutation time was not obvious.Spatially,the maximum one-day precipitation shared a similar pattern with the maximum five-day precipitation,with values increasing from the central-western part of the Ili River Basin toward the surrounding areas.Annual precipitation decreased from the east and southwest toward the northwest of the basin.In contrast,the number of days with moderate,heavy,and torrential rain increased from the northwest toward the southeast.The dominant period for consecutive dry days was 8～12 a,with the oscillation being particularly strong during 2000-2010.The periodicity of consecutive wet days was weak,and short-term oscillations of 4～6 a were observed during certain periods.All other indices displayed significant short-period oscillations of 4～8 a over the 1991-2020 period.After 2005,the oscillation energy increased,with a corresponding intensification of interannual variation.