鄂西南典型流域近30a降水集中特性时空变化特征分析OA

Based on daily precipitation observations from 10 meteorological stations in the Qingjiang Basin from 1993 to 2022,this study systematically analyzed the spatiotemporal distribution and variation characteristics of Precipitation Concentration Degree(PCD)and Precipitation Concentration Period(PCP)using multiple methods,including Rescaled Range Analysis(R/S),nonparametric statistical tests,wavelet transforms,and Empirical Orthogonal Function(EOF)decomposition.The results indicate that from 1993 to 2021,the PCD in the Qingjiang Basin fluctuated between 0.24 and 0.55,with a multi-year average of 0.41,which is significantly higher than the national average,showing a slowly increasing trend.The PCP varied between 15.1 and 21.2 dekads,with a multi-year average of 18.5,indicating that precipitation is mostly concentrated from mid-June to late July,with a slowly decreasing trend over time.Abrupt changes in PCD and PCP occurred around 2020 and 2001,respectively.Additionally,the PCP exhibits a distinct Hurst phenomenon,suggesting that the precipitation concentration period in the basin is expected to continue shifting earlier in the future,while precipitation concentration intensity will further increase.The spatial distribution of the first EOF mode of both PCD and PCP in the Qingjiang Basin is highly consistent,showing an opposite variation pattern between the upstream and middle and downstream regions.This characteristic highlights the significant influence of basin topography on the spatial heterogeneity of precipitation.