罗定江径流多时间尺度演变规律分析OA

The Luoding River,a first-order tributary of the Xijiang River and a critical node in the Guangdong Water Resources Allocation Project for the Northern Gulf Region,exhibits runoff evolution characteristics that directly influence the project's water transfer efficiency,flood control safety,and ecological balance.This study systematically investigates the multi-temporal scale variations in runoff using monthly runoff data(1959-2024)from the Guanliang Hydrological Station,the primary control station on the Luoding River.Methods including the coefficient of variation(Cv),runoff concentration degree/runoff concentration period(RCD/RCP),Mann-Kendall trend test,and Morlet wavelet analysis were applied.The results indicate:Intra-annual distribution:Monthly runoff follows a bimodal pattern with peaks in May-June and August-September.The highest variability occurs in October(Cv=0.77)and March(Cv=0.69),while the lowest variability is observed in December(Cv=0.41)and June(Cv=0.43).March runoff shows a highly significant increasing trend,the proportion of the flood season(April-September)is declining,intra-annual distribution is becoming more uniform,and the runoff distribution center is shifting backward.Interannual variation:Annual runoff exhibits a non-significant upward trend with no abrupt change points,and interannual unevenness is gradually decreasing.Cyclical patterns:Three cycles(5～8 years,10～14 years,and 14～22 years)are identified,with the 14～22-year cycle as the dominant one.Based on superimposed cycle analysis,runoff is projected to enter a wetter phase over the 10～22-year timescale.