长江下游多维径流丰枯遭遇及丰枯演变分析

Analysis on wetness-dryness encounter and evolution of multi-dimensional runoff in lower reaches of Changjiang River

九江站、湖口站和大通站是长江下游的3个重要水文站,识别三者之间的径流关系、丰枯演变和丰枯遭遇特征,对识别长江下游多维径流关系具有重要的意义。基于滑动相关系数法分析了长江下游多维径流相关性的时变特征,基于Copula理论构建了长江下游多维径流联合分布和径流演变联合分布,分析了丰枯遭遇及丰枯演变特性。结果表明:(1)径流相关性时变强度由高至低为九江-湖口站、湖口-大通站、九江-大通站;各站径流具有较高的丰枯同步性,由高至低为九江-大通站、湖口-大通站、九江-湖口站,丰枯异步性特征反之。(2)九江-湖口站、九江-大通站、湖口-大通站的丰枯同步率最高时期分别为非汛期、汛期、非汛期;各站径流丰枯状态的自转和互转概率均较稳定,目前无极端情况出现。(3)九江、大通水文站的年和汛期径流最易丰枯互转,非汛期径流最易连丰、连枯。(4)湖口水文站的年和汛期径流最易连丰、连枯,非汛期径流最易丰枯互转。研究成果可为长江下游的多维径流关系分析提供理论参考。

Jiujiang Station,Hukou Station and Datong Station are three crucial hydrological stations in the lower reaches of the Changjiang River.Analyzing their runoff relationships,wetness-dryness evolutionand encounter characteristics is of great significance for identifying multi-dimensional runoff relationships in the lower reaches of the Changjiang River.Based on the sliding correlation coefficient method,we analyzed the time-varying characteristic of multi-dimensional runoff correlations in the lower reaches of the Changjiang River.Then we constructed a joint distribution of multi-dimensional runoff and runoff evolution in the lower reaches of the Changjiang River based on the Copula theory,and analyzed the wetness-dryness evolutionand encounter characteristics.The results show that the time-varying intensity of runoff correlation is the highest in Jiujiang-HukouStation,followed by Hukou-Datong Station,and the minimum is Jiujiang-Datong Station.The runoff at each station has a high synchronization of wetness-dryness state,the highest isJiujiang-Datong Station,followed by Hukou-Datong Station,the lowest isJiujiang-Hukou Station,while theasynchronous feature of wetness-dryness state is reverse.The periods with the highest synchronization rates of wetness-dryness state for Jiujiang-Hukou Station,Jiujiang-Datong Station and Hukou-Datong Station are non-flood period,flood period,and non-flood period,respectively.The self-change and mutual change probabilities of runoff wetness-dryness state at each station are relatively stable,and there are no extreme situations at present.The annual runoff and flood period runoff at Jiujiang and Datong Stationare most likely to be in the wetness-dryness mutual changestate,and the runoff in non-flood period is most likely to be in the continuous wetness and continuous dryness state.While the annual runoff and the flood periodrunoff of Hukou Station is most likely to be in the continuous wetness and continuous dryness state,and the runoff in non-flood period is most likely to be in the mutual wetness-drynesschange state.The research results can provide theoretical references for the analysis of multi-dimensional runoff relationships in the lower reaches of the Changjiang River.