考虑径流非一致性的渭河径流丰枯遭遇研究

Study of Basin-scale Abundance and Depletion Encounters under Non-conforming Conditions

准确评估径流非一致性条件下的流域多时间维度(全年期、汛期和非汛期)和多空间维度(不同控制站)的径流丰枯遭遇特性对区域防洪抗旱和水资源统筹开发利用具有重要意义。提出一种考虑径流非一致性的流域径流丰枯遭遇分析方法,以渭河干流为例,通过滑动平均法和Mann-Kendall法分析了渭河干流的林家村站、咸阳站和华县站的1960-2020年径流演变规律,并从流域尺度分时段构建了不同站点间的Copula联合分布函数,对径流非一致性条件下的渭河干流丰枯遭遇特性进行了分析。结果表明:①渭河干流的径流丰枯演变特征明显,且在1978年前后出现突变,突变后的径流序列呈现显著下降趋势。②渭河干流的径流丰枯遭遇同步性随着站点间的距离增大而下降,林家村-咸阳站的丰枯遭遇同步性最高,林家村站-华县站的丰枯遭遇同步性最低;两个站点间最容易发生的径流丰枯遭遇是平-平组合,最不易发生的是丰-枯组合。③在径流变异后,不同站点之间的丰枯遭遇同步性明显发生改变,林家村站-咸阳站之间的丰枯遭遇同步性明显下降,咸阳站-华县站之间的丰枯遭遇同步性明显上升;变异前各站点之间在非汛期的丰枯同步性最强,全年期的丰枯同步性最弱,变异后各站点之间在非汛期的丰枯同步性最弱,在汛期的丰枯同步性最强。研究成果可为渭河干流的径流丰枯遭遇特性分析提供参考。

Accurate assessment of runoff abundance and depletion encounter characteristics in the basin under runoff non-consistency conditions in multiple temporal dimensions(year-round,flood season and non-flood season)and multiple spatial dimensions(different hydrological stations)is of great significance to the regional flood and drought resistance,and the integrated development and utilization of water resources.We propose a method to analyze the runoff abundance and depletion encounters in a watershed considering the runoff non-consistency.Taking the mainstem of Weihe River as an example,we analyze the runoff evolution of the mainstem of Weihe River at Linjiacun,Xianyang and Huaxian stations from 1960 to 2020 through the sliding average method and Mann-Kendall method,and construct the Copula joint distribution function among different stations from the watershed scale in different time periods,and the abundance and depletion encounter characteristics of the Weihe River mainstem under runoff non-consistency conditions are analyzed.The results show that:①The runoff of the main stream of the Weihe River has obvious characteristics of wet and dry evolution,and there was a sudden change around 1978,and the runoff sequence after the sudden change showed a significant downward trend.②The synchronism of the run-off in the main stream of the Weihe River decreases with the increase of the distance between the stations.The synchronism of the run-off in the main stream of the Weihe River is the highest at Linjia Village-Xianyang Station,and the synchronism of the run-off in the main stream of the Weihe River is the lowest at Linjia Village-Huaxian Station;Among the different wet and dry encounter combinations,the most likely occurrence of two sites is the flat-flat combination,and the least likely occurrence is the wet and dry combination.③After the runoff variation,the synchronization of wet and dry encounters between different stations has changed significantly.The synchronization of wet and dry encounters between Linjiacun Station and Xianyang Station has decreased significantly,and the synchronization of wet and dry encounters between Xianyang Station and Huaxian Station has increased significantly.Before the variation,the synchronization between the stations in the non-flood season is the strongest,and the synchronization between the stations in the whole year is the weakest.After the variation,the synchronization between the stations in the non-flood season is the weakest,and the synchronization between the stations in the flood season is the strongest.The research results can provide a reference for the characterization of runoff abundance and depletion encounters in the main stream of the Weihe River.