黄河主要子流域径流及其同旱概率变化研究

Study on the Changes in Streamflow and Simultaneous Drought Probability over Major Sub⁃Basins of the Yellow River

干旱加剧黄河水资源短缺情势、影响黄河径流量的稳定、威胁流域水资源安全,使黄河流域生态环境保护和高质量发展面临严峻挑战。为了给应对黄河流域性干旱提供参考,针对多子流域同旱这一极端干旱灾害,基于黄河15个子流域1956—2016年实测年径流量数据,采用Mann⁃Kendall趋势检验法分析年径流量序列变化的显著程度,采用藤Copula函数分析不同子流域发生同旱的概率,研究了多子流域同旱的变化趋势,结果表明:(1)1956—2016年黄河各子流域实测年径流量普遍呈减少趋势,其中多年平均径流量较大的洮河、伊洛河等子流域年径流量减少趋势显著;(2)黄河各子流域年径流量间存在显著的相关关系,按同旱年数计算的同旱频率可能会低估大范围同旱的概率;(3)2个及以上多子流域发生同旱的概率,1956—2016年为37%,1956—1989年为23%,1990—2016年为59%,1990年后多子流域同旱的概率显著增大,意味着黄河流域遭受大范围同旱灾害的形势变得严峻。为保障黄河水资源安全和流域可持续发展,应合理规划和利用河川径流,加强水资源集约节约利用,推动南水北调后续工程建设和发展,提升流域水安全保障能力。

Drought has exacerbated the shortage of water resources and threatens the stability of streamflow in the Yellow River,posing a significant challenge to ecological environmental protection and sustainable development.In order to provide a reference for dealing with the basin⁃scale drought in the Yellow River Basin,we focused on an extreme drought,namely concurrent drought over multiple sub⁃basins,collected annual streamflow measurements from 15 sub⁃basins in the period from 1956 to 2016,and adopted the methods of Theil⁃Sen Median and Vine Copula function to examine the multi⁃year average and annual tendency of streamflow and analyzed the probability of drought simultane⁃ously occurred across multiple basins.We find out that (a)streamflow reduction is evident across most sub⁃basins of the Yellow River during the period of 1956-2016,with the Taohe and Yiluo River basins displaying pronounced downward trajectories;(b)A significant correlation exists between streamflow in different sub⁃basins,and the frequency of concurrent droughts greatly underestimates the potential for such events;(c)The probability of concurrent droughts in two or more sub⁃basins is 37%in the period from 1956 to 2016,23%in the period from 1956 to 1989 and 59%in the period from 1990 to 2016,with a noticeable increase from the period of 1956-1989 to the period of 1990-2016.This escalation indicates that the Yellow River Basin is contending with increasingly severe large⁃scale drought extremes.In order to ensure the security of water resources and the sustainable development of the Yellow River,there is an urgent need to meticulously devise and optimize water allocation strategies for the Yellow River,enhance the judicious utilization of water resources,advance the South⁃to⁃North Water Diversion follow⁃up initiative and bolster the capacity to ensure water security.