南水北调中线工程水源区与海河受水区干旱遭遇研究

The analysis of encounter probability of drought between the water source area and the Hai River water receiving area in the middle route of the South-to-North Water Transfer Project in China

基于Copula理论,以标准化降水蒸散指数(SPEI)为干旱指标,建立了南水北调中线工程水源区与海河受水区汛期、非汛期及全年SPEI的联合分布,并结合未来气候模式数据,研究了变化情景下南水北调中线工程水源区与海河受水区各时期干旱遭遇概率变化及其对工程运行风险的影响。研究结果表明:过去几十年,南水北调中线工程水源区与海河受水区总体呈现变旱趋势;在RCP4.5和RCP8.5两种未来气候变化情景下,水源区与海河受水区汛期、非汛期及全年同旱事件发生概率较现状有不同程度的增加,尤其汛期遭遇同旱和非汛期遭遇同重旱的概率明显增大,增加的幅度分别达到2.99%~6.1%和2.67%~3.63%。在未来变化情景下,水源区与海河受水区干旱遭遇变化可能会对工程运行带来风险,因此,有必要研究相应的适应性对策以保证工程的正常安全运行。

Based on the Copula theory,this study has constructed the joint distribution of SPEI between the water source area and the Hai River water receiving area in the middle route of the South-to-North Water Transfer Project in China(SNWTP)at three time scales,i.e.the flooding season,the dry season,and the whole year.Using the future climate model data,we computed the encounter probability of drought between the water source area and the Hai River water receiving area.The results showed that both the water source area and the water receiving area were undergoing a slight drying trend over the past few decades.Compared with the baseline,the probability of concurrent drought events will increase by different degrees in the RCP4.5 and RCP8.5 scenarios.Especially,the probability of concurrent drought during the flooding season and the probability of concurrent heavy drought during the dry season increased obviously by 2.99%~6.1% and 2.67%~3.63%,respectively.The increase in the probability of concurrent drought between the water source area and water receiving area will probably influence the operation of SNWTP.Therefore,it′s necessary to take some adaptive measures to ensure the safety and efficiency of SNWTP.