基于Copula的2022年长江流域极端干旱重现期研究  

Return period of extreme drought over Changjiang River Basin of 2022 based on Copula function

作　　者：张洁祥 吕娟[1,2] 张学君[1,2] 屈艳萍 冯爱青 ZHANG Jiexiang;LYU Juan;ZHAN Xuejun;QU Yanping;ENG Aiqing(China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Center of Flood and Drought Disaster Reduction of Ministry of Water Resources,Beijing 100038,China;College of Hydrology and Water Resources,Hohai Universi-ty,Nanjing 210098,China;National Climate Centre,Bejing 10081,China)

机构地区：[1]中国水利水电科学研究院防洪抗旱减灾研究所,北京100038 [2]水利部防洪抗旱减灾工程技术研究中心(水旱灾害防御中心),北京100038 [3]河海大学水文水资源学院,江苏南京210098 [4]国家气候中心,北京100081

出　　处：《人民长江》2023年第8期32-39,共8页Yangtze River

基　　金：国家重点研发计划项目(2021YFC3000202);国家自然科学基金项目(42001039);水利部水旱灾害防御创新团队项目(WH0145B042021)。

摘　　要：2022年夏季,长江流域遭遇了史上罕见的高温干旱事件,给农业、生态和社会经济带来严重影响。利用1961~2022年的气象数据资料,分析了2022年长江流域夏季高温少雨的时空分布特征;在此基础上,采用基于Copula函数的多变量风险评估方法,对此次高温复合型干旱事件的重现期进行了分析。结果表明:长江流域2022年夏季高温日数较常年同期偏多147.5%,为1961年以来历史第一位,且高温发展严重区域与降雨量偏少区域高度重合。基于Copula函数联合重现期的分析显示2022年夏季长江流域干旱超过100a一遇,为有完整气象观测记录以来最极端的干旱;而只考虑降水或者高温的单变量重现期分析将此次干旱事件定义为30a或者60a一遇,难以合理描述此类复合型灾害的发生风险。从空间看,2022年夏季长江流域干旱在上、中、下游的联合重现期分别为100,75,55a一遇。针对日益频发的复合型极端事件,未来风险评估需考虑两个或多个变量极端状况的同期叠加效应,这对于科学把握灾害的极端性及其风险影响、及时制定抗旱减灾措施具有重要的科学指导意义。In the summer of 2022,the Changjiang River Basin suffered a rare high-temperature drought event,posing a serious impact on agriculture,ecology and social economy.Based on the 61-year meteorological data(1961-2022)and the multivariate risk assessment method based on the Copula function,the return period of extreme climate in the Changjiang River basin in the summer of 2022 was evaluated.Results show that the number of high-temperature days in the summer of 2022 in the Changjiang River Basin is 147.5% higher than that in the same period of normal year,which is the first in history since 1961.Areas where severe high temperatures developed are highly coincident with areas with litle precipitation.The 2022 concurrent event has a return period of about 100 years,which is the most extreme drought event in the complete historical record.However,the return period of individual climate factors such as precipitation or temperature is just 30 years or 60 years,which significantly underestimates the risk of such compound disasters.Spatially,the joint return periods of this drought in the upper,middle,and lower reaches are 100,75,and 55 years.These analyses show that for compound events of concurrent droughts and heat waves,the superposition effect of multiple variables(high temperature and low precipitation)should be considered in the future risk of extreme events.This will largely give a help to scientifically grasp the extremes of disasters and their risk effects and to formulate drought mitigation measures in time.

关 键 词：重现期 极端干旱 COPULA函数 复合型事件 高温少雨 2022年长江流域干旱 

分 类 号：P426.6[天文地球—大气科学及气象学]