海温异常对长江流域夏季典型旱涝的影响研究  

Study on influence of SST anomaly on typical summer drought and flood in Changjiang River Basin

作　　者：张灵[1] 熊开国 郭广芬[1] 张俊 ZHANG Ling;XIONG Kaiguo;GUO Guangfen;ZHANG Jun(Wuhan Regional Climate Center,Wuhan 430074,China;Three Gorges Cascade Dispatching and Communication Center,Yichang 443000,China)

机构地区：[1]武汉区域气候中心,湖北武汉430074 [2]三峡水利枢纽梯级调度通信中心,湖北宜昌443000

出　　处：《人民长江》2024年第4期118-124,共7页Yangtze River

基　　金：长江流域气象开放基金项目(CJLY2022Y07);国家自然科学基金项目(41705074);湖北省自然科学基金项目(2022CFD014);中国气象局复盘总结专项(FPZJ2023-082);长江电力股份有限公司项目(2421020001)。

摘　　要：为研究长江流域夏季旱涝特征及其与海温异常之间的关联性,基于中国326个气象站降水量、NCEP/NCAR再分析资料等,采用合成分析、EOF分解等方法,分析了长江流域夏季典型旱涝年的降水分布、同期大气环流及前期海温特征,并以2018年为例,初步揭示了2018年前期海温异常对大气环流的可能影响。结果表明:①长江流域夏季典型旱年,仅嘉陵江和岷沱江会表现出局部偏涝,全国为典型的Ⅰ类雨型,多雨区位于黄河流域及以北地区。前期冬季赤道太平洋表现出类拉尼娜的东冷西暖分布,同时黑潮区海温偏低,西风漂流区海温偏暖。受多海域协同作用,同期欧亚环流场上自西北向东南呈现出“+-+”三极型分布,东亚地区为自北向南“-+-”的EAP负位相。长江流域典型涝年,全国多为典型的Ⅱ类和Ⅲ类雨型,环流及海温呈现出相反特征。②2018年为典型的长江中下游偏旱年,仅在岷沱江降水偏多近3成,为历史第4多,与长江流域夏季降水的主模态正位相类似,解释方差达24%。③2018年前冬出现弱拉尼娜、春末夏初西风漂流区异常偏暖、NAT异常正位相,三者共同作用,使得东亚副热带西风急流偏北,东亚沿岸出现EAP负位相,大陆热低压明显偏强,东亚夏季风为1961年以来最强,同时副高脊线最北,造成夏季降水主雨带北推至华北、西北地区,岷沱江、嘉陵江异常多,而长江中下游异常少,为典型的Ⅰ类雨型。研究成果可为长江流域旱涝预测、水资源调度提供参考。To study the characteristics of summer drought and flood in the Changjiang River Basin and its correlation with Sea Surface Temperature(SST)anomaly,based on the precipitation data of 326 meteorological stations in China and NCEP/NCAR reanalysis data,we adopted synthetic analysis and EOF decomposition to analyze precipitation,circulation and SST features in typical drought and flood years in the Changjiang River Basin in summer and briefly revealed the possible influence of SST anomaly on atmospheric circulation at the early stage of 2018.The results indicated that:①when it came to the summer of a typical dry year in the Changjiang River Basin,only some regions in the Jialing River,Minjiang River,and Tuojiang River Basin suffered flood.China presented a typical Rain Pattern I with the rainy area located in the Yellow River Basin and its north.Moreover,in the early winter,the equatorial Pacific showed a La Nina-like distribution with low temperature in the Kuroshio area and warm SST in the westerly drift area.Due to the joint effects of different sea areas,the Eurasian circulation field presented a tripolar distribution of“+-+”from northwest to southeast,and the East Asian region was a“-+-”EAP negative phase distribution from north to south.②2018 was a typical drought year in the middle and lower reaches of the Changjiang River,and the precipitation was nearly 30%more than normal only in the Minjiang River and Tuojiang River,which was the fourth most in history.Its mode was similar to the positive phase of the main summer precipitation mode in the Changjiang River Basin,and the explained variance was 24%.③The SST anomaly distribution was attributed to the occurrence of weak La Nina in the early winter of 2018,the warmer SST in the west wind drift area,and the abnormal positive NAT from April to June.Due to the interactive effects of these three factors,the northerly Asia subtropical westerly jet moved north,East Asia Littoral showed a negative EAP,continental low pressure became stronger and the stron

关 键 词：夏季典型旱涝 海温异常 Ⅰ类雨型 拉尼娜 西风漂流区 长江流域 

分 类 号：P426.616[天文地球—大气科学及气象学]