梅雨期太湖超标洪水水文气象特征分析  

Hydrometeorological Characteristics of Plum Season for the Taihu Exceeding-Standard Floods

作　　者：吴娟 施春红[2] 林荷娟 邹兰军[2] 杨雅薇[3] 季同德 薛涛 WU Juan;SHI Chunhong;LIN Hejuan;ZOU Lanjun;YANG Yawei;JI Tongde;XUE Tao(Bureau of Hydrology(Information Center)of Taihu Basin Authority,Shanghai 200434,China;Shanghai Meteorological Center,Shanghai 200030,China;Shanghai Climate Center,Shanghai 200030,China)

机构地区：[1]太湖流域管理局水文局(信息中心),上海200434 [2]上海中心气象台,上海200030 [3]上海市气候中心,上海200030

出　　处：《水文》2022年第2期73-79,共7页Journal of China Hydrology

基　　金：国家重点研发计划资助项目(2018YFC0407900);上海市科技创新行动计划“长三角河网密集型城市群极端降雨预报和洪涝风险研究与示范应用”(21002410200)。

摘　　要：基于太湖流域逐日报汛降水量、ERA5逐日大气再分析等资料,对比分析太湖2016和2020年梅雨期超标洪水水文气象特征。结果表明:(1)2016年、2020年梅雨量分别为412.0 mm、583.8 mm,太湖最高水位分别为4.87 m、4.79 m;对于各个时段极值降水量及重现期,2016年北部湖西区、武澄锡虞区较高,2020年南部浙西区、杭嘉湖区较高。(2)梅雨期大气环流共同点:前期热带印度洋海温异常偏暖,导致副高偏强、西伸脊点偏西,中高纬度经向环流发展,有利于来自南海的偏南气流、印度洋经孟加拉湾的西南气流与北方弱冷空气相结合,导致梅雨量异常偏多;不同点:2016年副高脊线6月中下旬北跳以后位置相对稳定,雨带主要集中在流域北部,2020年副高脊线6月初北跳以后南北摆动幅度较大,流域南北分区交替出现暴雨过程。(3)两年太湖超标洪水形成原因不同,2016年由异常偏高的入梅水位叠加核心汇流区集中强降水形成,而2020年太湖高水位则由异常偏长的梅雨期、核心汇流区降水总量大共同形成。Based on daily precipitation from flood reporting stations,reanalysis atmospheric data from ERA5,hydrometeorological characteristics for Taihu exceeding-standard floods between 2016 and 2020 were compared.The results demonstrated that(1)the accumulated precipitation of the plum season in 2016,2020 was 412.0 mm,583.8mm,respectively,while the highest Taihu water stage of the two years was 4.87m,4.79m,respectively.In the Huxi,Wuchengxiyu sub-region,the extreme precipitation and return period for 2016 were higher,while the extreme precipitation and return period for 2020 were higher in the Zhexi,Hangjiahu subregion.(2)There are many similarities in the atmospheric circulation characteristics during the plum season.The strong warming in tropical Indian Ocean in the preceding seasons lead to stronger than normal and more westward-extending west Pacific subtropical high(WPSH).The radial circulation situation was conducive to the warm moisture transport from South China Sea,and the warm moisture transport from Indian Ocean via the Bay of Bengal,interacting with cold air from the north in the Taihu basin.The WPSH jumped northward in Mid-late June of 2016 and kept stable,and the heavy precipitation mainly occurred in the northern part of Taihu Basin.However,the WPSH jumped northward in early June of 2020,and the north-south swing of WPSH was larger,resulting in north-south swing of heavy precipitation occurrence in the Taihu Basin.(3)Reasons for the Taihu exceeding-standard floods of the two years were different,the significant high Taihu water stage on Meiyu onset date,as well as the persistent heavy rainfall in core flow concentration area were main reasons for 2016.Nevertheless,the significant long Meiyu length and more precipitation in core flow concentration area were main reasons for 2020.

关 键 词：太湖超标洪水 梅雨期 天气形势 核心汇流区 

分 类 号：P339[天文地球—水文科学]