长江流域2022年极端高温干旱特征和成因及其对水电资源的影响  

Characteristics and Cause Analysis of Extreme Heat and Drought Event in Yangtze River Basin During Summer 2022 and Impacts on Hydropower Resources

作　　者：郭广芬[1] 吴瑶[1] 秦鹏程[1] 刘敏[1] 夏智宏[1] 张灵[1] 薛海涵 冯扬 GUO Guang-fen;WU Yao;QIN Peng-cheng;LIU Min;XIA Zhi-hong;ZHANG Ling;XUE Hai-han;FENG Yang(Wuhan Regional Climate Center,Wuhan 430074,China)

机构地区：[1]武汉区域气候中心,湖北武汉430074

出　　处：《长江流域资源与环境》2023年第10期2098-2108,共11页Resources and Environment in the Yangtze Basin

基　　金：国家重点研发计划(2017YFC1502306);长江电力股份有限公司项目(2421020001);中国气象局创新发展走项(CXFZ2023J051);中国气象局复盘总结专项(FPZJ2023-082);2022年度省自然科学基金创发展联合基金(2022CFD014)。

摘　　要：基于长江流域711个气象站逐日气象观测资料及流域主要控制站水文观测资料,分析了长江流域2022年夏季异常高温和干旱特征及其对水电资源的影响,并从海温和环流异常方面对高温少雨成因进行了初步分析。结果表明:(1)长江流域2022年夏季平均气温和高温日数为历史同期最高,降水量历史同期最少,高温少雨导致气象干旱快速发展,气象干旱发生范围为历史同期最大。(2)持续高温少雨造成流域干支流来水显著减少,出现“汛期反枯”的罕见现象,长江上游主要水文控制站8月径流量较历史同期偏少45%~65%,长江上游部分大型水电站入、出库流量和发电量明显下降,为近5年最少或次少。(3)西太副高异常偏强西伸,水汽输送偏北为此次高温干旱过程形成的主要原因。从外强迫因子来看,持续发展的LaNina是重要的海温背景,赤道中部太平洋海温偏低,西太平洋暖池海温异常偏暖,walker环流增强,通过调制Hadley环流,导致西北太平洋反气旋发展,西太副高增强。ysis were conducted upon the extreme heat and drought event in the basin during the summer 2022 and upon the impacts of this event on hydropower resources.Preliminary analysis was also carried out in the cause analysis regarding the anomalies of the sea temperature and the atmospheric circulation.The results showed that:(1)The summer 2022 reached the highest in the average temperature and high temperature days,and the lowest in the average precipitation for the same period since 1961 in the YRB.Heat wave and deficit rainfall led to the rapid development of meteorological drought,which covered the largest area in the basin for this summer since 1961.(2)Continuous high temperature and deficit rainfall significantly reduced stream flow for the mainstreams and tributaries in the basin,creating an unusual“Dryness during the Flood Season”phenomenon.The runoff in August 2022 was reduced by 45%to 65%compared with that in the same period in historic records.The inflow,outflow and hydropower generation of the major large hydropower stations in the YRB significantly decreased,reaching the lowest or almost the smallest during the last 5 years.(3)The weak transport of water vapor driven by the abnormal high and westward extension of the Western Pacific Subtropical High(WPSH)was regarded as the main factors causing this extreme heat and drought event.Moreover,the continuous development of La Nia was an important SST background.The SST in the central equatorial Pacific was relatively low,while the SST in the western Pacific warm pool was abnormally warm,and therefore,the Walker Circulation was enhanced.By modulating the Hadley Circulation,an anticyclone was developed over the northwestern Pacific and finally strengthened the WPSH.

关 键 词：高温干旱 长江流域 水电资源 蓄水 西太副高 

分 类 号：P466[天文地球—大气科学及气象学]