摘要
【目的】梅雨是东亚特有的天气现象,梅雨期间的降水情况影响着夏季旱涝灾害的形成及发展,对社会经济造成严重的损失。因此需要对江淮流域梅雨期降水特征及影响因素进行分析,为该地区旱涝灾害预警提供参考。【方法】基于江淮流域239个站点1961—2020年日降水资料、全球海表温度、Nino3.4指数和水汽通量资料,分析近60 a江淮流域梅雨期无雨日和特大暴雨频次,通过正交经验函数分析法(EOF)分析江淮流域梅雨期的降水特征及其与海温和水汽通量的关系。【结果】1961—2020年江淮流域梅雨期多年平均无雨日数由南向北递增分布,并且在江淮区(Ⅲ区)呈显著的增加趋势;期间累计发生特大暴雨47次,且梅雨期间各日期日降水量达特大暴雨等级的站点个数有显著的上升趋势。通过EOF分析得出江淮流域梅雨期降水空间分布类型主要有两种,第一模态呈现全流域降水变化趋势一致性,且呈显著的增加趋势,第二模态流域降水呈南北反相分布特征。【结论】江淮流域梅雨期局部地区无雨日数及达特大暴雨等级降水量的站点个数的增多需引起关注;Nino3.4指数出现较高(低)值的次年,江淮流域梅雨期降水的偏多(少)。江淮流域梅雨期降水的变化与热带印度洋、热带中东太平洋、热带大西洋海区在前期冬季、春季和同期的海表温度异常有显著正相关,即当这些海区海温为正异常时,江淮流域梅雨期降水往往偏多;反之,则偏少。影响江淮流域梅雨期降水的水汽输送主要来自孟加拉湾、南海和西太平洋副热带高压西侧,6月南海和西太平洋水汽输送汇合形成强烈的水汽通量带,到了7月,水汽通量带因南海和孟加拉湾水汽输送的汇合而进一步增强。
[Objective]The Meiyu phenomenon stands as a distinctive weather occurrence in East Asia,with its precipitation lev-els during this period exerting significant influence on the emergence of droughts and floods during the summer,thereby incurring substantial socio-economic losses.Therefore,it is necessary to analyze the precipitation characteristics and influencing factors during the Meiyu period over the Yangtze-Huai River Basin,which will help to provide reference for the early warning of drought and flooding.[Methods]This study used observed daily precipitation data from 239 meteorological stations over the Yangtze-Huai River Basin from 1961 to 2020 combined with NOAA and ERA5 reanalysis data to analyze the frequency of the number of days without rainfall and heavy downpour and through the application of Empirical Orthogonal Functions(EOF),it examines the pre-cipitation patterns during the Meiyu period,alongside its correlation with sea surface temperature(SST)and water vapor flux.[Results]Over the Yangtze-Huai River Basin,the average number of days without rainfall during the Meiyu period is distributed incrementally from south to north,and there is a significant increasing trend in Jianghuai area(area Ⅲ)from 1961 to 2020.Over the past six decades,the basin has witnessed 47 heavy downpour events,and the number of stations with daily precipitation up to the level of exceptionally heavy rainfall on each date during the Meiyu period had a significant upward trend.Two primary spatial precipitation distribution patterns emerge during the Meiyu period within the basin:one demonstrating uniform basin-wide trends,showcasing an overall upward trend in precipitation,while the other manifests a north-south antiphase distribution.[Conclusion]The increase in the number of days without rain and the number of stations with precipitation up to the level of ex-ceptionally heavy rainfall during the Meiyu period over the Yangtze-Huai River Basin need to be of some concern.A notable cor-relation between the Nino3.4 index and Meiyu period precipitation,with higher(lower)Nino3.4 values indicative of increased(decreased)Meiyu precipitation in the Yangtze-Huai River Basin.Furthermore,precipitation fluctuations during this period exhib-it significant positive correlations with SST anomalies across tropical Indian Ocean,tropical central-eastern Pacific,and tropical At-lantic regions during preceding winter,spring and concurrent periods.Specifically,positive SST anomalies in these regions corre-spond to increased Meiyu precipitation,and vice versa.Water vapor transport influencing Meiyu period precipitation primarily origi-nates from the Bay of Bengal,South China Sea,and the western periphery of the western Pacific subtropical high.By June,the convergence of water vapor transport from the South China Sea and western Pacific fosters a robust water vapor flux belt.Subse-quently,in July,intensified water vapor transport from the South China Sea and Bay of Bengal further fortifies this flux belt.
作者
张洁
杨秀芹
滑申冰
刘晓琳
姚德贵
李哲
朱德华
ZHANG Jie;YANG Xiuqin;HUA Shenbing;LIU Xiaolin;YAO Degui;LI Zhe;ZHU Dehua(Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China;School of Hydrology and Water Resources,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China;China Electric Power Research Institute,Beijing 100192,Jiangsu,China;State Grid Henan Electric Power Company Electric Power Research Institute,Zhengzhou 450000,Henan,China)
出处
《水利水电技术(中英文)》
北大核心
2025年第3期15-29,共15页
Water Resources and Hydropower Engineering
基金
国家电网有限公司总部科技项目(5500-202324180A-1-1-ZN)
国家自然科学基金项目(52209032)。
关键词
江淮流域
梅雨
EOF分析
海温
水汽输送
降水
气候变化
影响因素
Yangtze-Huai River Basin
Meiyu
EOF analysis
SST
water vapor transport
precipitation
climate change
influ-ence factor
作者简介
张洁(2000-),女,硕士研究生,主要从事流域水文气候和水资源规划与管理研究。E-mail:202212360004@nuist.edu.cn;通信作者:杨秀芹(1981-),女,副教授,硕士研究生导师,博士,主要从事流域水文气候和水资源规划与管理研究。E-mail:young_sd@nuist.edu.cn。
