2020年江淮地区梅雨异常的阶段性特征和成因分析  

Stage characteristics and cause analysis of Meiyu anomaly in the Yangtze-Huaihe region in 2020

作　　者：李悦 成剑波 张增平[1] 吴永萍[1] 封国林[1] LI Yue;CHENG Jianbo;ZHANG Zengping;WU Yongping;FENG Guolin(School of Physical Science and Technology,Yangzhou University,Yangzhou 225002,China;School of Environmental Science and Engineering,Yancheng Institute of Technology,Yancheng 224000,China)

机构地区：[1]扬州大学物理科学与技术学院,江苏扬州225002 [2]盐城工学院环境科学与工程学院,江苏盐城224000

出　　处：《扬州大学学报（自然科学版）》2021年第3期11-18,31,共9页Journal of Yangzhou University：Natural Science Edition

基　　金：国家重点基础研究发展计划资助项目(2017YFC1502303);国家自然科学基金资助项目(41875097,41975062,42075017).

摘　　要：基于江淮地区逐日降水的低频分量将2020年梅雨期划分为6个阶段,采用全球大气环流三型分解方法研究各阶段大气环流的演变特征,揭示超强梅雨的形成机理.结果表明:经圈型环流在江淮地区引起的强烈大气上升运动是2020年超强梅雨形成的关键因素;强降水阶段,高空南亚高压和中高纬槽脊系统的相互作用引导北方冷空气不断南下;西太平洋副热带高压长期偏强、位置偏西北,驱动其西北侧的低空西南暖湿气流持续向江淮地区输送;高低层冷暖空气在江淮地区辐合,形成梅雨锋和强烈上升运动,引发多次强降水过程,导致2020年梅雨异常偏强.The Meiyu Period in 2020 was divided into six stages based on the low-frequency component of daily precipitation. Using the three-pattern decomposition of global atmospheric circulation, the evolution characteristics of atmospheric circulation in different stages were studied to reveal the formation mechanism of extreme Meiyu. Results show that the strong atmospheric upward movement caused by meridional circulation over the Yangtze-Huaihe region was the key factor for the formation of the extreme Meiyu in 2020. In the heavy precipitation phase, the interaction between the South Asia high and the trough ridge system in the middle and high latitudes guided the cold air from the north to the south continuously. The western Pacific subtropical high has been strong and located to the west/north for a long time, which drives the low-altitude warm and wet southwest air to the northwest of the west Pacific subtropical high to the Yangtze-Huaihe region. The cold and warm air of the upper and lower layers converged over the Yangtze-Huaihe region, forming the Meiyu front and strong atmospheric upward movement, leading to several heavy precipitation processes and the extreme Meiyu in 2020.

关 键 词：梅雨 全球大气环流三型分解 大气上升运动 西太平洋副热带高压 

分 类 号：P434[天文地球—大气科学及气象学]