2020年江淮地区梅雨异常的成因分析  

Cause analysis of Meiyu anomaly in Jianghuai region in 2020

作　　者：杨梦兮 刘梅[2] 柯丹[3] 陈圣劼[2] YANG Mengxi;LIU Mei;KE Dan;CHEN Shengjie(Taizhou Meteorological Observatory,Taizhou 225300;Jiangsu Meteorological Observatory,Nanjing 210008;Institute of Heavy Rain,China Meteorology Administration,Wuhan 430205)

机构地区：[1]江苏省泰州市气象局,泰州225300 [2]江苏省气象台,南京210008 [3]中国气象局武汉暴雨研究所,武汉430205

出　　处：《暴雨灾害》2020年第6期555-563,共9页Torrential Rain and Disasters

摘　　要：利用江苏、安徽国家基本气象站的观测资料、实况探空资料,结合ERA5的再分析资料,分析了2020年江淮地区梅雨异常特征,并对其成因进行了探讨。结果表明:(1) 2020年江淮地区梅期偏长,梅雨期间雨量显著偏多,强降水过程频繁,覆盖范围广;梅雨雨带基本以30°-32°N为中心,在28°-34°N的范围内经历了4次为期约双周的持续性南北振荡。(2)低纬度稳定的副热带高压维持,高纬度前期稳定的双阻形势,后期多浅槽波动是造成超长梅雨的关键影响系统;低空急流的稳定维持是造成梅雨期持续强降水的关键因素,偏多的水汽主要来自于南海。(3)强降水位于江淮北部时,冷涡中心一般位于120°E以西,且向偏东或东略偏北方向移动;当冷涡位于120°E以东或南下明显时,降水南压。(4)梅雨期间副高经历了4次双周振荡、9次波动性北跳,伴有12次冷涡活动,副高北抬时段和冷涡南落东移时段两者的同期反位相叠加长时间维持,为江淮地区超长梅雨的形成和雨带的南北摆动维持提供了较好的系统配置。Based on the observational data of national ordinary stations in Jiangsu and Anhui,the live sounding data,combined with the re⁃analysis data of ERA5,the abnormal characteristics of Meiyu in Jianghuai region in 2020 are analyzed and a study on the causes of the Mei⁃yu anomaly is carried out.The results show:1)the Meiyu period in 2020 is longer than usual,the rainfall is significantly more,and the heavy rain process is frequent with the coverage wide.The Meiyu rain belt is basically centered on 30°-32°N,and experience 4 continuous north-south oscillations about biweekly cycle in the range of 28°N to 34°N.2)The stable subtropical high at low latitudes,the stable double resistance situation at high latitudes in the early stage and the multi shallow trough fluctuations in the late stage are the key influencing sys⁃tems for the super Meiyu.The stable maintenance of low-level jet is the key factor to cause the continuous heavy rainfall in Meiyu period,and the excess water vapor come from the South China Sea.3)When the heavy rainfall located in the north of the Jianghuai region,the center of the cold vortex is generally located in the west of 120°E,and moves eastward or slightly northward;when the cold vortex is located in the east or south of 120°E,the precipitation is forced to the South.4)The subtropical high experience 4 biweekly oscillations and 9 volatile jumps to the North during the Meiyu period,with 12 cold vortex activities.During the period of the northward rising of the subtropical high and the southward and eastward moving of the cold vortex,the anti-phase overlap and prolong,which provide a good system configuration for the formation of the super long Meiyu and the maintenance of the North-South oscillation of the rain belt in the Jianghuai region.

关 键 词：2020年 江淮地区 梅雨 副热带高压 冷涡 低空急流 

分 类 号：P426.6[天文地球—大气科学及气象学]