Abrupt Flood–Drought Alternation in Southern China during Summer 2019  

作　　者：Yuan YUAN Hui GAO Ting DING 

机构地区：[1]National Climate Center,China Meteorological Administration,Beijing 100081

出　　处：《Journal of Meteorological Research》2021年第6期998-1011,共14页气象学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(U1902209,41776039,and 421705078)。

摘　　要：We investigated the abrupt alternation from flood to drought in southern China during summer 2019 using multiple datasets.Positive anomalies of precipitation occurred in southern China in the summer of 2019 and the daily precipitation in the south of the middle and lower reaches of the Yangtze River valley showed an abrupt change from flood to drought conditions around mid-July.The highest precipitation in 39 yr was recorded between 1 June and 14 July 2019.The circulation systems affecting this high precipitation included a persistent deepened East Asian trough,the southward location of the western Pacific subtropical high,an intensified East Asian subtropical jet,an anomalous low-level cyclone from southern Japan to southern China,and extremely strong positive vorticity over the Jiangnan area.Completely different atmospheric circulation anomalies from 15 July to 31 August caused continuously high temperatures,below-normal precipitation,and severe drought in Jiangnan area.Further investigations showed that the sudden change in atmospheric circulation around mid-July started in the mid and lower troposphere and was influenced by the northward track of Tropical Cyclone Danas in the northwestern Pacific.

关 键 词：abrupt changes summer precipitation East Asian trough western Pacific subtropical high tropical cyclone 

分 类 号：P426.616[天文地球—大气科学及气象学]