Understanding the role of SST anomaly in extreme rainfall of 2020 Meiyu season from an interdecadal perspective  

作　　者：Yuanyuan GUO Ruijie ZHANG Zhiping WEN Juncong LI Chao Zhang Zijiang ZHOU 

机构地区：[1]Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences,Fudan University,Shanghai 200438,China [2]Innovation Center of Ocean and Atmosphere System,Zhuhai Fudan Innovation Research Institute,Zhuhai 518057,China [3]Jiangsu Collaborative Innovation Center for Climate Change,Nanjing 210023,China [4]National Meteorological Information Center,Beijing 100081,China

出　　处：《Science China Earth Sciences》2021年第10期1619-1632,共14页中国科学（地球科学英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2016YFA0600601);the National Natural Science Foundation of China(Grant Nos.41905072,41530530&41875087).

摘　　要：Extreme Meiyu rainfall in 2020,starting from early June to the end of July,has occurred over the Yangtze River valley(YRV),with record-breaking accumulated precipitation amount since 1961.The present study aims to examine the possible effect of sea surface temperature(SST)on the YRV rainfall in Meiyu season from the interdecadal perspective.The results indicate that YRV rainfall in June exhibits more significant variability on interdecadal time scale than that in July.The interdecadal-filtered atmospheric circulation in June,compared with the counterpart in July,shows a more predominant and better-organized Western North Pacific Anticyclone(WNPAC)anomaly,which could transport abundant moisture to the YRV by anomalous southwesterly prevailing in northwestern flank of anomalous WNPAC.Both observation and numerical experiment indicate that the interdecadal change of the SST anomaly in tropical western Indian Ocean(TWI)from preceding May to June can significantly affect the anomalous WNPAC,leading to enhanced YRV rainfall in June.The TWI SST anomaly shifts from a cold phase to a warm phase around the early 2000s,with a magnitude of 0.7°C in 2020,which implies that such interdecadal warming might partly contribute to the heavy rainfall in June 2020 by providing a large-scale favorable background flow.

关 键 词：Extreme Meiyu rainfall Western North Pacific anticyclone SST anomaly 

分 类 号：P461.2[天文地球—大气科学及气象学]