Moisture Origins and Transport Processes for the 2020 Yangtze River Valley Record-Breaking Mei-yu Rainfall  

作　　者：Lixia ZHANG Dan ZHAO Tianjun ZHOU Dongdong PENG Chan XIAO 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]University of the Chinese Academy of Sciences,Beijing 100049,China [3]Institute of Tropical and Marine Meteorology,China Meteorological Administration,Guangzhou 510640,China [4]National Climate Center,China Meteorological Administration,Beijing 100081,China

出　　处：《Advances in Atmospheric Sciences》2021年第12期2125-2136,共12页大气科学进展（英文版）

基　　金：This paper was supported by the National Natural Science Foundation of China(Grant No.42075037);the Ministry of Science and Technology of China(Grant No.2018YFA0606501);the Program of International S&T Cooperation(Grant No.2018YFE0196000).

摘　　要：The summer of 2020 recorded a record-breaking flood due to excessive mei-yu rain falling over the Yangtze River Valley(YRV).Using the Lagrangian model FLEXPART,this paper investigates moisture sources and transport processes behind this extreme event.Based on climate data from 1979 to 2019,the air-particle(an infinitesimally small air parcel)trajectories reaching the YRV show sectors that correspond to five main moisture sources:the Indian monsoon region(IND,27.5%of the total rainfall),the local evaporation(27.4%),the Western Pacific Ocean(WPO,21.3%),the Eurasian continent(8.5%)and Northeast Asia(4.4%).In the 2020 mei-yu season,moisture from all source regions was above normal except that from Northeast Asia.A record-breaking moisture source from the IND and WPO dominated this extreme mei-yu flood in 2020,which was 1.5 and 1.6 times greater than the climate mean,respectively.This study reveals a significant relationship between the moisture source with three moisture transport processes,i.e.,trajectory density,moisture content,and moisture uptake of air-particles.A broad anomalous anticyclonic circulation over the Indo-Northwestern Pacific(Indo-NWP)provides a favorable environment to enhance the moisture transport from the IND and WPO into the YRV.In the 2020 mei-yu season,a record-breaking Indo-NWP anomalous anticyclonic circulation contributed to a higher trajectory density as well as higher moisture content and moisture uptake of air-particles from the IND and WPO regions.This collectively resulted in unprecedented moisture transport from source origins,thus contributing to the mei-yu flood over the YRV in 2020.

关 键 词：mei-yu flood FLEXPART moisture tracking extreme moisture transport 

分 类 号：P426.62[天文地球—大气科学及气象学]