Interannual Influences of the Surface Potential Vorticity Forcing over the Tibetan Plateau on East Asian Summer Rainfall  

作　　者：Chen SHENG Bian HE Guoxiong WU Yimin LIU Shaoyu ZHANG 

机构地区：[1]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Advances in Atmospheric Sciences》2022年第7期1050-1061,共12页大气科学进展（英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.91837101,42122035,and 91937302);the National Key Research and Development Program of China(Grant No.2018YFC1505706 and 2020YFA0608903).

摘　　要：The influences of interannual surface potential vorticity forcing over the Tibetan Plateau(TP)on East Asian summer rainfall(EASR)and upper-level circulation are explored in this study.The results show that the interannual EASR and associated circulations are closely related to the surface potential vorticity negative uniform leading mode(PVNUM)over the TP.When the PVNUM is in the positive phase,more rainfall occurs in the Yangtze River valley,South Korea,Japan,and part of northern China,less rainfall occurs in southern China,and vice versa.A possible mechanism by which PVNUM affects EASR is proposed.Unstable air induced by the positive phase of PVNUM could stimulate significant upward motion and a lower-level anomalous cyclone over the TP.As a result,a dipole heating mode with anomalous cooling over the southwestern TP and anomalous heating over the southeastern TP is generated.Sensitivity experiment results regarding this dipole heating mode indicate that anomalous cooling over the southwestern TP leads to local and northeastern Asian negative height anomalies,while anomalous heating over the southeastern TP leads to local positive height anomalies.These results greatly resemble the realistic circulation pattern associated with EASR.Further analysis indicates that the anomalous water vapor transport associated with this anomalous circulation pattern is responsible for the anomalous EASR.Consequently,changes in surface potential vorticity forcing over the TP can induce changes in EASR.

关 键 词：surface potential vorticity East Asian summer monsoon RAINFALL the Tibetan Plateau 

分 类 号：P461[天文地球—大气科学及气象学]