Studies of the Dynamic Processes of East Asian Monsoon System and the Quasi-Stationary Planetary Wave Activities
CHEN Wen,GU Lei,WEI Ke,and HUANG Ronghui Center for Monsoon System Research,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100080
The studies of the dynamic processes and mechanism of East Asian monsoon system(EAMS) variability and anomaly,especially on the relation of the interannual and interdecadal variabilities and anomalies of EAMS to quasi-stationary planetary wave activities,are systematically reviewed.During recent years,many studies showed that the dynamic processes of East Asian summer monsoon(EASM) system variability and anomaly are mainly associated with the East Asia/Pacific(EAP) teleconnection pattern.By using the EAP teleconnection theory,it can be described not only how the various components of EASM system are related,but also how the thermal effect of the tropical western Pacific and the convective activities around the Philippines influence the variations of EASM system on intraseasonal and interannual timescales with a distribution of meridional tripole pattern.And studies also have shown that there is a summer teleconnection pattern of upper-tropospheric meridional wind anomalies along the jet stream from North Africa to East Asia,which has an important impact on the meridional tripole pattern of EASM anomalies.Moreover,the recent studies on the relations of the variabilities and anomalies of the East Asian winter monsoon(EAWM) to planetary wave activities have achieved important progress.The studies have shown that in the Northern Hemisphere winter,the variations of the two waveguides of planetary wave propagation have an out-of-phase oscillation on both interannual and interdecadal timescales.If the polar waveguide is strengthened,then the low latitude waveguide may be weakened,and vice versa.And it is found that the oscillation of these two waveguides is closely related to the interannual and interdecadal variations of Northern Annular Mode(NAM),which can lead to the interannual and interdecadal variabilities of the EAWM via anomalous planetary wave activities.Besides,the results indicate that the relationship between the planetary wave activity and the EAWM on interannual timescale is strongly modulated by the tropical quasi-biennial oscillation(QBO) of zonal wind in the stratosphere,and possible mechanisms are further proposed.Finally,it has been shown that anomalous EAWMs from 2005 to 2007 are not only associated with the variations of Siberian high and Aleutian low,but also closely related to the evolution of polar vortex and the quasi-stationary planetary wave activities.
【Fund】： 国家自然科学基金资助项目40730952、40775035、40575026;; 中国科学院知识创新工程重要方向项目KZCX2-YW-220
【CateGory Index】： P462.41
【CateGory Index】： P462.41