Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature

作     者：PENG Cheng FAN Ke DAI Haixia PENG Cheng;FAN Ke;DAI Haixia

作者机构：Nansen-Zhu International Research CentreInstitute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina College of Earth and Planetary SciencesUniversity of the Chinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjingChina 

出 版 物：《Atmospheric and Oceanic Science Letters》 (大气和海洋科学快报（英文版）)

年 卷 期：2019年第12卷第5期

页      面：369-375页

核心收录：

学科分类：07[理学] 070601[理学-气象学] 0706[理学-大气科学] 

基　　金：supported by the National Natural Science Foundation of China [grant numbers 41730964 41575079 and 41421004] 

主　　题：Stratospheric polar vortex weak stratospheric polar vortex events in December subseasonal variability stratosphere-troposphere interaction winter Eurasian air temperature(0-40 days) 

摘      要：Weak stratospheric polar vortex(WPV)events during winter months were *** events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar *** the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate *** I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating *** Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the *** anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over *** zero line between negative and positive temperature anomalies moves southwards during days *** cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole *** PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the ***,a wave train is initiated from the North Atlantic region to northern *** propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central ***,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period.