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Abstract:
The impacts of different deviation events of the stratospheric polar vortex on the cold temperature anomaly at middle and low latitudes in Asia were analyzed in case of major sudden stratospheric warming (SSW) events. When the polar vortex leaned to Eastern Eurasia, a positive potential vorticity anomaly occurred in the Tibetan Plateau and its surrounding areas with a lag of 10~30 days, which caused the tropopause folding and strengthened abnormal cyclonic circulation, resulting in cold temperature anomaly in the Tibetan Plateau, India and the Indochina Peninsula. When the polar vortex leaned to Western Eurasia or North America, the negative Northern Annular Mode (NAM) signal descended to the troposphere and caused an abnormal cyclonic circulation in East Asia, leading to cold temperature anomalies in most of China or northeastern Asia. In addition, zonal Rossby waves triggered in the Atlantic also play a key role in the general circulation over East Asia.
