The extreme Northeast China cold vortex activities in the late spring of 2021 and possible causes involved

• DOI: 10.1016/j.accre.2022.09.002
• Publication Date: 2022-09-11T13:44:03Z
• Authors: Jie Wu; Ying Liu; Yong-Sheng Li; Jin-Qing Zuo; Yu Nie; Qing-Quan Li; Shuai Zhang; Dong-Qian Wang
• Keywords: Teleconnection; Anticyclone; Jet stream; Extratropical cyclone

Record-breaking numbers of Northeast China cold vortex (NCCV) occurred during the late spring (April–May) 2021, which provided favorable background for more severe convection weather (such as hailstorm and tornado) happened struck Jiangsu Hubei provinces, China, causing heavy casualties property losses. To better understand possible causes extremely abnormal NCCV activities, external forcing dynamical analysis was conducted. The results show that extreme activity is regulated by preceding sea surface temperature (SST) anomalies in tropical Pacific, snow conditions over Tibetan Plateau, wave-mean flow interaction Eurasian continent. During autumn winter 2020, a moderate La Niña event triggered Pacific–North America teleconnection pattern (PNA) like wave train further dispersed Rossby energy downstream along mid-latitude westerly jet, forming zonal Moreover, second minimum depth recorded southeastern Plateau boreal 2020/2021, induced concurrent local anomalous anticyclone cyclone northeast Asia following spring. Finally, circulation capable achieving from mean state through barotropic conversion strengthening accordingly. This study highlights joint impacts forcings internal atmospheric processes on activity.