2019-2020冬季北半球超强极涡事件

2019-2020冬季北极平流层极涡异常并且持续的偏强,偏冷.利用NCEP再数据和OMI臭氧数据,本文分析了此次强极涡事件中平流层极涡的动力场演变及其对地面暖冬天气和臭氧低值的影响.此次强极涡的形成是由于上传行星波不活跃.持续的强极涡使得2020年春季的最后增温出现时间偏晚.平流层正NAM指数向下传播到地面,与地面AO指数和NAO指数相一致,欧亚大陆和北美地面气温均比气候态偏暖,在欧亚大陆的一些地区,2020年1月和2月的气温甚至偏高了 10K.2020年2月以来北极臭氧出现了2004年以来的最低值,2020年3-4月60°-90°N的平均臭氧柱总量比气候态偏低了 80DU.

The exceptionally strong and persistent Arctic stratospheric polar vortex in the winter of 2019-2020

The Arctic stratospheric polar vortex was exceptional strong,cold and persistent in the winter and spring of 2019-2020.Based on reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research and ozone observations from the Ozone Monitoring Instrument,the authors investi-gated the dynamical variation of the stratospheric polar vortex during winter 2019-2020 and its influence on surface weather and ozone depletion.This strong stratospheric polar vortex was affected by the less active upward propagation of planetary waves.The seasonal transition of the stratosphere during the stratospheric final warm-ing event in spring 2020 occurred late due to the persistence of the polar vortex.A positive Northern Annular Mode index propagated from the stratosphere to the surface,where it was consistent with the Arctic Oscilla-tion and North Atlantic Oscillation indices.As a result,the surface temperature in Eurasia and North America was generally warmer than the climatology.In some places of Eurasia,the surface temperature was about 10 K warmer during the period from January to February 2020.The most serious Arctic ozone depletion since 2004 has been observed since February 2020.The mean total column ozone within 60°-90°N from March to 15 April was about 80 DU less than the climatology.