Unusual Changes in the Antarctic Middle Atmosphere During the 2019 Warming in the Southern Hemisphere

Abstract

A rare sudden stratosphere warming (SSW) occurred in the southern hemisphere polar region in 2019. The polar stratosphere temperature and planetary wave (PW) enhancements are found to be unusual from the history for 40 years, hence, it is an “Extremely-Rare” SSW. The distinct features of the mesosphere winds were observed during the SSW, in association with the traveling PWs in the stratosphere. The mesosphere zonal winds reversed for about 20 days before the peak SSW. Meteor Radar(MR) and MERRA-2 observations indicate that the zonal wind reversal was descended with time, and the reversal was larger over ~72oS than the MR site (62oS). The MR detected the PWs of 14-22-days before and 8-12-days following the SSW in the mesosphere. We further noticed the enhancement of wavenumber 1 signature in the mesosphere during the peak SSW over the polar region. Thus, the polar middle-atmosphere is greatly affected by the SSW.