Observing the 2019 Southern Hemisphere Sudden Stratospheric Warming over Antarctica using ground-based and satellite measurements

Abstract:

Sudden Stratospheric Warmings (SSW) are well known in the northern hemisphere (NH) but are rare in the southern hemisphere (SH). The 2019 SH SSW in September was a minor event characterized by a strong stratosphere temperature response. Temperature measurement for 2019 from the Solar Occultation For Ice Experiment (SOFIE) on Aeronomy of Ice in the Mesosphere (AIM) satellite exhibited a warming during the SSW period at stratospheric heights and cooling in the mesopause region. The Utah State University (USU) Advanced Temperature Mapper (AMTM) was deployed at McMurdo station, Antarctica in 2017 to measure gravity waves (GW) in the OH (3,1) band intensity and mesospheric temperature at ~87 km. During the 2019 SH SSW event, the AMTM temperature exhibited a sudden drop of 15K but with a much shorter duration than observed in the stratosphere by SOFIE.

In this study, SOFIE temperature are used to study the GW activity and Planetary Waves over Antarctica, revealing the zonal variability of the warming in the stratosphere and sudden cooling in the mesopause region. At McMurdo, the AMTM data are used to study GWs of different horizontal scales during the SSW event, while the meteor radar wind data are examined for possible causes in the GW activity changes during the spring of 2019 over Antarctica.