Responses of the Ionosphere and Neutral Winds in the Mesosphere and Lower Thermosphere in the Asian‐Australian Sector to the 2019 Southern Hemisphere Sudden Stratospheric Warming

Abstract

AbstractIn this study, the neutral winds from meteor radars and the total electron content (TEC) from Beidou Geostationary (GEO) satellites were utilized to study the responses of the mesosphere and lower thermosphere and the ionosphere in the Asian‐Australian sector to the recent Sudden Stratospheric Warming (SSW) occurred in the Antarctic polar region during September 2019. It was demonstrated that the ionospheric TEC increased significantly, especially around the equatorial ionization anomaly (EIA) region during this SSW. A pronounced semidiurnal signature in the deviation TEC was observed near the EIA crest region, which was more significant in the southern hemisphere. Meanwhile, the enhancement period of the amplitudes of solar and lunar semidiurnal tides in winds in the mesosphere was coincided with that in TEC. The solar semidiurnal amplitudes increased from about 18 to 35 m/s in the zonal wind and from 15 to 25 m/s in the meridional wind at Mengcheng (33.4°N, 116.5°E, MLAT 27.4°N), and from about 15–38 m/s in the zonal wind at Kunming (25.6°N, 103.6°E, MLAT 19.3°N). The lunar semidiurnal amplitudes increased from 2 to 6 m/s in the zonal wind and from about 3–9 m/s in the meridional wind at Mengcheng, and from about 3–7 m/s in the meridional wind at Kunming, respectively. These indicated that the semidiurnal signature in TEC during the 2019 southern hemisphere SSW could be associated with the SSW induced by the atmospheric semidiurnal tide variations in the mesosphere.