Polar stratospheric chemistry is highly sensitive even to minor disruptions in water vapor or temperature. Unusual behavior in temperature and water vapor has been identified in the southern polar winter stratosphere in 2023. The potential correlation between the post-Hunga-Tonga eruption elevation of water vapor (detected in the tropics), temperature changes, and ozone anomalies is under discussion, as these parameters play a crucial role in stratospheric chemistry and dynamics. In the winter of 2023 in the Southern Hemisphere, an unexpected decrease in ozone levels and the emergence of a substantial ozone hole were observed. This event marked one of the most significant ozone decreases in the past 15 years, with an unusually large ozone hole occurring during this period, and it appears to be at least partly associated with the Hunga Tonga eruption.

An exceptionally strong stationary planetary wave with Zonal Wavenumber 1 led to a sudden stratospheric warming (SSW) in the Southern Hemisphere in September 2019. Ionospheric data from ESA’s Swarm satellite constellation mission reveal prominent 6-day variations in the dayside low-latitude region at this time, which can be attributed to forcing from the middle atmosphere by the Rossby normal mode “quasi-6-day wave” (Q6DW). Geopotential height measurements by the Microwave Limb Sounder aboard NASA’s Aura satellite show a burst of Q6DW activity in the mesosphere and lower thermosphere during the SSW, which is one of the strongest in the record. The Q6DW is apparently generated in the polar stratosphere at 30-40 km, where the atmosphere is unstable due to strong vertical wind shear connected with planetary-wave breaking. These results suggest that an Antarctic SSW can lead to ionospheric variability through wave forcing from the middle atmosphere.