A sudden stratospheric warming (SSW) is a large-scale meteorological phenomenon in the winter stratosphere, which involves a rapid rise in the polar temperature by a few tens of kelvins in several days. SSWs are triggered by an injection of stationary planetary waves from the troposphere. These events are rare in the Southern Hemisphere, therefore they could not be extensively investigated in the past.
6-day variations in both electron density and total electron content at 20◦ magnetic latitude were detected in the ionosphere with Swarm data in September 2019. For the same dates stationary planetary waves were examined using the geopotential height data from Aura Microwave Limb Sounder, confirming a SSW event. Results of the study suggest that a SSW can lead to ionospheric variability by altering middle atmosphere dynamics and propagation characteristics of large-scale waves from the middle atmosphere to the upper atmosphere.
Full results of the study can be found in: Y. Yamazaki, V. Matthias, Y. Miyoshi, C. Stolle, T. Siddiqui, G. Kervalishvili, J. Laštovička, M. Kozubek, W. Ward, D.R. Themens, S. Kristoffersen, P. Alken (2020). September 2019 Antarctic Sudden Stratospheric Warming: Quasi‐6‐Day Wave Burst and Ionospheric Effects, Geophysical Research Letters, 47, (https://doi.org/10.1029/2019GL086577).
Featured image: Longitude versus time plot of the electron density (left) and total electron content (right) at 20◦ magnetic latitude for Swarm B satellite from 5 September to 5 October 2019.