Longitudinally-Dependent Low-Latitude Ionospheric Disturbances Linked to the Antarctic Sudden Stratospheric Warming of September 2019 | CU Experts

The strongest Southern Hemisphere minor sudden stratospheric warming; (SSW) in the last 40 years occurred in September 2019 and resulted in; unprecedented weakening of the stratospheric polar vortex. Ionospheric; total electron content (TEC) observations are used to provide an; overview of statistically significant anomalies in the low-latitude; ionosphere during this event. Quasi-semidiurnal perturbations of TEC are; observed in response to the SSW, similar to those seen during Northern; Hemisphere SSWs. Analysis indicates the existence of quasi-periodic; oscillations in TEC in the crests of the equatorial ionization anomaly,; with strong 5-6 day and 2-3 day periodicities. Ionospheric anomalies; from the combined effects of multiple mechanisms exceed a factor of 2,; comparable to the strongest anomalies associated with Northern; Hemisphere SSWs. These results also indicate, for the first time, a; remarkable longitudinal variation in the character and magnitude of; variations that could be related to a modulation of the non-migrating; diurnal tide.

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