[P-EM13] Coupling Processes in the Atmosphere-Ionosphere System

[PEM13-19] Stratosphere to ionosphere interhemispheric coupling during sudden stratospheric warmings

★Invited Papers

*Larisa P Goncharenko¹ (1.Massachusetts Institute of Technology)

キーワード：sudden stratospheric warming, ionosphere, thermosphere

Sudden stratospheric warmings (SSWs) are large-scale meteorological disturbances that have been associated with profound anomalies in the Earth atmosphere, from troposphere all the way to the upper thermosphere and ionosphere. During the last decade, numerous studies shown that Arctic SSWs cause large anomalies in the low-latitude ionosphere, but our knowledge of SSW-related disturbances at middle and high latitude ionosphere/thermosphere system is much more limited. Recent observations demonstrate a strong interhemispheric coupling during such events and truly global disturbances. SSW over Antarctica that occurred in September 2019 has been linked with persistent (at least 30 days) and strong (up to 80-100%) positive anomalies in the daytime total electron content (TEC) and increases in the thermospheric O/N2 ratio in the western region of North America. In a case of major Arctic SSW of January 2013, large disturbances observed in the Arctic winter polar stratosphere (20-50 km above ground and at 60-90N) are communicated across the globe and cause large disturbances in the summertime ionospheric plasma over Antarctica (60-90S). Ionospheric anomalies reach ~100% of the background level and are observed for multiple days. Combination of several mechanisms could contribute to the formation of upper atmospheric and ionospheric anomalies in the opposite hemisphere, and sustained modeling and observational effort is required to understand their relative roles. Understanding the relative importance of mechanisms affecting the ionosphere/thermosphere system beyond solar and geomagnetic activity is essential for progress in multi-day predictions of the near-Earth space environment.