[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-12] The 3-4 November 2021 Geomagnetic Storm: An Event Study with Focus on Ionosphere-Thermosphere Coupling over North America

*Jonna Marie Wehmeyer¹, Yoshihiro Tomikawa^2,1, Takanori Nishiyama^2,1, Yasunobu Ogawa^2,1 (1.The Graduate University for Advanced Studies, 2.National Institute of Polar Research)

Keywords:Ionosphere-Thermosphere Coupling, SAPS, storm-time thermospheric winds

This study focuses on ionosphere-thermosphere coupling over the North American sector during the 3-4 November 2021 strong geomagnetic storm with a peak Kp index of 8-. We investigated thermospheric winds through the combined use of Fabry-Pérot Interferometer (FPI) measurements at high, middle and low latitudes and ICON MIGHTI measurements. Ionospheric parameters were mainly investigated through Global Navigation Satellite System Total Electron Content, measurements from an ionosonde stationed at middle latitude and high-latitude radar measurements of F-layer ion velocities and electron densities from the Poker Flat Incoherent Scatter Radar.

We observed large disturbances in mid-latitude storm-time meridional thermospheric winds, that included a period of poleward perturbation within the otherwise strongly equatorward winds. We were able to identify a Subauroral Polarization Stream (SAPS) event during the storm main phase, that has not been reported in previous studies on the 3-4 November 2021 geomagnetic storm. The SAPS moved equatorward during the night and passed over the mid-latitude FPI observatories where the large disturbances in storm-time meridional thermospheric winds were observed at the time. We will present our hypothesis regarding the influence of SAPS on disturbances in meridional thermospheric winds.