Thermospheric responses to the 3 and 4 November 2021 geomagnetic storm during the main and recovery phases as observed by NASA's GOLD and ICON missions

Leveraging observations by two NASA missions-GOLD (Global-scale Observations of the Limb and Disk) and ICON (Ionospheric Connection Explorer), we investigate concurrent responses of thermospheric composition, temperatures, and neutral winds to the geomagnetic storm on 3-4 November 2021, as well as their interplay at low and middle latitudes. The synergetic observations reveal remarkable depletions up to 60%-70% in GOLD O/N-2, along with large enhancements in GOLD temperatures poleward of 30 degrees in the middle thermosphere.

Meridional winds from ICON observations are altered by similar to 100 m/s equatorward of 25 degrees N latitude and at 250 km, characterized by a reversal of prevailing northward winds to geomagnetic storm-driven southward winds. This study fills a need, after a decade-long gap, for observing concurrent and co-located responses of composition, temperatures, and neutral winds in the thermosphere to geomagnetic storms.