Multi‐Technique Study of the Thermospheric Wind Responses to the November 3–4, 2021 Storm

The responses of thermospheric winds at mid and low latitudes to the intense geomagnetic storm of November 3–4, 2021, are examined using multi‐technique observations and simulations with the Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM). During the storm, the Kp index reaches 8 and the DST index reaches −105 nT. This study provides detailed profiles of thermospheric winds, especially the nighttime winds measured by the Michelson Interferometer for Global High‐Resolution Thermospheric Imaging (MIGHTI). Significant nighttime wind disturbances are shown at latitudes between 30°N and 42°N, and there is a reversal structure in the zonal wind disturbances: westward below 250 km and eastward above it. Large westward and poleward nighttime disturbances emerge between 220 and 290 km at latitudes between 30°N and 42°N, coinciding with the minimum DST index. The maximum nighttime westward disturbance is −249 m/s around 220 km, and poleward is 193 m/s around 280 km. Daytime zonal wind disturbances are mainly eastward at latitudes between 0° and 20°N, except for latitudes between 15°S and 0°, where disturbances shift from westward to eastward as energy is injected. Significant daytime equatorward wind disturbances of −252 m/s at 160 km are shown as the DST index reaches the minimum between 10°N and 20°N. TIEGCM simulations underestimate MIGHTI after 07:00 Universal Time but are consistent with ground‐based wind measurements.