Concurrent GOLD and SABER observations of thermosphere composition and temperature responses to the April 23–24, 2023 geomagnetic storm

Global‐scale Observations of Limb and Disk observed a faster recovery of thermospheric column density ratio of O to N 2 (ΣO/N 2 ) in the southern hemisphere (SH) after the storm ended at 12 Universal time (UT) on 24 April.

After 12 UT on 25 April, ΣO/N 2 had mostly recovered in both hemispheres. Global‐scale Observations of Limb and Disk also observed an increase of middle thermospheric temperature (140–200 km) (Tdisk) on 24 April with a maximum of 340 K. Within 4–6 hr of the storm ending on 24 April, Tdisk enhancement persisted between 30°N and 60°N, 100°W and 30°W, while Tdisk lower than pre‐storm quiet day (17 April) was observed between 45°W and 15°W, 40°S and 50°N. Tdisk recovered between 100°W and 45°W, 30°N and 55°S. On 25 April, Tdisk was lower than on 17 April across the entire GOLD Field‐of‐Regard (FOR) by ∼50–110 K. Additionally, solar irradiance decreased by 15%–20% from 17 to 25 April, indicating that the lower Tdisk on 25 April resulted from both storm and solar irradiance variations.