GOLD Observations of Thermospheric Neutral Temperature Variability During the 14 October 2023 Annular Solar Eclipse

Abstract The 14 October 2023 annular solar eclipse was visible from the US Pacific coast to Brazil's east coast. NASA's Global‐scale Observations of Limb and Disk (GOLD) mission observed the first synoptic thermospheric temperature changes from a geo‐stationary orbit above 47.5°W longitude between 17 and 20 UT during the eclipse. These daytime thermospheric changes were derived using GOLD's disk far ultraviolet (FUV) measurements. A significant decrease in the daytime disk temperatures (∼100 K) was seen near the peak annularity compared to the day before (baseline). The temperature reduction's spatial morphology is also like that of the eclipse shadow. Previous modeling studies of other eclipses typically show a much smaller temperature decrease (∼30–40 K; a factor of 2–3 lower) compared to GOLD observations. These first of kind results provide new insight into the dynamic response of the coupled thermosphere and ionosphere system to transient solar events, including eclipses.