Response of ICON/MIGHTI Measured Low-Mid Latitude OI630.0 and OI557.7 nm Dayglow Emissions to the 27 August 2021 Geomagnetic Storm

Observations from the Michelson Interferometer for Global High-Resolution Thermospheric Imaging onboard the Ionospheric Connection Explorer spacecraft are used to study the response of OI630.0 and OI557.7 nm dayglow to a moderate geomagnetic storm on 27 August 2021. The storm reaches a minimum Dst index of -82 nT, significantly impacting the dayglow within the latitudinal range of approximately 20 degrees N-42 degrees N, where the dayglow observations are of good quality. During the geomagnetic storm, the OI630.0 dayglow intensity slightly increases, while the peak volume emission rate (VER) decreases, and the peak height rises noticeably. The F-layer intensity, peak VER, and the entire-layer intensity of OI557.7 dayglow decrease significantly. The rise in peak height is not noticeable for the OI557.7 dayglow. The VERs of the both dayglow emissions respond differently to the geomagnetic storm at different altitudes. The OI630.0 dayglow layer as a whole extends upward and rises in altitude. For dayglow averaged above 35 degrees N, the OI630.0 dayglow VER increases above approximately 225 km but decreases below this altitude. The largest increase occurs near 300 km, reaching approximately 82.8%, while the largest decrease occurs around 160 km, reaching about -22.0%. The OI630.0 dayglow intensity increases by approximately 6.3%, the peak VER decreases by about -8.0%, and the peak height rises by approximately 16.3 km, corresponding to a 7.8% increase. The F-layer intensity, peak VER, and the entire-layer intensity of OI557.7 dayglow decrease by approximately -27.5%, -32.4% and -17.4%, respectively. The response of the dayglow also depends on longitude and is accompanied by a southward meridional wind. The atomic oxygen dayglow emissions at 630.0 and 557.7 nm are the brightest airglows in the upper atmosphere and important subjects of research. They indicate the connection between the thermosphere and ionosphere as they are influenced by both plasma and neutral species. Understanding this connection is crucial for studying the effects of space weather. During geomagnetic storms, increased Joule heating and particle heating in the polar regions cause the expansion of the upper atmosphere. This interaction disrupts the ionosphere, affecting the 630.0 and 557.7 nm airglows. The Michelson Interferometer for Global High-Resolution Thermospheric Imaging onboard the Ionospheric Connection Explorer simultaneously gathers data from both dayglow emissions without the need for duty cycling or scanning. This study examined the response of both dayglow to a moderate geomagnetic storm on 27 August 2021. The results enhance our understanding of thermosphere-ionosphere coupling and space weather impacts. The OI630.0 dayglow emission layer moves and extends upward during the geomagnetic stormThe OI630.0 dayglow emission response varies with altitude, increasing above similar to 225 km and decreasing below itBoth OI630.0 and OI557.7 dayglow responses depend on longitude, maximizing in the longitude sector around 70 degrees W during this storm