Interhemispheric and Longitudinal Differences of Ionosphere-Thermosphere Coupling Process during 2024 May Superstorm

Geomagnetic storm events have a strong influence on the Ionosphere-Thermosphere (I-T) coupling system. Analyzing the regional response process of the I-T system and its differences across the Northern and Southern Hemispheres is a significant but challenging task. In this study, we employed a combination of multiple observations and model simulation to examine the North-South hemispheric difference of the I-T coupling system in the American and Asian sectors during the super geomagnetic storm that occurred in May 2024. The Total Electron Content (TEC) observations show that the Asian sector has negative storms in the Northern Hemisphere and positive storms in the Southern Hemisphere, a process that exacerbates the hemispheric differences of TEC. However, both hemispheres of the American sector showed negative storms. The thermospheric composition changes also differed between the two sectors, and their variation can partially explain the hemispheric differences caused by positive and negative storms. Moreover, the influence of thermospheric density change is less than that of thermospheric composition. Last but not least, the dynamic effect of the thermospheric wind and the plasma transport processes strongly modulate the North-South differences of TEC at nighttime in the American and Asian sectors during this superstorm, respectively.