Hemispheric Differences in Ionosphere–Thermosphere Responses to Traveling Atmospheric Disturbances

During geomagnetic storms, large amounts of electromagnetic energy are deposited into Earth’s ionosphere–thermosphere (I–T) system, primarily through Joule heating. This energy input can excite traveling atmospheric disturbances (TADs), which propagate globally and significantly impact the coupled I–T system. Notably, Joule heating often exhibits strong interhemispheric asymmetries (IHAs), leading to hemispheric differences in both the generation and propagation of TADs, as well as in the resulting I–T responses to storm-time energy input. Key questions remain open: How do the characteristics of TADs differ between the Northern and Southern Hemispheres? And to what extent do IHAs in TADs contribute to the interhemispheric asymmetries observed in the storm-time I–T system? In this presentation, I will highlight several recent data–model studies we have conducted that begin to address these questions, offering new insights into the complex interplay between IHAs in Joule heating, TAD dynamics, and storm-time variations in the I-T system.