Impact of Lower Atmospheric Global-Scale Waves on the CoupledIonosphere–Thermosphere System

Presented on July 9, 2026, by

Deepali Aggarwal

Ph. D. Candidate

Clemson University

ABSTRACT

The ionosphere–thermosphere (IT) system is influenced not only by solar and geomagnetic activity but also by atmospheric waves generated in the lower atmosphere. Understanding how these waves propagate upward and modify the ionosphere is essential for improving space weather prediction and supporting satellite communication, navigation, and very low Earth orbit (VLEO) operations. This seminar presents an overview of my research on the impact of lower atmospheric forcing on the coupled IT system. Using observations from COSMIC-2 and ICON together with SD-WACCM-X and TIE-GCM simulations, I investigate how the Madden–Julian Oscillation (MJO), stratospheric polar vortex variability, and Sudden Stratospheric Warming (SSW) events influence ionospheric tides and F-region electron density. The results show that these lower atmospheric processes significantly modulate migrating, non-migrating, and lunar tides through changes in the E-region dynamo. Numerical experiments further demonstrate that vertical plasma drifts are the primary mechanism transmitting these disturbances into the F-region, with neutral winds playing a secondary role. These findings provide new insight into whole-atmosphere coupling and highlight the importance of incorporating lower atmospheric variability into future space weather forecasting.