Resolved Gravity Wave Impact on Atmospheric Tides in the Thermosphere

Atmospheric tides are a substantial source of variability in the thermosphere and play a key role in coupling the lower and upper atmosphere. While gravity waves (GWs) are known to influence thermospheric dynamics through momentum and energy deposition, their role in modulating thermospheric tides remains poorly understood. In this study, the impact of resolved gravity waves on diurnal and semidiurnal tides is investigated using a high-resolution (HR) configuration of the Whole Atmosphere Community Climate Model with thermosphere–ionosphere eXtension (WACCM-X). The HR simulations explicitly resolve a broad spectrum of mesoscale gravity waves that are largely parameterized in corresponding coarse-resolution (CR) WACCM-X simulations. Comparisons between HR and CR simulations reveal substantial differences in the amplitude and spatial structure of thermospheric tides. To diagnose the physical origin of these differences, resolved GW momentum forcing is quantified in HR-WACCM-X by applying zonal wavelength filtering (200–2000 km) to isolate mesoscale perturbations and computing associated forcing terms. The forcing is further analyzed at diurnal and semidiurnal tidal periods to assess its contribution to tidal variability. The results indicate that resolved gravity waves produce momentum deposition at tidal timescales that can either amplify or damp tidal amplitudes. These findings highlight the importance of high-resolution modeling for accurately representing wave–tide interactions in the upper thermosphere and have implications for the forthcoming satellite missions.