Observational and Modeling Evidence of Electrodynamic Coupling Between E-Region Atmospheric Tides and F-Region Electron Density

Upward-propagating tropospheric waves curtailed by the lower thermosphere and mesosphere (MLT) influence Global-Scale Wave (GSW) structures, which exhibit evidence of coupling between terrestrial and space weather (Khadka et al., 2026). Satellite observations, ionospheric assimilative modeling, and climatological tidal modeling reveal the extent to which tidal and planetary waves drive variability in the ionosphere, thermosphere, and mesosphere (ITM) system. The wave number (WN) structures of GSW temperature from TIMED/SABER and electron density from COSMIC‐2 GIS data are extracted for the period 2020–2021 within ±45° latitudes. A new version of the Climatological Tidal Model of the Thermosphere (CTMT.v2) is used to analyze the vertical, temporal, and latitudinal tidal structures of temperature and density. The vertical profiles of CTMT.v2 tides from below are examined to investigate their evolution, variability, coupling processes, and impacts on atmospheric and ionospheric structures across the ITM region.

As reported in Khadka et al. (2026), the results are summarized as follows: (i) the antisymmetric structures of the WN1 move closer to the equator when the equatorial westward‐propagating semidiurnal components are strong above 140 km, (ii) the antisymmetric component of the WN2 structure in the northern hemisphere is stronger than that in the southern hemisphere at ionospheric heights (above 105 km), (iii) the WN3 structure shows intermittent equatorially symmetric structures at 105 km, but cannot form a clear hemispheric antisymmetric structure at other altitudes, (iv) the stronger the WN4 structures in the E‐region, the more separated the crests of equatorial ionization anomaly (EIA) in the F‐region. These results highlight the need for additional space‐based observations in the ∼100–400 km altitude range and for the development of models to advance understanding of the coupling between terrestrial and space weather processes across multiple spatial and temporal scales.