Evaluation of atmospheric 3‐day waves as a source of day‐to‐day variation of the ionospheric longitudinal structure

We report for the first time the day-to-day variation of the longitudinal structure in height of the F-2 layer (h(m)F(2)) in the equatorial ionosphere using multi-satellite observations of electron density profiles by the Constellation Observing System for Meteorology, Ionosphere and Climate-2 (COSMIC-2). These observations reveal a similar to 3-day modulation of the h(m)F(2) wavenumber-4 structure viewed in a fixed local time frame during January 30-February 14, 2021. Simultaneously, similar to 3-day planetary wave activity is discerned from zonal wind observations at similar to 100 km by the Ionospheric Connection Explorer (ICON) Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI). This signature is not observed at similar to 180-250 km altitudes, suggesting the dissipation of this wave below the F-region. We propose that the 3-day variation identified in h(m)F(2) is likely caused by the planetary wave-tide interaction through the E-region dynamo.