*Federico Gasperini1
(1.Orion Space Solutions LLC)
Keywords:Wave Coupling , Ionosphere-Thermosphere, Ultra-Fast Tropical Waves, DE3, UFKW
It is increasingly evident that a few global-scale waves from the tropical wave spectrum with periods between about 0.5 days to 3.5 days (ultra-fast tropical waves, or UFTW), preferentially propagate upward from their sources and significantly impact the dynamics and mean state of the ionosphere-thermosphere (IT, 100-600 km). Two of the most prominent and well-established UFTW are the eastward-propagating 2-3-day period ultra-fast Kelvin wave with zonal wavenumber s = -1 (UFKW1) and the diurnal eastward propagating tide with zonal wavenumber s = -3 (DE3) that are excited by deep convective processes in the tropical troposphere. In this work, ion densities from Ion Velocity Meter (IVM) instruments onboard the Ionospheric Connection Explorer (ICON) and Scintillation Observations and Response of the Ionosphere to Electrodynamics (SORTIE) satellites and horizontal winds from ICON’s Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument are combined to study the day-to-day and latitudinal IT variability associated with UFKW during May-October 2020. Lower and middle atmospheric fields from the Specified Dynamics (SD) Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X) with Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) nudging are then used to infer their vertical propagation characteristics and evolution with time.