Short-term Variability of the Non-migrating Tide DE3 (from SABER, TIDI, and MIGHTI) and its Impact on the Ionosphere

This investigation is focused on resolving daily diurnal eastward propagating tide with zonal number 3 (DE3) (3,3) Hough mode variations and their potential impact on the ionosphere, using TIMED/TIDI and SABER, ICON/MIGHTI, COSMIC-2 Global Ionospheric Specification (GIS), and TIME-GCM. A Hough mode fitting approach was used to estimate (3,3) amplitudes and phases from observations, while Fourier decomposition was utilized for TIME-GCM and COSMIC-2/GIS to validate and probe potential ionospheric impacts. In 2020-2021, TIDI, SABER, and MIGHTI (3,3) daily tidal estimates were in good agreement, with correlation coefficients ranging from 0.73-0.83. In 2010, mean daily (3,3) amplitude variability in TIDI and SABER reached ~5 m/s and ~2 K, respectively, but could increase by a factor of 2 or more over a week. Furthermore, strong increases in DE3 from days to weeks correspond with similar increases in F-region ionospheric wave-4 amplitudes from both models and observations which signify the lower atmospheric meteorology impact on the ionosphere.