Influence of lower atmospheric variability in an upper atmosphere general circulation model

The thermosphere-ionosphere (T-I) system is significantly controlled by solar EUV/UV variability. Apart from solar influences, a significant part of T-I variability is known to be driven by lower atmospheric forcings such as tides, gravity waves, and planetary waves originating in the lower atmosphere. To improve our understanding of this highly complex region of the Earth's atmosphere, a simulation study using the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model was conducted to systematically investigate the influence of lower atmospheric forcing. Several simulations were performed to investigate the impact of nudging using different lower atmosphere data sources such as Whole Atmospheric Model (WAM), Whole Atmosphere Community Climate Model-Extended (WACCM-X), and Navy Global Environmental Model a high-altitude version (NAVGEM-HA). The comparative study based on different nudging sources shows significant differences in the ionospheric parameters such as total electron content, electron density, and neutrals. In addition, we studied the delayed electron density in relation to the solar EUV variations at the time scale of the 27-day solar rotation period, taking into account the influence of the lower atmospheric forcings. The results show that the ionospheric delay is significantly modulated by the lower atmospheric forcings.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)