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Abstract Mountain waves are known sources of fluctuations in the upper atmosphere. However, their effects over the Continental United States (CONUS) are considered modest as compared to hot spots such as the Southern Andes. Here, we present an observation‐guided case study examining the dynamics of gravity waves (GWs) and their impacts on the ionosphere over the CONUS prior to the cold air outbreak in December 2022, which resulted from a significant distortion of the tropospheric polar vortex. The investigation relies on MERRA‐2 and ERA5 reanalysis data sets for the climatological contextualization, analysis of GWs based on National Aeronautics and Space Administration Aqua satellite's Atmospheric Infrared Sounder, 557.7 and 630.0 nm airglow emission observations, and the measurements of ionospheric disturbances retrieved from Global Navigation Satellite System signal‐based total electron content (TEC) and Super Dual Auroral Radar Network observations. We demonstrate that the tropospheric polar jet stream shifted toward the Rocky Mountains, generated large amplitude GWs (up to 11 K of brightness temperature), which, aided by winter‐time winds over mid‐latitudes, could propagate to mesospheric heights. The breaking of GWs plausibly led to the generation of a plethora of secondary acoustic and GWs that eventually emerged as the sources of extensive ionospheric fluctuations of ∼3–30 min periods and up to 0.7 TECu, observed across the entire CONUS for several days. This case offers a valuable demonstration of the interplay between tropospheric circulation and the ionosphere over CONUS, pointing to the need for a better understanding of wave‐driven deep‐atmosphere coupled dynamics. 

Abstract The ionosphere-thermosphere (IT) is a convergence point of energy and processes that interconnect Earth’s atmosphere with space. Processes generated by terrestrial weather in the lower atmosphere (i.e., troposphere and stratosphere, altitudes less than ~ 50 km) are recognized by the scientific community as sources of variability in both the structure and composition of the IT. Exposed to persistent wave forcing from terrestrial weather sources and solar and magnetic forcing, the IT is a domain of compelling scientific inquiry that connects thermodynamics, fluid dynamics, electrodynamics and plasma physics. Predicting its space weather is of significant national interest for space situation awareness including the very low earth orbit as the new frontier of space operations. Advancing the understanding of whole atmosphere interconnections between terrestrial and space weather requires coordinated modeling and observational efforts across different spatial and temporal scales. Toward this goal, the National Aeronautics and Space Administration (NASA), through the living with a star (LWS) program, established in 2022 a focused science topic (FST) to study the problem from various angles. In this manuscript we report on the vision, goals and status of the ongoing FST “Impact of Terrestrial Weather on the Ionosphere—Thermosphere”. Initial results show bigger impacts on the IT than hitherto thought and help to more clearly define the state-of-the-art in the context of future NASA missions such as EZIE, DYNAMIC and GDC.