NSF-SNSF: Interactions of Gravity Waves and Tides in the Mesosphere and Lower Thermosphere

This project investigates the complex "weather" of the upper atmosphere, specifically in the region above 80 km. This is referred to as mesosphere, and lower thermosphere, and ionosphere (MLTI). While often invisible to the naked eye, the MLTI encompasses a turbulent region where large-scale atmospheric tides and smaller-scale gravity waves—ripples of energy that originate in the lower atmosphere. Understanding how these waves and tides interact is essential, as these dynamics directly influence the space weather environment. Space weather can disrupt satellite communications, GPS accuracy, and power grid stability, all of which are vital to the nation's prosperity and defense. The project also promotes the international scientific collaboration with Switzerland and Chile and contributes to the training the next generation of scientists. The primary goal of this research is to quantify the dynamical interactions between gravity waves (GWs) and atmospheric tides within the MLTI region. The project will address four science topics: (i) how tides influence GW propagation, filtering, and dissipation; (ii) the mechanisms by which GWs modulate the amplitude and phase of diurnal tides; (iii) the feedback loops between GW-tide interactions and mean atmospheric circulation; (iv) the impact of regional and seasonal wave source variations on wave-tide coupling. The project utilizes both state-of-the-art high-resolution modeling and advanced observational data. The model is uniquely capable of resolving GW breaking and assimilating realistic tidal backgrounds to simulate nonlinear interactions. The observational data utilizes a multi-static meteor radar system in the Andes, which will provide continuous, high-resolution wind measurements. These can resolve both horizontal and vertical structures of all three wind vector components. This system will also be upgraded with orbital capabilities to achieve hourly temperature measurements. The observational data will be used to provide realistic background for performing simulation, while model simulations will be used to validate wind retrievals with advanced tomographic technique. This work is a combination of advanced observation, modeling, and instrumentation, that will fill a critical gap in our understanding of how small-scale instabilities shape the global energy transfers that drive ionospheric and space weather variability. This award was made possible through the U.S.NSF/SNSF (Swiss NSF) lead agency opportunity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2530422 | Program: 01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Alan Liu | Institution: Embry-Riddle Aeronautical University, DAYTONA BEACH, FL | Award Amount: $500,000 View on NSF Award Search: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2530422 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2530422.html