CAREER: The Role of Gravity Instability and Breakdown on Subsequent Gravity Wave Generation and Coupling

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The primary objective of this CAREER award is the study of the development of gravity wave (GW) coupling and breakdown in the mesosphere and lower thermosphere (MLT) over regions of orographic GW activity and strong inertia-GWs. This research will address an outstanding need for understanding complex multi-scale GW interactions and breakdown processes. It will also investigate the role that these processes play in GW generation and coupling throughout the atmosphere. The study will use data obtained by sodium lidar measurements over the Andes lidar observatory (ALO) (30.3 S, 70.7W) and Poker Flat (65.1N, 147.5W) as well as infrared hydroxyl (OH) airglow measurements from an OH airglow imager to be placed at Poker Flat. The following questions will be examined: 1) What are the implications of GW breakdown over a range of altitudes and spatial regions or partial breaking regions in the MLT, and how does this influence secondary and higher order GW generation? 2) What high-frequency spectra arise in less stable regions of the atmosphere and how does this relate to or influence dynamics such as turbulence generation and GW breakdown? A doctoral graduate student and a master student will be supported in the conduct of this research as well as undergraduate research students during the summer periods. The educational outreach thrust of this award will be based upon the development of a lidar-based instrumental technology class introduced into the academic curriculum for senior engineering students. Videos will be developed aimed at teaching the general public about the influence that breaking gravity waves have on the atmosphere region near the edge of space, 80 to 100 km high.Research activities include the application of high-resolution analysis software to raw sodium lidar data to obtain densities, winds, and temperatures for the study of both inertia-GWs and small-scale (40km), high frequency (10 minutes) dynamics. These measurements will be used for the study of GWs at multiple scales and frequencies in the MLT region, and instabilities associated with GW breakdown and multi-scale interactions. Additionally, OH airglow images obtained in the infrared spectrum will be used to determine the horizontal spectrum of spatial features associated with GWs and instabilities.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.