CEDAR: High-resolution Multistatic Mapping of Small-Scale Flow Structures in Earth's Auroral Thermosphere

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This project will measure winds at ~250 km altitude in Earth?s auroral thermosphere. These winds remain poorly understood, especially at spatial scales spanning ~100 km or less. The project is based on the hypothesis that eddies and waves at horizontal length scales of ~100 km or less are important contributors to the dynamics of Earth?s auroral thermosphere and that their cumulative impact is important both for the basic physics of the thermosphere and for operational prediction of space weather. To determine small-scale flow structures, all seven of the Fabry-Perot spectrometers now in Alaska will be configured to focus their attention simultaneously onto one small geographic region roughly coinciding with the field of view of the PFISR radar. These instruments will simultaneously monitor thermospheric temperatures and wind vectors, producing two-dimensional maps of temperatures and 3-component vector winds, with a spatial resolution of around 80 km. The array will operate in this mode for three campaigns each lasting around two-months. To quantify the importance of small-scale eddies and waves in the thermosphere, the project will address three focused science questions: (1) What is the occurrence frequency, intensity, spectral distribution, and overall morphology of the small-scale eddies and waves in Alaska?s auroral thermosphere, for both quiet and active conditions? (2) Is it possible to identify the driver mechanisms and source regions for these small-scale features, based on timing of their occurrence relative to other measurements, the spatial alignment of their phase fronts, and the directions in which they?re propagating? (3) Is it possible to estimate the momentum flux and dissipation rates of these waves, based on the amplitudes, periods, and horizontal & vertical wavelengths of the temperature and 3-component wind perturbations, and on the time evolution of these quantities? This project will include training one graduate student, enhancing the research facility at Toolik Lake in Alaska, supporting rocket missions from Poker Flat, and bringing cutting-edge scientific research to remote Alaskan villages.