CEDAR: Global and Seasonal Occurrence and Characteristics of Mesospheric Bores

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This award is an experimental effort to characterize rare but strong disturbances in the Earth's atmosphere that are often visible to the naked eye as large bands of faint optical emission called airglow that extend from horizon to horizon. These disturbances are atmospheric waves that are known as mesospheric bores. These waves are characterized by an extensive propagating "step-like" frontal region of enhanced or depleted airglow followed a train of waves. Mesospheric bores exhibit large brightness amplitudes (typically 10%) and can transport large amounts of energy and momentum through the mesosphere-lower-thermosphere (MLT) region. The wave dynamics significantly affects the large-scale temperature and circulation structure of the MLT and higher atmospheric regions. Understanding the full scope of wave effects on the MLT region is important for obtaining a complete physical picture of atmospheric processes. This work will utilize the data from eight existing ground-based optical imaging systems, together with a suite of co-located multi-diagnostic instrumentation and satellite data, to investigate the global and seasonal occurrence characteristics of mesospheric bores and other frontal gravity waves in the MLT region. The effort will:1) conduct a global survey and characterization of these waves and an estimate of the momentum flux contributing to the MLT using the Boston University all-sky imager network, and2) utilize co-located ground-based multi-diagnostic measurements and satellite measurements to supplement the imager data in order to fully characterize both the propagation environment and the gravity wave propagation modes.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.