CEDAR Postdoc: Observational and Modeling Study of Mesospheric Bores

Embry-Riddle Aeronautical University, Daytona Beach FL

Investigators

Abstract

The goal of this investigation is to perform a definitive study of the various mesospheric bore phenomena, combining analysis of multiple layer airglow observations with modeling in order to evaluate existing theories. Mesospheric bores are sharp airglow fronts observed by imaging systems at several locations. They are characterized by small-scale waves tracking behind the sharp onset of a large-scale front as seen in all-sky camera photographs. These features are called mesospheric bores because of their resemblance to tidal bores in river channels. Current theories are that mesospheric bores are nonlinear structures propagating within a thermal inversion layer, but confirmation of these ideas require observations of airglow layers with simultaneous temperature and/or wind vertical profile data available. This investigation includes data analysis from multiple instruments, including airglow imagers, lidar, and meteor radar, all of which are currently operating on Maui as part of the Maui-Middle Atmosphere Lower Thermosphere campaign. The study consists of a four-part approach: 1. Analyze data from multiple instruments to look for correlation between bores and thermal inversion layers or wind shears; potential guiding structures for bore propagation. 2. Model airglow response using 2-D chemistry & 2-D time-dependent dynamics models to explore the airglow response to ducted gravity waves, and in turn, the geographical and vertical coupling relationships which may exist. 3. Analyze new bore events, including, inverse bores, bore trains, and crossing bores. 4. Maintain airglow database for bore analysis. By combining the analysis of experimental data with modeling and theory, the study will yield important information on the morphology and dynamics of the mesospheric bores, their effects on the background flow, and their effects on energy deposition in other regions.