Antarctic MLT Gravity Wave Momentum Flux Observed by the Davis MST Radar

Abstract:

The MST radar at Davis Station, Antarctica, 68.6 S 78.0 E, was used to make dual coplanar beam measurements of short period (12-60 minutes) gravity wave momentum flux in the mesopause region during the southern hemisphere summer of 2014-2015. Mean zonal and meridional momentum flux estimates are eastward and southward respectively, throughout the region and season, with a bias towards both larger mean flux and number of eastward and southward propagating waves. Lognormal distributions of the absolute momentum flux attributable to individual wave events are broadly consistent with satellite and other middle atmosphere gravity wave observation and modelling techniques, with greater than 40% of the total flux being contributed by the largest 10% of wave events. Estimates of flux divergence are made during periods where sufficient density of observations exist. Ray tracing methods are employed to identify potential source regions and mechanisms to aid the development of meteorologically interactive parameterization schemes for the region.