Satellite Analyses of Antarctic Katabatic Wind Behavior

Abstract

Prominent warm signatures of strong, negatively buoyant, katabatic airstreams are present at thermal infrared wavelengths as a result of intense vertical mixing and drift-snow transport within stable boundary layers. These tracers are used to illustrate several aspects of the behavior of katabatic winds in the Ross Sea sector of the Antarctic. The satellite features are compared with surface-based observations whenever possible. Converging surface-wind signatures upslope from Terra Nova Bay are shown to closely follow the observed time-averaged streamlines of drainage airflow. The satellite-observed core of the katabatic airstream descends to sea level via a direct route, but complex three-dimensional trajectories are manifested in marginal regions. Katabatic winds propagating horizontally for hundreds of kilometers over the southwestern Ross Sea do not exhibit the expected influence of the Coriolis force. Katabatic signatures are shown to be climatological features over the Ross Ice Shelf which closely follow surface wind measurements. An approximate proportionality appears to exist between average signature size over the shelf and the magnitude of katabatic mass transport from the plateau.