Snowdrift Sublimation in a Katabatic Wind Region of the Antarctic Ice Sheet

Abstract

This paper presents snowdrift sublimation rates evaluated from meteorological and snowdrift data observed over Antarctic snow surfaces during austral summer. Snowdrift sublimation is found to be the major contributor to the total surface?atmosphere moisture flux in strong winds (equivalent latent heat fluxes up to 250 W m?2), during which surface sublimation becomes negligible because of formation of a near-surface saturated layer. Both surface and snowdrift sublimation interact strongly with the surface moisture budget of the near-surface atmospheric layer. The sum of surface and snowdrift sublimation rates compares reasonably well with the directly measured latent heat fluxes. On average, surface and snowdrift sublimation contributed about equally to the total latent heat flux of 13.1 W m?2 at one site, whereas snowdrift sublimation was estimated to contribute two-thirds of the total sublimation at three other sites. Spatial variations in snowdrift sublimation depend on differences in wind speed, temperature, and humidity in a complex manner. For instance, the highest and windiest location, with the largest snowdrift transport rates, experienced the lowest sublimation rates because of low ambient temperatures.