Estimating the Blowing Snow Component of Antarctic Precipitation

Antarctica is a continent of many meteorological unknowns, the most significant of which is the temporal and spatial distribution of precipitation. Traditional methods of quantifying precipitation, such as estimates from microwave sounders, snow gauges, or radar are not feasible or not available in Antarctica at the present time. Consequently, the amount of accumulation at a given site, whether by blowing snow or falling precipitation, remains largely unknown. Acoustic depth gauges (ADG) provide the only concrete real-time information for accumulation in Antarctica.

Ultimately the ability to determine precipitation from ADGs depends on estimating the component of accumulation due to blowing snow. These estimates must involve the numerical simulation of lofting of snow by wind and its displacement over time. We envision this can be accomplished by a mesoscale weather model that directly assimilates depth changes from both precipitation and blowing snow and minimizes the error between ADG observations and its own prediction. The first step in developing such an assimilation model is to create a verifiable model of blowing snow displacement. This, in turn, will require observational case studies where blowing snow observations are taken and used to evaluate model performance. We will describe a campaign to attain such observations and our initial attempts to represent these observations with model simulations of blowing snow using the University of Wisconsin-Nonhydrostatic Modeling System (UW-NMS). New efforts to directly measure the blowing snow component of Antarctic accumulation by merging models with ground-based measurements are presented.