The influence of blowing snow and precipitation on snow depth change across the Ross Ice Shelf and Ross Sea regions of Antarctica

Measuring precipitation in Antarctica from automated reporting stations is a complicated and challenging problem. Although snow depth changes can be measured with reasonable accuracy, the causes of the depth changes include not only precipitation but sublimation, compaction, and transport. The challenge is to determine the cause of snow depth change from the data available to isolate the primary contributor. This paper describes a field study undertaken between January 2005 and October 2006 in which automated snow depth instruments were deployed at seven automatic weather station locations on the Ross Ice Shelf and Ross Sea regions of Antarctica. The snow depth change measurements were then compared to wind speed and temperature data from the weather stations to determine the primary causes of the observed change. It was found that 37% of events were primarily influenced by blowing snow, 35% by drifting snow, 12% by precipitation, and 16% were unknown. Blowing and drifting snow were the primary causes of snow depth change at six sites, while the unknown category was at one site. Precipitation was never dominant. Blowing snow events were dominant during the winter and spring months, while precipitation was dominant during the summer. Accumulations overall were found to be the highest at the Windless Bight site with a two year accumulation of 1.67 m. Three sites showed snow losses of greater than 20% over the two years, while one site showed only a 2% snow loss. The sites were shown to have snow losses between 5.85 mm/year and 188.6 mm/year.