Wind-packing of snow in Antarctica

Abstract. The snow surface in polar and mountainous regions is mobile and this mobility determines surface mass balance and isotopic composition before final deposition, which is poorly understood thus far. During a field campaign in Antarctica, a snowfall and subsequent drifting snow event was recorded by meteorological and snow drift stations. Associated surface topology changes and snow hardness changes were measured by terrestrial laser scanning and with a SnowMicroPen. The polar field measurements show that drifting snow is necessary for wind-packing and that the hardening is more efficient at wind-exposed surfaces than in wind-sheltered areas. Furthermore, it is quantitatively demonstrated for the first time how fresh snow gets organized in barchan dunes during subsequent drifting events with significant increases in surface hardness at all locations on the dune. These results form a crucial step in understanding how drifting snow links precipitation to deposition via snow hardening.