Snow and blue-ice distribution patterns on the coastal Antarctic Ice Sheet

Surface patterns of alternating snow and blue-ice bands are found in the Ju tulgryta area of Dronning Maud Land, Antarctica. The snow-accumulation regi ons exist in the lee of blue-ice topographic ridges aligned perpendicular t o winter winds. The snow bands are c. 500-2000 m wide and up to several kil ometres long. In Jutulgryta, these features cover c. 5000 km(2). These alte rnating snow and blue-ice bands are simulated using a snow transport and re distribution model, SnowTran-3D, that is driven with a winter cycle of obse rved daily screen-height air temperature, humidity, and wind speed and dire ction. The snow-transport model is coupled to a wind model that simulates w ind flow over the relatively complex topography. Model results indicate tha t winter winds interact with the ice topographic features to produce altern ating surface patterns of snow accumulation and erosion. In addition, model sensitivity simulations suggest that subtle topographic variations, on the order of 5 m elevation change over a horizontal distance of 1 to 1.5 km, c an lead to snow-accumulation variations that differ by a factor of six. Thi s result is expected to have important consequences regarding the choice of sites for ice-coring efforts in Antarctica and elsewhere.