Spatial characteristics of snow accumulation in Dronning Maud Land, Antarctica

An accurate knowledge of spatial variations in snow accumulation on ice sheets is vital for numerical reconstructions and future projections of ice sheet dynamics, with implications for changes in global climate and sea level. This study considers net snow accumulation in Dronning Maud Land, East Antarctica. Ground-penetrating radar (GPR) soundings were carried out along two ground traverses, 800 and 1000 km long, extending from the ice shelves to the high plateau in order to map snow accumulation rates continuously along the route. Comparisons between the net accumulation rates obtained by GPR and those obtained by stake-line measurements exhibited a close correlation. Large dissimilarities in the accumulation distribution were observed between the two traverses. The ice sheet surface topography and the regional distribution of air pressure systems and cyclone tracks can explain these differences to a large extent. Spatial trends in snow accumulation rate were determined for characteristic traverse sections. The spatial variability was calculated as the standard deviation in snow accumulation rate over 5 km, expressed as percentages of the average accumulation within the 5-km section. On ice shelves, the spatial variability was less than 10%. In grounded coastal areas, it ranged between 20% and 40%, and on the high plateau, it ranged up to 20%. In areas of intense wind erosion, the spatial variability often exceeded 50%. The generally high spatial variability demonstrates that the spatial representativeness of individual point measurements is of vital importance in Antarctic snow accumulation studies. This is a problem that is presently not properly attributed.