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A new map of snow accumulation in Dronning Maud Land based on data of shallow firn cores and snow pits

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Oerter, H. , Rotschky, G. , van den Broeke, M. , Mulvaney, R. , Holmlund, P. and Winther, J. G. (2003): A new map of snow accumulation in Dronning Maud Land based on data of shallow firn cores and snow pits , EGS-AGU-EUG Joint Assembly, Session CL11.29 European Project for Ice Coring in Antarctica (EPICA), Nice, FranceApril 2003. .
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Abstract:

The accumulation rate is one important glaciological parameter influencing growth and movement of an ice sheet. It is also needed for the interpretation of physical and chemical properties measured at ice cores. Accumulation rates show a wide spatial and temporal variability. For Dronning Maud Land (DML) an attempt was made to collect the available accumulation data and compile a map of the distribution of accumulation rates. The data at 122 locations are based on snow pit studies (covering at least 5 years) and firn cores covering from decades up to 200 years of accumulation. The oldest data had been collected during the Norwegian-British-Swedish Expedition 1949-52. However, the major part of the data were collected during the EPICA pre-site survey in DML, carried out by Alfred-Wegener Institute for Polar and Marine Research, Germany, British Antarctic Survey, the Norwegian Antarctic Research Expeditions and the Swedish Antarctic Research Programme in co-operation with Utrecht University. In addition, also the data of the US South Pole Queen Maud Land Traverse 1965-68 were included. To judge the temporal variability of the accumulation rates the data for various periods are compared with a 200-years time series of accumulation rates for the interior part of the ice sheet, calculated from 20 firn cores. For compiling the map the ArcGis 8.1 software was used. After testing several interpolation algorithms the inverse distance weighted method (IDW) was chosen. The data are interpolated with 5 km x 5 km resolution, using 20 neighbouring points. A very characteristic feature in DML are the mountain ranges from Maudheimvidda in the West to Wohlthat-Massiv in the East which separate the interior high part of the ice sheet and the lower parts, e.g. Ritscherflya, extending towards the ice shelves. To account for this barrier two domains were introduced, separated approximately by the 2000 m contour line. The plotted isolines have a distance of 50 kg m-2 a-1, the steps of 10 kg m-2 a-1 are indicated by a colour code. The map shows clearly the general trend of decreasing accumulation rates from the coastal area to the interior of the ice sheet. However, recognizable is a certain patchiness with high accumulation, e.g. on Jutulstraumen, and low accumulation areas, obviously due to wind erosion. For one selected profile line the map data and accumulation data from multi-year stake readings are compared.

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