Climate variables along a traverse line in Dronning Maud Land, East Antarctica

Abstract

Temperature, density and accumulation data were obtained from sha]low firn cores, drilled during an overland traverse through a previously unknown part of Dronning Maud Land, East Antarctica. The traverse area is characterised by high mountains that obstruct the ice flow, resulting in a sudden transition from the polar plateau to the coastal region. The spatial variations of potential temperature, ncar-surface firn density and accumulation suggest that katabatic winds are active in this region. Proxy wind data derived [rom fim-density profiles confirm that annual mean wind speed is strongly related to the magnitude of the surface slope. The high elevation of the ice sheet south of the mountains makes for a dry, cold climate, in which mass loss owing to sublimation is small and erosion of snow by the wind has a potentially large impact on the surface mass balance. A simple katabatic-wind model is used to explain the variations o[ accumulation along the traverse line in terms o[ divergence/convergence of the local transport o[ drifting snow.The resulting wind-and snowdrift patterns are c1ose]yconnected to the topography of the ice sheet: ridges are especially sensitive to erosion, while ice streams and other depressions act as collectors of drifting snow.

Spatial characteristics of snow accumulation in Dronning Maud Land, Antarctica

“…The irregular topography of individual mountain peaks causes the blocking and channelling of the katabatic winds, causing local areas of erosion and deposition of snow. This is evident in the results from a katabatic wind model of surface winds in Dronning Maud Land reported by Van den Broeke et al (1999). Furthermore, Jonsson (1995) showed that the topography of the nunataks also amplifies wind strengths associated with major cyclones centred in the southeastern part of the Weddell Sea.…”

“…Probably, the general trend of decreasing accumulation rates on the plateau is related to the capacity of air to retain moisture, which decreases with decreasing temperature and thus increasing elevation (e.g., Robin, 1977). The higher parts of the polar plateau have a relatively smooth net accumulation pattern, except for the section of erosion along the eastern profile (P2) discussed in Richardson and Holmlund (1999) and Van den Broeke et al (1999). Along the western profile, the spatial variability is probably caused by wind redistribution, as it seems to be closely related to the local surface topography.…”

“…The test was carried out for 38 individual radar images. Listed firn-core accumulation rates were reported in Van den Broeke et al (1999). The accumulation rate discrepancy represents the minimum deviation in GPR-derived accumulation rate from the accumulation rate range determined by firn-core analyses.…”

Importance of aeolian processes in the origin of the north polar chasmata, Mars

“…cluding Antarctica and Greenland (Cresswell, 1988;Van Den Broeke et al, 1999;Parish and Cassano, 2000;Heinemann and Klein, 2002). Movement of a dense glacial air mass is strongly controlled by the underlying surface terrain and for larger air masses, by Coriolis forces as well.…”

Using in situ cosmogenic 10Be to identify the source of sediment leaving Greenland

“…Today the ice sheet is again retreating, increasing the extent of paraglacial landscapes. Recently, ice sheet melt has accelerated (Gordon, 1981;van den Broeke et al, 1999;Krabill et al, 2004). The summer of 2012 was the warmest in recent history setting records for total melt, melt surface extent, and melt season duration (Tedesco et al, 2012).…”