[Show abstract][Hide abstract] ABSTRACT: Temperature, density and accumulation data were obtained from shallow 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, near-surface firn density and accumulation suggest that katabatic winds are active in this region. Proxy wind data derived from 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 of accumulation along the traverse line in terms of divergence/convergence of the local transport of drifting snow. The resulting wind- and snowdrift patterns are closely connected 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.
Journal of Glaciology 01/1999; · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Results are described from four years of mass balance measurements near the ice margin of the Greenland ice sheet in the period 1990-1994. The profiles of the specific balance indicate that a simple linear regression between elevation and specific balance is not valid. Meteorological measurements carried out during the first two summers, enable an explanation of the observed specific balance. The gradient in the absorbed shortwave radiation just below the equilibrium-line is higher than on the lower parts of the ice sheet. This results in a stronger mass balance gradient just below the equilibrium-line than near the ice margin.
[Show abstract][Hide abstract] ABSTRACT: We present four years of mass balance measurements for a transcct in the ablation zone of the Greenland ice sheet (near Sondre Stromfjord, West Greenland). The measurements cover an altitude range of 337 to 1524 m. The mean equilibrium line-altitudc is found to be 1424 m. The largcst balance gradient is found just below the equilibrium line. This is a consequence of the albedo pattern, showing the smallest values in the middle of the ablation zone and not at the ice margin.