Abstract
A record of accumulation and ablation from a network of 47 stakes at a coastal blue-ice area in Terre Adélie, Antarctica, is presented and analyzed. The record covers early 2004 to early 2006, from 25 field surveys including some in austral winter. The two years are very different, with a virtually null surface mass balance during the 2004 winter but large accumulation during the 2005 winter. A snow/ice energy- and mass-balance model is used to reproduce the accumulation and ablation record. A parameterization for snow erosion by wind is included. Input meteorology is from the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses and forecasts, corrected using 1 year of local meteorological observations from an automatic weather station. Model results agree reasonably well with the observations. Wind erosion is the largest contributor to ablation, removing much of the precipitation. Sublimation and, to a lesser extent, melt/runoff together account for >60 cm w.e. of ablation in 2 years, mainly in summer. Although the record is short, it confirms high interannual variability and thus high sensitivity to meteorology and climate. Monitoring and understanding the mass balance of such coastal blue-ice areas may help monitor and detect climate change in the Antarctic coastal regions.
Highlights
Snow accumulates at the surface of most of the Antarctic ice sheet, at a mean rate of $15 cm a–1 w.e
Input meteorology is from the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses and forecasts, corrected using 1 year of local meteorological observations from an automatic weather station
The main point here is that, in order to use an accumulation and ablation model to evaluate the components of the relative surface elevation change at the Cap Prudhomme blue-ice areas (BIAs) and understand the reasons for annual and interannual variability, it is necessary to account for wind erosion in a way that removes surface snow at a rate compatible with observations
Summary
Snow accumulates at the surface of most of the Antarctic ice sheet, at a mean rate of $15 cm a–1 w.e. The net annual mean surface mass balance is negative over a small fraction of the Antarctic surface (Van den Broeke and others, 2006) even though, because of compensating ice flow, the mean surface elevation does not change correspondingly In such areas, ice is exposed at the surface for at least part of the year. BIAs can be found at relatively high elevation (up to 2500 m) on the Antarctic ice sheet as a result of orographic features that favor warm, dry and windy conditions (katabatic flow, fohn effect) Such BIAs have been the subject of several studies (Jonssohn, 1990; Takahashi and others, 1992; Bintanja and Reijmer, 2001; Sinisalo and others, 2003) to analyze the meteorological components responsible for net ablation. The various components of accumulation and ablation estimated from the model are presented, compared and discussed
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