A new, high-resolution surface mass balance map of Antarctica (1979-2010) based on regional atmospheric climate modeling

摘要

A new, high resolution (27 km) surface mass balance (SMB) map of the Antarctic ice sheet is presented, based on output of a regional atmospheric climate model that includes snowdrift physics and is forced by the most recent reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), ERA-Interim (1979-2010). The SMB map confirms high accumulation zones in the western Antarctic Peninsula (>1500 mm y ~(-1)) and coastal West Antarctica (>1000 mm y ~(-1)), and shows low SMB values in large parts of the interior ice sheet (<25 mm y ~(-1)). The location and extent of ablation areas are modeled realistically. The modeled SMB is in good agreement with ±750 in-situ SMB measurements (R = 0.88), without a need for post-calibration. The average ice sheet-integrated SMB (including ice shelves) is estimated at 2418 ± 181 Gt y ~(-1). Snowfall shows modest interannual variability (σ = 114 Gt y ~(-1)), but a pronounced seasonal cycle (σ = 30 Gt mo ~(-1)), with a winter maximum. The main ablation process is drifting snow sublimation, which also peaks in winter but with little interannual variability (σ = 9 Gt y ~(-1)).