Extreme wind-ice interaction over Recovery Ice Stream, East Antarctica

Abstract

Surface snow accumulation over East Antarctica is an important climate indicator but a difficult parameter to constrain. Surface mass ablation dominates over persistent wind-scour zones as near-surface katabatic winds accelerate over locally steeper ice surface topography, and sublimate and redistribute snow. Here we quantify ablation rates and downwind redeposition of snow over wind-scour zones in the upper Recovery Ice Stream catchment. Airborne radio echo-soundings show a gradual ablation of ~16-18 m of firn, corresponding to ~200 years of accumulation, over these zones and ablation rates of ~54 kg m-2 a-1 (54 mm water equivalent a-1). We conclude that mass loss is dominated by sublimation and mass is transported downwind as water vapor, because snow redeposition downslope of the wind-scour zones constitutes only a small fraction (<10%) of the cumulative mass loss. Key Points Widespread wind-scour zones impact surface mass balance over Recovery Ice Stream catchment Radiostratigraphy shows gradual ablation of ~200 years of accumulation in East Antarctica The mass loss over the wind-scour zones is mostly by sublimation with little redeposition