Spatial and temporal variability of surface mass balance near Talos Dome, East Antarctica

Abstract

Predictions concerning Antarctica’s contribution to sea level change have been hampered by poor knowledge of surface mass balance. Snow accumulation is the most direct climate indicator and has important implications for paleoclimatic reconstruction from ice cores. Snow accumulation measurements (stake, core, snow radar) taken along a 500-km transect crossing Talos Dome (East Antarctica) have been used to assess accumulation signals and the representativeness of ice core records. Stake readings show that accumulation hiatuses can occur at sites with accumulation rates below 120 kg m 2 yr 1. Differences between cores and stakes can lead to statistical misidentification of annual layers determined from seasonal signals at sites with accumulation rates below 200 kg m 2 yr 1 because of nondetection of higher and lower values. Achieving ±10% accuracy in the reconstruction of snow accumulation from single cores requires high accumulation (750 kg m 2 yr 1). Low-accumulation sites are representative if cumulative rates computed over several years are used to reach the 750 kg m 2 yr 1 threshold. Temporal variability of accumulation over the last two centuries shows no significant increase in accumulation. Wind-driven processes are a fundamental component of surface mass balance. Spatial variations in accumulation are well correlated with surface slope changes along the wind direction and may exceed 200 kg m 2 yr 1 within 1 km. Wind-driven sublimation rates are less than 50 kg m 2 yr 1 in plateau areas and up to 260 kg m 2 yr 1 in slope areas and account for 20–75% of precipitation, whereas depositional features are negligible in surface mass balance.