Past rates of accumulation in central West Antarctica

The spatial variation in ice accumulation is critical to the form and stability of ice sheets. In West Antarctica, knowledge of present ice accumulation rates is restricted to sparse measurements and interpolations across data free regions, while information on former ice accumulation is restricted to a small number of ice cores and numerical modeling results. Here, isochronous internal ice sheet layers, recorded by airborne radio-echo sounding and dated at their stratigraphic position at the Byrd ice core site, are used to reconstruct the spatial pattern of accumulation across the main West Antarctic ice divide for the past 16,000 years. Mean accumulation calculated for the last 3100 years matches well to present-day accumulation rates, which is compatible with previous observations on Siple Dome. Accumulation between 6400 and 16,000 years ago is calculated to be around half that at present, in accordance with recent ice sheet modeling results.