The origin of present-day Antarctic precipitation from surface snow deuterium excess data

Abstract

The deuterium excess (d) is defined as a linear combination of the D/H and 18O/16O ratios in natural waters. We present an interpretation of deuterium excess data in surface Antarctic snow, using an isotopic model to derive information on the origin of present-day Antarctic precipitation. The data come from near the coast and from inland. We use the seasonal phase of d versus δ, which is less sensitive to the saturation conditions, as an independent validation of the model predictions. Both inland and near the coast, our model can simulate the observed phase between d and δ in snow with moisture of subtropical origin (40°-20°S). -from Authors