A decade (2008-2017) of water stable isotope composition of precipitation at Concordia Station, East Antarctica

Abstract

A 10-year record of oxygen and hydrogen isotopic composition of precipitation is presented here: from 2008 to 2017, 1483 daily precipitation samples were collected year-round on a raised platform at Concordia Station, East Antarctica. Weather data were retrieved from the Italian Antarctic Meteo-Climatological Observatory automatic weather station (AWS), while ERA5 was used to estimate total precipitation. The δ-temperature relationships were moderately high for daily data (r2=0.63 and 0.64 for δ18O and δ2H, respectively) and stronger using monthly data (r2=0.82 for both δ18O and δ2H), with a slope of about 0.5 ‰ °C-1 for δ18O/TAWS (3.5 ‰ °C-1 for δ2H/TAWS), which remains consistent also using annual averages. The isotopic composition of precipitation is the input signal of the snow-ice system, and this dataset will be useful to improve the interpretation of paleoclimate records and promote a better understanding of the post-depositional processes affecting the isotopic signal in ice cores. This dataset represents a benchmark for the evaluation of isotope-enabled general circulation models. Here, the ECHAM6-wiso output was compared to experimental data, showing moderately good relationships for δ18O and δ2H but not for d-excess, nonetheless marking a substantial improvement from the previous release of the model.