From snow accumulation to snow depth distributions by quantifying meteoric ice fractions in the Weddell Sea

Abstract. A year-round snow cover is a characteristic of Antarctic sea ice, which has significant implications for the energy and mass budgets of sea ice, e.g., by preventing surface melt in summer and enhancing sea ice growth through extensive snow ice formation. However, substantial observational gaps in the seasonal cycle of Antarctic sea ice and its snow cover limit the understanding of important processes in the ice-covered Southern Ocean. They also introduce large uncertainties in satellite remote sensing applications and climate studies.

Here we present results from 10 years of autonomous snow observations from Snow Buoys in the Weddell Sea. To distinguish between actual snow depth and potential snow ice thickness within the accumulated snowpack, a one-dimensional thermodynamic sea ice model is applied along the drift trajectories of the buoys. The results show that for 44 % of the analyzed Snow Buoy tracks snow ice formation with an average thickness of 35 cm was detected, which corresponds to about one quarter of the snow accumulation. In addition, we simulate the snow accumulation with the more complex SNOWPACK model, which results in superimposed ice thicknesses between 2 and 9 cm. These estimates will provide an important reference dataset for both snow depth and meteoric ice rates in the Southern Ocean.