Seasonality of snow depth on sea ice derived from autonomous measurement

Abstract:

The snow cover on sea ice receives more and more attention in recent sea ice studies and model simulations, because its physical properties dominate many processes at the surface and inside the sea ice layer. In particular the temporal and spatial distribution of snow depth is of crucial importance for the energy and mass budgets of sea ice as well as for the interaction with the atmosphere and for the oceanic fresh-water budget. Snow depth is a crucial input parameter for sea ice thickness retrieval algorithms that are based on satellite altimetry data. Recent ice volume time series of Arctic sea ice are based on a monthly climatology, which is not able to take annual changes of the snow depth and properties into account. With a few exceptions, snow depth on sea ice is typically determined from manual measurements with very limited coverage in space and time. Hence, the need for more and more consistent observational data sets of snow depth on sea ice is frequently highlighted. Here, we present time series measurements of snow depths on Antarctic and Arctic sea ice, recorded by a novel and affordable platform. The instrument is optimized to autonomously monitor the evolution of snow depth on sea ice and will allow new insights into the seasonality of snow depth. We highlight two pairs of buoys, which drifted simultaneously through the Weddell Sea for more than one year, covering a full seasonal cycle. The data sets reveal characteristic differences within each pair (<200 km distance), between the pairs (>1000 km distance), and in comparison to Arctic time series. The results suggest the great importance of local effects and potential influences of dynamic sea ice processes on snow accumulation.