Vertical snow structures from local to regional scale
Snow on sea ice alters the properties of the underlying ice cover as well as associated exchange processes at the interfaces between atmosphere, sea ice, and ocean. As Antarctic snow cover persists during most of the year, it contributes significantly to the sea-ice mass budget due to comprehensive physical (seasonal) transition processes within the snowpack. It is therefore necessary to locate and quantify internal snowmelt, snow metamorphism, and snow-ice formation in the Antarctic snowpack on different spatial scales. Doing so, we present here in-situ observations of physical snow properties from point measurements and transect lines during recent expeditions in the Weddell Sea from 2013 to 2018, covering summer and winter conditions. Analysis of snow pit measurements on both small (<100m) and floe-size (<2km) scales reveal significant variations in the horizontal snowpack structure. In order to describe internal snow processes on regional scales, we grouped the observed snow conditions, differentiating for snow conditions between eastern (seasonal sea ice) and western Weddell Sea (perennial sea ice). While the thick perennial snowpack is highly metamorphous with a large number of internal layers, the seasonal snowpack is less stratified. Results of the study will improve our understanding on processes and interactions in the snowpack as well as at the snow/ice interface associated with seasonal and inter-annual variations in the sea-ice mass budget of the Southern Ocean.