Abstract of the workshop project\r\nSnow depth on sea ice is an Essential Climate Variable, because it dominates the energy and \r\nmomentum exchanges across the atmosphere-ice-ocean interfaces and actively contributes to \r\nsea ice mass balance. Yet, snow depth is one of the least known and most difficult to observe \r\nparameters of the Arctic and Antarctic sea ice cover, mainly due to its exceptionally high spatial \r\nand temporal variability and the lack of suitable remote sensing retrieval concepts. This is \r\nparticularly true for Antarctic sea ice, as it exhibits a comparably high year-around snow load to \r\nice thickness ratio, resulting in a strong impact of the sea ice freeboard causing high \r\nuncertainties in Antarctic sea ice thickness retrievals.\r\nThe workshop on “Snow depth on Antarctic sea ice: A big unknown” aims therefore to outline\r\nand propose a processing chain to derive snow depth on Antarctic sea ice from a variety of \r\nremotely-sensed observations. Evaluating existing and new (forthcoming) data products of snow \r\ndepth with comprehensive in-situ snow depth data will allow to propose commonly used snow \r\ndepth climatology. \r\nJoint discussions and scientific analysis of such a snow depth dataset within a group of experts \r\nof satellite-data interpretation, field data provider as well as numerical modelers, are expected \r\nto result in the review of current ocean-ice-atmosphere process analyses, which is in turn likely \r\nto lead to greatly improved numerical parameterizations in sea ice and climate models.