C22A-03:
Snow distribution on Antarctic sea ice: precipitation, accumulation, and connections to sea ice thickness from in situ and NASA IceBridge observations.
Tuesday, 16 December 2014: 10:50 AM
Ted L Maksym1, Clay Kunz1, Ron Kwok2, Katherine Colby Leonard3,4, Hanumant Singh1, Ernesto Trujillo4, Guy Darvall Williams5, Seth White3 and Nander Wever6, (1)WHOI, Woods Hole, MA, United States, (2)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (3)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (4)EPFL Swiss Federal Institute of Technology Lausanne, Lausanne, Switzerland, (5)ACE CRC, University of Tasmania, Hobart, Australia, (6)WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland
Abstract:
Snow plays a dominant role in Antarctic sea ice mass balance and its seasonal evolution. It is a primary control on sea ice thickness and the structure of sea ice ecosystems, it dominates the uncertainty in satellite estimates of ice thickness, and it may significantly modulate the response of sea ice to climate change and variability. Here, we provide an overview of recent surveys of snow distribution (both small and large scale), its temporal evolution, and its connection with the processes that drive it – precipitation, accumulation, blowing snow events, flooding, and the role of ice deformation. We present recent 3-D in situ floe-scale measurements of snow surface topography, snow depth, and ice thickness distribution that allow relationships between surface roughness features, snow accumulation, and ice thickness to be examined in unprecedented detail. These data are compared with estimates of snow depth from the NASA IceBridge radar from spring surveys in the Weddell and Amundsen/Bellingshausen Seas. Both airborne and in situ measurements suggest a significant extent of thick ice with a deep snow cover that is underrepresented in prior surveys. Finally, the seasonal evolution of precipitation, snow depth, and accumulation is examined with data from drifting buoy platforms deployed in several regions of the Antarctic. These observations show that precipitation is not necessarily a good estimator for snow accumulation and that treatment of blowing snow must be included for sea ice models to accurately simulate Antarctic snow and sea ice mass balance. The implications of these results for modeling and satellite measurement of the sea ice thickness distribution are discussed.
