Intellectual Merit: The PI's propose to investigate the impact of projected future changes in Arctic sea ice (extent, concentration and thickness) and snow cover (extent and depth) upon the global atmospheric circulation, the oceans, and surface climate using the new high-resolution (T85) version of the NCAR Community Climate System Model Version 3 (CCSM3). Their first step will be to investigate the linkages among the atmosphere, ocean, sea ice and snow cover in the 500 year control integration of CCSM3 under present-day greenhouse gas concentrations and in the multi-member ensemble of historical 20th century integrations of CCSM3. These linkages will then be compared to those occurring in the multi-member ensemble of 21st century IPCC integrations of CCSM3 under various greenhouse gas concentration scenarios (e.g., SRES A1B). To isolate the global atmospheric circulation response to projected future changes in Arctic sea ice and snow cover, the PI's shall prescribe (individually and in combination) the changes in Arctic snow extent and thickness, and sea ice concentration and thickness, during 2080-2100 (obtained from the CCSM3 21st century IPCC integrations) relative to the late 20th century as lower boundary conditions to the Community Atmospheric Model Version 3 (CAM3), the atmospheric model component of CCSM3. They will also investigate the coupled ocean-atmosphere response to the sea ice and snow cover changes by means of experiments with CAM3 coupled to the Parallel Ocean Program (POP), the oceanic model component of CCSM3. The proposed work will further understanding of the interactions among Arctic sea ice and snow cover, the global atmospheric circulation, and the oceans under present and future climates. Broader impacts: The proposed research will benefit society by furthering understanding of how current and projected future declines in Arctic sea ice and snow cover will impact the global atmospheric circulation, with attendant impacts on surface climate, and the oceans. The PI's will engage in synergistic collaboration with other ARCSS and NSF supported researchers. The proposal will support a postdoctoral scientist, and the results will be disseminated broadly by means of web sites, peer reviewed journal articles, and presentations at scientific meetings. The model output generated from this proposal will be delivered to the ARCSS Data Coordination Center (ADCC) at the National Snow and Ice Data Center (NSIDC) before the end of the project and will also be made available to the scientific community via the NCAR CCSM Climate Variability Working Group web page. The proposed research will broaden the participation of under-represented groups as defined by the National Science Board by involving women scientists.
