9703539 Skyllingstad This research project is a key component of a large, coordinated, multi-investigator program called SHEBA (Surface Heat Budget of the Arctic) Ocean. The SHEBA program will simultaneously measure, over an annual cycle, the various fluxes and properties of the atmosphere, ice pack, and upper ocean that determine the aggregate mass and energy budgets of Arctic sea ice. Its goal is improved understanding of how and to what extent, the ice covered Arctic Ocean affects climate variability in lower latitudes and in global climate models (GCMs). Towards that goal, two potentially important radiation/climate feedback processes have been singled out for study: Ice-Albedo Feedback and Cloud-Radiation Feedback. This project represents a process modeling effort to examine the detailed turbulent structure of the upper ocean under pack ice and leads. The work augments the field work of the SHEBA program by providing a method for interpreting and analyzing data taken in leads and under the ice pack. Results from this study will help clarify how turbulence and sea ice interact in the polar oceans, and will aid in the construction of physically-based parameterizations of the ice covered mixed layer. A thermodynamic model of sea ice will be coupled to an existing three-dimensional ocean large-eddy simulation model that resolves a significant portion of the turbulent eddy scales in the mixed layer. The project has three main objectives: 1) to determine the temporal and spatial scales of turbulent eddies beneath ice and leads, 2) to examine the relationship between ocean mixed layer turbulence and sea ice formation and decay, and 3) to quantify the role that the mixed layer has as a heat reservoir for the Arctic Ocean. By combining the results of the modeling experiments with observations from SHEBA, the study will help establish a strong physical understanding of upper ocean sea ice processes in the Arctic that can be used to develop and test improved parameterizations.
