High Latitude Coupled Sea-Ice-Air Thermodynamics
Abstract
Presently ice extent forecast models such as the U.S. Navy Polar Ice Prediction System (PIPS) neglect or treat small-scale thermodynamic processes and entrainment unrealistically. Incorporating better algorithms that include more complete physics of the mixed layer dynamics will allow for improved prediction of ice thickness and distribution, open water distribution, polynyas, and deep-water formation in the polar seas. A one-dimensional mixed layer turbulent kinetic energy (TKE) budget model based on Garwood's NPS mixed layer model for deep convection (Garwood, 1991) was written in MATLAB(trade name). The model consisted of a system of ten equations derived by vertically integrating the budgets for heat, momentum, salinity, and turbulent kinetic energy between the sea-ice-air interface and the base of the turbulent mixed layer. The NPS mixed layer model was tested using atmospheric forcing and ocean profiles collected at the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) site, where wind stress and forced convection predominates. Sensitivity studies using ocean profiles of the Greenland Sea were also conducted to address thermodynamics and ocean profiles, where surface cooling and free convection predominates. Specific findings and results include: the role of unsteadiness, the responses of feedback processes depending on the mixed layer structure, and the importance of the temporal resolution of the model forcing on both skill and sensitivity of the output. The role of unsteadiness such as heat storage within the mixed layer has a large impact on ice melting or formation. Feedback between the atmosphere and ice is responsive and depends not only on atmospheric forcing but the underlying ocean structure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2004
- Accession Number
- ADA427275
Entities
People
- William A. Swick
Organizations
- Naval Postgraduate School