Development of an improved dynamic-thermodynamic sea ice thickness distribution model.

摘要

One of the major challenges in climate modeling is development and implementation into general circulation models of a sea ice model that accurately predicts sea ice mass balance, ice extent, interfacial fluxes, and the associated feedbacks with the atmosphere and ocean. Initially, general circulation models contained simple parameterizations of sea ice thermodynamic and dynamic processes. The development of sophisticated stand-alone ice dynamic models facilitated improvement in the treatment of ice dynamics in GCMs. However, while there has been substantial progress in the development of single-column thermodynamic sea ice models, little work has been done to unify sophisticated thermodynamics and dynamics into a single model.; Towards this end, a new sea ice model is described which incorporates the sophisticated thermodynamics of a single-column sea ice model developed at the University of Colorado into an existing basin-scale dynamic-thermodynamic model. Using a viscous-plastic ice dynamic model and an ice strength parameterization which accounts for the distribution of sea ice thicknesses, the model resolves a domain covering the Arctic Ocean and much of its surrounding seas. Beneath the ice at each grid cell is an interactive ocean mixed layer. A preliminary comparison of baseline characteristics of the model---ice thickness distribution, surface temperature, surface albedo, ocean mixed layer salinity, and ocean mixed layer temperature---with observations indicates the new model performs reasonably well.; The new model includes more sophisticated parameterizations of physical processes than previous basin-scale sea ice models. These features, such as an ice thickness distribution, an interactive ocean mixed layer model, explicit treatment of surface melt ponds, spectrally calculated surface albedo, and explicit sea ice ridging and redistribution, have been identified as key processes for correct modeling of sea ice in climate models. With these improved thermodynamics, the basin-scale model can provide more accurate representation of both present-day and climate change scenarios. Moreover, efforts will be made to streamline and modularize the numerics of the model, making it computationally efficient and desirable for inclusion in a coupled atmosphere-ice-ocean climate model.