A multi-category sea-ice model

The framework for a multi-category sea-ice model is presented. The ice model describes the ice thickness distribution by using a set of delta-functions, where each delta-function has an associated fractional coverage and ice thickness. The formulation of ice ridging and rafting is given. The thermodynamic formulation is also given, with emphasis on how the model treats the heat conduction in the ice. The formulation is extended by introducing the concept of ice classes. The ice classes are constraints put on the description of the ice thickness distribution, whose purpose is to give a practical formulation of the ice thickness distribution. A demonstration of the ice model performance is given, where the model is coupled to the HYCOM ocean model and the EVP sea-ice rheology. It is shown how the ice model is able to reproduce the main features of the Arctic ice cover as well as the transport of sea ice out of the Fram Strait.