A dynamical model of Kara Sea land-fast ice

Abstract

This paper introduces modifications to the traditional viscous-plastic sea-ice dynamical model, which are necessary to model land-fast ice in the Kara Sea in a realistic manner. The most important modifications are an increase in the maximum viscosity from the standard value of (Formula presented.) to (Formula presented.), and to use a solver for the momentum equation capable of correctly solving for small ice velocities (the limit here is set to (Formula presented.) m/s). Given these modifications, a necessary condition for a realistic fast-ice simulation is that the yield curve give sufficient uniaxial compressive strength. This is consistent with the idea that land-fast ice in the Kara Sea forms primarily via static arching. The modified model is tested and tuned using forcing data and observations from 1997 and 1998. The results show that it is possible to model land-fast ice using this model with the modifications mentioned above. The model performs well in terms of modeled fast-ice extent, but suffers from unrealistic break-ups during the start and end of the fast-ice season. The main results are that fast ice in the Kara Sea is supported by arching of the ice, the arches footers resting on a chain of islands off shore.