Effects of rheology and ice thickness distribution in a dynamic-thermodynamic sea ice model

Abstract

Realistic treatment of sea ice processes in general circulation models is needed to simulate properly global climate and climate change scenarios. As new sea ice treatments become available, it is necessary to evaluate them in terms of their accuracy and computational time. Here, several dynamic ice models are compared using both a 2-category and 28-category ice thickness distribution. Simulations are conducted under normal wind forcing, as well as under increased and decreased wind speeds. It is found that the lack of a shear strength parameterization in the cavitating fluid rheology produces significantly different results in both ice thickness and ice velocity than those produced by an elliptical rheology. Furthermore, use of a 28-category ice thickness distribution amplifies differences in the responses of the various models. While the choice of dynamic model is governed by requirements of accuracy and implementation, it appears that, in terms of both parameterization of physical properties and computational time, the elliptical rheology is well-suited for inclusion in a GCM.