Viscous–Plastic Sea Ice Dynamics with the EVP Model: Linearization Issues

Behavior of the elastic–viscous–plastic (EVP) model for sea ice dynamics is explored, with particular attention to a necessary numerical linearization of the internal ice stress term in the momentum equation. Improvements to both the mathematical and numerical formulations of the model have moderated the impact of linearizing the stress term; simulations with the original EVP formulation and the improved version are used to explain the consequences of using different numerical approaches. In particular, we discuss the model behavior in two regimes, low ice concentration such as occurs in the marginal ice zone, and very high ice concentration, where the ice is nearly rigid. Most of these results are highly relevant to the viscous–plastic (VP) ice dynamics model on which the EVP model is based. We provide examples of certain pathologies that the VP model and its numerical formulations exhibit at steady state.