Abstract
We propose to make the damping time scale, which governs the decay of
pseudo-elastic waves in the Elastic Viscous Plastic (EVP) sea ice
solvers, independent of the external time step and large enough to
warrant numerical stability for a moderate number of internal time
steps. In this case, EVP becomes very close to the recently proposed
modified EVP (mEVP) method in terms of stability. With the proposed
damping time scale, the numerical stability of EVP is independent of
mesh resolution in setups where the sea ice model component is called
every time step of the ocean model. In a simple test case dealing with
sea ice breaking under the action of a moving cyclone, EVP with
specified damping time scales can produce linear kinematic features very
similar to those from the mEVP method. There is more difference in
simulated Arctic sea ice thickness and linear kinematic features in
realistic configurations, but the difference is minor considering model
uncertainties associated with parameter choices in sea ice models.