Viscous-Plastic sea-ice solutions with Elastic-Viscous-Plastic sea-ice solvers

Most dynamic sea ice models for climate type simulations are based on the viscous-plastic (VP) rheology. The resulting stiff system of partial differential equations for ice velocity is either solved implicitly at great computational cost, or explicitly with added pseudo-elasticity (elastic- viscous-plastic, EVP). The more popular, because apparently faster EVP scheme has been found to create noisy solutions that do not converge to the VP rheology. A slight modification re- interprets EVP as a pseudotime VP solver and thus salvages the convergence to VP. In addition, the modification regularizes the EVP solutions so that they can be used in climate simulations at relatively low cost compared to efficient implicit methods. We present comparisons of two variants of the new EVP scheme with converged VP solution in Arctic. At coarse resolution (grid cell width of about 27km), the EVP solutions are very similar to the VP solutions. At higher resolution (4.5km), convergence of all schemes is more difficult to achieve and the solutions are obviously different