A Comparison of Sea Ice Dynamics Models at High Resolution

Abstract

An elastic-viscous-plastic (EVP) model for sea ice dynamics has recently been proposed as a computationally efficient alternative to the viscous-plastic (VP) model widely in use. The EVP model features a fully explicit discretization that improves the model?s efficiency, particularly on high-resolution grids, and adapts easily to parallel computation. Comparison of two high-resolution Arctic sea ice simulations, identical except for the ice dynamics, indicates that the EVP model reproduces the VP model behavior on timescales relevant to climate studies. The ice concentration and thickness distributions over a 1-yr integration period are remarkably similar in the two models, although the EVP model responds more rapidly and accurately to strong synoptic weather systems than does the VP model, compared to drifting Arctic buoys. A close look at rates of strain shows that elastic waves in the EVP model do not significantly alter the ice behavior in highly compact areas, where the waves most benefit numerical efficiency. Internal stress of the ice is also similar in the two models; both deviate from viscoplasticity in regions of nearly rigid ice and in regions of low concentration undergoing approximately free drift motion.