Abstract

The mechanical interaction between ice floes in the polar sea-ice packs plays an important role in the state and predictibility of the ice cover. Using a Lagrangian-based numerical model we investigate the mechanics of sea ice floe-floe interactions. Our simulations show that elastic and reversible deformation offers significant resistance to compression before ice floes yield with brittle failure. When pressure ridges start to form, compressional strength dramatically decreases, implying thicker sea ice is not necessarily stronger compared to thinner ice. These effects are not accounted for in current sea-ice models that describe ice strength by thickness alone. As our results show, the observed transition in mechanical state during ridging initiation may lead to biases in simulated ridge building rates and sea-ice thickness. We propose a parameterization that describes failure mechanics from fracture toughness and Coulomb sliding, improving the representation of ridge building dynamics in particle-based and continuum sea-ice models.