Simulating landfast sea ice breakage due to ocean eddies using a discrete element model

Abstract. Marginal ice zones are influenced by energetic oceanic motions over a range of scales, including forcing due to surface waves and (sub-)mesoscale eddies. While the role of waves in breaking sea ice has been well recognized, the influence of ocean eddies in the fracturing process remains less explored. This work considers simulations of a landfast sea ice pack represented by a bonded Discrete Element Model (LS-DEM-BPM) and forced by eddying ocean currents generated by a quasi-geostrophic model. These experiments reveal that ocean eddies can generate realistic fracture patterns and floe size distributions (FSDs). For the same amount of eddy kinetic energy, ocean currents with a larger characteristic eddy size penetrate deeper into the pack and fracture more floes. This creates floe distributions with a slightly higher FSD slope as compared to forcing by smaller eddy length scales. On the other hand, stronger bonds between the DEM elements lead to less breakage and a notably shallower FSD. These results are qualitatively consistent with an analytical model of the fracturing process, which provides an upper limit to the expected breakage area. These insights may help formulate more comprehensive parameterizations of breakage within coarse and continuum-based sea ice models.