A Three-Dimensional Model of Ice Floe Breakup by Ocean Waves in the Marginal Ice Zone

Considerable evidence supports the assertion that ocean waves advancing into and within the marginal ice zone can fracture the constituent ice floes and influence floe size distribution as a result. The process of breakup undoubtedly depends on the physical properties of the sea ice, i.e. the sizes and thicknesses of ice floes present and their mechanical strength. But it is also regulated by the spectral energy content of the sea at each location, recognizing that waves reduce in amplitude as they penetrate farther into an ice field in a manner that systematically eliminates short waves but allows longer waves to travel deeper into the ice. A wave-induced breakup process is described that accounts for the horizontal two-dimensional character of the ice floes in the field. Floes are modeled as circular thin elastic plates with recoverable damping and adjusted elastic moduli caused by the brine volume gradient through the floe thickness. Simulations of random sea states propagating through large arrays of ice floes are performed, using a multiple scattering model of wave attenuation in the marginal ice zone. Estimates of the likelihood and location of floe breakup are obtained by comparing the principal strains across the surface of the floes with a failure strain. It is found that multiple scattering influences the likelihood of breakup but not its location. Results from the study will be compared and contrasted with floe size distributions and related ice conditions compiled by Holt, which are derived from multiple remote sensing data sets collected during the Sea State and Boundary Layer Physics 2015 Arctic campaign.