Modeling Wave-Induced Sea Ice Breakup Reveals a Transition in Floe Size Distribution

With wave heights projected to increase in the Arctic and Southern Oceans, understanding wave–sea ice interactions is increasingly important for sea ice projections. Wave-induced sea ice breakup affects floe size distributions (FSDs) and lateral melting, yet large-scale sea ice models rely on poorly constrained wave-attenuation and post-breakup FSD parameterizations. We develop a GPU-accelerated, three-dimensional coupled wave–sea ice model that resolves wave propagation and attenuation, ice flexure and fracture, and floefloe collisions. Under monochromatic wave forcing, the resulting FSDs exhibit a preferential floe size that decreases with increasing wave amplitude. Combining our eight simulations with twenty published experimental, numerical, and observational cases, we identify a transition in mean post-breakup floe size from approximately half the incident wavelength to one-eighth of the ice flexural wavelength as wave forcing increases. We propose a parameterization of this transition for large-scale coupled wave–sea ice models.