Modelling wave-induced sea ice break-up in the marginal ice zone

• Published in: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
• Main Authors: Montiel, F., Squire, V. A.
• Other Authors: Office of Naval Research, Seventh Framework Programme
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2017
• Subjects: Sea ice
• Online Access: http://dx.doi.org/10.1098/rspa.2017.0258; https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2017.0258; https://royalsocietypublishing.org/doi/full-xml/10.1098/rspa.2017.0258

A model of ice floe break-up under ocean wave forcing in the marginal ice zone (MIZ) is proposed to investigate how floe size distribution (FSD) evolves under repeated wave break-up events. A three-dimensional linear model of ocean wave scattering by a finite array of compliant circular ice floes is coupled to a flexural failure model, which breaks a floe into two floes provided the two-dimensional stress field satisfies a break-up criterion. A closed-feedback loop algorithm is devised, which (i) solves the wave-scattering problem for a given FSD under time-harmonic plane wave forcing, (ii) computes the stress field in all the floes, (iii) fractures the floes satisfying the break-up criterion, and (iv) generates an updated FSD, initializing the geometry for the next iteration of the loop. The FSD after 50 break-up events is unimodal and near normal, or bimodal, suggesting waves alone do not govern the power law observed in some field studies. Multiple scattering is found to enhance break-up for long waves and thin ice, but to reduce break-up for short waves and thick ice. A break-up front marches forward in the latter regime, as wave-induced fracture weakens the ice cover, allowing waves to travel deeper into the MIZ.