Modeling and Observations of Wave Energy Attenuation in Fields of Colliding Ice Floes

Abstract

Interactions between sea ice and waves in the marginal ice zone (MIZ) have attracted much attention in the last years. However, many important aspects of those interactions remain poorly understood. This paper summarizes recent results by the authors related to the role of floe collisions in shaping sea ice dynamics and wave energy attenuation in the MIZ. The analysis is based on simulations with a discrete-element sea ice model coupled to a wave energy transport model, as well as on laboratory observations of wave attenuation in broken sea ice. We analyze collision patterns for different floe size/wave forcing combinations and their phase-averaged effects. Combined processes of floe collisions and ice–water drag are shown to lead to floe-size-dependent wave energy attenuation rates. Importantly, we demonstrate that several different combinations of model parameters satisfactorily reproduce the observed variability of attenuation rates, underlining the need for more observations covering multiple processes that would allow to constrain those parameters.