A three-dimensional model of wave attenuation in the marginal ice zone

A three-dimensional model of wave scattering by a large array of floating thin elastic plates is used to predict the rate of ocean wave attenuation in the marginal ice zone in terms of the properties of the ice cover and the incoming wavefield. This is regarded as a small step toward assimilating interactions of ocean waves with areas of sea ice into oceanic general circulation models. Numerical results confirm previous findings that attenuation is predominantly affected by wave period and by the average thickness of the ice cover. It is found that the shape and distribution of the floes and the inclusion of an Archimedean draft has little impact on the attenuation produced. The model demonstrates a linear relationship between ice cover concentration and attenuation. An additional study is conducted into the directional evolvement of the wavefield, where collimation and spreading can both occur, depending on the physical circumstances. Finally, the attenuation predicted by the new three-dimensional model is compared with an existing two-dimensional model and with two sets of experimental data, with the latter producing convincing agreement.