In situ measurements and analysis of ocean waves in the Antarctic marginal ice zone

In situ measurements of ocean surface wave spectra evolution in the Antarctic marginal ice zone are described. Analysis of the measurements shows significant wave heights and peak periods do not vary appreciably in approximately the first 80 km of the ice-covered ocean. Beyond this region, significant wave heights attenuate and peak periods increase. It is shown that attenuation rates are insensitive to amplitudes for long-period waves but increase with increasing amplitude above some critical amplitude for short-period waves. Attenuation rates of the spectral components of the wavefield are calculated. It is shown that attenuation rates decrease with increasing wave period. Further, for long-period waves the decrease is shown to be proportional to the inverse of the period squared. This relationship can be used to efficiently implement wave attenuation through the marginal ice zone in ocean-scale wave models.