Wave-Ice Interactions in the Marginal Ice Zone

WAVEWATCHIII (WW3) ocean wave is the 3rd generation operational state-of-the-art forecast model for many operational marine forecast offices, internationally. In this study, WW3 is adapted for wave scattering in the marginal ice zone (MIZ) following Masson and LeBlond (1989, JFM), Perrie and Hu (1996, JPO) and Meylan and Masson (2006, Ocean Modell.), and correcting errors in earlier formulations. Presently, no practical methodology has been developed to directly incorporate an accurate wave attenuation scattering model for the MIZ, in a model like WW3. By comparison, Squire et al. (2014) developed a phase resolved scattering model which can simulate ice floes. The theory of how to include scattering into ocean wave models was developed by Masson and LeBlond (1989), Meylan et al. (1997), and Meylan and Masson (2006); and Perrie and Hu (1996) made an implementation in an earlier 2nd generation wave model. One limitation on their method is that they used rigid floes, whereas ice floe flexure can be a dominant factor in some situations in the MIZ, for large floes, (Meylan and Squire, 1994; 1996). However, Perrie and Hu (1996) were able to predict some of the features observed in measurements such as the roll over effect and the strong dependence of wave scattering on wave period. Moreover, the change from rigid to flexural ice floes is feasible in this formulation. We update and optimize this model approach for wave-ice attenuation and scattering, with implementation in WW3. The resulting model system is validated with in situ and satellite remotely sensed MIZ data, collected during recent field experiments. These include some of: (b) a storm in the Greenland Sea in February 2012, (b) ice motion data from the MIZ off Antarctica, collected by Kohout et al. (2014, Nature) to estimate ocean wave attenuation, (c) a Sea State experiment in the Beaufort Sea during October 2015.