Wave Evolution in Off-Ice Wind Conditions

Kurzfassung

The reduction of the sea ice coverage increases the importance of wind waves in the Arctic. Updates to the standard spectral wave models in recent years have included many aspects of wave-ice interaction. Here we use high-resolution wave parameters retrieved from TerraSAR-X images and in situ SWIFT buoy observations to evaluate the performance of WAVEWATCH III® in ice-free waters in the western Arctic over a 7-week period including the fall freeze-up. About two thirds of the analyzed data sets show a good agreement between observations and model results. In other cases, more accurate representation of the wind input fields and the ice coverage could improve the model predictions. Two data sets with larger discrepancy are discussed in more detail. In these two cases of low model skill, with off-ice wind conditions, we show that the model wind‐sea growth is too weak to match TerraSAR‐X observations, and this situation is improved only slightly by including the effects of atmospheric stability using existing methods. Application of an effective fetch parameterization, which allows for reduced wave generation within the marginal ice zone prior to the open ocean, provides the best estimation of wave growth during off-ice winds.