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Fabrice Ardhuin, Erick Rogers, Alexander V. Babanin, Jean-François Filipot, Rudy Magne, Aaron Roland, Andre van der Westhuysen, Pierre Queffeulou, Jean-Michel Lefevre, Lotfi Aouf, and Fabrice Collard

Abstract

New parameterizations for the spectral dissipation of wind-generated waves are proposed. The rates of dissipation have no predetermined spectral shapes and are functions of the wave spectrum and wind speed and direction, in a way consistent with observations of wave breaking and swell dissipation properties. Namely, the swell dissipation is nonlinear and proportional to the swell steepness, and dissipation due to wave breaking is nonzero only when a nondimensional spectrum exceeds the threshold at which waves are observed to start breaking. An additional source of short-wave dissipation is introduced to represent the dissipation of short waves due to longer breaking waves. A reduction of the wind-wave generation of short waves is meant to account for the momentum flux absorbed by longer waves. These parameterizations are combined and calibrated with the discrete interaction approximation for the nonlinear interactions. Parameters are adjusted to reproduce observed shapes of directional wave spectra, and the variability of spectral moments with wind speed and wave height. The wave energy balance is verified in a wide range of conditions and scales, from the global ocean to coastal settings. Wave height, peak and mean periods, and spectral data are validated using in situ and remote sensing data. Some systematic defects are still present, but, overall, the parameterizations probably yield the most accurate estimates of wave parameters to date. Perspectives for further improvement are also given.

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Jennifer A. Hanafin, Yves Quilfen, Fabrice Ardhuin, Joseph Sienkiewicz, Pierre Queffeulou, Mathias Obrebski, Bertrand Chapron, Nicolas Reul, Fabrice Collard, David Corman, Eduardo B. de Azevedo, Doug Vandemark, and Eleonore Stutzmann

In the North Atlantic, there are more than 10 extratropical storms every year with hurricane-force winds (Fig. 1). Observing the dynamics and effects of these storms is a particular challenge because in-situ observations are scarce and opportunities to apply and validate remote-sensing techniques for wind speeds above hurricane force and for phenomenal sea states are rare. We show here that a suite of data from different sources—a combination that may not be typical in forecasting environments—can give a remarkably coherent characterization of an extreme storm event and associated wave fields. In February 2011, the North Atlantic storm Quirin

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