Characteristics of directional wave spectra and implications for detailed-balance wave modeling

There is an increasing need for accurate wave spectra in remote sensing applications and for accurate estimates of momentum exchanges between waves and the atmosphere and ocean in coupled modeling. Existing operational models are calibrated in a holistic context which focuses on integrated wave growth and dissipation, not on the detailed-balance exchanges required for these emerging needs. Here we propose a set of metrics, based on a number of careful observational studies, for use in future model evaluations. An overall perspective seen in the observational data is a general agreement with shapes anticipated from energy, action and momentum flux constraints produced by nonlinear wave interactions in wave spectra. Given the apparent importance of the nonlinear source term to detailed-balance model, we review the basis of the existing approximation used in existing operational models and find this form deviates significantly from the full integral representation of these interactions. It is proposed here that new observational evidence and theoretical formulations be utilized in the development of wave models specifically to meet remote sensing and coupled modeling needs.