Computations and parameterizations of the nonlinear energy transfer in a gravity-wave spectrum. Part II: parameterizations of the nonlinear energy transfer for application in wave models.

Abstract

Four different parameterizations of the non-linear energy transfer S SUB n SUB l in a surface wave spectrum are investigated. Two parameterizations are based on a relatively small number of parameters and are useful primarily for application in parametrical or hybrid wave models. In the first parameterization, shape distortion parameters are introduced to relate the distributions S SUB n SUB l for different values of the peak enhancement parameter. The second parameterization is based on an EOF expansion of a set of S SUB n SUB l computed for a number of different spectral distributions. The remaining two parameterizations represent operator forms that contain the same number of free parameters as used to describe the wave spectrum. Such parameterizations with a matched number of input and output parameters are required for numerical stability in high resolution discrete spectral models. (from authors' abstract)