Improved Parameterizations of Nonlinear Four Wave Interactions for Application In Operational Wave Prediction Models

Abstract : The long-term goal of this project is to improve spectral wave prediction models by providing an accurate and fast method for computing the nonlinear four wave interactions in deep and shallow water. Although an accurate integral description of these interactions exists for more than 27 years (Hasselmann 1962, see also Zakharov, 1998), the computation thereof is hampered by the complexity of its functional form and its computational demands. In 1985 the Discrete Interaction Approximation (Hasselmann et al., 1985) was developed which enabled the development of third generation wave prediction models. The DIA, however, has some shortcomings which hamper the further development of third generation wave prediction models, see Figure 1. These models all use the action balance equation for describing the time and space evolution of wave spectra. By providing an accurate and fast method for computing these interactions, wave evolution characteristics will improve and more attention can be given to the development of the other terms.