Interpretation of the spectral wave forecast model results using the phase-resolving model

Abstract

The paper presents an interpretation of the results of spectral wave-forecast model using the phase-resolving model. Spectral models provide the information on the evolution of the potential energy distribution in terms of angle and frequency though the information about the geometry and statistical wave characteristics in such models are not available. This information has to be extracted through the additional, often unsubstantiated, hypotheses. The proposed computational procedure transforms spectral information into a two-dimensional wave field which consists of a set of linear modes with randomly distributed phases is proposed. The wave field is not realistic since it does not have non-linear properties, for example, various asymmetry properties such as increased kurtosis. Afterwards the linear wave field reproduced on the basis of the wave spectrum is set as the initial condition for the exact phase-resolving model. The exact models formally suitable for such calculations are cumbersome and inefficient and that practically restricts their broad and regular application. This restriction can be overcome by using a new type of 3D wave simulation based on 2D equations. The 2D model reproduces the statistical characteristics of the wave field similar to the results of the 3D exact model and runs several times faster. The examples of using the developed method of interpretation of the spectral wave forecast in the Baltic Sea are demonstrated.