On some uncertainties related to the short term stochastic modelling of ocean waves

A short-term model for the representation of ocean waves is considered. The model is described and the associated uncertainties are briefly reviewed. Emphasis is placed on a discussion of the validity of the basic assumptions regarding stationarity and Gaussianity, together with an elaboration on uncertainties related to the shape of the spectral density function. The basis for the present investigation is 4586 time series for the sea surface elevation, representing a rather wide range of different sea states. Conclusions presented subsequently rest to some extent on the assumption that the actual time series reproduce the true time fluctuations of the surface with a sufficient accuracy. A verification of this assumption requires a very extensive investigation, and could not be included within the scope of this work.