A generalized approach for long-term modelling of extreme crest-to-trough wave heights

This paper deals with the long-term modelling of high sea waves. The solution is given for the return period of sea storms during which an arbitrary chosen number of waves, with crest-to-trough heights exceeding a fixed threshold, occur. This return period is derived starting from the Equivalent Triangular Storm (ETS) model, which associates a triangle to each actual storm and thus represents a significant wave height time series at a fixed location by means of a sequence of triangular storms, The short-term statistics is then applied to investigate the occurrence of large crest-to-trough wave heights during a given storm. Finally, by combining the statistical distribution of significant wave heights, the ETS model anti the short-term wave statistics, the solution is given for the return periods R(N) and R(N) of a sea storm in which N or at least N waves higher than a fixed threshold occur. The Values of RN are then calculated, starting from data of two buoys moored in the Pacific Ocean and in the Mediterranean Sea. (C) 2008 Elsevier Ltd. All rights reserved.