Notes on the maximum wave height distribution

TitleNotes on the maximum wave height distribution
Publication TypeMiscellaneous
Year of Publication2015
AuthorJanssen, P
Secondary TitleTechnical Memorandum

This memo discusses a number of updates of the present freak wave warning system (Janssen & Bidlot, 2009) which will be introduced in cycle 41R1 of the IFS. The list of changes is given below and they are discussed in more detail in the remainder of this memo. They are: 1. Finite skewness effects, related to bound waves are introduced, and their impact is verified. 2. In the derivation of the maximum wave height distribution it is assumed that subsequent events are independent. In contrast, here it is assumed that subsequent wave groups are independent, rather than the individual waves. The number of independent events follows by making use of the average length of a group, which depends on the width of the spectrum. A Monte Carlo simulation for linear waves shows that the above assumption of statistical independence of wave groups is a good choice. In particular, there is a close agreement between the simulated and the theoretical maximum wave height distribution