Extreme offshore wave statistics in the North Sea : extension of the measurement time series and comparison of methodologies

The scope of the report is to describe how extreme values of wave period and wave height are derived in the new version of Golfstat, to explain how the methods differ between the two versions of Golfstat, and to highlight the motivation behind any changes that were made. The approach was to begin with the original version of Golfstat from 2004 and to make changes which were considered a possible improvement to the old methodology, with the major revision being the use of the GPD instead of the conditional Weibull distribution for the extrapolation of wave statistics. The report compares the results of both methodologies and both time series, and discusses whether the new methodology, based on GPD, is a reliable alternative for the presently applied conditional Weibull distribution for WTI