A comparison of extreme wave analysis methods with 1994–2010 offshore Perth dataset

This study took the hourly wave height records collected 10 km southwest of Rottnest Island, offshore of Perth, Western Australia, from 1994 to 2010 as a testing ground and compared the results obtained by the Goda method commonly used in costal engineering community, the generalised extreme value (GEV) and generalised Pareto distribution (GPD) methods which are currently the standard practice in mainstream extreme statistics. The results highlight the merits and limitations associated with those methods and formulas. It is recommended that the coastal engineering community should embrace the GPD distribution as one of the credible candidates due to its merits in the threshold selection techniques and the nature of the distribution. The conventional distributions recommended by Goda could be the other candidates provided a properly selected threshold value. The final selection of the distributions should be made based on the goodness-of-fit test demonstrated in this study. Finally the extreme wave heights for offshore Perth are recommended based on 1994 to 2010 dataset.

► Three widely used extreme wave analysis methods have been compared.
► The selection of the wave threshold value is crucial for the quality of extreme wave analysis.
► For this Perth offshore dataset the GPD distribution is recommended based on the favourable goodness-of-fit test results.