Calculating the return value using a mathematical model of significant wave height

This study presents a new method for calculating return values. The essence of the method is that it utilizes nonstationary data to calculate the return value for a region in the Northeast Pacific. The nonstationary data was obtained from a model which was previously developed for the behavior of the significant wave height as a function of time in the region. The method is illustrated by convolving two generalized Pareto distribution functions fitted to two parts of the model, computing a suitable extreme value from the new distribution function, and calculating the return value using this extreme value.