Influence of an Atypical Value in the Extreme Wave Analysis Using Non-Stationary GEV Models

In the present study an extreme value analysis of maximum significant waves recorded at a buoy
located in the Pacific Ocean was carried out by including/excluding an atypical extreme wave height.
The analysis was carried out using a non-stationary Generalized Extreme Value (GEV) model, which
incorporates the monthly seasonality of maximum observed values in time increments; the maximum
significant wave behavior was parameterized using harmonic functions for the distribution measures.
A single buoy was considered for the scope of this paper. In the study differences in the seasonality
effect were found due to the exclusion of the atypical value, which is especially significant because it
occurred in a season with supposedly low wave heights values.