The statistics of wave height and crest elevation during the December 2012 storm in the North Sea

Abstract

This paper concerns new field measurements of wave height and crest elevation probability distributions as measured in the North Sea during a storm in December 2012. The water surface elevation was recorded by Saab WaveRadar REX instruments mounted on eight fixed-jacket platforms in addition to a Datawell Directional Waverider buoy. The storm generated an easterly sea state which peaked well in excess of the 100-year wave height for that direction in the region. Furthermore, 19 freak waves occurred during the storm according to the definition as reported by Haver (2000). The present study demonstrates that the significant steepness and spectral bandwidth during the storm remain almost constant. Consequently, there is little change in the commonly applied design wave height and crest elevation probability distributions throughout the storm. Whilst the bulk of the recorded data was in good agreement with the theoretical distributions, it was demonstrated that when the wind speed was larger than 25 m/s, the measured crest elevation lies above the second-order Forristall distribution.