The statistical properties of individual wave heights and wave crests from time series of recorded surface elevation are analyzed with a particular focus on the occurrence of extreme and rogue waves in the datasets. The datasets include surface elevation measurements from three different sensors: a wave buoy, a wave laser and a Saab wave radar — all situated at the Ekofisk field in the North-Sea and providing sea surface elevation measurements at 2Hz temporal resolution.
The resulting statistical properties of wave heights and wave crests are compared with common reference statistical distributions such as Rayleigh, Tayfun (1980) and Forristall (1978, 2000) distributions for wave heights and crest heights. In particular, the occurrence of rogue waves (H > 2.2Hs or C > 1.25Hs) in the datasets is investigated. Possible relations between the occurrence of rogue waves and spectral characteristics of the corresponding sea states are briefly discussed.