On the shape and likelihood of oceanic rogue waves
|Copyright||The Author(s) 2017. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution...|
|Author(s)||Benetazzo Alvise1, Ardhuin Fabrice2, Bergamasco Filippo3, Cavaleri Luigi1, Guimaraes Pedro Veras2, 5, Schwendeman Michael4, Sclavo Mauro1, Thomson Jim4, Torsello Andrea3|
|Affiliation(s)||1 : Italian Natl Res Council ISMAR CNR, Inst Marine Sci, I-30122 Venice, Italy.
2 : Univ Brest, IFREMER, CNRS, IRD,Lab Oceanog Phys & Spatiale LOPS,IUEM, Plouzane, France.
3 : DAIS Univ Ca Foscari, Venice, Italy.
4 : Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA.
5 : Ecole Cent Nantes, LHEEA Lab, UMR6598, Nantes, France.
|Source||Scientific Reports (2045-2322) (Nature Publishing Group), 2017-08 , Vol. 7 , N. 8276 , P. 1-11|
We consider the observation and analysis of oceanic rogue waves collected within spatio-temporal (ST) records of 3D wave fields. This class of records, allowing a sea surface region to be retrieved, is appropriate for the observation of rogue waves, which come up as a random phenomenon that can occur at any time and location of the sea surface. To verify this aspect, we used three stereo wave imaging systems to gather ST records of the sea surface elevation, which were collected in different sea conditions. The wave with the ST maximum elevation (happening to be larger than the rogue threshold 1.25Hs) was then isolated within each record, along with its temporal profile. The rogue waves show similar profiles, in agreement with the theory of extreme wave groups. We analyze the rogue wave probability of occurrence, also in the context of ST extreme value distributions, and we conclude that rogue waves are more likely than previously reported; the key point is coming across them, in space as well as in time. The dependence of the rogue wave profile and likelihood on the sea state conditions is also investigated. Results may prove useful in predicting extreme wave occurrence probability and strength during oceanic storms.