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Freak Waves in the Ocean

Efim Pelinovsky

Institute of Applied Physics, N. Novgorod, Russia, pelinovsky@hydro.appl.sci-nnov.ru

Rogue wave events have been reported in many physical areas, e.g. geophysics, nonlinear optics, astrophysical plasma and even the financial market. They are extraordinary accidents of wave dynamics leading to transient occurrence of abnormally strong waves. The interest in these phenomena was in a great deal spawned due to the recent progress in the study of rogue or freak waves in the Ocean. Seamen are known to be unsurpassed authors of exciting and horrifying stories about the sea and sea waves. This could explain why the sailors’ observations of “walls of water” have been considered fictitious for a while. Now these stories are addressed to again due to the certain number of doubtless proofs of the existence of the phenomenon, but still insufficient information to enable the concerned researchers and engineers to understand it. Until now the largest reliable instrumentally measured waves have heights of 30 m; in particular, such waves were registered during the “Halloween Storm” in 1991 and Hurricane Luis in 1995. Waves with heights a little bit more than 29 m were measured under severe but not exceptional wind conditions in 2000 by a British oceanographic research vessel near Rockall, west of Scotland. The rogue waves are among waves naturally observed by people on the sea surface that represent inseparable feature of the Ocean. Rogue waves appear from nowhere, cause danger and disappear at once. They may occur on the surface of a relatively calm sea, reach not very high amplitudes, but be fatal for ships and crew due to their unexpectedness and abnormal features. The billows appear suddenly exceeding the surrounding waves twice and more, and have obtained many names: abnormal, exceptional, extreme, giant, huge, sudden, episodic, freak, monster, rogue, vicious, killer, mad- or rabid-dog waves; cape rollers, holes in the sea, walls of water, three sisters… Freak monsters, though living for seconds, were able to arouse superstitious fear of the crew, cause damage, death of heedless sailors or the whole ship. The serious studies of the phenomenon started about 20–30 years ago and have been intensified during the recent decade. The research is being conducted in different fields: in physics (search of physical mechanisms and adequate models of wave enhancement and statistics), in geoscience (determining the regions and weather conditions when rogue waves are most probable), and in ocean and coastal engineering (estimations of the wave loads on fixed and drifting floating structures). Thus, scientists and engineers specializing in different subject areas are involved in the solution to the problem. Freak waves annually become the subject of special session at the European Geophysical Union Assembly (2001-2010); Ifremer (France) organized three “Rogue Waves” workshops in Brest (2000, 2004, 2008). The ‘Aha Huliko’a Hawaiian Winter Workshop in 2005 and a workshop held the same year by the International Centre for Mathematical Sciences (Edinburgh) were also dedicated to this phenomenon. The state-of-art of the rogue wave study is summarized in book [1] and presented on seminar, supplemented by the most recent results of the on-going research.

References
1.C. Kharif, E. Pelinovsky, and A. Slunyaev, Rogue Waves in the Ocean, Springer, Berlin, 2009.