RISK ASSESSMENT OF ENCOUNTERING KILLER WAVES IN THE BLACK SEA

Abstract

The problem of assessing the risk for a vessel to encounter a killer wave in the Black Sea is considered. Analysis of in situ wave data obtained from the platform of Marine Hydrophysical Institute in the autumn of 2009 shows that occurrence frequency of abnormally high waves (freak, rogue, or killer waves) varies considerably on the time scale of several hours. It is shown that the formation of such waves is associated with nonlinear processes in the wave field, presumably, with the development of modulational instability. Ninety percent of the total number of killer waves was observed in the swell wave system, and 70% of them propagated approximately in wind direction. We propose a scenario of the killer waves formation in the Black Sea. The scenario was confirmed by numerical reconstruction of the wind and wave fields in the Black Sea for the history of storms on Oct. 14, 2009 in Katsiveli and on Feb. 01, 2003 in Gelendzhik, using the MM5 mesoscale atmospheric model and the WAM-C4 wave model. A practical approach to assessing the risk for a vessel to encounter a killer wave in the Black Sea is presented.

Keywords

• storm seas
• killer waves
• freak waves
• rogue waves
• benjamin-feir instability
• field study in the black sea
• numerical recovery of wind and wave fields
• risk assessment for extreme maritime events