An international team of scientists has proven that the so-called “killer waves” are not a mystical phenomenon, but the result of natural laws of the ocean. Analysis of thousands of wave records from the North Sea showed that these extremely high waves are formed due to a simple combination of several ordinary processes.
For many years, sailors told legends about suddenly appearing giant waves, but scientific confirmation of this phenomenon was only received in 1995, when a 24-meter wave covered the oil platform “Draupner”. A research team led by Francesco Fedele of the Georgia Institute of Technology analyzed 27,500 records collected over 18 years. The results disproved the popular theory of “modulation instability,” which was believed to be the main cause of such waves.
How do rogue waves form?
Instead of a complex instability, rogue waves are formed by two simple processes:
- Linear focusing: Waves with different speeds and directions coincide in time and space, superimposing each other to form one large wave.
- Nonlinear effects: A natural lengthening and stretching of the wave, making it 15 to 20 percent taller and steeper.
When these two effects coincide, a truly gigantic wave is created. “Rogue waves follow the natural laws of the ocean, rather than breaking them,” Fedele explained.
The discovery has huge implications for the safety of shipping and offshore platforms. Now that scientists understand how rogue waves are created, they can create more accurate forecasting models. Fedele and his team are already using machine learning to analyze data and predict the conditions that might cause such extreme waves.
“It’s just a bad day at sea. They’re part of the language of the ocean, and we’re finally learning to understand it,” the researcher concluded.