The rogue waves have attracted the attention of both seafarers and scientists for decades. These are huge, isolated waves that suddenly appear in the open ocean.
These inexplicable giants are short and usually take less than a minute before they disappear. They can reach heights of over 65 feet (20 meters) and reach more than twice the height of the surrounding waves. The once voyage myth is that illegitimate waves have been observed all over the world. They are very tall and powerful, which can pose danger to ship and offshore structures.
I have gathered an international team of researchers to rethink what the illicit waves are and what causes them. Our study, published in Nature Scientific Reports, uses the most comprehensive data set of this kind to shed light on these marine giants.
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By analyzing 18 years of high-frequency laser measurements from the Ecofisk Oil Platform in the North Sea, we have come to the surprising conclusion that illicit waves are not merely occurrences. They arise under the natural laws of the ocean. They are not mystical, but rather simple.
27,500 seas
We analyzed 27,500 half-hour wave records, or sea states, collected in the North Sea between 2003 and 2020. These records were taken every 30 minutes, explaining that sea level was compared to average sea level. It includes major storms, such as the 2007 Andrea Wave event.
Under normal conditions, waves arise from winds blowing over the sea. It’s like when you blow your cup of coffee off and create small ripples on the surface. In the ocean, if there is enough time and space, those ripples can turn into large waves.
We focused on understanding why waves suddenly become illegitimate and far outweigh the adjacent waves. One of the proposed theories is based on modulation instability, a phenomenon described by complex mathematical models. I have revised these models in the past, as my work suggests that this theory does not fully explain what causes injustice waves in the open ocean.
Related: The 4-storey illicit wave randomly appeared in the Pacific Ocean is the “most extreme” detected so far
Modulation instability theory explains waving movements well when waves are confined within narrow channels. However, when you see the actual ocean, it starts to fall apart. In open environments such as the North Sea, waves can propagate freely from multiple directions.
To understand the difference, imagine a crowd of spectators leaving the stadium after a soccer game. If the exit is a long, narrow corridor with tall walls, people are forced to move in one direction. The people on the back move forward, some climb onto others, stacking up between the walls trapped. This catastrophic pileup resembles the injustice waves caused by their confinement.
In contrast, when the stadium exit opens to a wide field, the audience can freely disperse in all directions. They do not push each other against each other, avoiding the stakes.
Similarly, researchers can generate rogue waves in the trapped channels of the lab, where they follow modulation instability. However, without channel confinement, rogue waves usually do not follow their physics or form in the open seas in the same way.
Our team knew we had to study the open sea in person to understand what was actually going on. The real-world data my team has looked at from the North Sea is not in line with modulation instability. That’s a different story.
It’s a bad day at the sea
To clarify the patterns behind these rare events, Sea State Records were analyzed using statistical methods. Our findings show that instead of modulation instability, extreme waves are likely to form through a process called constructive interference.
Constructive interference occurs when two or more waves are combined side by side into one large wave. This effect is amplified by the natural asymmetry of ocean waves. Those coat of arms are usually sharper and steeper than flat troughs.
The waves of the rogue form when many small waves line up, and steeper coats of arms begin to stack, accumulate in a single, huge wave, far above the surroundings. All you need to ride a peaceful boat is to turn into a bad day at sea.
These incorrect waves rise within a minute, following what is known as the quasi-determinant patterns of space and time. This type of pattern is recognizable and reproducible, but has a random touch. In an ideal ocean, its randomness almost disappears, allowing illegitimate waves to grow to almost infinite heights. But so many people need to line up perfectly, it takes eternity to witness one of these waves. Just as Fortuna, the goddess of chance, rolls a trillion dice, waiting for almost all of them to land in the same number.
In real oceans, nature limits how large an injustice can become thanks to wave destruction. As the wave height and energy rise, it cannot hold itself beyond a certain point of no revenue. The tip of the wave is spilled out and split into bubbles, or white caps, releasing excess energy.
The semi-deterministic pattern behind the injustice waves
Rogue waves are not limited to the ocean. Constructive interference can occur in many types of waves. A general theory called wave quasi-sampleism developed by oceanologist Paolo Boccotti explains how injustice waves are formed in both the ocean and in other wave systems.
For example, in the case of turbulent water flowing through trapped waterways, illegitimate waves appear in the form of violent, short-lived spikes of vortexes. The pattern of swirling swirls increases instantaneously as they move downstream.
Ocean waves seem unpredictable, but Boccotti’s theory shows that extreme waves are not completely random. When a truly large wave is formed, the ocean waves around it follow a recognizable pattern formed by constructive interference.
Boccotti’s theory was applied to identify and characterize these patterns in measured North Sea wave records.
Please take a look
The giant waves observed in these records can have a kind of signature or fingerprint in the form of a group of waves, revealing how the illegitimate waves were born. Think of a group of waves like a small package of waves. They rise, peak and fade out through constructive interference. By tracking these groups of waves, researchers can understand the overall picture of the rogue events as they unfold.
As an example, a powerful storm hit the North Sea on November 24, 2023. The Ecofisk platform cameras have acquired a illicit wave of 55 feet (17 meters). To investigate the origins of this extreme wave, we applied the theory of quasi-dataminism and AI models. My analysis revealed that illicit events followed these theories (quasi-decision and constructive interference) and that multiple small waves were repeatedly stacked together.
Recognizing how Rogue Waves is formed will help engineers and designers build safer ships and offshore platforms, and better predict risks.
This edited article will be republished from the conversation under a Creative Commons license. Please read the original article.
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