Sunday, June 19, 2011

On the crest of a freaque wave

There are a number of articles with semi-interesting titles floating around the media in the last few days, they are On the crest of a freak wave by Pete Wilton in and Freak Waves Could Spring from Clash of Wave Patterns by Jennifer Welsh of Another article "Cause of Mystery Freak Waves Discovered" by Talia Tolliver of that needs a sign in to read -- but I signed in and still can't access it! And also this one "Mystery of towering freak waves may be solved" in which is actually the Jennifer Welsh's article above article listed above.

All of these articles are in essence reporting the new speculations from a new paper just published in the Proceedings of the Royal society A with a paper title: "Did the Draupner wave occurs in a crossing sea?" According to the abstract of the paper:
This paper investigates the directionality of the Draupner wave and concludes it might have resulted from two wave-groups crossing, whose mean wave directions were separated by about 90° or more. This result has been deduced from a set-up of the low-frequency second-order difference waves under the giant wave, which can be explained only if two wave systems are propagating at such an angle.
I guess one special feature of this new work, unlike the previous theoretical works, is that they employed ECMWF's modeling corroboration -- what they called "backed up by a hindcast". May be that's what persuaded the media writers to come up with the optimistic headlines like "discovered" and "may be solved" to characterize the new speculation. It is just another speculation. We have no way of knowing of how do "two wave-groups crossing, whose mean wave directions were separated by about 90° or more" to come about in real oceans to produce the freaque waves.

I just wish to add that Jennifer Welsh's article included a video clip of real life freaque wave encounter from the Discovery Channel TV show "The Deadliest Catch" that's well worth watching! And I find myself being intrigued by the title "On the crest of a freak wave" so much so that I choose to use it for the title of this posting today. Really, how do you feel or what do you see if you can somehow manifest yourself onto the crest of a wave in the ocean? To me, I think, an immediate reaction would be to look for where is the trough. Now the trough is certainly there somewhere nearby, but most definitely it will not be directly underneath the crest as the modern conventional single point wave measurements would imply! This new paper stems from thinking about the directional spreading -- an antiquated conceptualization of the late 1950's. In the 2nd decade of the 21st century, isn't it timely for us to think about spatial wave measurement now?

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