Could global warming lead to more monster waves?
http://story.news.yahoo.com/news?tmpl=story&cid=1540&e=3&u=/afp/science_sea
'Rogue waves' reported by mariners get scientific backing
Wed Jul 21, 1:07 PM ET
PARIS (AFP) - European satellites have given confirmation to terrified mariners who describe seeing freak waves as tall as 10-storey buildings, the European Space Agency (ESA) said.
"Rogue waves" have been the anecdotal cause behind scores of sinkings of vessels as large as container ships and supertankers over the past two decades.
But evidence to support this has been sketchy, and many marine scientists have clung to statistical models that say monstrous deviations from the normal sea state only occur once every thousand years.
Testing this promise, ESA tasked two of its Earth-scanning satellites, ERS-1 and ERS-2, to monitor the oceans with their radar.
...
Even though the research period was brief, the satellites identified more than 10 individual giant waves around the globe that measured more than 25 metres (81.25 feet) in height, ESA said in a press release.
- Loran
Thursday, July 22, 2004
I view this with scepticism, but...
Geologic evidence exists for this. Sedimentary rocks often have ripple marks on them, undulating ripples that were buried by more sediment, thus preserving the ripple-texture. Then pressure and heat turn the sand into rock.
Thing is, very large ripple marks have been found in sed. rock that is known (from fossils) to be very, very deep underwater. The wave height needed to make such big ripples at such a depth is somewhat unbelievable. But there is yet to be a better theory to explain them.
Andy, did I remember this about right? ^_^
- Ian Darrow
Thursday, July 22, 2004
Ripples are caused by a current, not neccessarily from a wave, so the ripples on deep oceanic sediments could have been caused by a deep current, which is the more likely possibility.
The effects of a wave, it's height and the depth to which is osscilates the water column increases the shallower the sea gets. Even a mega tsunami is only a mild swell out in the deep ocean, the power is in the wavelength, not the amplitude. These super waves seem to have a big amplitude and short wavelength, making them locally nasty but relatively short lived affairs.
- Andy Tucker
Saturday, July 24, 2004
25 m sounds like the waves you could expect from a super-tsunami. Yes, it only reaches this height when the wave are closing in on land, where the sea becomes shallow - but what about two tsunami waves clashing into each other? If there relative force is more or less equal, shouldn't they build a considerable bulge of water? Voilá - a 25 m wave.
Just a guess, though;-)
- Rainer
Saturday, July 24, 2004
huge waves are made by a storm off shore that starts a cyclic energy in the water, winds of high speeds would have to be blowing across the water. The actual wave is created when the swells created by the winds hit an obstruction in the water, for example reefs. So the waves are natural it's the enormous storms with huge winds that are unnatural.
- Roy Zhou
Saturday, July 24, 2004
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