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Ship-sinking monster waves revealed by ESA satellites
European Space Agency ^ | 7/21/04

Posted on 07/22/2004 10:25:27 PM PDT by uglybiker

Rare photo of a rogue wave
Ship-sinking monster waves revealed by ESA satellites
21 July 2004
Once dismissed as a nautical myth, freakish ocean waves that rise as tall as ten-storey apartment blocks have been accepted as a leading cause of large ship sinkings. Results from ESA's ERS satellites helped establish the widespread existence of these 'rogue' waves and are now being used to study their origins.
Severe weather has sunk more than 200 supertankers and container ships exceeding 200 metres in length during the last two decades. Rogue waves are believed to be the major cause in many such cases.

Mariners who survived similar encounters have had remarkable stories to tell. In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick described as "a great wall of water… it looked as if we were going into the White Cliffs of Dover."

And within the week between February and March 2001 two hardened tourist cruisers – the Bremen and the Caledonian Star – had their bridge windows smashed by 30-metre rogue waves in the South Atlantic, the former ship left drifting without navigation or propulsion for a period of two hours.


Damage done by a rogue wave
"The incidents occurred less than a thousand kilometres apart from each other," said Wolfgang Rosenthal - Senior Scientist with the GKSS Forschungszentrum GmbH research centre, located in Geesthacht in Germany - who has studied rogue waves for years. "All the electronics were switched off on the Bremen as they drifted parallel to the waves, and until they were turned on again the crew were thinking it could have been their last day alive.

"The same phenomenon could have sunk many less lucky vessels: two large ships sink every week on average, but the cause is never studied to the same detail as an air crash. It simply gets put down to 'bad weather'."

Offshore platforms have also been struck: on 1 January 1995 the Draupner oil rig in the North Sea was hit by a wave whose height was measured by an onboard laser device at 26 metres, with the highest waves around it reaching 12 metres.


Merchant ship
Giant wave in Bay of Biscay
Objective radar evidence from this and other platforms – radar data from the North Sea's Goma oilfield recorded 466 rogue wave encounters in 12 years - helped convert previously sceptical scientists, whose statistics showed such large deviations from the surrounding sea state should occur only once every 10000 years.

The fact that rogue waves actually take place relatively frequently had major safety and economic implications, since current ships and offshore platforms are built to withstand maximum wave heights of only 15 metres.

In December 2000 the European Union initiated a scientific project called MaxWave to confirm the widespread occurrence of rogue waves, model how they occur and consider their implications for ship and offshore structure design criteria. And as part of MaxWave, data from ESA's ERS radar satellites were first used to carry out a global rogue wave census.

ERS-1 and 2
ERS satellite
"Without aerial coverage from radar sensors we had no chance of finding anything," added Rosenthal, who headed the three-year MaxWave project. "All we had to go on was radar data collected from oil platforms. So we were interested in using ERS from the start."

ESA's twin spacecraft ERS-1 and 2 – launched in July 1991 and April 1995 respectively – both have a Synthetic Aperture Radar (SAR) as their main instrument.

The SAR works in several different modes; while over the ocean it works in wave mode, acquiring 10 by 5 km 'imagettes' of the sea surface every 200 km.


Example of an imagette from ERS-2
These small imagettes are then mathematically transformed into averaged-out breakdowns of wave energy and direction, called ocean-wave spectra. ESA makes these spectra publicly available; they are useful for weather centres to improve the accuracy of their sea forecast models.

"The raw imagettes are not made available, but with their resolution of ten metres we believed they contained a wealth of useful information by themselves," said Rosenthal. "Ocean wave spectra provide mean sea state data but imagettes depict the individual wave heights including the extremes we were interested in.

"ESA provided us with three weeks' worth of data – around 30,000 separate imagettes – selected around the time that the Bremen and Caledonian Star were struck. The images were processed and automatically searched for extreme waves at the German Aerospace Centre (DLR)."


Giant wave detected in ERS-2 imagette data
Despite the relatively brief length of time the data covered, the MaxWave team identified more than ten individual giant waves around the globe above 25 metres in height.

"Having proved they existed, in higher numbers than anyone expected, the next step is to analyse if they can be forecasted," Rosenthal added. "MaxWave formally concluded at the end of last year although two lines of work are carrying on from it – one is to improve ship design by learning how ships are sunk, and the other is to examine more satellite data with a view to analysing if forecasting is possible."

A new research project called WaveAtlas will use two years worth of ERS imagettes to create a worldwide atlas of rogue wave events and carry out statistical analyses. The Principal Investigator is Susanne Lehner, Associate Professor in the Division of Applied Marine Physics at the University of Miami, who also worked on MaxWave while at DLR, with Rosental a co-investigator on the project.

"Looking through the imagettes ends up feeling like flying, because you can follow the sea state along the track of the satellite," Lehner said. "Other features like ice floes, oil slicks and ships are also visible on them, and so there's interest in using them for additional fields of study.

"Only radar satellites can provide the truly global data sampling needed for statistical analysis of the oceans, because they can see through clouds and darkness, unlike their optical counterparts. In stormy weather, radar images are thus the only relevant information available."

So far some patterns have already been found. Rogue waves are often associated with sites where ordinary waves encounter ocean currents and eddies. The strength of the current concentrates the wave energy, forming larger waves – Lehner compares it to an optical lens, concentrating energy in a small area.

Giant wave in a wave tank
This is especially true in the case of the notoriously dangerous Agulhas current off the east coast of South Africa, but rogue wave associations are also found with other currents such as the Gulf Stream in the North Atlantic, interacting with waves coming down from the Labrador Sea.

However the data show rogue waves also occur well away from currents, often occurring in the vicinity of weather fronts and lows. Sustained winds from long-lived storms exceeding 12 hours may enlarge waves moving at an optimum speed in sync with the wind – too quickly and they'd move ahead of the storm and dissipate, too slowly and they would fall behind.

"We know some of the reasons for the rogue waves, but we do not know them all," Rosenthal concluded. The WaveAtlas project is scheduled to continue until the first quarter of 2005.

TOPICS: News/Current Events
KEYWORDS: archaeology; canaries; catastrophism; corliss; ggg; godsgravesglyphs; hawaii; history; muttonisland; roguewave; wave
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1 posted on 07/22/2004 10:25:29 PM PDT by uglybiker

To: blam


2 posted on 07/22/2004 10:26:24 PM PDT by uglybiker (No. Those are NOT classified documents inadvertently shoved down my pants)

To: uglybiker

Bummer, I already hate flying and now giant waves! I guess I'll have to walk everywhere.

3 posted on 07/22/2004 10:30:40 PM PDT by little jeremiah ("You're possibly the most ignorant, belligerent, and loathesome poster on FR currently." - tdadams)

To: All
4 posted on 07/22/2004 10:31:30 PM PDT by uglybiker (No. Those are NOT classified documents inadvertently shoved down my pants)

To: uglybiker
"The same phenomenon could have sunk many less lucky vessels: two large ships sink every week on average,

I had no idea.

5 posted on 07/22/2004 10:33:06 PM PDT by GVnana (Tagline? I don't need no stinkin' tagline!)

To: uglybiker

Great find UB. BTTT.

6 posted on 07/22/2004 10:33:19 PM PDT by bd476

To: uglybiker
We need to stop Michael Mooron from doing any more belly flops into the ocean.
7 posted on 07/22/2004 10:35:06 PM PDT by COEXERJ145


Or Rosie O'Donnell, or Linda Ronstadt, or Margaret Cho, or......

8 posted on 07/22/2004 10:38:39 PM PDT by uglybiker (No. Those are NOT classified documents inadvertently shoved down my pants)

To: uglybiker
Rogue waves and tsunamis don't appear to be related but maybe they should be. Currents and eddies seem to be partial cause of rogue waves and earthquakes cause tsunamis.

Wonder what would happen if a major earthquake coincided with adverse weather, currents and eddies.

9 posted on 07/22/2004 10:40:50 PM PDT by bd476

To: uglybiker

Bush's fault.

10 posted on 07/22/2004 10:49:22 PM PDT by kb2614 ( You have everything to fear, including fear itself. - The new DNC slogan)

To: kb2614

Sandy Berger inadvertently stuffed a rougue wave inside his pants.

11 posted on 07/22/2004 10:54:38 PM PDT by uglybiker (No. Those are NOT classified documents inadvertently shoved down my pants)

To: kb2614

"Rogue" waves? Which means that the UN won't do anything about them.

12 posted on 07/22/2004 10:54:54 PM PDT by WestVirginiaRebel (Never misunderestimate our Commander-In-Chief.)

To: bd476
All proof we're still knuckle dragging cavemen when comes to really understanding weather patterns with respect to relationships within the earth.

With one exception;

Thomas Gold

He seems to a bit ahead of the pack in understanding;


Read his books!

13 posted on 07/22/2004 11:01:45 PM PDT by norraad ("What light!">Blues Brothers)

To: uglybiker


14 posted on 07/22/2004 11:06:50 PM PDT by Porterville (Your sensitivity offends me you disgusting liberal.)

To: uglybiker
I first heard of these in the Navy.

A young officer was on the bridge scanning the horizon with binocculars.......I asked what he was looking for as we were 100's, if not 1000's of miles from nothing in the central Pacific. The radar techs in CiC would alert us to any approaching vessels.

And he told me about the "great waves" that have been dismissed by science throughout the modern era. Enormous, fast moving and not necessarily parallel to the surrounding seas. They sometimes appear suddenly. Sailors have known of them for ever. This statement received concurrance from the XO who was also on the bridge and it started me looking into it.

About 3-4 years later, on another ship (USS Benjamin Stoddert) we just skirted (about 60 deg vs 90) an 80 foot wave in stormy seas in the NW Pacific. The surrounding sea-state averaged 20-25 feet. I saw BLUE WATER smash over the bow and into the bridge before it broke white. That white water splashed us on the signal bridge.

Of course that DDG just sliced on through..........minus many antenae, a boat and most of everything else not below decks. It's an amazing sight if you live to tell about it:)

15 posted on 07/22/2004 11:09:33 PM PDT by Mariner

To: uglybiker
"Once dismissed as a nautical myth"
"helped convert previously skeptical scientists"
I think these were the same guys working on the global warming thing. What an arrogant bunch. Why believe experienced ships officers trained in ocean meteorology who are out there observing when you can form your own theory without observing.

"Rare photo" The photo may be rare but I've seen my share of waves that looked exactly like that. White water on deck is ok but the green water got scary (solid water). Salmon across the deck.
16 posted on 07/22/2004 11:14:32 PM PDT by Cold Heart

To: uglybiker

I just saw this on Drudge and had to save it to my "archives".

17 posted on 07/22/2004 11:25:02 PM PDT by BunnySlippers (Must get moose and squirrel ... B. Badanov)

To: BunnySlippers

We ran into a really big,,maybe rouge wave out on the New England banks. The wave shattered the bridge glass on the ship(DD-765 Keppler) and took most everything off the bow..lifelines, stantions etc. It moved Mount 52 back about 18" and opened a smile in the deck which got the Chief's quarters very wet. We lost all power, the gyro tumbled. The bridge height was 45ft. above the water line.

18 posted on 07/22/2004 11:33:04 PM PDT by Oldexpat

To: norraad
Thanks for the book recommendation, Norraad.

Here's the latest big quake in Japan:

2004 July 22 09:45:17 UTC

Preliminary Earthquake Report
U.S. Geological Survey, National Earthquake Information Center
World Data Center for Seismology, Denver

A strong earthquake occurred at 09:45:17 (UTC) on Thursday, July 22, 2004. The magnitude 6.2 event has been located in the RYUKYU ISLANDS, JAPAN. (This event has been reviewed by a seismologist.)

Small map showing earthquake

6.2 Quake Ryukyu Islands, Japan

19 posted on 07/22/2004 11:59:11 PM PDT by bd476

To: uglybiker

20 posted on 07/23/2004 1:33:56 AM PDT by Straight Vermonter (06/07/04 - 1000 days since 09/11/01)

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