(orignal posting is on Yahoo News, here)
'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. The radars send back "imagettes" -- a picture of the sea surface in a rectangle measuring 10 by five kilometers (six by 2.5 miles) that is taken every 200 kms (120 miles). Around 30,000 separate "imagettes" were taken by the two satellites in a three-week project, MaxWave, that was carried out in 2001.
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. The waves exist "in higher numbers than anyone expected," said Wolfgang Rosenthal, senior scientist with the GKSS Research Centre in Geesthacht, Germany, who pored over the data. "The next step is to analyse if they can be forecasted," he said.
Ironically, the research coincided with two "rogue wave" incidents in which two tourist cruisers, the Bremen and the Caledonian Star, had their bridge windows smashed by 30-metre (100-feet) monsters in the South Atlantic. The Bremen was left drifting without navigation or propulsion for two hours after the hit.
In 1995, the British cruise liner Queen Elizabeth II encountered a 29-metre (94.25-feet) wall of water during a hurricane in the North Atlantic. Its captain, Ronald Warwick, likened it to "the White Cliffs of Dover."
In the next phase of research, a project called Wave Atlas will use two years of "imagettes" to create a worldwide atlas of rogue wave events and carry out statistical analyses, ESA said. The goal is to find out how these strange, cataclysmic phenomena may be generated by ocean eddies and currents or by the collision of weather fronts, and which regions of the seas may be most at risk. Finding out could help ship architects and the designers of oil rigs and their operators to skirt the menace.
