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A Curious Pacific Wave
A massive swell of warm water is buffeting South America. Is it the first sign of a new El Niño -- or just another "Kelvin wave?"
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March 5, 2002
Somewhere on a beach in Ecuador or Peru, someone is out for stroll. A warm breeze is blowing, water laps at their feet. It's paradise.
But something is amiss. The air is a bit warmer than usual. So is the water. And, for weeks now, tides have been cresting a few inches higher. Maybe only frequent beach-walkers would notice the difference, but the changes are real.
These countries have just been hit by a gentle yet massive swell of warm water -- a so-called "Kelvin wave."
A Kelvin wave crosses the Pacific, Dec. 8, 2001 - Mar. 3, 2002. This plot shows a 500m-deep slice of the Pacific Ocean along the equator. The warm pool is on the left, the Americas are on the right. False colors denote temperature anomalies (measured by Pacific ocean buoys) in degrees Celsius. "The warmest part of a Kelvin wave is usually 100 to 150 meters below the ocean's surface," notes Adamec. [more]
"Kelvin waves are warm bumps in the Pacific Ocean," says JPL oceanographer Bill Patzert. They form around Indonesia and travel east toward the Americas. "A typical Kelvin wave is 5 or 10 cm high, hundreds of kilometers wide, and a few degrees warmer than surrounding waters."
Usually not much happens when a Kelvin wave arrives -- beach combers experience a bit of extra rain, perhaps, and slightly warmer surf. Nevertheless, scientists pay careful attention to them because these gentle waves occasionally herald something far more powerful: the next El Niño.
(Full Story Here)
Cheers,
Dan
A Curious Pacific Wave . . .