Sunday, July 19, 2009

Higher tides affecting the US east coast, especially mid-Atlantic

Scott Harper in the Virginian-Pilot (Hampton Roads, Virginia): Scientists are closely watching unusually high tides along the entire East Coast, especially in mid-Atlantic states including Virginia, where average daily levels are running between 6 inches and 2 feet above predicted norms.

One veteran researcher at the Virginia Institute of Marine Science, John Boon, said he suspects the trend could be the beginning of a decade-long phenomenon of high water caused by an El Niño-like effect in the Atlantic. “It’s possible we’re entering a new cycle,” he said this week.

Boon, a professor emeritus of marine science who has studied tides most of his career, described how Atlantic wind patterns and currents can subtly shift, often without explanation. The shift, in turn, pushes more water onto East Coast beaches, marshes and coastline through higher tides.

...The extreme tides, he and other scientists said, have occurred before and can last, on and off, for years at a time before suddenly changing back to normal. “There’s no scientific debate that these anomalous cycles happen,” Boon said. “It’s what causes them that’s debated.”

…Similarly on the Atlantic, quirky shifts in atmospheric pressure and winds, known as the North Atlantic Oscillation, contribute to weather variability – and might be at play now, said Larry Atkinson, an oceanographer at Old Dominion University in Norfolk. Atkinson said that what Hampton Roads is experiencing now will likely become the norm in 30 or 40 years due to sea level rise associated with the slow warming of ocean temperatures….

A statue of Neptune in Virginia Beach, Virginia, shot by Dmc313, who has generously released the image into the public domain

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