Arctic

Arctic sea ice annual minimum is 6th lowest on satellite record

Arctic sea ice has started to reform after reaching what appears to be an annual minimum that was the sixth-lowest on satellite record, the National Snow and Ice Data Center said on Monday.

Sea-ice coverage fell to 5.016 million square kilometers (1.94 million square miles) Wednesday, slightly below the minimum reached last year and well below the average recorded from 1981 to 2010, according to the NSIDC. This year's ice minimum was well above the record minimum of 3.41 million square kilometers in 2012, according to NSIDC data.

Sea-ice patterns this year have been uneven across the Arctic, with vast stretches of open water off northern Alaska and eastern Siberia but relatively more ice in the Barents and Kara Seas north of Western Europe, according to the Boulder-based NSIDC.

"The most notable feature was the lack of ice north of the Laptev Sea that at one point in the melt season extended beyond 85 degrees north latitude, within 550 kilometers (342 miles) of the North Pole," the NSIDC said in a statement.

The Northern Sea Route, the marine passage from Bering Strait across the top of Russia, was clear this summer. But the alternate shipping route, the Northwest Passage -- which runs from the North Atlantic through the Canadian Archipelago in Canada's eastern Arctic region -- was blocked by ice.

The NSIDC considers areas of the Arctic with at least 15 percent sea ice to be ice-covered. The center measures surface coverage by satellite; coverage statistics do not account for ice age or thickness, but the NSIDC and other organizations, including NASA, monitor those factors as well. NASA is studying Arctic ice and its connection to atmospheric conditions in a program called ARISE, for Arctic Radiation IceBridge Sea and Ice Experiment.

While there is more September sea ice now than two years ago, coverage is remarkably low, considering other factors, said a NASA scientist.

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"The summer started off relatively cool and lacked the big storms or persistent winds that can break up ice and increase melting," Walter Meier, a research scientist at NASA's Goddard Space Flight Center, said in a statement issued by the space agency. "Even with a relatively cool year, the ice is so much thinner than it used to be. It's more susceptible to melting."

Arctic ice cover had grown back to 5.087 million square kilometers as of Sunday, according to the NSIDC, but it is possible that freeze-up will be interrupted by weather patterns. A shift in wind or an unusual late-season melt could reduce ice coverage briefly, the center said.

Yereth Rosen

Yereth Rosen was a reporter for Alaska Dispatch News.

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