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Research finds water from Russian rivers increased water levels on Canadian side of Arctic Ocean

Global warming has focused a lot of attention on climactic changes in the Arctic but new research has is pointing to another factor that may be affecting Arctic waters and global water flows.

Scientists are pinpointing a climactic phenomenon called Arctic Oscillation as the cause of an increased freshwater runoff into the Beaufort Sea from major Russian rivers.

An article in the Jan. 5 issue of the science magazine Nature points to a freshening of the Canada basin of the Arctic Ocean beginning in the 1990s and continuing until at least 2008.

"By then, the Arctic Ocean might have gained four times as much fresh water as comprised the Great Salinity Anomaly of the 1970s, raising the spectre of slowing global ocean circulation," the researchers reported.

"Freshening has been attributed to increased sea ice melting and contributions from runoff, but a leading explanation has been a strengthening of the Beaufort High—a characteristic peak in sea level atmospheric pressure —which tends to accelerate an anticyclonic (clockwise) wind pattern causing convergence of fresh surface water."

Physorg.com said frigid freshwater from three major Russian rivers was diverted for hundreds of miles to a completely different part of the Arctic Ocean due to a decades-long shift in atmospheric pressure.

"The new findings show that a low pressure pattern created by the Arctic Oscillation from 2005 to 2008 drew Russian river water away from the Eurasian Basin, between Russia and Greenland, and into the Beaufort Sea, a part of the Canada Basin bordered by the United States and Canada," Physorg.com reported. "It was like adding 10 feet (three metres) of freshwater over the central part of the Beaufort Sea."

Lead author Jamie Morison said the impact of the phenomenon goes beyond the Arctic.

"Knowing the pathways of freshwater in the upper ocean is important to understanding global climate because of freshwater's role in protecting sea ice _ it can help create a barrier between the ice and warmer ocean water below _ and its role in global ocean circulation," said Morison, an oceanographer with the University of Washington's Applied Physics Laboratory "Too much freshwater exiting the Arctic would inhibit the interplay of cold water from the poles and warm water from the tropics."

Morison and his colleagues were the first to detect the freshwater pathway and its connection to Arctic Oscillation. The work is based on water samples gathered in the field combined with satellite oceanography possible for the first time with data from NASA satellites known as ICESat and GRACE.

The increase in freshwater levels on the U.S. and Canadian side of the Arctic between 2005 and 2008 was offset by decreased freshwater on the Russian side, the article noted, so average freshwater levels for the Arctic as a whole did not increase. Salinity levels were similar to those in the past for the whole ocean, but the Canada Basin's waters have become fresher, while the Eurasian Basin became saltier.

Morison said the research adds to the knowledge of climactic effects in the Arctic.

"A number of people have come up with ways of looking at regional forces at work in the Arctic," Morison said, "To better understand changes in sea ice and the Arctic overall we need to look more broadly at the hemispherewide Arctic Oscillation, its effects on circulation of the Arctic Ocean and how global warming might enhance those effects."