giovedì 6 novembre 2008

Scientists recover North Pole mooring from 2½ miles deep in ocean

Scientists returned last week from the North Pole after recovering 3,500 pounds of instruments and equipment from a mooring anchored to the seafloor for a full year, eight times longer than the only previous mooring at the pole.

The recovery – which involved hauling miles of cable and instruments out of a 4-foot-wide hole in the ice, with three divers in special dry suits standing by in case the mooring became snarled under the ice – was part of this year's North Pole Environmental Observatory camp April 18-28. Led by oceanographer James Morison of the UW's Applied Physics Laboratory, the North Pole Environmental Observatory program is a 5-year, $3.9 million project funded by the National Science Foundation to take the year-round pulse of the Arctic Ocean and learn how the world's northernmost sea helps regulate global climate.

Scientists hope data from instruments on the mooring will help them understand, among other things, changes in the top layer of cold water (28 degrees Fahrenheit) that acts as a barricade against a deeper, but warmer, layer of water capable of causing melting whenever it reaches the underside of the polar ice cap.

That upper, very cold layer grew thinner and warmer in the last decade. That trend is now reverting toward conditions prior to 1990, according to survey work done during the last two years of the North Pole Environmental Observatory program, while the warming is slowly spreading to deeper parts of the Arctic Ocean, Morison says.

In addition to recovering the mooring during this year's camp, polar scientists and engineers installed a new mooring for the coming year. And, as in the past two years, they conducted surveys of water conditions across hundreds of miles and deployed a fleet of sophisticated drifting buoys on the ice. This year one of the buoys carries a camera linked to the Internet so scientists can relate conditions on the ice to readings received via satellite from their instruments. View the images at or at the NOAA site Images are usually updated every six hours although the camera can be used more frequently if needed and can be zoomed.

The North Pole Environmental Observatory program involves researchers and engineers from the University of Washington, NOAA's Pacific Marine Environmental Laboratory in Seattle, the Army's Cold Regions Research and Engineering Laboratory in Hanover, N.H., Japanese Marine Science and Technology Center in Yokosuka City, Oregon State University and the Naval Postgraduate School in Monterey, Calif.

Fourteen researchers and engineers traveled to the ice. The worst weather, with winds of 30 to 35 miles per hour causing poor visibility, came at the start of the operation and delayed flights to the ice for two days. Most days temperatures were minus 13 to minus 30 F. A few days were sunny, without wind and a balmy minus 5.

The observatory program was staged this year from a privately operated camp, dubbed Borneo, that is established each April near the pole for tourist and commercial enterprises from France, Russia, Canada and Norway. While tourists cross-country skied to the pole and rode hot-air balloons, observatory researchers used the station as the starting point for their various projects. The place where scientists returned to retrieve the mooring, for example, was roughly 60 miles north of Borneo. A smaller base camp, with two 8- by 12-foot tents, was installed there for the work.

As in past years, staging and logistics were possible with the generous cooperation and support from the Canadian Forces Station Alert, part of the Canadian Department of National Defence, as well as the Defence Research Establishment Atlantic.

Click here for supplemental information, images and contacts for the North Pole Environmental Observatory.

The North Pole Environmental Observatory Web site.

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