Two icebreaking ships will depart Tuktoyaktuk, Canada aroundSeptember 18 to establish Ice Station SHEBA in the Arctic Ocean,launching the largest and most complex science experiment eversupported in the Arctic by the National Science Foundation (NSF).One ship will be frozen into the pack ice of the Arctic Ocean andleft to drift as a floating science platform for 13 months. Thetarget of the Surface Heat Budget of the Arctic Ocean project:charting the fate of the great canopy of pack ice about the sizeof the United States, which seals off the Arctic Ocean.
SHEBA's ultimate goal is to better understand the climate ofthe Arctic so that forecasts of global climate change can beimproved, according to Mike Ledbetter, NSF program director forArctic system science. The $19.5 million project, also funded bythe Office of Naval Research, is coordinated by the University ofWashington's Applied Physics Laboratory. NSF is also supporting$2 million worth of other science related to SHEBA.
The Canadian Coast Guard icebreakers Louis S. St. Laurentand Des Groseilliers will steam to the SHEBA site 300 miles northof Prudhoe Bay, Alaska -- approximately 75 degrees north and 143degrees west -- arriving about October 1.
More than a century after Norwegian Fridtjof Nansen frozehis specially designed ship, the Fram, into the ice of the ArcticOcean and left it to drift for three years of scientificexploration, the Des Groseilliers will be left in place to serveas a floating dormitory and science quarters. It will besurrounded by small huts and experiments on the sea ice, alongwith an airplane skiway for supply flights throughout the year.The Louis S. St. Laurent departs the site about October 15.
Climate modelers currently differ over the future of theArctic's pack ice. If carbon dioxide doubles in the atmosphere,an occurrence possible in less than a century, some modelspredict that the pack ice could disappear completely; otherssuggest less shrinkage. All models concur, however, that Arcticpack ice will play an important role in climate change.
The varied landscape of sea ice -- rent by cracks, pathwaysof open water called leads, pressure ridges tens of meters thickand other fantastic forms -- is constantly deformed and shifting.The ice also chills the atmosphere by blocking warmth from thesea in winter and reflecting most incoming sunlight in summer."More than half the Arctic pack ice melts and refreezes eachyear, but even the most sophisticated computer models cannotsimulate this change," said Richard Moritz, SHEBA project officedirector at the University of Washington.
Pack ice looms large in several realms, its fate bearingupon shipping routes, petroleum extraction and a rich marineecosystem embracing whales, polar bears, fish and plankton, a webof life key to the livelihood of Arctic peoples.
SHEBA scientists plan to trace the transfer of energybetween the atmosphere, sea ice and ocean waters over an entireyear of freezing and melting. "SHEBA's hallmark is to gather acomprehensive data set documenting all the variables andprocesses at work," Moritz said.
In addition to the frozen-in ship, the project will employ afleet of icebreakers, research aircraft and balloons, a U.S. Navynuclear submarine and satellites. More than 50 scientists fromuniversities and agencies such as NASA and the Department ofEnergy will participate, along with researchers from Japan,Canada and the Netherlands carrying out related studies.
Materials provided by National Science Foundation. Note: Content may be edited for style and length.
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