NSF PR 97-57 - September 17, 1997
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Ships Depart to Launch Ice Station Sheba in the Arctic
Ocean
Two icebreaking ships will depart Tuktoyaktuk, Canada
around September 18 to establish Ice Station SHEBA
in the Arctic Ocean, launching the largest and most
complex science experiment ever supported in the Arctic
by the National Science Foundation (NSF). One ship
will be frozen into the pack ice of the Arctic Ocean
and left to drift as a floating science platform for
13 months. The target of the Surface Heat Budget of
the Arctic Ocean project: charting the fate of the
great canopy of pack ice about the size of the United
States, which seals off the Arctic Ocean.
SHEBA's ultimate goal is to better understand the
climate of the Arctic so that forecasts of global
climate change can be improved, according to Mike
Ledbetter, NSF program director for Arctic system
science. The $19.5 million project, also funded by
the Office of Naval Research, is coordinated by the
University of Washington'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.
Laurent and Des Groseilliers will steam to the SHEBA
site 300 miles north of Prudhoe Bay, Alaska -- approximately
75 degrees north and 143 degrees west -- arriving
about October 1.
More than a century after Norwegian Fridtjof Nansen
froze his specially designed ship, the Fram, into
the ice of the Arctic Ocean and left it to drift for
three years of scientific exploration, the Des Groseilliers
will be left in place to serve as a floating dormitory
and science quarters. It will be surrounded by small
huts and experiments on the sea ice, along with 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 the Arctic's pack ice. If carbon dioxide doubles
in the atmosphere, an occurrence possible in less
than a century, some models predict that the pack
ice could disappear completely; others suggest less
shrinkage. All models concur, however, that Arctic
pack ice will play an important role in climate change.
The varied landscape of sea ice -- rent by cracks,
pathways of open water called leads, pressure ridges
tens of meters thick and other fantastic forms --
is constantly deformed and shifting. The ice also
chills the atmosphere by blocking warmth from the
sea in winter and reflecting most incoming sunlight
in summer. "More than half the Arctic pack ice melts
and refreezes each year, but even the most sophisticated
computer models cannot simulate this change," said
Richard Moritz, SHEBA project office director at the
University of Washington.
Pack ice looms large in several realms, its fate bearing
upon shipping routes, petroleum extraction and a rich
marine ecosystem embracing whales, polar bears, fish
and plankton, a web of life key to the livelihood
of Arctic peoples.
SHEBA scientists plan to trace the transfer of energy
between the atmosphere, sea ice and ocean waters over
an entire year of freezing and melting. "SHEBA's hallmark
is to gather a comprehensive data set documenting
all the variables and processes at work," Moritz said.
In addition to the frozen-in ship, the project will
employ a fleet of icebreakers, research aircraft and
balloons, a U.S. Navy nuclear submarine and satellites.
More than 50 scientists from universities and agencies
such as NASA and the Department of Energy will participate,
along with researchers from Japan, Canada and the
Netherlands carrying out related studies.
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