NSF PR 99-21 - April 9, 1999
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Nuclear Submarine Puts To Sea To Serve Science
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USS Hawkbill
At Scientific Ice Expedition '98
Photo Credit: courtesy of Dale Chayes
of the Lamont-Doherty Earth Observatory
at Columbia University
Select image for larger version
(Size: 23KB)
Photo Credit: courtesy of Dale Chayes
of the Lamont-Doherty Earth Observatory
at Columbia University
Select image for larger version
(Size: 19KB)
Photo Credit: courtesy of Dale Chayes
of the Lamont-Doherty Earth Observatory
at Columbia University
Select image for larger version
(Size: 36KB)
Photo Credit: courtesy of Dale Chayes
of the Lamont-Doherty Earth Observatory
at Columbia University
Select image for larger version
(Size: 16KB) Note
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Researchers supported by the National Science Foundation
(NSF) are sailing aboard a U.S. Navy nuclear submarine
in April to map the oceanic ridges and basins beneath
the Arctic ice cap and study ocean currents that may
have an effect on global climate.
NSF is mounting Scientific Ice Expedition (SCICEX)
'99 in cooperation with the U.S. Navy and the Office
of Naval Research. The exercise is the fifth in a
series of annual SCICEX missions, all of which have
employed some of the world's stealthiest and most
maneuverable warships. "This is a capability that
is not available anywhere else in the world," stressed
Thomas E. Pyle, head of Arctic Sciences in NSF's Office
of Polar Programs.
SCICEX '99 will be conducted aboard USS Hawkbill (SSN
666), which is able to travel almost at will under
the ice, making it a unique platform for a sophisticated
sonar system dubbed the Seafloor Characterization
and Mapping Pods (SCAMP).
SCAMP consists of two separate, but complimentary
devices. The Sidescan Swath Bathymetric Sonar (SSBS)
produces an image of the sea floor on either side
of the submarine. A second sonar, the High-Resolution
Sub-bottom Profiler (HRSP), sends signals into the
upper 200 meters of the seabed to make images of the
structure of underlying sediments.
"The fundamental problem that we're trying to solve
is how to do high-resolution imaging of the sea floor
in the Arctic in a fashion that is similar to what
we do in the open ocean from surface vessels," said
Dale Chayes, a senior staff associate at Columbia
University's Lamont-Doherty Earth Observatory (LDEO).
Chief scientist for SCICEX '99 Margo H. Edwards, of
the University of Hawaii, said SCAMP will help investigate
the character of the ocean-floor in waters that ice
cover previously made largely inaccessible to civilian
researchers. The SCICEX team will examine the Gakkel
Ridge, the slowest spreading mid-ocean ridge in the
world. Although the ridges usually are sites of volcanic
activity, scientists expect to find fewer eruptions
there. Less volcanism may make it possible to better
understand the other processes that contribute to
the creation of oceanic crust. Scientists also will
look for evidence of glacial scouring on the Chukchi
Borderland off Alaska that could provide evidence
of the extent and depth of ice cover during the last
Ice Age. They also will examine the Lomonosov Ridge
to obtain clues as to how the Amerasian basin, one
of several basins in the Arctic, may have formed.
This year's SCICEX mission includes an unusual venture
into Norwegian territorial waters to study undersea
sediments on the Yermak Plateau. Permission for the
excursion was secured by Yngve Kristofferson, a researcher
at the Institute for Solid Earth Physics at the University
of Bergen.
Sensors mounted on the submarine's "sail", probes launched
into the water that transmit data by wire and chemical
analyses of water samples collected while underway
will help determine the temperature, salinity and
composition of a strong circumpolar current that flows
around the boundary of the Arctic Ocean, said Tom
Weingartner, a marine scientist at the University
of Alaska-Fairbanks.The current transports water from
the Atlantic and Pacific oceans throughout the Arctic,
he noted. "Those water masses play a very important
role in the present-day status of the ice pack and
changes in the delivery would have an influence and
effect on ice distribution," he added. Such changes
could affect how much heat is reflected and absorbed
by the ice pack, which could, in turn, have global
implications.
Aboard Hawkbill, measurements of temperature and salinity
that can be made at very closely spaced increments
of time over a period of five days, would probably
require at least a month to conduct on an icebreaker,
he said. Such drastic differences in the duration
and frequency of the sampling could dramatically affect
its usefulness, he noted.
Editors: For more information, including abstracts
of previous SCICEX research, see: http://www.ldeo.columbia.edu/scicex/
For more on SCICEX '99, see: http://www.csp.navy.mil/scicex/index.htm
See also: Statement
by Dr. Rita Colwell, Director, National Science
Foundation, On Scientific Ice Expedition '99 (SCICEX)
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