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The NASA Antarctic Announcement

From: UFO UpDates - Toronto <ufoupdates.nul>
Date: Thu, 15 Feb 2007 15:26:50 -0500
Fwd Date: Thu, 15 Feb 2007 15:26:50 -0500
Subject: The NASA Antarctic Announcement





From: NASA News <hqnews.nul>
To: UFO UpDates - Toronto <ufoupdates.nul>
Date: Thu, 15 Feb 2007 14:34:28 -0500
Subject: Joint NASA Study Reveals Leaks In Antarctic 'Plumbing System'


Feb. 15, 2007

Tabatha Thompson
Headquarters, Washington
202-358-3895

Ed Campion
Goddard Space Flight Center, Greenbelt, Md.
301-286-0697

RELEASE: 07-42

Joint NASA Study Reveals Leaks In Antarctic 'Plumbing System'


WASHINGTON - Scientists using NASA satellites have discovered an
extensive network of waterways beneath a fast-moving Antarctic
ice stream that provide clues as to how "leaks" in the system
impact sea level and the world's largest ice sheet. Antarctica
holds about 90 percent of the world's ice and 70 percent of the
world's reservoir of fresh water.

With data from NASA satellites, a team of scientists led by
research geophysicist Helen Fricker of the Scripps Institution
of Oceanography, La Jolla, Calif., detected for the first time
the subtle rise and fall of the surface of fast-moving ice
streams as the lakes and channels nearly a half-mile of solid
ice below filled and emptied. Results were presented Thursday at
the annual meeting of the American Association for the
Advancement of Science (AAAS) in San Francisco. The study will
be published in the Feb. 16 issue of Science magazine.

"This exciting discovery of large lakes exchanging water under
the ice sheet surface has radically altered our view of what is
happening at the base of the ice sheet and how ice moves in that
environment," said co-author Robert Bindschadler, chief
scientist of the Laboratory for Hydrospheric and Biospheric
Sciences at NASA's Goddard Space Flight Center, Greenbelt, Md.

"NASA's state-of-the-art satellite instruments are so sensitive
we are able to capture an unprecedented three-dimensional look
at the system beneath the thick ice sheet and measure from space
changes of a mere 3 feet in its surface elevation. That is like
seeing an elevation change in the thickness of a paperback book
from an airplane flying at 35,000 feet."

The surface of the ice sheet appears stable to the naked eye,
but because the base of an ice stream is warmer, water melts
from the basal ice to flow, filling the system's "pipes" and
lubricating flow of the overlying ice. This web of waterways
acts as a vehicle for water to move and change its influence on
the ice movement. Moving back and forth through the system's
"pipes" from one lake to another, the water stimulates the speed
of the ice stream's flow a few feet per day, contributing to
conditions that cause the ice sheet to either grow or decay.
Movement in this system can influence sea level and ice melt
worldwide.

"There's an urgency to learning more about ice sheets when you
note that sea level rises and falls in direct response to
changes in that ice," Fricker said. "With this in mind, NASA's
ICESat, Aqua and other satellites are providing a vital public
service."

In recent years, scientists have discovered more than 145 subglacial
lakes, a smaller number of which composes this "plumbing system" in
the Antarctic. Bindschadler and Fricker; Ted Scambos of the National
Snow and Ice Data Center in Boulder, Colo.; and Laurence Padman of
Earth and Space Research in Corvallis, Ore.; observed water
discharging from these under-ice lakes into the ocean in coastal
areas. Their research has delivered new insight into how much and how
frequently these waterways "leak" water and how many connect to the
ocean.

The study included observations of a subglacial lake the size of
Lake Ontario buried under an active area of west Antarctica that
feeds into the Ross Ice Shelf. The research team combined images
from the Moderate Resolution Imaging Spectroradiometer (MODIS)
instrument aboard NASA's Aqua satellite and data from the
Geoscience Laser Altimeter System (GLAS) on NASA's Ice Cloud and
Land Elevation Satellite (ICESat) to unveil a multi-dimensional
view of changes in the elevation of the icy surface above the
lake and surrounding areas during a three-year period. Those
changes suggest the lake drained and that its water relocated
elsewhere.

MODIS continuously takes measurements of broad-sweeping surface
areas at three levels of detail, revealing the outline of under-
ice lakes. ICESat's GLAS instrument uses laser altimetry
technology to measure even the smallest of elevation changes in
the landscape of an ice sheet. Together, data from both have
been used to create a multi-year series of calibrated surface
reflectance images, resulting in a new technique called
satellite image differencing that emphasizes where surface
slopes have changed.

For more information online about NASA and agency programs, visit:

www.nasa.gov


-end-





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