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NSF PR 99-54 - September 14, 1999
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Newly Released Satellite Images of Antarctica a Valuable
Scientific Benchmark
Surveillance satellite images of Antarctica's Dry Valleys
region, made public today by President Clinton, will
be an important tool for establishing a baseline to
measure environmental fluctuations in one of the harshest
environments on Earth known to harbor life.
"The imagery released today represents a valuable
benchmark for studies of changes in the region," said
Scott Borg, who manages the U.S. Antarctic Program's
geology and geophysics program. The National Science
Foundation (NSF), through the USAP, coordinates numerous
scientific research efforts in the region.
Borg noted that the satellite images will provide
a basis for comparison with other data gathered in
the region, thereby adding to a growing database of
information that includes smaller-scale aerial photographs
and high-resolution commercial satellite images.
The President announced during a state visit to New
Zealand that the National Imagery and Mapping Agency
(NIMA) would make the satellite images available to
scientists. He said this action makes Cold War products
available for research on a continent reserved by
treaty for peace and science.
The President also noted that Vice President Gore has
been working for many years to open U.S. intelligence
image archives for scientific use. The release of
the Dry Valleys images and a previous release of satellite
images from the Arctic Ocean are milestones in the
process.
The NIMA image set includes a wide-angle snapshot,
taken by surveillance satellites in 1975, which will
help scientists compare conditions then in the Transantarctic
Mountains with other available images and data of
a more recent vintage.
The McMurdo Dry Valleys region is the only Polar desert
site in the National Science Foundation's Long-Term
Ecological Research (LTER) program, which consists
of a network of 21 ecosystem research sites extending
from Alaska to the continental United States to Puerto
Rico to Antarctica. The LTER sites represent a variety
of ecosystems, including grassland, desert, forest,
tundra, lake, stream, river, agricultural, coastal
systems, and urban systems. Two LTER sites are located
in Antarctica, one in the Antarctica Peninsula marine
ecosystem, near USAP's Palmer Station; and the other
in the Dry Valleys, near McMurdo Station.
The Dry Valleys are ecologically significant because
they are a region where life approaches its environmental
limits and they stand in stark contrast to most of
the world's other ecosystems, which exist under far
more moderate environmental conditions.
Less than two percent of the Antarctic continent is
ice-free. The Dry Valleys region is the largest of
several areas that are predominantly ice-free. The
perennially ice-covered lakes, ephemeral streams and
extensive areas of exposed soil within the Dry Valleys
are subject to low temperatures, limited precipitation
and salt accumulation. Unlike most other ecosystems,
lifeforms in the Dry Valleys are dominated by few,
sparsely distributed microorganisms, mosses, and lichens.
Higher forms of life are virtually non-existent.
Studying the ecological dynamics of the Dry Valleys
region is difficult because of its geographic isolation
and the fact that the area is in total darkness for
many months out of the year. Although changes are
known to take place in the glaciers, sand dunes, and
stream channels of the area, documenting those changes
has previously been done only through conventional
aerial photography, which covers only a very small
area at a time and other, similarly limited means.
"The data released today provide a uniform image over
the entire dry valleys region, at a single instant,
as context for a wide range of studies on the ecology,
hydrology, geology, and glaciology of the region,"
said Borg. "This comprehensive view, at a single point
in time, is a unique aspect of these images."
Editors: High-resolution digital versions
of the declassified images may be downloaded from:
http://www.nsf.gov/od/opp/antarctic/imageset/satellite/start.htm
The images are at 300 dpi.
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