Surveillance satellite images of Antarctica's Dry Valleys region, made public Sept. 14 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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