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Changes in the area and volume of the two polar ice sheets in Antarctica
(fig. 1) and Greenland are intricately linked to changes in global climate,
and could result in sea-level changes that could severely affect the densely
populated coastal regions on Earth. Melting of the West Antarctica part
of the Antarctic ice sheet alone could cause a sea-level rise of approximately
6 m. The potential sea-level rise after melting of the entire Antarctic
ice sheet is estimated to be 73 m. In spite of its importance, the mass
balance (the net volumetric gain or loss) of the Antarctic ice sheet is
poorly known; it is not known whether the ice sheet is growing or shrinking.
As a result, measurement of changes in the Antarctic ice sheet has been
given a very high priority in recommendations by the Polar Research Board
of the National Research Council, by the Scientific Committee on Antarctic
Research (SCAR), and by the National Science Foundation.s Office of Polar
Programs.
An extensive archive of early 1970s Landsat 1, 2, and 3 Multispectral
Scanner (MSS) images of Antarctica was the impetus for the U.S. Geological
Survey (USGS), in cooperation with Scott Polar Research Institute (Cambridge,
U.K.), to carry out a comprehen-sive analysis of the glaciological features
of the coastal regions of Antarctica. The project was later modified to
include analysis of coastal change using Landsat 4 and 5 MSS and Thematic
Mapper (TM) images from the late 1980s/early 1990s, declassified 1963
Argon (Corona Program) images, 1992 and 1995 European Space Agency) (ESA)
Remote Sensing Satellite (ERS) radar images, 9 September.2 October 1997
RADARSAT images, Landsat 7 Enhanced Thematic Mapper (ETM+) images (April
1999.May 2003), and Moderate Resolution Imaging Spectroradiom-eter (MODIS)
images (post-mid-December 1999). The different data sets allow determi-nation
of coastal change in Antarctica for >30 years where suitable images
exist. Coastal change has been most pronounced on the Antarctic Peninsula
in the last few decades, where the Wordie Ice Shelf has practically disappeared,
the northern part of the Larsen Ice Shelf has disintegrated, and other
ice shelves are also changing. Cooperation with other Antarctic mapping
groups now includes scientists from Italy, Russia, Norway, Canada. Australia,
Argentina, and Germany.
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