`Thursday March 22 1:03 PM ET
NASA Satellite Finds Massive New Antarctic Iceberg
http://dailynews.yahoo.com/htx/nm/20010322/sc/environment_iceberg_dc_1.html
WASHINGTON (Reuters) - A NASA satellite has detected the formation of a
15-mile crack on an Antarctic glacier that will lead to the creation of
a massive new iceberg, the U.S. space agency said on Thursday.
The rapidly spreading crack on the Pine Island Glacier was discovered by
the Landsat 7 satellite as it examined hidden continental features that
shape the future of the world's largest ice sheets, the National
Aeronautics and Space Administration said.
Glacier expert Robert Bindschadler of NASA's Goddard Space Flight Center
in Greenbelt, Maryland, said the crack first was detected on Jan. 16
during his daily review of new Landsat 7 images of Antarctica.
The thin crack extended more than two-thirds of the way across the
glacier, he said. There was no crack in a previous image 10 months
earlier.
Most of this crack formed very rapidly, in less than five weeks,'' Bindschadler said in a statement. Right now it is growing much more
slowly, at about 13 meters (40 feet) a day. My prediction is that the
crack will result in the calving of a major iceberg in probably less
than 18 months.''
Bindschadler contacted colleagues working with other earth-observing
sensors -- two instruments aboard NASA's Terra satellite, the Canadian
Space Agency's Radarsat and the European Space Agency's radar imager --
to try to determine when the fracture had formed and how quickly it was
growing, NASA said. The researchers managed to estimate the growth rate
of the crack and when it had formed by comparing observations from
different dates.
Landsat 7, a cooperative mission between NASA and the U.S. Geological
Survey, last month finished its second annual continent-wide mapping of
Antarctica.
NASA launched Landsat 7 in April 1999 and began routine scientific
observations in June of that year.
With its capability to detect features as small as 50 feet across,
Landsat 7 provides the most detailed observations available of the
remote continent, many parts of which have never been mapped at such
fine resolution before, the space agency said.
Landsat 7 passed over the world's southernmost continent 16 times a day
in its nearly pole-to-pole orbit, taking an average of 300 images each
week during the Antarctic summer (November to February) when the surface
is best illuminated by sunlight.
Because of a change in the spacecraft's observing schedule, this year's
collection of images promises to provide a wealth of new surface
features, NASA said. The new viewing angle altered the patterns of
shadows on the uniform, white surface, revealing subtle differences in
surface topography.
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