hard facts: Underwater robot measures Antarctic sea ice
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[November 25, 2014]
By Will Dunham
WASHINGTON (Reuters) - Measuring the
thickness of Antarctic sea ice, an important gauge of environmental
conditions in this remote polar region in a time of global climate
change, has proven to be a tricky task. But an underwater robot is
providing a nice solution.
Satellite measurements can be skewed by surface snow, and some ice
floes are simply too difficult to reach by ship, even icebreakers,
to make direct measurements by drilling into them.
Scientists on Monday unveiled the first detailed, high-resolution
3-D maps of Antarctic sea ice, based on measurements of the
underside of ice floes by a remote-controlled submarine's
The measurements, covering an area of about 5.4 million square feet
(500,000 square meters), were made in 2010 and 2012 using a
so-called Autonomous Underwater Vehicle dubbed SeaBED launched off a
British and an Australian ship at three sites around the Antarctic
The scientists found sea ice thickness in some places up to about 55
feet (17 meters), with average thickness much less. The findings
indicate the ice cover may be thicker in some areas than previously
"Sea ice thickness and its variability in the Antarctic remains one
of the great unknowns in the climate system," said sea ice expert
Ted Maksym of Woods Hole Oceanographic Institution in Massachusetts.
Unlike in the Arctic region, where large declines in thickness have
been measured in recent decades, scientists do not really have a
good handle on the average Antarctic sea ice thickness or on any
possible trends there, Maksym said.
"By demonstrating that
detailed mapping of the thickness of the ice over large areas is
possible deep in the ice pack, this represents and important step
toward greater understanding of the processes that control the ice
volume, particularly in areas that have been difficult to access,"
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The twin-hull underwater robot, about 6 feet (2 meters) long,
operated at a depth of 65 to 100 feet (20 to 30 meters).
"While we have not measured all Antarctic sea ice thickness and
cannot state if Antarctic sea ice is getting thicker, this study is
a huge step toward the sort of expanded and more routine
measurements we will need to do to truly answer these questions,"
said polar oceanographer Guy Williams of the Institute of Marine and
Antarctic Studies in Australia.
The research was published in the journal Nature Geoscience.
(Reporting by Will Dunham; Editing by Cynthia Osterman)
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