Arctic Ice Revealed
Arctic Ice Revealed
An orbiting radar has cut through the clouds and
dark of night to monitor the ebb and flow of Arctic ice. Scientists
say the data could reveal trends in global climate change.
August
22, 2000 -- NASA researchers have new insights into the mysteries
of Arctic sea ice, thanks to the unique abilities of Canada's
RADARSAT satellite. The Arctic is the smallest of the world's
four oceans, but it may play a large role in helping scientists
monitor Earth's climate shifts.
Using RADARSAT's
special sensors to take images at night and to peer through clouds,
NASA researchers can now see the complete ice cover of the Arctic.
This allows tracking of any shifts and changes, in unprecedented
detail, over the course of an entire winter. The radar-generated,
high-resolution images are up to 100 times better than those
taken by previous satellites.
Above: A global view of the Arctic Ocean. Using advanced
radar that sees through all weather conditions, researchers will
now be able to determine how the Earth's warming may be changing
the Arctic's sea ice cover. Sea ice in the polar region is an
important indicator of global climate conditions. Credit: NASA/JPL.
Using this new information, scientists at NASA's Jet Propulsion
Laboratory (JPL), Pasadena, CA, can generate comprehensive maps
of Arctic sea ice thickness for the first time. "Before
we knew only the extent of the ice cover," said Dr. Ronald
Kwok, JPL principal investigator of a project called Sea Ice
Thickness Derived From High Resolution Radar Imagery. "We
also knew that the sea ice extent had decreased over the last
20 years, but we knew very little about ice thickness.'"
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Until now, observations of polar sea ice thickness have been available for specific areas, but not for the entire polar region.
The new radar mapping technique has also given scientists a close look at how the sea ice cover grows and contorts over time. "Using this new data set, we have the first estimates of how much ice has been produced and where it formed during the winter. We have never been able to do this before," said Kwok. "Through our radar maps of the Arctic Ocean, we can actually see ice breaking apart and thin ice growth in the new openings."
RADARSAT gives researchers a piece of the overall puzzle every three days by creating a complete image of the Arctic. NASA scientists then put those puzzle pieces together to create a time-lapsed view of this remote and inhospitable region. So far, they have processed one season's worth of images.
Above: These two radar images of ice covering a 96 x
128 km area of the Baufort Sea, north of the Alaskan coast, were
captured nine days apart. Brighter features are older thicker
ice and the darker areas show young, recently formed ice. The
earlier image is shown on the left. Within the nine-day span,
large and extensive cracks formed in the ice cover as a result
of ice movement.
"We can see large cracks in the ice cover, where most ice
grows," said Kwok. "These cracks are much longer than
previously thought, some as long as 1200 miles (2000 kilometers)."
Kwok continued, "If the ice is thinning due to warming,
we'll expect to see more of these long cracks over the Arctic
Ocean."
Scientists believe this is one of the most significant breakthroughs
in the last two decades of ice research. "We are now in
a position to better understand the sea ice cover and the role
of the Arctic Ocean in global climate change," said Kwok.
Radar
can see through clouds and any kind of weather system, day or
night, and as the Arctic regions are usually cloud-covered and
subject to long, dark winters, radar is proving to be extremely
useful. However, compiling these data into extremely detailed
pictures of the Arctic is a challenging task.
"This is truly a major innovation in terms of the quantities
of data being processed and the novelty of the methods being
used," said Verne Kaupp, Director of the Alaska SAR Facility
at the University of Alaska, Fairbanks.
Above: Scientist are also using RADARSAT data to study
Antarctica's evolving ice sheets. This low-resolution radar map
of Antarctica was released in 1999. [more
information]
The mission is a joint project between JPL, the Alaska
SAR Facility, and the Canadian Space Agency. Launched by NASA
in 1995, the RADARSAT satellite is operated by the Canadian Space
Agency. JPL manages the Sea Ice Thickness Derived From High-Resolution
Radar Imagery project for NASA's Earth Science Enterprise, Washington,
DC. The Earth Science Enterprise is dedicated to studying how
natural and human-induced changes affect our global environment.
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Press Release #00-128 Production Editor: Dr. Tony Phillips Curator: Bryan Walls Media Relations: Steve Roy Responsible NASA official: John M. Horack |