Pine Island Glacier region focus of many research studies
Page 2/2 - Posted April 17, 2009
The results come at a time of increased interest in the polar regions thanks to a series of recent studies that warn Antarctica is more vulnerable to climate change than previously thought. NASA scientists, in a study led by Eric Rignot , reported last year that ice loss in Antarctica increased by 75 percent in the last 10 years due to a speed-up in the flow of its glaciers. The loss is now about equal to that from the Greenland Ice Sheet, and most of it appears to be occurring in the Amundsen Sea.
More recently, in February and March of this year during separate meetings of scientists in Europe, researchers reported that current estimates of sea-level rise appear too low. The International Scientific Congress on Climate Change in Copenhagen released a statement in March that said the average sea level around the world could rise by more than a meter by century’s end, double the 2007 prediction by the United Nation’s Intergovernmental Panel on Climate Change (IPCC) .
“The numbers from the last IPCC are lower … because it was recognized at the time that there was a lot of uncertainty about ice sheets,” said Rignot in a release from the Copenhagen meeting. He and Konrad Steffen , director of the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado at Boulder , led a study of the Larsen C Ice Shelf along the Antarctic Peninsula this past season. [See related story: House call.]
“As a result of the acceleration of outlet glaciers over large regions, the ice sheets in Greenland and Antarctica are already contributing more and faster to sea level rise than anticipated,” added Rignot, a professor of Earth System Science at the University of California Irvine and senior research scientist at NASA’s Jet Propulsion Laboratory .
Another scientist with NASA but with support from the National Science Foundation , Robert Bindschadler , will lead a team to Pine Island Glacier to drill through the ice sheet with a hotwater drill to study the ice-ocean interaction from a different perspective. That multi-year project is scheduled to begin work in 2009-10 after some preliminary work back in 2007-08. [See related story: Going to the edge.]
Jacobs said it is likely the CDW has been coming on the Antarctic continental shelf in the southeast Pacific for quite some time, as records dating back more than a century in the Bellingshausen Sea report similar water temperatures as today. What may be different, he said, is the volume of water being drawn onto the shelf, possibly due to changes in atmospheric circulation.
The researchers expect to return in 2011 to retrieve the 14 moorings deployed during this cruise, and hope the data they record can help answer some of the questions about the CDW. More immediate information may come from an ice-tethered profiler (ITP) , an instrument developed at the Woods Hole Oceanographic Institution .
The ITP consists of a cylindrical capsule, outfitted with oceanographic sensors that slide up and down on a line attached to a small capsule anchored on the surface of an ice floe. A weight at the bottom helps keep the line vertical. The instrument, the first of its kind used in the Antarctic, transmits measurements to the scientists in near-real time.
The scientists had a difficult time finding a suitable place for the ITP system because of the low ice cover this season, and the ‘fast’ ice on which the ITP was tethered has since gone adrift. But the good weather was a blessing in every other way, particularly for using the British autosub, Jacobs said.
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