Page 2/2 - Posted October 8, 2010
Ridge is a game-changer
“The ridge has changed the show,” said Tim Stanton , a scientist in the Oceanography Department at the Naval Postgraduate School . His lab designs, builds and deploys unique ocean profilers, a system of instruments that moves vertically up and down on a cable through the entire water column, with power and communications at the surface. Its job is to measure and monitor the complex ocean currents swirling below the ice.
The ridge is a game-changer because it means that any deployment of the ocean profiler upstream of the ridge — remember that the ice flows toward the ocean — might have hit the raised seafloor. Now any upstream deployment of the instrument package will have to account for the ridge.
The ridge was discovered in 2009 during a research cruise aboard the USAP’s Nathaniel B. Palmer , led by chief scientist Stan Jacobs , an oceanographer at Lamont-Doherty Earth Observatory at Columbia University . [See previous article: Pine Island cruise.]
A British team aboard the ship sent a robotic submarine underneath the ice shelf where it mapped various properties of the underwater cavity, discovering the ridge along the way. [See previous article: Rapid retreat.]
“It was really a blessing to have that information. Otherwise, it was a blank slate,” Bindschadler said of the data retrieved by the yellow submarine. “The annoying thing about the ridge is that our instruments can’t touch the floor.”
The British are also collaborators on the PIG project. A British Antarctic Survey (BAS) plane will fly over the region from BAS’ base at Rothera Station off the Antarctic Peninsula this year. The plane’s radar will provide additional details about the ice shelf that will be useful for planning the 2011-12 and 2012-13 field campaigns.
“[Pine Island] has been a focus for us for quite a few years,” said David Vaughan , a scientist at BAS who attended the strategy session at Penn State. “Pine Island is the biggest red dot” for climate change in Antarctica, he added.
Two American teams will also head to the Ice this season on separate missions.
David Holland will lead a two-person team to the edges of the glacier to recover an existing automatic weather station (AWS) he installed three years ago and move it to the PIG camp being set up this season.
Meanwhile, Stanton and a separate team will join New Zealand researchers at a field camp near Erebus Ice Tongue, a glacier that pokes out about 10 kilometers into McMurdo Sound from the Ross Island coastline near Cape Evans.
The U.S. scientists will conduct a second test of the ocean profiler system on the sea ice. Last year’s “dress rehearsal” of the project successfully punched through the 200-meter-thick section of ice shelf near McMurdo Station with a hotwater drill. [See previous article: Dress rehearsal.]
It was the first time scientists had deployed such a complex ocean profiler beneath an Antarctic ice shelf, even discovering a wee marine organism with a borehole camera that preceded the profiler down the fresh hole.
However, the system malfunctioned shortly after the team left. Stanton believes he has worked out the problem and wants another shot at testing the equipment before the team does it for real in about a year.
By then there will be little room for mistakes among the crevasse fields of the Pine Island Glacier Ice Shelf.
“We’re going to be eager to bang this camp in,” Stanton said.
NSF-funded research in this story: Robert Bindschadler and Alberto Behar, Goddard Space Flight Center, Award No. 0732906 ; Tim Stanton, Naval Postgraduate School, Award No. 0732926 ; David Holland, New York University, Award No. 0732869 ; Sridhar Anandakrishnan, Penn State University, Award No. 0732844 ; Miles McPhee, McPhee Research Company, Award No. 0732804 ; and Martin Truffer, University of Alaska, Fairbanks, Award No. 0732730 .
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