Scientific campaign brings new insights to East Antarctica, broadens international collaboration
Posted April 3, 2009
The International Polar Year (IPY) officially came to an end in March. But the legacy of the two-year campaign to learn more about the world’s polar regions will likely last far into the future.
IPY scientists accomplished a dizzying amount of work in the Antarctic and Arctic — from mapping rugged mountain ranges buried hundreds of meters below the ice cap to making underwater observations below an ice shelf. They crisscrossed Antarctica on ski-equipped airplanes and on tracked vehicles. Ice-strengthened ships carried them to little-visited corners of the Southern Ocean, discovering new species in the frigid waters.
“The glimpses I’ve had of the data sets from this season and last year are astounding. I’m very pleased with our investments in IPY,” said Antarctic Sciences Division Director Scott Borg in the NSF’s Office of Polar Programs .
Launched in March 2007, the IPY actually spanned a two-year period to encompass seasonal research in both polar regions. Several of the larger Antarctic projects will continue for several more years.
One such project is ICECAP, for Investigating the Cryospheric Evolution of the Central Antarctic Plate , which just completed the first of three field seasons.
ICECAP researchers used a converted World War II-era DC-3 aircraft, outfitted with a suite of geophysical instruments, to fly over a region of East Antarctica to measure the thickness of the ice sheet and the texture, composition, density and topography of the bedrock below the ice.
The scientists — representing the United States, the U.K. and Australia — believe two subglacial basins that sit well below sea level, but hidden by the ice, could help speed the flow of ice into the ocean, raising sea level. Funding for the project came from NSF, the U.K. Natural Environment Research Council , the Australian Antarctic Division and the University of Texas . The researchers will use both U.S. and Australian facilities for the experiment.
“This is a real IPY project, where everybody is chipping a lot in,” noted Don Blankenship, a research scientist at the Jackson School’s Institute for Geophysics at the University of Texas at Austin and ICECAP principal investigator.
Another IPY project, Antarctica’s Gamburtsev Province (AGAP) , also used aircraft to survey East Antarctica and the bedrock below its icecap, but focused on a ragged mountain range buried in the ice that was first discovered more than 50 years ago during the International Geophysical Year (IGY) , a predecessor to the IPY. The project also used seismometers to image the area.
The sharp peaks showing in the raw data suggest the East Antarctic Ice Sheet formed quickly, because the slow grind of glacial movement didn’t wear down the mountains into a plateau.
“People will be digesting those data and interpreting them for quite a while,” Borg said. “We can look forward, in the next year or two, to a lot of papers describing the data, and more importantly, inferring things about the subglacial continent and the ice sheet.
“The AGAP and ICECAP projects are going to give us some very fundamental information about the continental surface beneath the ice cap. … Those are data sets that will be mined for decades into the future,” he added.
The aerial surveys by both projects should also help scientists locate the continent’s oldest ice, estimated to be more than 1 million years old. The oldest ice core recovered to date is about 800,000 years old, coming from the European Program for Ice Coring in Antarctica (EPICA) project conducted earlier this decade.
One-million-year-old ice isn’t just a big number. It represents a time when the duration of glacial cycles more than doubled. Some time before 1 million years, ice ages waxed and waned on a 41,000-year cycle. Now, it’s a 100,000-year cycle. Understanding what flipped the switch is important for climate change researchers trying to model the pull-and-tug between temperature and greenhouse gases.
“That’s why people are interested in getting a hold of this old ice,” Borg said. “The radar data sets will define areas where there is likelihood [of old ice].”