Off the shelf
Researchers combine data to understand more fully how Antarctica's ice is changing
Posted August 5, 2011
An international team of researchers has combined data from multiple sources to provide the clearest account yet of how much glacial ice surges into the sea following the collapse of Antarctic ice shelves.
The work, published online in July in the Journal of Glaciology, details recent ice losses while promising to sharpen future predictions of further ice loss and sea level rise likely to result from ongoing changes along the Antarctic Peninsula, one of the fastest warming regions on the planet.
“Not only do you get an initial loss of glacial ice when adjacent ice shelves collapse, but you get continued ice losses for many years — even decades — to come,” said Christopher Shuman , a researcher at University of Maryland, Baltimore County’s Joint Center for Earth Systems Technology (JCET) at the NASA Goddard Space Flight Center , in a press release.
“This further demonstrates how important ice shelves are to Antarctic glaciers,” added Shuman, lead author of the paper.
An ice shelf is a thick, floating tongue of ice, fed by a tributary glacier, extending into the sea off a land mass. Previous research has shown that the recent collapse of several ice shelves in Antarctica led to acceleration of the glaciers that feed into them.
Combining satellite data from NASA and the French space agency CNES , along with measurements collected by aircraft, the authors produced detailed ice loss maps from 2001 to 2009 for the main tributary glaciers of the Larsen A and B ice shelves , which collapsed in 1995 and 2002, respectively.
“The approach we took drew on the strengths of each data source to produce the most complete picture yet of how these glaciers are changing,” said Etienne Berthier, a co-author on the paper from the University of Toulouse, in the press release.
Berthier noted that the study relied on easy access to remote sensing information provided by NASA and CNES. The team used data from NASA sources including the Moderate Imaging Spectroradiometer (MODIS) instruments and the Ice, Cloud, and land Elevation Satellite (ICESat) .
The analysis reveals rapid elevation decreases of more than 150 meters for some glaciers. The authors’ analysis shows ice loss in the study area of at least 11.2 gigatons per year from 2001 to 2006. Their ongoing work shows ice loss from 2006 to 2010 was almost as large, averaging 10.2 gigatons per year.
“This study shows where the tracking of sea level rise is heading in terms of the level of detail possible and the instrumentation that can be brought to bear,” said Ted Scambos , another co-author and lead scientist at the University of Colorado’s National Snow and Ice Data Center , which is partly funded by the National Science Foundation .
“We’re showing that glacier changes can start fast, with a single climate or ocean ‘bang,’ but they have a long persistence,” Scambos said.