Mapping Antarctic Ice In Motion
Felicity Barringer, The New York Times
Put the arguments over how fast Antarctic ice is melting to one side for the moment. The latest study of the southern continent, by a group of scientists led by Eric Rignot of the University of California, Irvine, shows how fast the ice rivers are moving and where they are going.
The map of ice in motion, which traces parts of the eastern Antarctic region that have previously been hard to see, offers a new and powerful tool for the study of the dynamics of ice melting into the southern seas.
The data used in the map was obtained from satellites in polar orbit. Dr. Rignot said in an interview that 3,000 different orbital tracks were studied, then combined into a mosaic of the continent.
The study was published on Thursday in Science Express. The work was done in conjunction with NASA, which said in a press release that the map, showing glaciers moving from the deep interior to its coast, “will be critical for tracking future sea-level increases from climate change.”
Dr. Rignot said that one important finding that emerged during the mapping effort was that inland glaciers do not degrade solely because the ice beneath is being crushed by the ice above.
It is impossible to explain the extent of motion revealed in the study, he said, without assuming that the deformation process is supplemented by melting at the base of the ice. “We have to account for a significant component of sliding on ice,” he said. Dr. Rignot is also affilated with NASA’s Jet Propulsion Laboratory.
The scientists’ mapping technique involves using radar pulses to identify unique formations like geological fingerprints several meters below the surface and then tracking these as they move. Some moved as much as 800 feet each year.
The researchers were able to use billions of individual data points sent by satellites that belong not just to the United States but also to the European, Canadian and Japanese space agencies, the Alaska Satellite Facility at the University of Alaska at Fairbanks and MacDonald, Dettwiler and Associates, a Canadian aerospace company.
Both NASA and the University of California, Irvine, also posted an animation of the ice’s movement.
