Researchers Observe Mile-long Chunk of Ice Calving off Greenland Glacier

Jakobshavn Isbrae glacier

Cedit: DigitalGlobe

7/9/2010

NASA-funded researchers monitoring Greenland's Jakobshavn Isbrae glacier report that a 7 square kilometer (2.7 square mile) section of the glacier broke up on July 6 and 7, as shown in the image above. The calving front – where the ice sheet meets the ocean – retreated nearly 1.5 kilometers (a mile) in one day and is now further inland than at any time previously observed. The chunk of lost ice is roughly one-eighth the size of Manhattan Island, New York.

Research teams led by Ian Howat of the Byrd Polar Research Center at Ohio State University and Paul Morin, director of the Antarctic Geospatial Information Center at the University of Minnesota have been monitoring satellite images for changes in the Greenland ice sheet and its outlet glaciers. While this week's breakup itself is not unusual, Howat noted, detecting it within hours and at such fine detail is a new phenomenon for scientists.

"While there have been ice breakouts of this magnitude from Jakonbshavn and other glaciers in the past, this event is unusual because it occurs on the heels of a warm winter that saw no sea ice form in the surrounding bay," said Thomas Wagner, cryospheric program scientist at NASA Headquarters. "While the exact relationship between these events is being determined, it lends credence to the theory that warming of the oceans is responsible for the ice loss observed throughout Greenland and Antarctica."

The researchers relied on imagery from several satellites, including Landsat, Terra, and Aqua, to get a broad view of ice changes at both poles. Then, in the days leading up to the breakup, the team received images from DigitalGlobe's WorldView 2 satellite showing large cracks and crevasses forming.

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