Greenland's Petermann Glacier Calves (IMAGE)
Caption
The Petermann Glacier slides toward the sea along the northwestern coast of Greenland, terminating in a giant floating ice tongue. Like other glaciers that end in the ocean, Petermann periodically calves icebergs. A massive iceberg, or ice island, broke off the Petermann Glacier in 2010. Nearly two years later, another chunk of ice has broken free. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite observed the new iceberg calving on July 16, 2012. Because Aqua is a polar-orbiting satellite, it makes multiple passes over the Polar Regions each day. At 10:25 Coordinated Universal Time (UTC), the iceberg remained close to the glacier. By 12:00 UTC, the iceberg had moved northward down the fjord. Konrad Steffen, director of the Swiss Federal Institute for Forest, Snow, and Landscape Research, estimated that this iceberg was roughly half the size of the ice island that calved off of Petermann. Ted Scambos, lead scientist at the U.S. National Snow and Ice Data Center, added that this calving event marks a retreat of the Petermann Glacier “farther back than historical calving fronts.” A comparison of this calving to the 2010 event shows that this iceberg broke off the glacier tongue farther upstream. The crack along the southern margin of this new iceberg, however, has been visible in satellite imagery for several years. That rift was first identified in 2001. For Comparison image: http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=78556
Credit
NASA Earth Observatory image by Jesse Allen, using data from the Land Atmosphere Near real-time Capability for EOS (LANCE). Caption by Michon Scott with information from Walt Meier and Ted Scambos, National Snow and Ice Data Center; and Konrad Steffen, Swiss Federal Institute for Forest, Snow and Landscape Research.
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