Wednesday, July 18, 2012

Giant Iceberg Breaks Off Greenland

The Petermann Glacier (pictured above) grinds and 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 into the nearby Arctic Ocean.  A massive iceberg, or ice island, broke off of the Petermann Glacier in 2010. Now, nearly two years later, another chunk of ice has broken free.

The Moderate Resolution Imaging Spectroradiometer, or MODIS, on NASA’s Aqua satellite observed the new iceberg calving and drifting downstream on July 16–17, 2012. Because Aqua is a polar-orbiting satellite, it makes multiple passes over the polar regions each day.

Ted Scambos, lead scientist at the U.S. National Snow and Ice Data Center, noted that this calving event marks a retreat of the Petermann Glacier “farther back than historical calving fronts.” A comparison of this event 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.

Source and Image Credit: NASA