Colossal iceberg spurs speculation

The observation by UW–Madison scientists of two huge icebergs breaking off the Antarctic ice pack has set off a worldwide chain of concern.

Media from New York to Sydney, Australia, reported on the first 4,000-square-mile slab of ice, which the Antarctic Meteorological Research Center observed breaking free from the Ross Ice Shelf March 17. Then, March 30, using polar-orbiting satellite imagery, senior researcher Matthew Lazzara spotted a new, massive iceberg breaking free just east of the one discovered earlier.

Many experts have weighed in on what the continued breakup of the ice shelf could signify about global warming.

The massive icebergs peeling off of Antarctica’s Ross Ice Shelf may soon be adrift in the Ross Sea. Lazzara continues to monitor the icebergs via satellite.

If for no other reason, says Lazzara, the icebergs deserve heed because of their immense size.

“This is a very big iceberg, close to a record if not a new record,” Lazzara told the Irish Times (March 27) after the first berg broke away. “It’s not often that you see them of this magnitude.”

Images of the icebergs from two polar orbiting satellites are available through the UW–Madison Antarctic Meteorological Research Center, a research center supported by the National Science Foundation and housed within the Space Science and Engineering Center.

A National Oceanic and Atmospheric Administration polar orbiter, as well as a polar orbiter of the Defense Meteorological Satellite Program, gathered the data for the images, which were assembled at the UW–Madison Space Science and Engineering Center. Each satellite orbits the Earth, pole to pole, at an altitude of about 700 kilometers.

The Antarctic Meteorological Research Center is the only Antarctic site that provides real-time imagery. “The high- resolution satellite data that we receive enables us to track these bergs easily, at least in clear conditions,” Lazzara says.

The eastern end of B-15, the first large iceberg discovered earlier this month, can be seen hitting the new iceberg, corroborating geophysical predictions of “tidal jostling” stimulating another “calving,” or ice shelf breakage.

Real-time satellite imagery of the iceberg can be viewed at: http://uwamrc.ssec.wisc.edu/amrc/iceberg.html.