Monday, December 20, 2010

Climate scientists sharpen their focus on Western Antarctica

James Dacey in Environmental Research Web: Ice shelves in Western Antarctica need to be monitored in much closer detail to build a clearer picture of how, and to what extent, ice is being lost. That was the clear message of two climate-research groups addressing journalists on Wednesday at the AGU Fall meeting in San Francisco, US.

A team of NASA scientists presented new maps of ice elevations in Antarctica, using data obtained from satellite missions such as the Ice, Cloud and Land Elevation Satellite (ICESat). They found that the Larsen ice shelf region in Western Antarctica continued to lose 12 GTonnes of ice per year between 2001 and 2006, accounting for 30% of all ice lost throughout the Antarctic peninsula. The Larsen A ice shelf broke up in 1995, while the Larsen B ice shelf disintegrated in 2002.

The reason for the continued melt, they believe, is likely due to the depleted ozone layer above Antarctica, which allows more UV radiation to feed into the local weather system. This extra energy triggers stronger winds, which in turn cause surface waters to move more rapidly. Warmer water from the circumpolar deep water then wells up towards the surface where it can get beneath the ice shelf and increase melting.

The NASA team has singled out another region in Western Antarctica known as Pine Island Bay, which the scientists say is losing ice at similar rates. “Ice shelves are important because they hold Antarctica’s ice back to some degree,” said Michael Studinger, one of the researchers based at the NASA Goddard Space Center. “We need to be there, to try to understand the processes that are driving these changes.”…

Pine Island Bay is tucked into a corner of the West Antarctic’s Walgreen Coast. Shot by NASA

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