Robotic sub

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.”

Studinger says that NASA’s ICESat 2, set for launch in 2015, will provide climate scientists with a far more detailed view of Antarctica. He believes that it is also essential, however, to continue collecting aerial data in the interim through missions such as NASA’s ICEBridge, which involves a series of airborne surveys. “We want to avoid an ‘Oh my God! moment’ when we realise [in 2015] that the situation is far worse than we thought.”

Also presenting at the AGU Fall meeting was a separate group of scientists with details of how they intend to send an unmanned vessel beneath Western Antarctica by 2013. The project, involving researchers from Northern Illinois University (NIU), US, is designed to investigate the physics and chemistry at the boundary between seawater and ice where melting is occurring.

Shaped like a long cigar, the 8.5-m robotic submarine weighs one tonne and is equipped with five cameras, along with an array of scientific instruments for recording and collecting geochemical data. To send the vessel beneath the ice, boreholes will be carved at selected sites to depths in the region of 800 m using a drill that melts through the ice with jets of hot water. Once underneath Antarctica, the vessel can be propelled up to a 2 km radius from the base of the borehole. It can also change its shape significantly to deploy its features, including a laser for measuring distances and a robotic arm with “fingers” for gathering samples.
Reed Scherer, one of the NIU scientists, told environmentalresearchweb that his team plans to deploy the submarine at two locations on the Ross ice shelf. He described how the vessel will be shipped from New Zealand before it is transported along a similar route to that taken by Captain Scott at the start of his fatal second mission to Antarctica in 1910.

Testing will begin on the vessel in March next year when it will be used in various scientific programmes taking place at Lake Tahoe, in the Sierra Nevada mountain range.