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10 MTR April 2009 news Autosub, a robot submarine built and developed by the UK's National Oceanography Center, Southampton, has reportedly completed a high-risk campaign of six missions traveling under an Antarctic glacier. Autosub has been explor- ing Pine Island Glacier, a floating exten- sion of the West Antarctic ice sheet, using sonar scanners to map the seabed and the underside of the ice as it juts into the sea. Scientists hope to learn why the glacier has been thinning and accelerating over recent decades. Pine Island Glacier is in the Amundsen Sea, part of the South Pacific bordering West Antarctica. Changes in its flow have been observed since the early 1970s, and together with neighboring gla- ciers it is currently contributing about 0.25 mm a year to global sea level rise. Steve McPhail led the Autosub team dur- ing the 10-day survey. "Autosub is a com- pletely autonomous robot: there are no connecting wires with the ship and no pilot. Autosub has to avoid collisions with the jagged ice overhead and the unknown seabed below, and return to a pre-defined rendezvous point, where we crane it back onboard the ship. "Adding to the problems are the sub zero water temperatures and the crushing pressures at 1000 m depth. All systems on the vehicle must work perfectly while under the ice or it would be lost. There is no hope of rescue 60 km in, with 500 m of ice overhead." An international team of scientists led by Dr. Adrian Jenkins of British Antarctic Survey and Stan Jacobs of the Lamont- Doherty Earth Observatory, Columbia University, New York on the American ship, the RVIB Nathaniel B Palmer, has been using the robot sub to investigate the underside of the ice and measure changes in salinity and temperature of the sur- 60km into an Ice Shelf Cavity Searching for Signs of Melting MTR#3 (1-17).qxd 3/27/2009 1:44 PM Page 12
