ACE CRC glaciologists Dr Roland Warner and Dr Jason Roberts are now working on the third and final field survey for the international ICECAP Project. ICECAP will provide a better understanding of the configuration of critical sections of the East Antarctic Ice Sheet. It began in 2008, the International Polar Year, and this season ACE is funding 20 flights (40,000 kilometres) from Casey. Data from these flights will also advance ACE’s own Ice Sheet and Sea-Level Project. ICECAP stands for Investigating the Cryospheric Evolution of the Central Antarctic Plate. It is an aerogeophysical survey of the vast Aurora and Wilkes subglacial basins in East Antarctica. The project operates from McMurdo and Casey stations, and, apart from three ground traverses in the 1970s and 1980s, has provided the first detailed survey information to the south and west of Casey. Results from the first two field seasons have already shown that the area may be more vulnerable in the long term to climate change than previously thought. "We already have gained a clearer picture of the extent of the deep Aurora Subglacial Basin due south of Casey Station, where much of the bedrock is below sea-level," Dr Roberts said. Much of the ice from the Aurora Subglacial Basin flows to the sea through the Totten Glacier, one of the largest in Antarctica. "The Totten is changing, showing significant surface lowering, which is an unusual situation in East Antarctica," Dr Warner said. It has been known for some time that major glaciers in the Amundsen Sea sector of West Antarctica are thinning and speeding up. The thinning of the Totten has been discovered more recently. Exploring the region where the Totten Glacier reaches the ocean and begins to float, in a very deep bedrock trench behind Law Dome, is a major focus this season, along with exploring past connections between the Aurora Subglacial Basin and the Denman Glacier, another major outlet glacier several hundred kilometres to the west of Casey. The ICECAP project uses a ski-equipped DC-3T Basler aircraft which carries a range of geophysical instruments. These measure the surface elevation of the ice sheet and the properties of the bedrock and sediments beneath. The aircraft carries an ice-penetrating radar to measure the thickness of the ice sheet, map the basal conditions and detect internal reflecting layers in the ice sheet, which can be used to infer past changes in the ice sheet’s configuration. At the end of this season ICECAP’s focus will shift to data analysis and interpretation, and then, for the ACE scientists, to using the results in modelling of future ice sheet change. ICECAP involves scientists from the ACE CRC, the Australian Antarctic Division, the Laboratoire d’Études en Géophysique et Océanographie Spatiales, the Universities of Edinburgh and Bristol, and the University of Texas at Austin, with logistics support from the Australian Antarctic Division, United States Antarctic Program and Institut Paul Émile Victor.

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