Source: Australian Government – Antarctic Division
Ice sheet stability
ICECAP’s aerial surveys and instrument deployments aim to gather information to improve modelling of ice sheet dynamics, and our understanding of the role of the Antarctic ice sheet in global climate and sea level rise.
About 2200 billion tonnes of snow accumulates on the Antarctic continent each year, which is equivalent to about six millimetres of global sea level. This ice gain is offset by ice loss, as it flows from the interior to the coast, where it melts and calves off as icebergs.
“The structure and composition of the bedrock beneath the ice affects the path and speed of ice flow,” Dr Roberts said.
“So we want to know where there are mountain ranges, basins or flat plains under the ice and what type of rocks are under there. For example, are they ‘hot’, naturally radioactive rocks that can lubricate the movement of the ice sheet by contributing to the formation of liquid water at its base?”
To find out, the team conducts geophysical surveys in a venerable Basler BT-67 (a modernised DC3), bristling with instruments and sensors, including an ice-penetrating radar, laser altimeter, camera, gravimeter and magnetometer.
These instruments measure the thickness, internal structure and surface elevation of the ice, the presence of liquid water, and bedrock depth, structure and composition.
So far the international effort has mapped more than 700,000 kilometres of survey lines, and contributed to more than 3500 publications, including more than 100 that informed the Intergovernmental Panel on Climate Change reports.
ICECAP has also helped identify the location of ice more than one million years old (Australia’s Million Year Ice Core Project drilling site) at Little Dome C, about 1200 km from Casey (see radargram image).
The 1940s-era Basler refuelling at Bunger Hills near the Denman Glacier. Photo: Anders Kusk