Australia: For the first time, scientists have developed a 3D map of the surface beneath the sea ice in eastern Antarctica. The map will help reveal the amount of ice in the region, which is important for understanding how climate change is affecting Antarctica.
The Australian researchers, on a two-month voyage to the region on the Australian Antarctic Division”s icebreaker Aurora Australis, used helicopters and a special, autonomous underwater vehicle (AUV) to produce a map of both the top and underside of the extensive sea ice, finding peaks and valleys that resemble land topography. This data is a valuable addition, because although satellites can keep tabs on the amount of ice cover, they aren”t good at measuring the ice”s thickness or volume — information this new 3D map provides.
Project leader Guy Williams, from the Antarctic Climate and Ecosystems Cooperative Research Centre, said in a statement that the technology represents a huge advance over what researchers had previously used. “In the past, we took drill-line measurements or observed ice thickness as we moved through [the ice] on a ship, but with the AUV, we can now use multi-beam sonar to measure an entire ice floe in unprecedented detail,” he said.
The underwater vehicle swims 65 feet (20 metres) below the ice, traveling in a “lawnmower” grid-pattern and using sonar to make a map of the ice. Data collected by the vehicle is stored in an onboard computer and converted into a 3D map at the end of each survey.
“The thickness of sea ice is regarded amongst climate scientists as one of the crucial indicators of [climate] change,” said researcher Jan Lieser. “When we know how the thickness of sea-ice cover is changing over time, we can estimate the influence of global climate change on the Antarctic environment,” he added.