Bedrock map reveals ice-free Antarctica
The soaring mountain peaks and deep valleys hidden beneath Antarctica’s ice sheet have been revealed in a new map produced using decades of survey data acquired by planes, satellites, ships and dog-drawn sleds.
Called BEDMAP2, the close-up view of Antarctica without its ice, is a comprehensive digital map of the bedrock, produced using more than 27 million points of data collected by a range of international partners.
The Australian Antarctic Division and the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC) played a major role in collecting some of this data over three seasons of aerial radar surveys out of Casey (through the ICECAP project), and through the Antarctica’s Gamburtsev Province project (AGAP) in 2008-09.
The map reveals deep troughs within the interior of the continent, where the bedrock is far below sea level, and rugged mountain ranges peaking at 3000 m – the height of the European Alps – but hidden below more than 1000 m of ice.
Scientists at the British Antarctic Survey (BAS), who produced the map, say it provides critical information for understanding how Antarctica might respond to climate change.
Australian scientist Dr Roland Warner said the map will enable scientists to use real bedrock to apply the physics of how ice flows across the Antarctic continent.
‘These improvements are central to more accurate predictions of how Antarctica will respond to climate change and what that means for future sea level,’ he said.
Dr Warner and his scientific colleagues, Drs Jason Roberts, Tas van Ommen and Glenn Hyland, were part of the ICECAP survey team based at Casey, between 2008 and 2011, which used radar on a Basler DC3 aircraft to map bedrock topography around the Totten and Denman glaciers, the Aurora Subglacial Basin and Law Dome, in East Antarctica.
Dr Warner says that when radar pulses penetrate the ice sheet and hit bedrock, they bounce back, and these returning echoes can be used to measure the thickness of the ice and hence the depth of the bedrock.
More survey data is needed to improve the detail of BEDMAP2 in two large regions; in the Australian Antarctic Territory between the Gamburtsev Mountains and the coast near Davis Station, and south of the Shackleton mountain range towards the South Pole.