Mapping technique will help predict impact of climate change on ice beds
A NEW high-precision map of Antarctica’s ice sheet bed will help scientists predict the impact of climate change on the frozen continent.
Glaciologists revealed the most accurate portrait yet of the contours of the land beneath Antarctica’s ice sheet and, by doing so, have helped identify which regions of the continent are going to be more, or less, vulnerable to future global warming.
The discoveries of the Bedmachine project include a bed under the Recovery and Support Force glaciers hundreds of metres deeper than previously thought, making those ice sheets more susceptible to retreat, and the world’s deepest land canyon below Denman Glacier in East Antarctica.
Other new finds include stabilising ridges that protect ice flowing across the Transantarctic Mountains and a bed geometry that increases the risk of rapid ice melting in the Thwaites and Pine Island glaciers sector of West Antarctica.
Study lead author Professor Mathieu Morlighem, of University of California, Irvine, said: “There were lots of surprises around the continent, especially in regions that had not been previously mapped in great detail with radar. Ultimately, Bedmachine Antarctica presents a mixed picture: ice streams in some areas are relatively wellprotected by their underlying ground features, while others on retrograde beds are shown to be more at risk from potential marine ice sheet instability.” The team used ice thickness information from 19 different research institutes dating back more than 50 years to 1967.
Bedmachine’s creators also utilised measurements from NASA’S Operation Icebridge campaigns, as well as ice flow velocity and seismic information, where available.
Professor Morlighem said: “Using Bedmachine to zoom into particular sectors of Antarctica, you find essential details such as bumps and hollows beneath the ice that may accelerate, slow down or even stop the retreat of glaciers.” Previous Antarctica mapping methods using radar soundings have been generally effective, albeit with some limitations.
But Bedmachine relies on a physics-based method of mass conservation to discern what lies between the radar sounding lines, utilising highly detailed information on ice flow motion that dictates how ice moves around the varied contours of the bed.