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Map reveals land beneath Antarctic ice sheet in unprecedented detail

Dec. 12 (UPI) — Scientists have successfully mapped the topography of the land beneath Antarctica’s ice sheet at high resolution by combining radar observations with ice volume and flow velocity data.

The new map will help scientists identify regions of ice that are likely to be more or less susceptible to the deleterious effects of climate change.

The results of the BedMachine project, published this week in the journal Nature Geoscience, revealed a variety of interesting topographical features.

Scientists found ridges that stabilize ice flowing across the Transantarctic Mountains, as well as structural features conducive to accelerated melting beneath the Thwaites and Pine Island glaciers in Western Antarctica.

To build the new map, scientists sourced data from a wide diversity of sources, including observations from 19 surveys of Antarctic ice thickness. The mapping model utilized ice flow velocity and seismic data, as well as topography measurements made by NASA’s Operation IceBridge surveys.

“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,” Mathieu Morlighem, an associate professor of Earth system science at the University of California, Irvine, said in a news release.

The project revealed a surprisingly deep bed beneath Antarctica’s Recovery and Support Force glaciers, which could accelerate their retreat. The new map also revealed the world’s deepest land canyon underneath East Antarctica’s Denman Glacier.

Traditionally, scientists have relied on radar to map Antarctica’s subglacial topography, but the method has limitations, especially when surveying fast-moving glaciers. The new BedMachine mapping effort mostly brought fundamental physics in the mix. Scientists designed a model to analyze ice volume and flow velocity data in order to reveal the obstacles and contours that ice is flowing up, down, over and around.

By combining radar data with measurements of ice volume and flow velocities, researchers were able to boost mapping resolutions. The new method was instrumental in revealing the true depth of the canyon beneath Denman Glacier.

“Older maps suggested a shallower canyon, but that wasn’t possible; something was missing,” Morlighem said. “With conservation of mass, by combining existing radar survey and ice motion data, we know how much ice fills the canyon — which, by our calculations, is 3,500 meters below sea level, the deepest point on land. Since it’s relatively narrow, it has to be deep to allow that much ice mass to reach the coast.”

As scientists continue to gather more detailed measurements of the amounts and movements of ice through Antarctica, BedMachine will be be able to produce even more detailed maps of the continent’s topography.

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Science News – UPI.com

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