Robo drones to study under 'forbidding' Antarctic ice shelf
Thursday, December 28, 2017, 13:42 - The increasingly common sight of cliff-sized chunks of glacial ice 'calving' into the Southern Ocean are an evocative expression of climate change. What concerns scientists more, however, is what may be happening beneath the Antarctic ice sheet, where relatively warm ocean water comes into contact with the chill ice.
University of Washington Professor of Oceanography, Craig Lee, is seeking answers, "The contribution of the great ice sheets in the Antarctic and Greenland are the largest sources of uncertainty in our numerical predictions of what sea level rise might be, how it might respond to climate change."
Early in 2018 Lee and Seattle colleagues are joining with scientists from around the world to deploy a fleet of robotic instruments that will explore the underbelly of the Antarctic Ice Shelf. It's a forbidding place according to team member, Knut Christianson. "The environment is more dynamic than you might expect. It's not a smooth surface underneath the ice shelf. There are canyons that are tens of hundreds of metres high. There are basal crevasses. It's a treacherous environment to explore without knowing a lot about it."
Three 'Seagliders', as they are known, will be released with researchers hoping they will spend the winter gathering information under the ice before finding their way to open water a year later, from where they will send their data.
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The Seagliders are not powered but will travel underwater using unique properties, as Craig Lee explains. "The gliders are powered in the sense that they change their buoyancy, so they either sink or they rise and they change their attitude, their pitch and their roll, and that allows them to project that vertical motion to the horizontal, so they can essentially glide from place to place in the same way that a glider in the air will glide from place to place."
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In September an iceberg 72 square miles in size broke away from Antarctica's Pine Island Glacier, the second such major iceberg calving of the year.
Scientists fear that as the ice shelf thins from beneath more rifts will appear, threatening the increased calving of ever bigger icebergs.
That's why this is where scientists hope to deploy the seagliders and floats, so that they can more accurately determine what will happen in the future.
Although the research team is confident that their instruments will send data from the ice shelf, as Craig Lee acknowledges, they're also realistic about the real danger that they might not recover the gliders and floats.
"As you can imagine, going under the ice shelves is so risky that we don't do it with people and it's risky enough with robotic instruments that more traditional funding agencies might be hesitant to assume that risk, he said. "There's a chance of complete failure when you do this."
The risk of failure was too high for conventional scientific research agencies, so Microsoft founder Paul Allen, a long-standing ocean climate change research supporter, stepped in, as Spencer Reeder, Director of Climate and Energies for Allen's foundation, explained. "I think the hope is that we get at least one of these instruments back out from underneath the ice shelf so we get some scientific data. Ideally, we get all of them back but I think we're certainly comfortable with losing a couple of these instruments, if that's what happens in the hopes that we get some data back. So that would be a success because it'll be data that's never before been obtained by the scientific community."
Along with the three seagliders, four ARGO float monitors will be deployed. They are able to control their own depth but cannot steer a course.
As the fleet disappear from view in the New Year, the hopes of an international research team will go with them. The fate of coastal communities around the world may lie in the data they send back.