A remotely operated underwater vehicle called Nereid Under Ice (NUI) will participate in a mission to explore Greenland’s glaciers.
The mission, led by researchers from the University of Texas at Austin, will be launched in 2023 and will be the first time that Greenland’s glaciers — which form the world’s second largest ice sheet — will be seen up close underwater.
Designed by project partner the Woods Hole Oceanographic Institution (WHOI), NUI will encounter icebergs and tidal waves as it approaches within the base of the glaciers, returning with data and samples from the underwater environment.
The scientists’ primary focus will be on the sand walls (moraines) that support the glaciers and are thought to naturally stabilize the ice sheet. What they learn will reveal what supports the glaciers across the Greenland ice sheet, which could lead to more accurate model projections for future sea level rise.
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“The big uncertainty in Greenland’s contribution to sea level rise is how quickly the ice sheet will lose mass,” said Ginny Catania, a professor at UT’s Jackson School of Geosciences who is leading the trip. “We know how much sea level is stored in the ice sheet. We know that the climate is warming and the ice sheet is changing, but what we don’t know is the rate at which these glaciers will contribute to sea level rise.”
Funded by the WM Keck Foundation, the mission will investigate three glaciers in western Greenland that lie in the path of warming Atlantic waters but have responded in different ways. Since 2000, Kangilliup Sermia has experienced only a minor decline, Umiammakku Sermiat quickly retreated before stabilizing again in 2009, and Kangerlussuup Sermia has remained largely unaffected by warming.
“They provide a nice test case for ideas about what builds the moraines and how those processes might vary by location,” Catania said in a statement.
NUI makes its way underwater to the face of each glacier, mapping the topography of the seafloor. Once it’s at its target location, operators aboard a nearby support ship will remotely guide the robot’s manipulator arm to extract sediment cores from the glacier’s moraines. The vehicle will also collect samples from the huge plumes of sediment coming from beneath the glaciers.
According to co-project leader Mike Jakuba, a senior engineer at WHOI, the robot is designed with layers of built-in redundancy, including multiple thrusters, battery packs and navigation systems, to allow it to operate far from its support vessel in difficult conditions.
The primary communications link is a 10-mile optical fiber connecting NUI to its support ship, allowing operators to control the cameras and arm. The robot can still be controlled using underwater acoustics if the fiber breaks and will automatically return to a pick-up point if all communication is lost.
Jakuba said the mission will help scientists understand the crucial link between the world’s oceans and ice sheets.
“With NUI, the vision from the start was to provide a system that would project human presence into environments like these that require more access if we want to get a better handle on how the planet is changing,” he said.
Partner institutions include the University of Idaho, the University of Florida, and the University of Texas Institute for Geophysics (UTIG).
“This is high-risk, high-reward science, but it’s exactly the kind of bold move needed to address the pressing and socially relevant questions about climate change and geographic hazards,” said Demian Saffer, director of UTIG. “If successful, it could change our understanding of sea level rise.