A team of ocean robots deployed in January 2018 have, over the past year, been the first self-guided ocean robots to successfully travel under an ice sheet and return to report long-term observations.

Beyond mere survival, the robotic mission — a partnership between the 91̽»¨’s College of the Environment, the 91̽»¨Applied Physics Laboratory, the Lamont-Doherty Earth Observatory of Columbia University, the Korean Polar Research Institute and Paul G. Allen Family Foundation — has ventured 18 times under the ice shelf, repeatedly reaching more than 40 kilometers (25 miles) into the cavity, among the farthest trips yet into this treacherous environment.

“This is the first time any of the modern, long-endurance platforms have made sustained measurements under an ice shelf,” said , a 91̽»¨professor of oceanography and member of the Applied Physics Laboratory. “We made extensive measurements inside the cavity. Gliders were able to navigate at will to survey the cavity interior, while floats rode ocean currents to access the cavity interior.

“It’s a major step forward,” Lee added. “This is the first time we’ve been able to maintain a persistent presence over the span of an entire year.”

The project funded by Paul G. Allen Family Foundation seeks to demonstrate the technology and gather more data from the underside of ice shelves that are buttressing the much larger ice sheets. Direct observations of how warmer seawater interacts with the underside of ice shelves would improve models of ice sheet dynamics in Antarctica and Greenland, which hold the biggest unknowns for global sea level rise.

“Some ice sheets terminate in large ice shelves that float out over the ocean, and those act as a buttress,” Lee said. “If the ice shelves collapse or weaken, due to oceanic melting, for example, the ice sheets behind them may accelerate toward the sea, increasing the rate of sea level rise.”

“Most of the uncertainty in global sea level rise predictions for decades to centuries is from ice sheets, which could contribute from 1 foot to as much as 6 feet by 2100,” said , a research professor of oceanography at the Lamont-Doherty Earth Observatory. “A key driver is interaction with the ocean heat and these new tools open tantalizing perspectives to improve on current understanding.”

The mission set out in late 2017 to test a new approach for gathering data under an ice shelf, and on Jan. 24, 2018, devices were dropped from the Korean icebreaker R/V Araon. This week, two self-navigating Seagliders reached the milestone of one year of continuous operation around and under the ice shelf.

Robot submarines operated by the British Antarctic Survey, known as Autosub3 and , successfully completed 24- to voyages in 2009, 2014 and 2018. These missions surveyed similar distances into the cavity but sampled over shorter periods due to the need for a ship support.

By contrast, the U.S.-based team’s technology features smaller, lighter devices that can operate on their own for more than a year without any ship support. The group’s experimental technique first moored three acoustic beacons to the seafloor to allow navigation under the ice shelf. It then sent three Seagliders, swimming robots developed and built at the UW, to use preprogrammed navigation systems to travel under the ice shelf to collect data.

The mission also deployed four UW-developed EM-APEX floating instruments that drift with the currents at preselected depths above the bottom, or below the top of the cavity, while periodically bobbing up and down to collect more data. All four of these drifting instruments successfully traveled deep under the ice shelf with the heavier, saltier water near the seafloor. Three were flushed out with fresh meltwater near the top of the ice cavity about six to eight weeks later. One float remained under for much longer, only to reappear Jan. 5.

During the past year, the fleet of robots has reached several milestones:

• A Seaglider reached a maximum distance of 50 kilometers (31 miles) from the edge beneath Dotson Ice Shelf in West Antarctica;
• The Seagliders made a total of 18 trips into the cavity, with the longest trip totaling 140 kilometers (87 miles) of travel under the shelf;
• The Seagliders also made 30 surveys along the face of the ice shelf;
• After one year, two out of three Seagliders are reporting back;
• In the current Southern Hemisphere summer, one of the Seagliders has gone back under the ice shelf and has completed two roughly 100-kilometer (62-mile) journeys;
• Another Seaglider will begin its second year of sampling at the face of the ice shelf;
• Three drifting floats journeyed under the Dotson Ice Shelf and back out in early 2018;
• After 11 months under the ice, the fourth float reported home in mid-January 2019 close to the neighboring Crosson Ice Shelf.

Researchers are now analyzing the data for future publication, to better understand how seawater interacts with the ice shelves and improve models of ice sheet behavior.

Four months of data show three Seagliders dropped from the ship in late January, then traveling toward the Dotson Ice Shelf (white). Two Seagliders (pink and orange) venture under the ice sheet in summer, while a third (yellow) samples along the face. The gliders then spend the colder months sampling along the ice sheet’s edge. Meanwhile, the drifting floats are dropped closer to the ice edge in late February. The teal tracks show how they drift under the ice sheet and then get flushed out in late March. A fourth float drifted to the right of this image, reaching a neighboring ice sheet.

Other members of the team are , a 91̽»¨assistant professor of Earth and space sciences who is currently in Antarctica on a separate project; , and at the Applied Physics Laboratory; and the Korean Polar Research Institute, or KOPRI.

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For more information on the Seaglider component, contact Lee at craiglee@uw.edu or 206-685-7656; on the drifting floats, contact Girton at girton@uw.edu; and for more general questions, contact Dutrieux at pierred@ldeo.columbia.edu or 845-365-8393.

Images and video are available for download at .

More than 100 scientists and crew from more than 20 U.S. research institutions will embark for NASA’s month-long , or EXPORTS, oceanographic campaign. The 91̽»¨ is leading one of the expedition’s , with several others led by 91̽»¨School of Oceanography alumni who are now faculty members at other institutions.

A NASA event Aug. 9 in Seattle will kick off the expedition.

Two large research vessels — the R/V Revelle and R/V Sally Ride, both operated by the Scripps Institution of Oceanography at University of California, San Diego — will sail west 200 miles into the open ocean. From these seaborne laboratories, researchers will explore plankton life and the chemical and physical properties of the ocean from the surface down a half-mile to the “” — a region below the sunlit surface layer where carbon from the plankton can be sequestered, or kept out of the atmosphere, for periods ranging from decades to millennia.

“By employing two ships we’ll be able to observe complex oceanographic processes that vary both in space and time that we wouldn’t be able to capture with a single ship,” , program manager for Ocean Biology and Biogeochemistry at NASA Headquarters said in a NASA .

and , both oceanographers at the 91̽»¨Applied Physics Laboratory who also hold faculty appointments with the 91̽»¨School of Oceanography, are part of the using two robotic instruments developed at the UW. The first is a 6.5-foot-long underwater vehicle called the Seaglider that will gather measurements as deep as 1 kilometer, more than half a mile. The second is a float designed to follow the motion of water in the upper ocean that will be used to collect measurements just below the sunlit upper layer.

The 91̽»¨team will use these and other autonomous tools to track upper-ocean community structure, sinking organic matter, currents and migrating zooplankton at two measurement sites in the ocean.

“Understanding, and eventually predicting, the oceans’ role in fixing and exporting carbon to depth will require sustained, long-term measurements,” Lee said. “EXPORTS takes us a step farther down that path, by advancing the use of long-endurance robotic vehicles — profiling floats and underwater gliders — for collecting biological and biogeochemical observations.”

Seven years in the making, the 2018 campaign has been a huge undertaking, said , EXPORTS science lead from the University of California, Santa Barbara.

“The impact the EXPORTS data will have for understanding how our planet is changing will be significant,” Siegel said. “NASA’s ocean-color satellite record shows us these ecosystems are highly sensitive to climate variability. Changes in phytoplankton populations affect the marine food web, since phytoplankton are eaten by many animal species, big and small.”

The projects are being funded by NASA and the National Science Foundation. Other participating institutions include Oregon State University, Monterey Bay Aquarium Research Institute, Woods Hole Oceanographic Institution, Skidmore College, University of Rhode Island, University of North Carolina at Chapel Hill, NASA Goddard Space Flight Institute, Bowdoin College and the Virginia Institute of Marine Science.

Watch a video about the UW-developed Seaglider technology:

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For more information, contact Lee at craiglee@uw.edu or 206-685-7656. For information on EXPORTS, visit . Reporters can RSVP for the Aug. 9 before July 19.

Adapted from a NASA press release: ““

A new partnership between the 91̽»¨’s College of the Environment, the 91̽»¨Applied Physics Laboratory and Paul G. Allen Philanthropies will use a robotic network to observe the conditions beneath a floating Antarctic ice shelf.

Ice shelves act as buttresses that restrain the flow of inland ice into the sea, which under a warmer climate could trigger many feet of global sea level rise, on a timeline that is largely unknown. Observations in the water-filled caves under ice shelves could help explain how warmer seawater interacts with the glacier’s underbelly.

The team members performed a final test Nov. 6 in Puget Sound before the instruments are deployed in the Southern Ocean from a Korean research ship, the R/V Araon, that departs from New Zealand in mid-December.

“A project as experimental as this one would be impossible without the support of Paul G. Allen Philanthropies,” said , a 91̽»¨professor of oceanography and oceanographer at the 91̽»¨Applied Physics Laboratory. “This is a high-risk, proof-of-concept test of using robotic technology in a very risky marine environment.”

The ice shelf is the floating portion of a glacier that extends seaward from inland ice, which rests on bedrock. Most of Antarctica does not yet show significant surface melt, but scientists think melt is happening at the glacier’s underbelly, where relatively warm ocean water meets its underside. What is learned with this new data will help scientists better understand the stability of these ice shelves and help make predictions about sea level rise.

“This is one of a series of philanthropic investments by Paul Allen to improve our understanding of how the Earth is changing and how it’s being impacted by climate change,” said , director of climate and energy for Paul G. Allen Philanthropies.

91̽»¨oceanographers invented the Seaglider in the mid-1990s, with support from the National Science Foundation, and still build research models of the torpedo-shaped ocean drone. 91̽»¨researchers adapted the Seaglider for operating under ice, and have been using it to sample below Arctic sea ice since 2008. In 2014, Lee used a Seaglider and other technology in the Arctic Ocean to .

This new project will deploy a similar robotic network in the Southern Hemisphere. The environment is more challenging because the instruments must venture into the ocean cavities formed by ice shelves, which are very complex, but largely unknown, environments.

“We have almost no information about the area where the glacier is floating on top of the ocean,” said glaciologist , a 91̽»¨assistant professor of Earth and space sciences. “The ice is 300 to 500 meters (1/5 to 1/3 of a mile) thick. There’s no light penetrating, it’s impossible to communicate with any instruments, and this environment is extremely hard on equipment — picture big crevasses, rushing water and jagged ice.”

This effort included figuring out how to develop gliders that can get in and out from the ice sheet’s edge without being crushed by moving ice, swept away by fast-flowing water or trapped in the complex of ridges and crevasses on the ice shelf’s underside.

This year’s test also will use complementary technology designed by , an oceanographer at the 91̽»¨Applied Physics Laboratory, which drifts with the currents while moving up and down gathering data.

The team has devised new navigation algorithms for the Seaglider and tested them in simulations to make sure the instrument can navigate and return safely. The plan is for the gliders to initially travel in and out of a cave several times a day in summer, surfacing between each trip to beam data back to shore.

Once the ocean surface freezes for the Southern Hemisphere winter, the robots will continue to take measurements on their own, and will beam data back only when they emerge months later in the spring.

“We’ve never been able to get really deep into an ice cave, where the floating ice shelf meets the seafloor,” Christianson said. “If we can do that, we’ll be able to collect tons of new data. We often don’t even know what the topography of the seafloor is like beneath the shelf, which affects water flow, temperature and other factors that control the melting rate.”

Team member , a glaciologist at Columbia University’s Lamont-Doherty Earth Observatory, has used other technologies to gather more limited observations below ice shelves. He and , an oceanographer at the 91̽»¨Applied Physics Laboratory, will travel to Antarctica in December for the first deployments under Pine Island Glacier, if conditions allow, or another nearby extension of the West Antarctic Ice Sheet. They plan to deploy three gliders and four floats and leave them down for a period of about a year.

The Korean Polar Research Institute (KOPRI) is also partnering for this mission. KOPRI will provide field support for the deployments from its ice breaking research vessel Araon, will conduct complementary measurements from the ship and will collaborate on the subsequent analysis of the resulting data.

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For more information, contact Lee at craiglee@uw.edu or Christianson at knut@uw.edu.

The international effort hopes to figure out the physics of the ice edge in order to better understand and predict open water in Arctic seas.

“This has never been done at this level, over such a large area and for such a long period of time,” said principal investigator , an oceanographer at the 91̽»¨’s Applied Physics Laboratory. “We’re really trying to resolve the physics over the course of an entire melt season.”

The project is funded by the U.S. . It includes scientists from the Naval Postgraduate School, the Naval Research Laboratory, Cambridge University, Yale University, Laboratoire d’Oceanographie de Villefranche, Woods Hole Oceanographic Institution, the British Antarctic Survey, the Scottish Association for Marine Science and the Korean Polar Research Institute.

Over the next months, the campaign will look at whether the processes that drive sea ice melt will change with increasing open water to the south. For example, open water absorbs more solar radiation, which can lead to more ice melt. Open water also exposes the ocean to wind and waves, which could lead to more mixing that would bring warmer, deeper water up into contact with the ice.

Observations will show how much the open water allows surface waves to grow and break up the ice, or how winds blowing across open water or broken ice could churn up the water lower down. They also will study how deep the sun’s heat penetrates, how weather and currents affect the ice, and what all this means for the growth of tiny plants and animals living in the ice.

“As there is more and more open water in the summer, the processes that control the evolution of the sea ice are changing,” said , an oceanographer at the 91̽»¨Applied Physics Laboratory.

“Increased open water likely means more wind-driven mixing,” Rainville said. “Similarly surface waves will be able to travel further in open water, gaining height and power. Once these waves meet the ice they contribute to breaking the ice edge.”

The study’s focus is the , the region between the solid ice and the open water, which is just now beginning to form along the coast of northern Alaska and Canada.

In March, when the ice was thick enough to land aircraft, researchers installed four groups of sensors on the ice in a line that stretched nearly 200 miles to the north. Each site includes instruments to measure the atmosphere, ice and ocean. The line is designed to continuously measure the moving target of the marginal ice zone, with southern instruments melting out and the northern ones taking their place. Ocean sensors that move up and down will measure conditions under the ice.

In late July, after the ice edge recedes to expose the first open water along Alaska’s north coast, researchers will release four robotic gliders. These gliders, developed by the 91̽»¨Applied Physics Laboratory, will navigate using GPS in open water and from acoustic beacons suspended from the ice when under ice. When a glider pops up to the surface, researchers can download the data and send new commands from shore – for example, direct gliders to monitor the effects of a big incoming storm, or investigate a region that’s melting quickly. Another instrument developed at the UW, the , will take precise measurements of surface waves.

Lee will join the Korean icebreaker in August to place a fifth set of instruments and to study how chemistry and temperature affect microscopic marine organisms living in the ice.

Meanwhile, a team from the University of Miami is taking high-resolution satellite pictures of the ice floes that researchers will combine with the other observations.

“This field program will provide unique insight into the processes driving the summer melt of Arctic ice,” Lee said. “It’s the automation and unprecedented collaboration that allows us to be out there for the entire season,” he said. “You couldn’t afford to be out there at this intensity, for this length of time, any other way.”

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For more information, contact Lee at 206-685-7656 and craig@apl.washington.edu or Rainville at 206-685-4058 and rainville@apl.washington.edu.

Lee will be at sea July 28 through Aug. 25 and available via email.

More information at . High-resolution photos available .