Polar Bear Dens Are Tough for People to See, but Drone-Mounted Radar Can Assist

When he formulated a drone-mounted radar program that could penetrate a number of levels of snow, Rolf-Ole Rydeng Jenssen imagined utilizing it to measure snowfall or predict avalanches. Both of those apps would be handy in subarctic Tromsø, Norway, in which Jenssen performs as an engineer at the interdisciplinary Norwegian Study Middle (NORCE). But a single January night a group of researchers termed NORCE to request about a incredibly different use for the traveling radar: locating concealed polar bears.

Expecting polar bears establish dens by digging holes in the snow in early wintertime, crawling in and allowing contemporary snow cover the entrance. Inside of, the bears give birth while the snow shelters them and their newborn cubs from the harsh Arctic things. But polar bear professionals fear these animals may possibly be far too fantastic at hiding. That’s why researchers at Polar Bears International (PBI), a investigate and conservation team, gave Jenssen a connect with. PBI has since been collaborating with him and other engineers on a lot more powerful strategies to come across polar bear dens for the duration of aerial surveys prior to individuals stumble more than and inadvertently ruin the dens.

During the wintertime, oil and gasoline companies transportation rigs and other equipment by polar bear habitats in Alaska. “Over the past two several years we have experienced 4 dens that we know of that were being disturbed in the oil fields—all dens that have been earlier unfamiliar prior to the bears just popped out,” claims Susannah Woodruff, a polar bear researcher with the U.S. Fish and Wildlife Service. As oil and gas exploration expands in the Arctic, the chance of den disruptions improves this ramps up the dangers of damage to susceptible cubs. And for a threatened species these kinds of as polar bears, these offspring are in particular important.

U.S. government guidelines at the moment require oil and gasoline corporations to survey their websites for bear dens in get to stay away from disturbing them. The tool that providers normally use for this (called a ahead-wanting infrared, or FLIR, procedure), on the other hand, detects an animal’s bodily heat amid the snow and only is effective beneath certain problems. Warm climate weakens the heat signal from a polar bear, and deep or blowing snow obscures it. Also, working with FLIR is a tiny like seeking to scan the landscape by way of a smartphone camera—from an airplane. End users are bound to overlook patches.

“When we seemed back at how management agencies and business had been executing employing this instrument, the response was ‘not that wonderful,’” suggests Geoff York, PBI’s senior director of investigation and policy. A 2020 research co-authored by York observed that FLIR failed to place 55 % of polar bear dens. Element of the issue is that the ideal climate windows for FLIR—which is effective superior in the course of particularly extensive chilly periods—are now much less and farther in between since of climate alter. And even less than the ideal conditions, FLIR skipped some of its targets. “Ultimately, we need to have to uncover some approach that is heading to do a much better task at detecting dens,” Woodruff states.

York and two colleagues arrived to the exact conclusion although operating on the freezing tundra quite a few yrs back. Pissed off with how the FLIR’s inaccuracy impacted their analysis, the trio begun brainstorming. Radar at some point emerged as a feasible possibility due to the fact it functions well in the ailments less than which FLIR struggles. “They’re on the right track in terms of getting a little something that could it’s possible be made use of extra regularly and is not weather-dependent,” states Woodruff, who isn’t concerned in the radar work.

The principle powering making use of radar to detect polar bears is straightforward. The radar device is attached to a aircraft or drone and emits electromagnetic waves as it flies above the tundra. When the waves strike the ground, some replicate back again to the radar product, and some penetrate further. The time it usually takes waves to bounce again suggests how much away a surface area is. And the amount of reflected waves differs for distinct varieties of surfaces, this sort of as rocks, dust, snow or drinking water. A polar bear—which is fundamentally a container of water—will show up as an anomaly suspended in the snow.

As a result of a collaboration with radar professionals at Brigham Youthful University in 2021, PBI tested a radar device in Churchill, Manitoba, a town with a single of the world’s maximum concentrations of polar bears. Though they only took photos of bears on the snow’s surface, the researchers confirmed in a paper posted in Ursus in Oct that the radar detected 66 % of bears.

Upcoming, the scientists wished to check the radar’s capacity to in fact peer within dens in Norway’s Svalbard archipelago this past spring. Svalbard has a properly-examined inhabitants of GPS-collared bears, so the scientists currently knew many den destinations and were thus geared up to validate the radar’s results. The PBI team was discussing logistics with Jenssen’s colleagues at NORCE the working day he joined the den project. Which is when they recognized his drone-mounted radar system was also enticing to pass up.

Jenssen’s system employs ultra-wideband radar, a style that has reasonably significant resolution. Whereas the radar PBI analyzed in Churchill had a resolution of around one meter, extremely-wideband radar could function at the centimeter scale. Jenssen had also specially created his product to use frequencies that could penetrate snow and assess its attributes, these types of as irrespective of whether it was difficult-packed or fluffy. The scientists agreed a device that gathered so considerably information and facts on snow layers may well be better than other radar platforms at detecting a polar bear’s signature in a den. 1 PBI researcher described Jenssen’s method as a “slam dunk.” It was only six weeks amongst when Jenssen offered his research to PBI and when he still left for Svalbard to check the radar. “I dropped every thing else to do this,” he states.

During the trip, the scientists flew the drone about dens housing GPS-collared bears various instances. Later on, when examining the data, Jenssen picked out anomalies inside of the snow—and when they in contrast these with regarded bear positions based on the collars, the factors aligned. “The first effects are pretty promising that this functions,” Jenssen suggests. Nevertheless, he wishes to accumulate much more info in advance of obtaining far too thrilled.

York states that in winter 2024 the workforce programs to head to Alaska, wherever the United States Geological Study will be placing new tags on polar bears. This will give the researchers their to start with opportunity to exam their radar platforms head-to-head towards FLIR. “We’ll be equipped to last but not least say with some certainty which resource is desired or at least have a extra sturdy discussion of the execs and drawbacks for each individual option,” York states.

He has witnessed firsthand how improved detection could preserve dens risk-free. Various a long time back a polar bear denned following to an active highway employed by the oil and gas enterprise BP. PBI, the U.S. Fish and Wildlife Service and BP monitored the den website and restricted website traffic oil drilling until finally the bear still left. “That was a awesome accomplishment story of every person operating alongside one another,” York says. “That’s the variety of result we’d like to see.”