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Sea ice is thinning. Here’s how Boise State researchers are measuring its change

A research drone takes a test flight over Arctic sea ice. Boise State University researchers are partnering with the University of Alaska Fairbanks to develop a new system to determine Arctic ice depth. The system is attached to a drone that’s then flown around to collect measurements. BY HANS-PETER MARSHALL A new tool from Boise State University researchers, alongside an Alaska team, could help protect arctic communities as they deal with changing landscapes and inform future policy decisions on climate change in the coming decades. The tool combines electromagnetic induction, which generates magnetic fields to measure sea ice depth, with a snow-penetrating radar developed by Hans-Peter Marshall, an associate professor in the Department of Geosciences at Boise State University. When attached to a drone, researchers can accurately measure sea ice depth — a measurement that’s challenging to get, and that informs scientists about the impacts of climate change. TOP VIDEOS “I think what’s unique is coupling these two instruments,” Marshall told the Idaho Statesman. In the Treasure Valley, students have a chance to get a glimpse at the drones through Bogus Basin’s SnowSchool program, which takes kids up to Bogus Basin for winter activities. Marshall will sometimes demonstrate to the school students how the drone works to help with snow and ice measurements. The new technology is arriving at a crucial moment, with the National Snow and Ice Data Center reporting below-average arctic sea coverage this May. Arctic sea ice is shrinking by more than one-tenth every decade, according to NASA. The remaining ice is also getting thinner.

Arctic sea ice was once thick and bumpy. But warm temperatures concentrated in polar regions, caused a dramatic thinning of the region’s ice, that hasn’t recovered in the years since. Boise State University associate professor Hans-Peter Marshall poses at the the field site where researchers are studying snow and ice depth, alongside a radar system used for research and mounted on a snow mobile, in April 2024, Beaufort sea ice, near Utqiagvik, Alaska. Hans-Peter Marshall “The Arctic is changing so fast,” Marshall said, “Knowing the thickness of ice helps the models do a better job of predicting how long it’ll take for that ice to disappear.” BOISE, ALASKA RESEARCHERS DEVELOP TOOL FOR ICE DEPTH Measuring the vast landscape of the Arctic is no easy feat. While scientists have different methods to measure ice depth, many are slow or inaccurate, according to the National Snow and Ice Data Center, which collects ice and snow data as part a Colorado research institute. One of the more old-school ways is to drill into the ice and measure it directly, which is impractical when the Arctic is millions of square miles. Scientists often use satellites to measure altitude changes between the ocean and the ice surface. But those measurements are imprecise and need to be validated with on-the-ground measurements, said Achille Capelli, a University of Alaska Fairbanks post-doctoral fellow who was involved in the project with Boise State. Researchers from the University of Alaska Fairbanks instead have been using electromagnetic induction, which produces magnetic fields that are shot through the ice. Once those fields hit the water beneath, they induce currents that generate a secondary magnetic field. By measuring the secondary field, researchers can determine the depth of the ice. But electromagnetic induction has one big problem: It cannot differentiate between ice and snow.

Alaska scientists found a way around this problem with help from Boise State. Marshall explained he had been using a radar system to measure snowpacks in the Boise mountains to help improve modeling for water supply forecasting but was excited to deploy it in an Arctic environment. Adding the radar to the electromagnetic induction system allowed the researchers to subtract the snow from their measurements, leaving them with an accurate ice depth within 10 cm. A Boise State University graduate student, Thomas Van Der Weide, pilots a drone near a sea ice camp near Utqiagvik, Alaska, in April as part of research by Boise State University and University of Alaska Fairbanks to study ice depth in the Arctic. Hans-Peter Marshall While the drones alone cannot map the entire Arctic region, the research team plans to take detailed measurements of the ice in a variety of conditions to build a model to help predict snow and ice depth. ICE DEPTH CAN HELP TRACK CLIMATE CHANGE EFFECTS Accurate measurements are becoming increasingly important as the ice thins every year. Indigenous communities in the Arctic rely on the ice for hunting and transportation — both of which become dangerous if the ice is weak. Maps of ice measurements could provide data on thinning ice and inform communities about what’s safe. “The ice is really part of everyday life,” said Sinéad Louise Farrell, an associate professor in the Department of Geological Sciences at the University of Maryland, who is also developing different tools to measure ice and snow. According to Marshall and Capelli, the Department of Defense is also interested in the technology. Understanding the strength of the ice will be important for knowing when it’s safe to launch equipment, such as tanks, or travel to offshore ships, they said. On a broader scale, keeping records of ice depth will also mean helping track the effects of climate change. Ice reflects solar energy back into space. And less ice will mean the planet is absorbing more heat. “This is going to be a super cool technique that we will have in our toolkit,” Farrell said.

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