Thawing ground, future questions: Decoding Arctic climate in a Pennsylvania lab

UNIVERSITY PARK, Pa. — In a Penn State lab, a small cylinder of soil sits wired with sensors, slowly cooling as it mimics conditions thousands of miles away.

At first, it looks unremarkable, like dirt from an average backyard mixed with water. But as the temperature drops, the sample begins to freeze, and its internal structure shifts in ways that are invisible to the eye. Each measurement adds another piece to a complex puzzle, one that connects microscopic structures in a lab to vast landscapes in the Arctic and to global systems that affect people everywhere.

To a group of faculty and student researchers at Penn State, those changes carry critical information about one of the most pressing environmental challenges on Earth: the thawing of Arctic permafrost.

“When you think of the Arctic, maybe you picture a frozen iceberg or the mesmerizing Northern Light or the lonely arctic fox,” said MD Mashfiqur Rahman, doctoral candidate in engineering science and mechanics. “But you definitely won’t imagine a piece of scrubby brown dirt. But that brown dirt is permafrost.”

Permafrost is soil that remains frozen for at least two consecutive years. It is found across vast regions of the Arctic, including Alaska, northern Canada and Siberia. Permafrost is typically found immediately below the “active layer” — the surface layer that thaws each summer and refreezes in winter — so it can start within tens of centimeters to a few meters of the ground surface depending on local conditions. In terms of total thickness, permafrost varies widely: In warmer/discontinuous zones, it can be only a few to a few tens of meters thick, while in cold continuous permafrost regions it’s commonly hundreds of meters thick and in some places can exceed 1,500 meters, or nearly 5,000 feet.

While temperatures are rising globally, those regions are warming especially fast.

“The problem is these regions are now warming four times faster than the rest of the world,” Rahman said. “That’s enough to start the permafrost thaw, and it’s definitely something we should be concerned about.”

Understanding that relationship is the focus of the Penn State team’s research, work that is part of a multi-university collaborative project led by Saint Louis University. Each partner plays a distinct role. Researchers at the Ohio State University focus on interpreting satellite signals, analyzing how those signals reflect off the ground. The University of Alaska contributes field expertise and access to permafrost regions, helping connect laboratory findings with real-world conditions.

Researchers at Saint Louis University fly drones over permafrost in Alaska to collect electromagnetic data and provide the team with mechanical and thermal property data.

Penn State’s contributions to the project — which the researchers called both technical and deeply human — pull from across several Penn State institutes. The Materials Research Institute, the Huck Institutes of the Life Sciences, the Institute of Energy and the Environment, and the Institute for Computational and Data Sciences all contribute tools, expertise or analysis.

“It’s not only the equipment, the facilities, but it’s also the people in the facilities that are amazing,” said Mike Lanagan, professor of engineering science and mechanics at Penn State, who leads Penn State’s role in the project. “It’s very knowledgeable people within these facilities that really help us out. It’s a big effort, and a collaborative one. Being able to work this closely with the other universities has been both great for Penn State and great for the project.”

Better data and better models to predict the effects of climate change

A significant part of the project is focused on improving how satellite data is interpreted, since more accurate interpretations can lead to more accurate climate models, which are used to predict everything from temperature changes to greenhouse gas emissions. That information can help communities and governments plan for impacts from increasingly severe and frequent weather events that may impose infrastructure damage in Arctic regions, shifting ecosystems and increased carbon release. The techniques developed through the project could also be applied more broadly, Lanagan said, including monitoring soil moisture for agriculture, managing water resources and improving environmental tracking in remote or hard-to-access areas.

“Permafrost holds about 1,500 billion tons of carbon, almost double what’s already in our atmosphere,” Rahman said. “As the Arctic rapidly warms, this trapped carbon is released as greenhouse gasses such as methane and carbon dioxide, which drives global warming even more.”

Tracking those changes across remote Arctic landscapes is not easy. Scientists rely heavily on satellites and drones, which scan the surface from above using electromagnetic signals.

“When the satellites, or drones, fly over, they can capture information about very remote places where people just can’t be on the ground,” Lanagan said.

He explained that the instruments send signals down to the surface and measure how they reflect back. The property of the soil — such as wet, dry, frozen or not frozen — impact how a signal is reflected back to a satellite or drone, enabling scientists to infer what is happening below the surface.

By combining lab experiments, computer models and fieldwork in the Arctic, researchers are learning how the permafrost changes over time. They use this data to build models that can interpret satellite and airborne imagery, allowing them to monitor remote regions without needing constant on-site measurements. This work helps track environmental change, protect infrastructure, and support operations in polar regions, while also advancing powerful new remote sensing technologies.

Bringing the Arctic into the lab

Instead of traveling to the Arctic, Penn State researchers recreate permafrost conditions in the lab. They build samples using combinations of sand, silt and clay provided by St. Louis University, then vary the amount of water inside, mimicking the various kinds of permafrost in different regions and depths. The samples are cooled to below freezing, simulating the freeze-thaw cycles that occur in nature during seasonal changes in temperature.

“We are able to cool the soil samples from the room temperature to around negative 10 to negative 15 degrees Celsius,” said Mingjin Lu, a computer engineering major who led a Penn State College of Engineering senior capstone team on the project. That's about 14 degrees Fahrenheit to 5 degrees Fahrenheit.

As the temperature changes, the team measures how the soil samples respond to electromagnetic — or microwave — signals.

“Really, what the capstone project is doing is providing a way to simulate the permafrost and get the microwave response in a lab setting,” Lu said. “And then use the correlation between temperature and the microwave data to help support the remote sensing.”

The setup was built as part of Penn State’s engineering capstone program, where students design and construct real-world systems. The permafrost capstone project focused on designing a system to freeze and thaw the samples while measuring how they response to electromagnetic signals. Data from the measurement system are then used to develop a model for predicting permafrost changes from satellite imagery.”

“We really felt that we are able to contribute to a work that is going to be a larger project and a long-term project, and it will really be a really impactful one,” Lu said.

Connecting permafrost structure, satellite signals and climate

Inside each soil sample, the arrangement of particles and water changes as it freezes or thaws. Those structural changes affect how the material interacts with electromagnetic waves and ultimately how signals from satellites and drones reflect from the permafrost surface.

“So, in material science, we always look at the structure of the material and how it relates to the properties,” Lanagan said. “We’re always correlating structure and properties.”

To study that structure, the team uses a range of advanced imaging tools across Penn State, including CT scanning, electron microscopy and magnetic resonance imaging.

Agustin Harte, a senior in engineering science and mechanics working on the project, focuses on analyzing how soil structure changes with different water levels and compositions.

“It’s really important to quantify and really understand how the structure really pertains to the changes in the dielectric properties,” Harte said.

As the soil freezes or thaws, it changes its dielectric properties also known as permittivity, meaning that it will respond to an electromagnetic wave — a satellite signal — differently, which the satellite or drone can detect.

By linking structure and properties, the researchers can better understand how reflected signals from satellites are shaped by what lies beneath the surface, Lanagan said.

“So, when satellites fly over, they can do that correlation,” Lanagan said. “That’s what this is, this area is frozen, or this area has a lot of water. Then, we can interpret that to mean the permafrost is still frozen or thawing.”

Penn State undergraduates making real-world impact

For many of the students involved, the project’s connection to climate change is a major motivation.

“I have been interested in meteorology since I can remember,” Harte said. “As soon as I heard about this project that had to do with permafrost and how it pertained to global warming, I immediately jumped onto the ship.”

That connection between lab measurements and global impact is what makes the work meaningful, he said.

“Ultimately, that’s the motivation,” Harte said. “Because I know that research I’m doing directly pertains to the fight against climate change.”

Other students echoed that perspective.

“Sometimes, when you do research, you’re not sure about the real-world application or motivations,” said Frederick Blasi, a graduate student in electrical engineering who worked on the capstone project before he graduated with his bachelor’s degree in 2025. “For this project, improving the ability to sense permafrost and see the damage that climate change is doing has very real, very clear implications and applications. It’s about understanding a changing planet and preparing for what comes next.”

Looking beyond permafrost

While the research focuses on Arctic permafrost, itsh applications could extend far beyond frozen ground.

“The tools and knowledge developed in this project extend far beyond a single application,” Rahman said. “We are building a deeper understanding of how frozen ground responds to electromagnetic signals, and that has wide relevance for climate science and environmental monitoring.”

The same methods could be used to study soil moisture, agricultural conditions or groundwater in any environment.

“We’re looking at frozen soil, unfrozen soil,” Lanagan said. “The techniques we’re developing could be applied, really, anywhere in the world.”