Drone-Based GPR Accurately Maps Buried Ice Beneath Debris-Covered Glacier at Shár Shaw Tagà Valley

Integrated Systems

April 29, 2025

At Shár Shaw Tagà, a drone-mounted GPR system precisely mapped buried ice beneath debris-covered glaciers. This novel approach enabled safe, and detailed surveys in challenging terrain, enhancing the understanding of glacier dynamics and resource management.

Background

Accurate detection and detailed mapping of buried ice within debris-covered glaciers are crucial for predicting freshwater resources, managing hydrological systems, and understanding glacier responses to climate change. Traditional ground-penetrating radar (GPR) surveys are often hindered by steep slopes, unstable surfaces, and dense debris cover, making manual operations risky and limiting data collection.

The Shár Shaw Tagà site, located within the Kluane National Park and Reserve in southwestern Yukon, Canada, represents a complex glacial environment transitioning from clean glacier ice through debris-covered glaciers and rock glaciers. It’s characterized by rugged landscapes and variable debris thickness. Conventional survey methods were insufficient and required an innovative, safer, and more efficient approach.

*(a) Location of Shár Shaw Tagà valley within southwestern Yukon, Canada. The study area is identified by a red rectangle. (b) Geomorphological interpretation of the study area. Source: ArcticDEM*

Challenges

Conducting effective surveys in glacial environments presents several inherent challenges. At Shár Shaw Tagà, the team of École de technologie supérieure (ETS), a public research university in Montreal, encountered the following challenges:

Hazardous terrain conditions. Steep slopes, unstable boulders, talus, and thick debris layers hindered access and made ground-based surveys unsafe.
Economic and logistical barriers. Airborne surveys via helicopters or fixed-wing aircraft, while effective, are prohibitively expensive and typically only feasible for large-scale glacier assessments, limiting resolution and detailed analysis of smaller-scale features.
Technical limitations of existing methods. Traditional airborne radar methods struggle with precise resolution due to altitude separation, reduced signal quality, and difficulty in accurately identifying the ice-debris interface.‍
Complex debris cover. Variable thickness and heterogeneous debris cover added complexity in accurately detecting ice layers and measuring depths.

*Map showing the location of the drone-based, manual, and CMP transects within the study site (b) and larger sub-catchment valley (a).*

Solution

Researchers employed an advanced drone-based GPR solution utilizing a DJI M600 Pro drone equipped with Radar Systems Zond Aero LF radar antennas operating at multiple frequencies (50, 100, and 200 MHz). Precise drone navigation and georeferencing were achieved through an Emlid Reach RTK positioning system, integrated via SPH Engineering’s SkyHub 3 hardware and UgCS flight planning software.

Surveys were conducted at a controlled altitude of approximately 5 meters above ground level, controlled by a laser altimeter to minimize collision risk with surface boulders while maintaining sufficient signal penetration. Complementary ground surveys and Common Mid-Point (CMP) measurements were systematically performed to calibrate and validate drone-based radar data, providing robust depth and velocity data for accurate ice thickness measurements.

More about the drone-based GPR technology

Results

The results of the combined drone-based and ground-based GPR surveys confirmed the feasibility of mapping buried ice over steep, debris-covered glacial terrain. While some resolution limitations were observed, the drone configuration effectively captured subsurface structures, validated by CMP-calibrated manual surveys.

Successful identification of buried ice. The drone-based radar effectively mapped three distinct ice bodies over a 430-meter transect, clearly delineating buried ice features previously difficult to access.

Processed and annotated radargrams of the (a) 50 MHz, (b) 100 MHz and (c) 200 MHz drone-based GPR transects. Three areas of buried ice, B.I.1 , B.I.2 and B.I.3 , are outlined for emphasis across the three transect radargrams

Manual GPR radargrams from the debris-covered glacier, Manual 2 (a–c), and ice–debris complex, Manual 1 (d–f). In (e) h1 , h2 and h3 indicate ice layer height measurements and d1 , d2 and d3 show depths measured from the surface to the base reflector

High-accuracy validation. Comparison with manual CMP surveys demonstrated close alignment with drone-based measurements showing mean absolute differences of 1.8 meters in ice thickness and 1.1 meters in total depth, showcasing the reliability and precision of drone-based techniques.

CMP results showing the trajectory signals of the air wave (yellow), the surface debris/ice interface (red), and the ice/bottom layer (blue) for each of the three antenna frequencies at the CMP 2 (a–c) and CMP 1 (d–f) transects

Improved efficiency and safety. Drone-based GPR technology enabled efficient and safe coverage of previously inaccessible terrain, reducing the need for hazardous manual surveys.

Comprehensive geological insights. Radargrams revealed subsurface ice structures and supported field observations, though debris thickness estimates remained partially constrained.

‍Enhanced data resolution. Drone-based GPR allowed for broader mapping of buried ice in hazardous terrain where manual surveys were not feasible. Resolution was limited by antenna elevation, signal noise, and difficulty detecting debris–ice interfaces, especially with the 200 MHz antenna over rough surfaces.

Conclusion

The use of drone-based GPR at Shár Shaw Tagà demonstrated a safe and practical method for mapping buried ice in previously inaccessible terrain. While some discrepancies arose due to airborne radar limitations, the approach significantly improved survey accessibility and safety. With continued refinement in flight operations and data processing, drone-based GPR holds strong potential for future investigations of debris-covered glacier systems.

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