Sea ice thickness surveys with a drone-borne multi-frequency EM sensor

Electromagnetic (EM) ice thickness surveys are essential for sea ice thickness monitoring in Arctic communities and a valuable tool for sea ice research, helping mitigate sea ice travel risk by identifying areas with thin ice and assessing ice thickness distributions. Traditionally, the sensor is towed on a sled by a snowmobile for data collection; however, climate change induced variations in ice conditions are making ice travel more hazardous and less predictable. This study examines the use of airborne EM surveys to reduce the need for direct ice access. A lightweight commercial multi-frequency EM sensor combined with custom altitude and attitude sensors were mounted on a custom drone to remotely measure ice thickness, minimizing human risk exposure while potentially expanding the survey range. Challenges included ensuring stable drone performance under sensor load in typical conditions, managing noise and interference in the EM signal created by the drone, and collecting accurate sensor altitude data for precise thickness estimates. Test flights successfully retrieved combined ice and snow thickness in agreement with manual drill hole measurements, and tested an efficient in-flight sensor calibration. Our results are promising, indicating strong potential for efficient and accurate EM surveys from a safe distance of increasingly hazardous ice using a drone-borne multi-frequency EM sensor.