Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland

A significant elevation bias of up to 4–8 meters, caused by the penetration of X-band radar signals into perennial firn, was identified on Grosser Aletschgletscher using TanDEM-X DEMs. This bias, exceeding half the decadal ice loss rate, stems from volume scattering within firn layers, misaligning the radar-detected surface with actual firn horizons. The study compared near-simultaneous TanDEM-X and Pléiades optical stereo-imagery to quantify this effect, supported by ground-penetrating radar and snow core data. To mitigate such biases, researchers recommend using DEMs from consistent timeframes over long periods and applying corrections when integrating optical and radar-derived elevations.

Bannwart, J., Piermattei, L., Dussaillant, I., Krieger, L., Floricioiu, D., Berthier, E., Roeoesli, C., Machguth, H., & Zemp, M. (2024). Elevation bias due to penetration of spaceborne radar signal on Grosser Aletschgletscher, Switzerland. Journal of Glaciology, 70. https://doi.org/10.1017/jog.2024.37