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Abstract
Assessments of geodetic volume change are widely used in glaciology and have a long tradition dating back to the nineteenth century. Over time, the geodetic method and corresponding data storage have been developed further, but the resulting methodological heterogeneity can lead to errors that are difficult to separate from other survey uncertainties. In this study we used high‐resolution airborne laser scanning data from the indelengletscher in the wiss lps to evaluate state‐of‐the‐art volumetric glacier change methods. For the first time we have been able to simulate errors arising from different geodetic methods and spatial resolutions. The evaluation showed that, although the digital elevation models were perfectly co‐registered, systematic and random method‐ and scale‐dependent errors still occurred. These errors have an impact on the resulting volume changes at lower spatial resolutions and may lead to exponentially larger uncertainties. Volume changes from contour methods provided reasonably accurate results, while volumetric change assessments from central profile lines were especially prone to biases at any scale.
Acknowledgements
We are grateful to Wilfried Haeberli and Michael Schaepman for their valuable support with this project. Many thanks to Christopher Nuth and an anonymous reviewer for their constructive comments which helped to improve the manuscript considerably, and to Silvia Dingwall for polishing the English. We thank BSF Swissphoto for the acquisition of the ALS data and their continuous support. This project was supported by the Swiss energy utility Axpo.
Additional information
Notes on contributors
Philip Claudio Joerg
Philip Claudio Joerg and Michael Zemp, Department of Geography, University of Zurich, Winterthurerstrasse 190, CH‐8057 Zurich, Switzerland
E‐mail: [email protected]; [email protected]