3D GLACIER MAPPING BY MEANS OF SATELLITE STEREO IMAGES: THE BELVEDERE GLACIER CASE STUDY IN THE ITALIAN ALPS

Abstract. The authors group is within the Glacier Lab of Politecnico di Torino (part of the CC-LAB, a laboratory for climate change monitoring), which is working on glacier monitoring since 2016, mainly exploiting Geomatics techniques to measure the extent and to model the surface of glaciers over the years. Measurement campaigns were carried out within the ASP (Alta Scuola Politecnica – Poliecnico di Torino e Milano) DREAM projects (Drone tEchnnology for wAter resources and hydrologic hazard Monitoring) The manuscript is focused on a specific case study related to the Belvedere glacier, a valley glacier located in northern Italy.In the framework of the Belvedere glacier monitoring, several Geomatics approaches have already been applied in the last four years by the cc-glacier-lab and DREAM Projects with the goal to monitor both the extent of the glacier and its surface. Such monitoring enables the multi-temporal comparison of the glacier digital surface model (DSM), highlighting areas of ice loss and gain. Considering the limitations of aerial surveys in high altitude environments, the authors started assessing the suitability of a satellite based approach, mainly focusing on positional accuracy assessment. The paper is focused on a monitoring based on a high resolution (0.5 m) satellite optical stereo pair. Several tests were carried out with the goal to test the 3D positional accuracies, assessing the impact of different configurations of Ground Control Point (GCP) in terms of numerosity and distribution and focusing on the DSM validation. The results demonstrated the fit-for-purpose of a satellite-based approach for glacier monitoring.