Assessment of the Vertical Accuracy of Satellite-Based Glacier Monitoring. The Rutor Glacier in Italy

Periodical monitoring of glacier extent and volume changes is a fundamental tool, considering the relevant changes and volume losses glaciers have been undergoing in recent years. The climatological changes leading to increasing hazards and related risks in alpine areas require complex and updated 3D models. Specifically, mountain environments are characterised by complex orography and limited accessibility and often require risky and expensive in situ campaigns. The presented case stay is the Rutor Glacier (Aosta Valley, Italy), monitored and studied in a multidisciplinary framework by the Glacier Lab of the Politecnico di Torino and the Aosta Valley Environmental Agency (ARPA VDA). Different remote sensing platforms are being used to carry out an annual survey to generate detailed 3D models enabling the estimation of the mass balance, focusing on the 3D positional accuracy of the metric products. A very high-resolution Pleiades satellite image stereo pair acquired in September 2022 and a photogrammetric airborne survey carried out in the same month enable the comparison of 3D models based on different techniques and therefore characterised by different accuracies. In-depth analyses have been carried out to verify the suitability of satellite remote sensing for glacier monitoring, considering that a satellite-based approach would enable continuous monitoring over wide areas, including Alpine regions with limited access. The analyses are aimed at validating the 3D products by means of comparison with more accurate reference data as well as at evaluating the possibility of adopting synergistic multi-scale approaches, exploiting satellite and aerial platforms.