Abstract. The study presents a detailed photogrammetric analysis of the evolution of the Belvedere Glacier over the periods 2009–2017 and 2017–2023, with particular focus on the impact of the debris flow triggered by the flood event of August 27, 2023. High-resolution Pléiades and Pléiades Neo satellite imagery was used to generate point clouds and Digital Elevation Models, enabling the quantification of altimetric and volumetric changes and a detailed assessment of the morphological modifications caused by the debris flow. The results show a recent significant glacier retreat, with an average annual volume loss of 2.3 × 10⁶ m³/year between 2009 and 2017, increasing to 2.7 × 10⁶ m³/year between 2017 and 2023. The 2023 debris flow produced marked morphological changes, including the formation of two accumulation zones on the western tongue and the development of two erosional channels approximately 4–5 meters deep. These channels resulted from the new course of the Castelfranco Stream, which incised directly into the glacier surface. Overall, the findings confirm trends reported in previous studies on the Belvedere Glacier and other Alpine glaciers, highlighting the importance and advantages of satellite-based monitoring for assessing the impacts of climate change and extreme events on glacier dynamics.
F. Ioli, Luca Cerina, Alberto Cina et al.· The International Archives o...· 0 citations
Abstract. The Valpelline Valley, located in the northern Aosta Valley (Italy) along the Swiss border, is a typical Alpine valley shaped by glacial and fluvial processes. Characterized by a large altitudinal range (900-4000 m a.s.l.) and hosting glaciers feeding the Place Moulin reservoir, the area plays a key role in regional hydroelectric production. Since 2020, GlacierLAB has been conducting glacier monitoring activities through biannual aerial photogrammetric surveys, overcoming the logistical constraints imposed by the steep and inaccessible morphology of the valley.The surveys were performed using a medium-format camera mounted under an aircraft wing and equipped with GNSS and IMU systems. Due to the lack of synchronization between the camera shutter and GNSS receiver, georeferencing relied on Ground Control Points (GCPs), whose spatial distribution is often limited in high-mountain environments. This condition makes camera calibration a critical factor for ensuring reliable multi-temporal analysis.This study investigates the behavior of the radial distortion parameter k1 using images previously corrected for optical distortion. A multi-run bundle adjustment strategy was applied in Agisoft Metashape, including baseline configurations, global and image-wise estimation of k1, and robustness tests under different GCP setups. Statistical analyses reveal a systematic and significant dependence of k1 on the vertical camera–terrain distance.However, comparison with a theoretical atmospheric model based on the Saastamoinen formulation shows weak correlation, indicating that the observed effect cannot be attributed solely to atmospheric refraction. Instead, k1 acts as a compensatory parameter absorbing depth-dependent systematic effects related to block geometry and acquisition conditions.
M. Macelloni, N. Grasso, Alberto Cina· The International Archives o...· 0 citations
