| Résumé: |
Glaciers are strong indicators of climate change as their dynamics are extremely sensitive to small changes in precipitation and temperature. Monitoring glacier velocity is of key importance to understanding how climate perturbations impact the status of glaciers. However, this kind of survey requires expensive technologies and expert supervision. More recently, developments of Structure-from-Motion techniques have reduced the need for user supervision and allowed processing with consumer grade digital cameras. The main objective of this study is to explore the potential of ground-based monitoring using oblique Structure-from-Motion photogrammetry to provide accurate information on glacier melt and surface velocity in a remote area, the Olguin glacier in Patagonia. By means of ground-based photographs collected around the Olguin glacier on December 8th 2016 and January 8th 2017, two orthoimages and DSMs have been generated. The orthoimages have been analyse to calculate a mean ice displacement of 8.71 m with a standard deviation of ±1.56 m, which can also be extrapolated to a daily displacement of 0.28 ± **m. The DSMs were used to extract the surface melt with the help of a DSM of difference, which gave a mean melt of -1.72 m with a standard deviation of ±1.22 m. This value can also be extrapolated to a daily melt of 5.55 ± **cm per day. The ice displacement and melt were calculated during summer, which is the only season where the Olguin glacier is in a state of ablation. This glacier is situated in a cool temperate oceanic climate, humid all year long, which increase ice accumulation rates and reduce the ablation period. |