High resolution ground-based digital photography for quantitative slope dynamics analysis: application to an arctic glacier basin (AustreLoven glacier - Spitsbergen 79°N)

Snow input is a significant element in order to understand a glacier system behaviour. On the glacier area itself, quantifying information coming from remote and in situ sensing is easily performed thanks to the smooth and flat surface. Such quantitative processing is however more complex on the slopes, where effective areas converted to 2D projections hide a great part of the information : the steeper the slope, the larger the correction between projected area and effective area. In the present study, the mean slope angle is 35, while slopes account for a third of the whole area of the basin. In the frame of the Hydro-Sensor-FlOWS program (2006-2010), a network of sensors has been installed around the AustreLoven glacier (5 km(2)), on the West coast of Svalbard (79 degrees N). Some automated digital cameras are located at strategic places of the glacier basin to cover the whole glacier. While ground based tangential picture geometrical correction is efficient on the flattest parts of the glacier, it becomes ineffective on the steep slopes. The present article demonstrates how quantitative information can be recovered even without geometric correction of the pictures. Using the required datasets (digital elevation models, camera coordinates and satellite imagery), in situ pictures provide the snow coverage on the slopes. This work demonstrates the complementary use of zenithal and tangential views in order to better understand slope dynamics.