Using a small COTS UAV to quantify moraine dynamics in Arctic environments

Résumé En

Arctic regions are known to be places where climate shift yields most visible consequences. In this context, glaciers and their environment are highly subject to global warming effects. New dynamics are observed and the behaviour of arctic systems (such as glaciers, moraines, beaches etc) changes at rates visible over yearly observations. According to recent works on climate change impacts on the cryosphere, short/violent events are recently observed and are one characteristic of these changes. As a consequence, an accelerating rate of glacial and pro-glacial activity is observed, especially at the end of each hydrological season (early fall). As an example, many phases of streamflow increase/decrease are observed. This transforms glacier outflows or intra-moraine processes: within only a few days, the morphology of some parts of the moraine can be completely changed. In order to observe and quantify these dynamics, reactive methods of survey are needed. That's why the use of COTS (DJI Phantom3 Professional) UAV for aerial photography acquisition, combined with SfM analysis and DEM computation, were chosen. The robust architecture of this platform makes it well suited as a reliable picture acquisition system for high resolution imaging. These increasingly popular methods, at a convergence of technologies, allow to fly and to acquire data whatever the conditions of cloud cover are. Furthermore, data acquisition is much more flexible than traditional satellite imagery: the low-flying UAV yielding high picture resolution which can be achieved allow to generate high resolution DEMs and therefore to measure accurately dynamics on the field with sub-decimeter resolution. This presentation's goal is to show an experimental campaign of small UAV data acquisition on an arctic basin (Austre Lovén glacier, Svalbard, 78°N) separated by a few days. Knowing the changing conditions at this period, similar UAV flights have been reiterated in order to catch moraine dynamics. This allowed us to select two sets of images whose processing highlights and quantifies morphological changes into the moraine while a rain event occur between two cold periods.