Use of an Unmanned Aerial Vehicle to assess recent surface elevation change of Storbreen in Norway

Abstract. Routinely and accurate monitoring of the outlines and surface mass balance of glaciers is essential. In this study an unmanned aerial vehicle (UAV) was used in September 2015 on a mountain glacier (Storbreen) in Norway to map the glacier outline, snow line and to derive a digital elevation model (DEM) of the glacier surface. The generated DEM has a relatively high accuracy with maximum horizontal RMSE of 0.36 m vertical RMSE of 0.44 m and the Structure for Motion algorithm also proved to be suitable under low contrast, high saturation fully snow covered conditions. A well distributed set of markers, measured by GPS, was required to generate a high quality DEM under the yielding conditions. The final UAV DEM was compared to a laser based DEM of 2009 and the annual geodetic mass balance between 2015 and 2009 was estimated to be between −0.71 ± 0.1 m w.e. and −0.75 m ± 0.1 w.e., which is in good agreement with the glaciological mass balance of −0.80 m ± 0.18 w.e. a⁻¹. An analysis of the glacier outlines reveal that the glacier has lost 1.2 % of its surface area between 2009 and 2015. These findings confirm the strong mass loss and retreat of continental glaciers in southern Norway.