Multi-temporal DEMs used to quantify the geomorphological impact of a late 20th century glacier re-advance at Schwarzberggletscher, Switzerland

Abstract

Sedimentological investigations have advanced understanding of moraine formation at Alpine glaciers; however, few studies use multitemporal elevation datasets to observe landform generation during a period of glacier re-advance. Archive aerial image sets from 1974 to 2010 were processed using a photogrammetric workflow to visualise and quantify geomorphological change at the margin of Schwarzberggletscher, Switzerland. A combined co-alignment and iterative closest point-based approach was adopted to improve the comparative accuracy of the topographic datasets derived from the historical aerial imagery. This enabled the geomorphological impact of a glacier re-advance that occurred between 1974 and the early 1990s to be monitored. In the geospatial data, we recognise: (i) landform development associated with the advancing glacier terminus between 1974 and 1990; (ii) moraine erosion at the advancing, but fluctuating glacier margin; and (iii) the ablation of buried ice in the proglacial area between 1999 and 2010. The implications of this re-advance on the geomorphological record of glacier change are discussed, with this study providing a median and maximum error thresholded rate of surface lowering for ice-cored moraines of ∼0.2 ma⁻¹ and ∼0.4 ma⁻¹, respectively. Finally, this study highlights the potential of now-readily accessible datasets, and refined image processing workflows involving image co-alignment and fine registration, for aiding future geomorphological research in the Swiss Alps.