THE POTENTIAL OF REPEAT AIRBORNE LIDAR FOR THE ANALYSIS OF GEOMORPHODYNAMIC PROCESSES IN HIGH ALPINE TERRAIN

Airborne lidar offers a wide range of applicability in high alpine geomorphology. In contrast to non-recurring lidar surveys, which deliver base information of the topography and surface characteristics, repeat airborne lidar datasets can be used for the analysis of process induced changes. At the Institute of Geography, University of Innsbruck, Austria, unique datasets with varying repeat cycles and spatial captures are available. Beyond glaciological purposes and due to its high spatial resolution and accuracy these datasets facilitate not only the detection but also the quantification of geomorphodynamic process results over large mountainous regions. Hence, this study is focusing on the ability of airborne lidar data for the quantification of rock falls, debris flows and land slides as well as on permafrost related surface phenomena.

Annual lidar surveys of the Rofental region (Ötztal, Tyrol) started in 2001 aiming at the generation of geodetic mass balances of Hintereisferner. Due to its high vertical accuracy the lidar data are used for the analysis of dead ice melting, rock falls, fluvial processes and permafrost degradation in the vicinity of Hintereisferner on an annual base from 2001 to 2013. Even processes with very small annual changing rates such as permafrost degradation or fluvial erosion are analysed on the basis of the aforementioned multi-temporal airborne lidar dataset.

In addition a bi-temporal lidar survey (2006 and 2010) of a larger area in the Tyrolean Central Alps is used to detect, quantify and analyse gravitative processes. Within this area 189 noteworthy events have been detected. It has to be emphasized that the majority of these events (occurred between 2006 and 2010) are areas where permafrost conditions are likely. Within this region more than 400 rock glaciers are found and the airborne lidar dataset is used to assign an activity index to each of them. The activity index is exclusively based on airborne lidar data, using the volumetric changes and the surface velocities of each rockglacier.

We will give a comprehensive overview of the ability of repeat airborne lidar surveys in high alpine terrain, showing the capacities for the quantification of process results and subsequent process analysis like the introduction of a rockglacier activity index or the analysis of gravitative processes.