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Université de Fribourg

Mapping and quantifying sediment transfer between the front of rapidly moving rock glaciers and torrential gullies

Kummert, Mario ; Delaloye, Reynald

In: Geomorphology, 2018, vol. 309, p. 60–76

The sedimentary connection which may occur between the front of active rock glaciers and torrential channels is not well understood, despite its potential impact on the torrential activity characterizing the concerned catchments. In this study, DEMs of difference (DoDs) covering various time intervals between 2013 and 2016 were obtained from LiDAR-derived multitemporal DEMs for three rapidly...

Université de Fribourg

Erosion and sediment transfer processes at the front of rapidly moving rock glaciers: Systematic observations with automatic cameras in the western Swiss Alps

Kummert, Mario ; Delaloye, Reynald ; Braillard, Luc

In: Permafrost and Periglacial Processes, 2017, vol. 29, no. 1, p. 21–33

When connected to torrential channels, the fronts of active rock glaciers constitute important sediment sources for gravitational transfer processes. In this study, a 2013– 16 time series of in situ webcam images from the western Swiss Alps was analyzed to characterize the erosion processes responsible for sediment transfer at the front of three rapidly moving rock glaciers and their...

Université de Fribourg

Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

Mewes, Benjamin ; Hilbich, Christin ; Delaloye, Reynald ; Hauck, Christian

In: The Cryosphere, 2017, vol. 11, no. 6, p. 2957–2974

Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical...

Université de Fribourg

Using near‐surface ground temperature data to derive snow insulation and melt indices for mountain permafrost applications

Staub, Benno ; Delaloye, Reynald

In: Permafrost and Periglacial Processes, 2017, vol. 28, no. 1, p. 237–248

The timing and duration of snow cover in areas of mountain permafrost affect the ground thermal regime by thermally insulating the ground from the atmosphere and modifying the radiation balance at the surface. Snow depth records, however, are sparse in high-mountain terrains. Here, we present data processing techniques to approximate the thermal insulation effect of snow cover. We propose...

Université de Fribourg

Semi-automated calibration method for modelling of mountain permafrost evolution in Switzerland

Marmy, Antoine ; Rajczak, Jan ; Delaloye, Reynald ; Hilbich, Christin ; Hoelzle, Martin ; Kotlarski, Sven ; Lambiel, Christophe ; Noetzli, Jeannette ; Phillips, Marcia ; Salzmann, Nadine ; Staub, Benno ; Hauck, Christian

In: The Cryosphere, 2016, vol. 10, no. 6, p. 2693–2719

Permafrost is a widespread phenomenon in mountainous regions of the world such as the European Alps. Many important topics such as the future evolution of permafrost related to climate change and the detection of permafrost related to potential natural hazards sites are of major concern to our society. Numerical permafrost models are the only tools which allow for the projection of the future...

Université de Fribourg

Mapping slope movements in Alpine environments using TerraSAR-X interferometric methods

Barboux, Chloé ; Strozzi, Tazio ; Delaloye, Reynald ; Wegmüller, Urs ; Collet, Claude

In: ISPRS Journal of Photogrammetry and Remote Sensing, 2015, vol. 109, p. 178–192

Mapping slope movements in Alpine environments is an increasingly important task in the context of climate change and natural hazard management. We propose the detection, mapping and inventorying of slope movements using different interferometric methods based on TerraSAR-X satellite images. Differential SAR interferograms (DInSAR), Persistent Scatterer Interferometry (PSI), Short-Baseline...

Université de Fribourg

Inventorying slope movements in an Alpine environment using DInSAR

Barboux, Chloé ; Delaloye, Reynald ; Lambiel, Christophe

In: Earth Surface Processes and Landforms, 2014, p. -

Differential SAR Interferometry (DInSAR) is a technique that can be used to detect and characterize slope movements. It is investigated here as a tool for establishing a detailed overview of complex slope movements at a regional scale in an Alpine context. This paper gives specific recommendations to use and to understand DInSAR signals in mountainous areas located above the tree line, excluding...

Université de Fribourg

Monitoring of high alpine mass movements combining laser scanning with digital airborne photogrammetry

Kenner, R. ; Bühler, Y. ; Delaloye, Reynald ; Ginzler, C. ; Phillips, M.

In: Geomorphology, 2014, vol. 206, p. 492–504

Airborne- and terrestrial laser scanning are used in combination with digital airborne photogrammetry to monitor surface changes between 2009 and 2011 on rock glaciers and landslides at three mountain permafrost sites (Grabengufer, Schafberg and Flüela Pass) in the Swiss Alps. 3D surface changes detected through comparison of multitemporal laser scanning data, as well as horizontal creep rates...

Université de Fribourg

Landslide mapping in Switzerland with ENVISAT ASAR

Wegmuller, Urs ; Strozzi, Tazio ; Delaloye, Reynald ; Raetzo, Hugo

In: Geoscience and Remote Sensing Symposium (IGARSS), 2012, p. -

In the frame of the IGARSS 2012 special session on ENVISAT the landslide mapping activities in Switzerland using ENVISAT ASAR data are presented. Between 2005 and 2010 the building up of a well suited archive over the Swiss Alps was realized through programming of all IS2 mode data during the snow free period. In recent years DINSAR and PSI based landslide inventory and monitoring products...