Université de Fribourg

Permafrost is warming at a global scale

Biskaborn, Boris K. ; Smith, Sharon L. ; Noetzli, Jeannette ; Matthes, Heidrun ; Vieira, Gonçalo ; Streletskiy, Dmitry A. ; Schoeneich, Philippe ; Romanovsky, Vladimir E. ; Lewkowicz, Antoni G. ; Abramov, Andrey ; Allard, Michel ; Boike, Julia ; Cable, William L. ; Christiansen, Hanne H. ; Delaloye, Reynald ; Diekmann, Bernhard ; Drozdov, Dmitry ; Etzelmüller, Bernd ; Grosse, Guido ; Guglielmin, Mauro ; Ingeman-Nielsen, Thomas ; Isaksen, Ketil ; Ishikawa, Mamoru ; Johansson, Margareta ; Johannsson, Halldor ; Joo, Anseok ; Kaverin, Dmitry ; Kholodov, Alexander ; Konstantinov, Pavel ; Kröger, Tim ; Lambiel, Christophe ; Lanckman, Jean-Pierre ; Luo, Dongliang ; Malkova, Galina ; Meiklejohn, Ian ; Moskalenko, Natalia ; Oliva, Marc ; Phillips, Marcia ; Ramos, Miguel ; Sannel, A. Britta K. ; Sergeev, Dmitrii ; Seybold, Cathy ; Skryabin, Pavel ; Vasiliev, Alexander ; Wu, Qingbai ; Yoshikawa, Kenji ; Zheleznyak, Mikhail ; Lantuit, Hugues

In: Nature Communications, 2019, vol. 10, no. 1, p. 264

Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across...

Université de Fribourg

The reproducibility of SfM algorithms to produce detailed Digital Surface Models: the example of PhotoScan applied to a high-alpine rock glacier

Hendrickx, Hanne ; Vivero, Sebastián ; Cock, Laure De ; De Wit, Bart ; De Maeyer, Philippe ; Lambiel, Christophe ; Delaloye, Reynald ; Nyssen, Jan ; Frankl, Amaury

In: Remote Sensing Letters, 2019, vol. 10, no. 1, p. 11–20

In geomorphology, PhotoScan is a software that is used to produce Digital Surface Models (DSMs). It constructs 3D environments from 2D imagery (often taken by Unmanned Aerial Vehicles (UAV)) based on Structure-from-Motion (SfM) and Multi- View Stereo (MVS) principles. However, unpublished computer-vision algorithms used, contain random elements which can affect the accuracy of the outputs. For...

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

Decadal evolution of a very small heavily debris-covered glacier in an Alpine permafrost environment

Capt, M. ; Bosson, Jean-Baptiste ; Fischer, M. ; Micheletti, N. ; Lambiel, Christophe

In: Journal of Glaciology, 2016, vol. 62, no. 233, p. 535–551

Glacier response to climate forcing can be heterogeneous and complex, depending on glacier system characteristics. This article presents the decadal evolution of the Tsarmine Glacier (Swiss Alps), a very small and heavily debris-covered cirque glacier located in the Alpine periglacial belt. Archival aerial photogrammetry and autocorrelation of orthophotos were used to compute surface...

Université de Fribourg

Geomorphology of the Hérens valley (Swiss Alps)

Lambiel, Christophe ; Maillard, Benoît ; Kummert, Mario ; Reynard, Emmanuel

In: Journal of Maps, 2016, vol. 12, no. 1, p. 160–172

This paper presents a geomorphological map of the Hérens valley in the Western Swiss Alps. With an area of 270 km2 and altitudes ranging from 470 to 4357 m a.s.l., this valley is one of the main secondary catchments of the Upper Rhône valley. The high differences in altitudes, combined with a varied geology, create an important geomorphic diversity. The main processes active in mountain...

Université de Fribourg

Assessing the rock glacier kinematics on three different timescales: a case study from the southern Swiss Alps

Scapozza, Cristian ; Lambiel, Christophe ; Bozzini, Claudio ; Mari, Stefano ; Conedera, Marco

In: Earth Surface Processes and Landforms, 2014, vol. 39, no. 15, p. 2056–2069

Surface temperature increases since the 1990s have often been associated with an increase in the speed of rock glaciers. Evidence of similar links on the centennial to millennial scale are, however, still lacking due to less focus to date on the medium- and long-term kinematics of these landforms. In order to assess (palaeo)climatic variations in rock glacier kinematics, we analysed the movements...

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

Internal structure and permafrost distribution in two alpine periglacial talus slopes, Valais, Swiss Alps

Scapozza, Cristian ; Lambiel, Christophe ; Baron, Ludovic ; Marescot, Laurent ; Reynard, Emmanuel

In: Geomorphology, 2011, vol. 132, no. 3-4, p. 208-221

In order to determine the spatial extension and the characteristics of permafrost within alpine talus slopes, two sites located in the western part of the Swiss Alps were studied using borehole drilling and electrical resistivity tomography (ERT) profiles. Three boreholes were drilled along an upslope–downslope transect in both talus slopes. In both sites, frozen sediments are present only in...