Université de Fribourg

Mountain permafrost degradation documented through a network of permanent electrical resistivity tomography sites

Mollaret, Coline ; Hilbich, Christin ; Pellet, Cécile ; Flores-Orozco, Adrian ; Delaloye, Reynald ; Hauck, Christian

In: The Cryosphere, 2019, vol. 13, no. 10, p. 2557–2578

Mountain permafrost is sensitive to climate change and is expected to gradually degrade in response to the ongoing atmospheric warming trend. Long-term monitoring of the permafrost thermal state is a key task, but problematic where temperatures are close to 0 ∘C because the energy exchange is then dominantly related to latent heat effects associated with phase change (ice–water), rather...

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

New insights on permafrost genesis and conservation in talus slopes based on observations at Flüelapass, Eastern Switzerland

Kenner, Robert ; Phillips, Marcia ; Hauck, Christian ; Hilbich, Christin ; Mulsow, Christian ; Bühler, Yves ; Stoffel, Andreas ; Buchroithner, Manfred

In: Geomorphology, 2017, vol. 290, p. 101–113

The talus slope at Flüelapass was the first mountain permafrost study site in Switzerland in the 1970s and the presence of ice-rich permafrost at the foot of the slope has been investigated in the context of several studies focusing on the role of snow cover distribution. We review previously developed hypotheses and present new ones using various data sources, such as temperature...

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

Degrading mountain permafrost in southern Norway: spatial and temporal variability of mean ground temperatures, 1999–2009

Isaksen, Ketil ; Ødegård, Rune Strand ; Etzelmüller, Bernd ; Hilbich, Christin ; Hauck, Christian ; Farbrot, Herman ; Eiken, Trond ; Hygen, Hans Olav ; Hipp, Tobias Florian

In: Permafrost and Periglacial Processes, 2011, vol. 22, no. 2, p. 361–377

A ten-year record (1999–2009) of annual mean ground surface temperatures (MGSTs) and mean ground temperatures (MGTs) was analysed for 16 monitoring sites in Jotunheimen and on Dovrefjell, southern Norway. Warming has occurred at sites with cold permafrost, marginal permafrost and deep seasonal frost. Ongoing permafrost degradation is suggested both by direct temperature monitoring and indirect...

Université de Fribourg

Automated time-lapse ert for improved process analysis and monitoring of frozen ground

Hilbich, Christin ; Fuss, C. ; Hauck, Christian

In: Permafrost and Periglacial Processes, 2011, vol. 22, no. 4, p. 306–319

A new automated electrical resistivity tomography (A-ERT) system is described that allows continuous measurements of the electrical resistivity distribution in high-mountain or polar terrain. The advantages of continuous resistivity monitoring, as opposed to single measurements at irregular time intervals, are illustrated using the permafrost monitoring station at the Schilthorn, Swiss Alps. Data...

Université de Fribourg

Applicability of electrical resistivity tomography monitoring to coarse blocky and ice-rich permafrost landforms

Hilbich, Christin ; Marescot, L. ; Hauck, Christian ; Loke, M. H. ; Mäusbacher, R.

In: Permafrost and Periglacial Processes, 2009, vol. 20, no. 3, p. 269-284

The inversion and interpretation of electrical resistivity tomography (ERT) data from coarse blocky and ice-rich permafrost sites are challenging due to strong resistivity contrasts and high contact resistances. To assess temporal changes during ERT monitoring (ERTM), corresponding inversion artefacts have to be separated from true subsurface changes. Appraisal techniques serve to analyse an ERTM...