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Université de Fribourg

Rapid expansion of Greenland’s low-permeability ice slabs

MacFerrin, Mike ; Machguth, Horst ; As, Dirk van ; Charalampidis, C. ; Stevens, C. M. ; Heilig, A. ; Vandecrux, B. ; Langen, P. L. ; Mottram, R. ; Fettweis, Xavier ; Broeke, Michiel R. van den ; Pfeffer, W. T. ; Moussavi, M. S. ; Abdalati, W.

In: Nature, 2019, vol. 573, no. 7774, p. 403–407

In recent decades, meltwater runoff has accelerated to become the dominant mechanism for mass loss in the Greenland ice sheet1,2,3. In Greenland’s high- elevation interior, porous snow and firn accumulate; these can absorb surface meltwater and inhibit runoff4, but this buffering effect is limited if enough water refreezes near the surface to restrict percolation5,6. However, the influence...

Université de Fribourg

Quantitative imaging of water, ice and air in permafrost systems through petrophysical joint inversion of seismic refraction and electrical resistivity data

Wagner, Florian ; Mollaret, Coline ; Günther, Thomas ; Kemna, Andreas

In: Geophysical Journal International, 2019, vol. 219, no. 3, p. 1866–1875

Quantitative estimation of pore fractions filled with liquid water, ice and air is crucial for a process-based understanding of permafrost and its hazard potential upon climate- induced degradation. Geophysical methods offer opportunities to image distributions of permafrost constituents in a non-invasive manner. We present a method to jointly estimate the volumetric fractions of liquid water,...

Université de Fribourg

Two-dimensional inversion of wideband spectral data from the capacitively coupled resistivity method – first applications in periglacial environments

Mudler, Jan ; Hördt, Andreas ; Przyklenk, Anita ; Fiandaca, Gianluca ; Maurya, Pradip Kumar ; Hauck, Christian

In: The Cryosphere, 2019, vol. 13, no. 9, p. 2439–2456

The DC resistivity method is a common tool in periglacial research because it can delineate zones of large resistivities, which are often associated with frozen water. The interpretation can be ambiguous, however, because large resistivities may also have other causes, like solid dry rock. One possibility to reduce the ambiguity is to measure the frequency-dependent resistivity. At low...

Université de Fribourg

Ice-penetrating radar survey of the subsurface debris field at Camp Century, Greenland

Karlsson, Nanna B. ; Colgan, William T. ; Binder, Daniel ; Machguth, Horst ; Abermann, Jakob ; Hansen, Karina ; Pedersen, Allan Ø.

In: Cold Regions Science and Technology, 2019, vol. 165, p. 102788

The warming climate is changing the surface dynamics of the Greenland Ice Sheet, including the balance between snowfall and melt. Increasing surface melt impacts the structure of the relatively porous near-surface layer known as firn. Camp Century, a base abandoned in 1967, now comprises a subsurface debris field within the firn in Northwest Greenland. We collected 80 km of 100 or 250 MHz...

Université de Fribourg

Distinguishing ice-rich and ice-poor permafrost to map ground temperatures and ground ice occurrence in the Swiss Alps

Kenner, Robert ; Noetzli, Jeannette ; Hoelzle, Martin ; Raetzo, Hugo ; Phillips, Marcia

In: The Cryosphere, 2019, vol. 13, no. 7, p. 1925–1941

Mountain permafrost is invisible, and mapping it is still a challenge. Available permafrost distribution maps often overestimate the permafrost extent and include large permafrost-free areas in their permafrost zonation. In addition, the representation of the lower belt of permafrost consisting of ice-rich features such as rock glaciers or ice-rich talus slopes can be challenging. These...

Université de Fribourg

Strong contrast in mass and energy balance between a coastal mountain glacier and the Greenland ice sheet

Abermann, Jakob ; As, Dirk Van ; Wacker, Stefan ; Langley, Kirsty ; Machguth, Horst ; Fausto, Robert Schjøtt

In: Journal of Glaciology, 2019, vol. 65, no. 250, p. 263–269

We show a strong difference in surface mass and energy balance of a mountain glacier and two sites on the ice sheet at 64°N in West Greenland using stake and automated weather station observations. Net surface mass balance is on average 2.2 m w.e. less negative at the coast compared with the ice sheet in the same elevation. We find a larger energy turnover at the ice sheet margin on...

Université de Fribourg

GlacierMIP – A model intercomparison of global-scale glacier mass-balance models and projections

Hock, Regine ; Bliss, Andrew ; Marzeion, Ben ; Giesen, Rianne H. ; Hirabayashi, Yukiko ; Huss, Matthias ; Radić, Valentina ; Slangen, Aimée B. A.

In: Journal of Glaciology, 2019, vol. 65, no. 251, p. 453–467

Global-scale 21st-century glacier mass change projections from six published global glacier models are systematically compared as part of the Glacier Model Intercomparison Project. In total 214 projections of annual glacier mass and area forced by 25 General Circulation Models (GCMs) and four Representative Concentration Pathways (RCP) emission scenarios and aggregated into 19 glacier ...

Université de Fribourg

Disappearing world heritage glaciers as a keystone of nature conservation in a changing climate

Bosson, J.‐B. ; Huss, Matthias ; Osipova, E.

In: Earth’s Future, 2019, vol. 7, no. 4, p. 469–479

Since 1972, the United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Convention aims to identify and protect sites of Outstanding Universal Value for future generations. However, growing impacts of climate change are of the utmost concern for the integrity of many sites. Here, we inventory the glaciers present in natural World Heritage sites for the first...

Université de Fribourg

Calibrated ice thickness estimate for all glaciers in Austria

Helfricht, Kay ; Huss, Matthias ; Fischer, Andrea ; Otto, Jan-Christoph

In: Frontiers in Earth Science, 2019, vol. 7, p. -

Knowledge on ice thickness distribution and total ice volume is a prerequisite for computing future glacier change for both glaciological and hydrological applications. Various ice thickness estimation methods have been developed but regional differences in fundamental model parameters are substantial. Parameters calibrated with measured data at specific points in time and space can vary when...

Université de Fribourg

Northern Hemisphere permafrost map based on TTOP modelling for 2000–2016 at 1 km2 scale

Obu, Jaroslav ; Westermann, Sebastian ; Bartsch, Annett ; Berdnikov, Nikolai ; Christiansen, Hanne H. ; Dashtseren, Avirmed ; Delaloye, Reynald ; Elberling, Bo ; Etzelmüller, Bernd ; Kholodov, Alexander ; Khomutov, Artem ; Kääb, Andreas ; Leibman, Marina O. ; Lewkowicz, Antoni G. ; Panda, Santosh K. ; Romanovskyh, Vladimir ; Wayk, Robert G. ; Westergaard-Nielsen, Andreas ; Wu, Tonghua ; Yamkhin, Jambaljav ; Zou, Defu

In: Earth-Science Reviews, 2019, vol. 193, p. 299–316

Permafrost is a key element of the cryosphere and an essential climate variable in the Global Climate Observing System. There is no remote-sensing method available to reliably monitor the permafrost thermal state. To estimate permafrost distribution at a hemispheric scale, we employ an equilibrium state model for the temperature at the top of the permafrost (TTOP model) for the 2000–2016...