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Université de Fribourg

The firn meltwater retention model intercomparison project (retmip) : evaluation of nine firn models at four weather station sites on the greenland ice sheet

Vandecrux, Baptiste ; Mottram, Ruth ; Langen, Peter L. ; Fausto, Robert S. ; Olesen, Martin ; Stevens, C. Max ; Verjans, Vincent ; Leeson, Amber ; Ligtenberg, Stefan ; Munneke, Peter Kuipers ; Marchenko, Sergey ; Pelt, Ward van ; Meyer, Colin R. ; Simonsen, Sebastian B. ; Heilig, Achim ; Samimi, Samira ; Marshall, Shawn ; Machguth, Horst ; MacFerrin, Michael ; Niwano, Masashi ; Miller, Olivia ; Voss, Clifford I. ; Box, Jason E.

In: The Cryosphere, 2020, vol. 14, no. 11, p. 3785-3810

Perennial snow, or firn, covers 80 % of the Greenland ice sheet and has the capacity to retain surface meltwater, influencing the ice sheet mass balance and contribution to sea-level rise. Multilayer firn models are traditionally used to simulate firn processes and estimate meltwater retention. We present, intercompare and evaluate outputs from nine firn models at four sites that represent...

Université de Fribourg

Reversed surface-mass-balance gradients on himalayan debris-covered glaciers inferred from remote sensing

Bisset, Rosie R. ; Dehecq, Amaury ; Goldberg, Daniel N. ; Huss, Matthias ; Bingham, Robert G. ; Gourmelen, Noel

In: Remote Sensing, 2020, vol. 12, no. 10, p. 1563

Meltwater from the glaciers in High Mountain Asia plays a critical role in water availability and food security in central and southern Asia. However, observations of glacier ablation and accumulation rates are limited in spatial and temporal scale due to the challenges that are associated with fieldwork at the remote, high-altitude settings of these glaciers. Here, using a...

Université de Fribourg

Cold-water coral mound archive provides unique insights into intermediate water mass dynamics in the alboran sea during the last deglaciation

Fentimen, Robin ; Feenstra, Eline ; Rüggeberg, Andres ; Vennemann, Torsten ; Hajdas, Irka ; Adatte, Thierry ; Van Rooij, David ; Foubert, Anneleen

In: Frontiers in Marine Science, 2020, vol. 7, p. -

The Alboran Sea is widely recognized to host numerous cold-water coral ecosystems, including the East Melilla Coral Province. Yet, their development through time and response to climatic variability has still to be fully understood. Based on a combined investigation of benthic foraminiferal assemblages, foraminiferal stable isotope compositions, grain size analysis, sediment geochemistry, and...

Université de Fribourg

Synoptic conditions and atmospheric moisture pathways associated with virga and precipitation over coastal Adélie Land in Antarctica

Jullien, Nicolas ; Vignon, Étienne ; Sprenger, Michael ; Aemisegger, Franziska ; Berne, Alexis

In: The Cryosphere, 2020, vol. 14, no. 5, p. 1685–1702

Precipitation falling over the coastal regions of Antarctica often experiences low-level sublimation within the dry katabatic layer. The amount of water that reaches the ground surface is thereby considerably reduced. This paper investigates the synoptic conditions and the atmospheric transport pathways of moisture that lead to either virga – when precipitation is completely sublimated –...

Université de Fribourg

Algal growth and weathering crust state drive variability in western Greenland Ice Sheet ice albedo

Tedstone, Andrew J. ; Cook, Joseph M. ; Williamson, Christopher J. ; Hofer, Stefan ; McCutcheon, Jenine ; Irvine-Fynn, Tristram ; Gribbin, Thomas ; Tranter, Martyn

In: The Cryosphere, 2020, vol. 14, no. 2, p. 521–538

One of the primary controls upon the melting of the Greenland Ice Sheet (GrIS) is albedo, a measure of how much solar radiation that hits a surface is reflected without being absorbed. Lower-albedo snow and ice surfaces therefore warm more quickly. There is a major difference in the albedo of snow-covered versus bare-ice surfaces, but observations also show that there is substantial spatio-...

Université de Fribourg

First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia

Mörs, Thomas ; Reguero, Marcelo ; Vasilyan, Davit

In: Scientific Reports, 2020, vol. 10, p. 5051

Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documented previously from Antarctica, in contrast to all other continents. Here we report a fossil ilium and an ornamented skull bone that can be attributed to the Recent, South American, anuran family Calyptocephalellidae or helmeted frogs, representing the first modern amphibian found in Antarctica. The two bone...

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

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...