ISPR - Influences of snow cover on thermal and mechanical processes in steep permafrost rock walls

Project information:

ISPR is a D-A-CH project consisting of two connected parts. Part 1: internal response (University of Bonn) is financed by the German Research Foundation (DFG). Part 2: external forcing (SLF, University of Fribourg, University of Zürich) is financed by the Swiss National Science Foundation (SNF).

Our project aims at deciphering snow control in steep permafrost rocks and its sensitivity to climate change. We target at developing 1) a novel methodological/modelling framework to investigate snow forcing, 2) process understanding for snow impact quantification and 3) future scenarios for estimating the impact of snow cover changes in steep permafrost rock walls.

Part 2 focuses on surface heat/water flow characterization using continuous snow cover quantification,  terrestrial laser scanning (TLS), the calibration of physical snow properties (snow pits) and surface rock temperature (temperature loggers) measurements. Part 1 investigates the subsurface impact of snow on the thermal and mechanical behaviour inside rockwalls using laboratory-calibrated 3D geophysical monitoring (electrical resistivity and seismic refraction tomography) as well as acoustic, hydraulic and geotechnical observation of instability and hydro-mechanical forcing.

We aim at developing a realistic model for snow cover and snow melt  in steep bedrock (SNOWPACK) and a coupled model that reveals hydro-thermal and hydro-mechanical effects of snow melt infiltration in fractured bedrock (UDEC). Model results will be validated using thermal and mechanical observation in the snow cover, at the rock surface and in the rock subsurface (borehole). The sensitivity of the models to altered snow scenarios will provide a more holistic view on climate change impacts on potentially hazardous permafrost rock faces.

Methods:

Overview about ISPR research outline and applied methods (Fig.3).      

Geoelectric measurements at Gemsstock (Fig. 4 on the left, photo by M. Krautblatter), laboratory P-wave measurements (Fig. 5 on the right top, photo by D. Draebing) and Fracture roughness assessment with different profile gauges and Fecker-plates in the field and in the laboratory (Fig. 6 on the right bottom, photo by M. Krautblatter)

Aims:

1. Snow cover (Part 2): Temporal and spatial monitoring of snow cover in steep permafrost rock walls: snow deposition, snow depth/profile evolution and snow melt.
2. Surface heat flux (Part 2): Temporal and spatial assessment of heat flux between atmosphere, snow cover and ground.
3. Thermal response (Part 1): Temporal and spatial monitoring of the thermal response in steep rock walls.
4. Mechanic response (Part 1 and 2): Temporal and spatial monitoring of the mechanic response in steep rock walls.
5. Interaction (Part 1 and 2): Modelling of the interaction between snow cover, permafrost and instability.
6. Scenarios (Part 1 and 2): Evolution of snow pattern with climate change and sensitivity of the mechanic/thermal system.

Study Sites:

The study site Gemsstock (Andermatt, CH, 2963 m a.s.l.) (Fig. 3) is integrated in the PERMOS (Permafrost Monitoring Switzerland) network since 2005 funded by the Federal Office of the Environment (FOEN), the Swiss Academy of Sciences (SCNAT) and the Federal Office of Meteorology and Climatology (MeteoSwiss). The Gemsstock is presently at the fringe of permafrost distribution and highly sensitive to annual fluctuations while the Steintaelli displays annual fluctuations in the size and thermal constitution of a stable permafrost body.

Both study sites consist of steep, narrow crestlines between north- and south-facing rockwalls with heterogeneous snow accumulation and significant ice aggregation in rock fractures. The study site Gemsstock consists of granodiorite/ortho-gneiss rocks, and also shows high rockfall activity. The Gurschen-glacier has significantly retreated in the last decades and the north-facing rock wall has been increasingly exposed leading to debutressing.

The study site Steintaellli (Matter Valley, CH 3150 m a.s.l., Fig. 4) had been equipped and developed in the Research Training Group “Landform” (GRK 437/1-4) by the German Research Foundation (2005-2008) and was hereafter transferred to the bundle project Sensitivity of Mountain Permafrost to Climate Change (SPCC 2008-2011; DFG DI-414/19-1). The Steintaelli is a special permafrost monitoring site in steep bedrock due to its high degree of rock instability (fracture opening up to 6 mm/month) coincident with maximum thaw activity in late summer. In addition, there is a relatively safe access to the rock faces for 3D monitoring.

 It consists of paragneiss rocks and indicates high periglacial and paraglacial activity such as rock creep and rockfalls. The warming tendency after the Little Ice Age resulted in a more than 300 metre retreat of the Rothorn-NE-Glacier that is now dissected by newly exposed rock bars in small ice relics.

Publications:

Draebing, D. and M. Krautblatter, M. (2012): P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model, The Cryosphere Discuss., 6, 793-819, doi:10.5194/tcd-6-793-2012.

Kenner, R., Phillips, M., Danioth, C., Denier, C., Thee, P. and A. Zgraggen (2011):
Investigation of rock and ice loss in a recently deglaciated moutain rock wall using terrestrial laser scanning: Gemsstock, Swiss Alps. Cold Reg. Sci. Technol. 67: 157-164.

Krautblatter, M., Verleysdonk, S., Fores-Orozco, A. and A. Kemna (2010): Temperature-calibrated imaging of seasonal changes in permafrost rock walls by quantitative electrical resistivity tomography (Zugspitze, German/Austrian Alps). In: Journal of Geophysical Research - Earth Surface (VOL. 115, F02003). Online: http://www.agu.org/journals/jf/jf1002/2008JF001209/

Contact Information:

Part 1:

Dr. Michael Krautblatter (Main applicant)
Department of Geography, University of Bonn, Germany

Prof. Dr. Richard Dikau (Co-applicant, supervisor)
Department of Geography, University of Bonn, Germany

Daniel Dräbing (PhD student)
Department of Geography, University of Bonn, Germany

Part 2:

Dr. Marcia Phillips (Main applicant)
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland

Prof. Dr. Martin Hoelzle (Co-applicant)
Department of Geosciences, University of Fribourg, Switzerland

Dr. Stephan Gruber (Co-applicant)
Department of Geography, University of Zurich, Switzerland

Anna Haberkorn (PhD Student)
WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland)

Cooperations:

Part 1:

Prof. Dr. C. Hauck (Department of Geosciences, University of Fribourg, Switzerland),

Prof. Dr. A. Kemna (Applied Geophysics Section, Steinmann Institute of Geology, Mineralogy and Palaeontology,  University of Bonn),

Prof. Dr. M. Moser (Engineering Geology Section, Institute of Geology and Mineralogy, University of Erlangen-Nuremberg),

Dipl. Ing, H. Hausmann (Dept. of Geodesy and Geophysics, TU Wien, Austria).

Part 2:

Prof. Dr. H. Ingensand (Institute of Geodesy and Photogrammetry, ETH Zürich, Switzerland),

Prof. Dr. H.-G. Maas (Institute of Photogrammetry and Remote Sensing, TU Dresden, Germany),

Dr. M. Lehning, (WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland).