Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 10, 2693-2719, 2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
15 Nov 2016
Semi-automated calibration method for modelling of mountain permafrost evolution in Switzerland
Antoine Marmy1, Jan Rajczak2, Reynald Delaloye1, Christin Hilbich1, Martin Hoelzle1, Sven Kotlarski2, Christophe Lambiel3, Jeannette Noetzli4, Marcia Phillips5, Nadine Salzmann1, Benno Staub1, and Christian Hauck1 1Department of Geosciences, University of Fribourg, Fribourg, Switzerland
2Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland
3Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
4Department of Geography. University of Zurich, Zurich, Switzerland
5WSL, Swiss Federal Institute for Snow and Avalanche Research, Davos, Switzerland
Abstract. 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 evolution of permafrost. Due to the complexity of the processes involved and the heterogeneity of Alpine terrain, models must be carefully calibrated, and results should be compared with observations at the site (borehole) scale. However, for large-scale applications, a site-specific model calibration for a multitude of grid points would be very time-consuming. To tackle this issue, this study presents a semi-automated calibration method using the Generalized Likelihood Uncertainty Estimation (GLUE) as implemented in a 1-D soil model (CoupModel) and applies it to six permafrost sites in the Swiss Alps. We show that this semi-automated calibration method is able to accurately reproduce the main thermal condition characteristics with some limitations at sites with unique conditions such as 3-D air or water circulation, which have to be calibrated manually. The calibration obtained was used for global and regional climate model (GCM/RCM)-based long-term climate projections under the A1B climate scenario (EU-ENSEMBLES project) specifically downscaled at each borehole site. The projection shows general permafrost degradation with thawing at 10 m, even partially reaching 20 m depth by the end of the century, but with different timing among the sites and with partly considerable uncertainties due to the spread of the applied climatic forcing.

Citation: Marmy, A., Rajczak, J., Delaloye, R., Hilbich, C., Hoelzle, M., Kotlarski, S., Lambiel, C., Noetzli, J., Phillips, M., Salzmann, N., Staub, B., and Hauck, C.: Semi-automated calibration method for modelling of mountain permafrost evolution in Switzerland, The Cryosphere, 10, 2693-2719,, 2016.
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Short summary
This paper presents a new semi-automated method to calibrate the 1-D soil model COUP. It is the first time (as far as we know) that this approach is developed for mountain permafrost. It is applied at six test sites in the Swiss Alps. In a second step, the calibrated model is used for RCM-based simulations with specific downscaling of RCM data to the borehole scale. We show projections of the permafrost evolution at the six sites until the end of the century and according to the A1B scenario.
This paper presents a new semi-automated method to calibrate the 1-D soil model COUP. It is the...