Snow cover and permafrost in the alps: numerical simulation of the interaction processes

Effect of snow cover on soil temperatures

Avalanche snow remains in the slope base of an avalanche slope in summe.

Laboratory measurements in the climate chamber of SLF were conducted for model calibration.

Borehole drilling at Flüelapass for soil temperature measurements (Stump Bohr AG)

Snow temperature measurement at Schilthorn

Permafrost occurrence in the alps strongly depends on climatic and topographical factors. Thereby, the snow cover plays a central role due to its high insulation effect (low heat conductivity) and its high reflectivity (high albedo). For different seasons, these physical properties affect soil temperatures in a different way: In high winter with a deep snow cover, cold air temperatures do not reach the underlying ground (warming effect) due to the high insulation effect of snow. In summer avalanche snow remains protect the underlying soil from the direct solar radiation input (cooling effect), due to the high reflection at snow surface.

Model

For a better understanding of the interaction processes as a whole, the one dimensional model SNOWPACK was extended to the underlying soil. With this new soil version of the model the influence of snow cover parameters (snow density, snow thickness, snow cover period) on soil temperatures as well as the influence of the soil parameters (soil grain size, soil type) on snow cover characteristics is studied. Furthermore, the influence of the soil grain size on soil temperatures is simulated.

The model is calibrated with laboratory measurements in the climate chamber of SLF. The simulation results are compared to further field measurements, which include measurements in the snow cover, soil and atmosphere at typical permafrost locations in Swiss alps.

Climate scenarios

The soil version of the snow cover model SNOWPACK enables the simulation of the interaction processes under different climatic conditions. Climate scenarios as a supposed increase of 2 K in mean air temperatures is simulated and the effect on snow cover and soil temperatures can be studied. The model is a tool which can be used for different problems concerning interaction processes between atmosphere, snow cover, vegetation and soil.

Literature

• List of publications on  "Permafrost"

Links

• Geographisches Institut der Universität Zürich
  
• International Permafrost Conference ICOP, 2003
  
• Corvatsch
  
• Geographisches Institut der Universität Bern
  

Contact

• Marcia Phillips