HR: 15:10h
AN: C23B-07    [Abstracts]
TI: Model Assessment of Permafrost Development for a Large Alpine Catchment
AU: Voelksch, I
EM: voelksch@slf.ch
AF: WSL, Swiss Federal Institute for Snow and Avalanche Research SLF, Fluelastr. 11, Davos Dorf, 7260 Switzerland
AU: * Lehning, M
EM: lehning@slf.ch
AF: WSL, Swiss Federal Institute for Snow and Avalanche Research SLF, Fluelastr. 11, Davos Dorf, 7260 Switzerland
AB: The extremely hot summer of 2003 saw increased rockfall and slope instability problems in the European Alps. This is generally attributed to permafrost thawing. Therefore, the development of permafrost in steep Alpine terrain under the observed warming trend needs to be investigated. We use ALPINE3D, a detailed model of Alpine surface processes to assess permafrost occurrence under the current climate and to predict an expected change under the warming scenario that future summers will be on average as the summer 2003. The ALPINE3D modules consist of a radiation balance model using a view factor approach and include short-wave scattering and long-wave emission from terrain and tall vegetation. The processes in the atmosphere are coupled to a distributed one-dimensional model of vegetation, snow and soil (SNOWPACK) using the assumption that lateral exchange is small in these media. Snow and soil processes are treated in much detail with adaptive multi-layer finite elements. The model modules can be run in a parallel (distributed) mode using a GRID infrastructure to allow such computationally demanding tasks. The application of ALPINE3D to the Cordevole river basin in the northern Italian Dolomites has been based on weather station data from seven locations in the area. A spatial resolution of 200 m is used for the simulation, which covers approximately 900 square kilometers. Typically, mass and energy exchange processes for 20 soil layers and up to 30 snow layers are calculated with an hourly time step and 15 years of data. In the steep terrain of the southern Alps, only a small area fraction has permafrost. Permafrost disappears almost completely under the warming scenario, which is achieved by simulating repeatedly the 2003 year.
DE: 0704 Seasonally frozen ground
DE: 0722 Rock glaciers
DE: 0736 Snow (1827, 1863)
DE: 0738 Ice (1863)
DE: 0798 Modeling
SC: Cryosphere [C]
MN: Fall Meeting 2005