Das Projekt "Measuring and modelling of the energy fluxes in the permafrost active layer (Thermal offset)" wird vom Umweltbundesamt gefördert und von Universität Zürich, Geographisches Institut durchgeführt. The spatial distribution patterns of mountain permafrost is important because of the sensitivity of the upper permafrost layers with respect to decadal climatic changes. In high mountain areas, large variations of topography and thus, permafrost-related factors such as snow cover and the heterogeneity of surface material requires a form of spatial modelling to achieve a realistic picture of permafrost occurrences. Both in the Alps and the Scandinavian Mountains we have realised that knowledge of the thermal fluxes within the active layer is essential for a better understanding of the actual distribution of permafrost. Especially in view to climate change, the coupling of atmosphere with ground thermal models is only possible by an impoved understanding of the processes within the active layer. This project seeks to establish a network of ten shallow bore holes in the Eastern Swiss Alps, measuring the thermal regime in the active layer ('thermal offset'). The application of the thermal offset concept allows the distributed mapping of the mean annual top permafrost temperature, which allows us to estimate spatially distributed permafrost depths by applying standard heat conduction theory. This permits quantitatively better estimates for evaluating impact of climate warming on permafrost distribution in high-alpine environments. This project is carried out in close co-operation with the University of Oslo, Norway.
Das Projekt "Analysis and Spatial Modelling of Permafrost Distribution in Cold-Mountain Areas by Integration of Advanced Remote Sensing Technology" wird vom Umweltbundesamt gefördert und von Universität Zürich, Geographisches Institut durchgeführt. Glaciers and permafrost in cold mountain areas are especially sensitive with respect to changes in atmospheric temperature because of their proximity to melting conditions. The 20th century has seen striking changes in glacierized areas of mountain ranges and, hence, in the extension of glacial and periglacial mountain belts all over the world, causing a corresponding shift in geomorphodynamic processes. In the event of future accelerated warming, the cryosphere components of Alpine environments would most likely evolve at high rates beyond the limits of historical and holocene variability ranges. Such a development would necessarily lead to pronounced disequilibria in the water cycle, in mass wasting processes and sediment flux as well as in growth conditions of vegetation. By consequence, living conditions for humans and animals will likely be affected as well. Empirical knowledge would have to be replaced increasingly by improved process understanding and robust computer models for economic planning, hazard mitigation, landscape protection etc. Thereby, high priority has to be placed on application of modern know-how and technologies for preparing corresponding assessments in combination with improved knowledge about the evolution of glacier- and permafrost-related processes based on appropriate monitoring programmes. An energy balance model that calculates surface and ground temperatures from climatic data has recently been developed in the project area (Corvatsch, Upper Engadin) based on a 3-year time series from a microclimatological station. For the successful spatial application and further development of this one-dimensional model, accurate spatial data fields of key surface characteristics are needed. The development of process-based permafrost models is closely connected to the improvement of statistical models that will be applicable in areas where less information is available. For these models, accurate knowledge of vegetation abundance represents a sensitive independent indicator to be used in evaluation as well as a valuable parameter if included. The present project for the first time employs and explores airborne hyperspectral remote sensing as a source of quantitative spatial information for analysis and numerical modelling of permafrost distribution and evolution in an especially well documented test area of the Swiss Alps. The potential to accurately quantify snow-free albedo and sparse vegetation cover in rugged topography makes hyperspectral remote sensing a promising data source. Collaboration of the Physical Geography Division and Remote Sensing Laboratories (RSL) is expected to help in reducing the gap that commonly exists between development of new sensors and technology and their application in research. The application of established remote sensing techniques and, if necessary, their adaptation to high mountain environments, provides a measurable data-basis for this study. (abridged text)