Rock glacier mapping and permafrost distribution modelling in the Turtmanntal, Valais, Switzerland

摘要

Rock glaciers in a study area in the southern Swiss Alps have been mapped and compiled in an inventory that serves primarily as a database for the development of a regional permafrost distribution model. The field data support the simulation results of the empirical-statistical permafrost model PERMAMAP (HOELZLE 1994). The local validation of tills model shows that active rock glaciers are predominantly (almost 70%) situated within the permafrost class "permafrost probable". However, there is field indication that permafrost in northerly exposed areas of the Turtmanntal seems to be less extended than simulated by the model. The field data and the modelling determined that the permafrost area in the valley covers about 30 km(2). There is still a need for field evidence in terms of regional permafrost distribution assessment. Regional permafrost distribution models need to be verified on a regional scale. To date, apart from measurements of the bottom temperature of the winter snow cover (HAEBERLI 1973), the application of the indicator method is the most feasible and reliable possibility to determine permafrost distribution oil a regional scale and to test regional permafrost distribution models.