Using relict rockglaciers in GIS-based modelling to reconstruct Younger Dryas permafrost distribution patterns in the Err-Julier area, Swiss Alp

• Main Authors: Frauenfelder, Regula, Haeberli, Wilfried, Hoelzle, Martin, Maisch, Max
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis 2001
• Subjects: Institute of Geography; 910 Geography & travel; Geography; Planning and Development; General Earth and Planetary Sciences; permafrost
• Online Access: https://www.zora.uzh.ch/id/eprint/63452/; https://www.zora.uzh.ch/id/eprint/63452/1/Frauenfelder_etal_2001_using_relict.pdf; https://doi.org/10.5167/uzh-63452; https://doi.org/10.1080/00291950152746522

Differences in mean annual air temperature between the Younger Dryas period and today were estimated at the fronts of 32 relict rockglaciers in the Err-Julier area, eastern Swiss Alps. The analyses were based on a case-by-case calculation of direct incoming solar radiation and mean annual air temperature using a digital elevation model (DEM) and meteo data of recent years. Our results suggest that mean annual air temperature during the Younger Dryas was lowered by c. 3°C to 4°C, and that the lower limit of permafrost occurrence was depressed considerably more than glacier equilibrium lines. This indicates strongly reduced precipitation (30% to 40% reduction) and much larger abundance of mountain permafrost at that time. A model simulation of the corresponding spatial permafrost distribution during the Younger Dryas indicates that glaciers in the study area were mostly surrounded by permafrost at that time and probably had a polythermal structure of englacial temperatures.