Using relict rockglaciers in GIS-based modelling to reconstruct Younger Dryas permafrost distribution patterns in the Err-Julier area, Swiss Alp
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 temper...
| Main Authors: | , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Taylor & Francis
2001
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| Subjects: | |
| 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 |
| Summary: | 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. |
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