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

Authors: Frauenfelder R.; Haeberli W.; Hoelzle M.; Maisch M.

Source: Norwegian Journal of Geography, Volume 55, Number 4, 1 November 2001 , pp. 195-202(8)

Publisher: Routledge, part of the Taylor & Francis Group

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Abstract:

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.

Keywords: ROCKGLACIERS; SWISS; ALPS; YOUNGER; DRYAS; PERMAFROST; DISTRIBUTION

Language: English

Document Type: Research article

Publication date: 2001-11-01