Installation of a shallow borehole network and monitoring of the ground thermal regime of a high alpine discontinuous permafrost environment, Eastern Swiss Alps

Permafrost is known to respond to changes in atmospheric temperatures but our knowledge of the scale and the processes involved are still not fully understood, especially not when the surface is other than bedrock. In order to gain a better understanding of the influence of the surface and ground characteristics on the thermal regime of the active layer, boreholes were drilled in the high alpine discontinuous permafrost in the Murtèl-Chastelets area, Eastern Swiss Alps, and instrumented with chains of thermistor arrays. Five shallow boreholes were drilled during the summer of 2002, adding to the network of the existing four boreholes. Data from the first year of this multi-annual study demonstrate a pronounced thermal offset for loose material composed of gravel or boulders. Also, the thermal diffusivity was calculated over the summer period, adding to the understanding of the spatial discontinuity in the Alpine permafrost.

Keywords:

• active layer
• boreholes
• surface characteristics
• thermal offset
• thermal diffusivity

Acknowledgements

This work is funded by a University of Zürich research grant. We would like to especially thank Patrick Blétry from Blétry AG, whose knowledge was essential during the drilling; H. Gubler (AlpuG) for his continual interest in and support of our work; Stump AG; and the Corvatsch cable car company and their staff for their always friendly support. We would also like to thank the large number of passionate students and colleagues that made this fieldwork possible, especially Monika Oswald, who contributed an enormous effort. The feedback from the reviews is gratefully acknowledged.