Three deep Alpine‐permafrost boreholes in Svalbard and Scandinavia

• Published in: Permafrost and Periglacial Processes
• Main Authors: Isaksen, Ketil, Holmlund, Per, Sollid, Johan Ludvig, Harris, Charles
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Svalbard; Norway; La Balance; Janssonhaugen; Northern Sweden; permafrost; Permafrost and Periglacial Processes; pergélisol
• Online Access: http://dx.doi.org/10.1002/ppp.380; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.380; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.380

Abstract The presence and thermal character of permafrost reflect past and present surface energy balances plus the heat flux from the Earth's interior. Analysis of permafrost ground temperatures constitutes a key research tool for detecting thermal anomalies caused by twentieth‐century warming. Three deep boreholes in alpine permafrost were drilled in Svalbard and Scandinavia and form part of the latitudinal transect of mountain permafrost boreholes through the mountains of Europe established under the EU PACE (Permafrost and Climate in Europe) project. The northernmost borehole in the transect, at Janssonhaugen (depth 102 m), western Svalbard (78°10′46′′N, 16°28′01′′E, 270 m ASL) was drilled in May 1998. In Scandinavia, boreholes were drilled at Tarfalaryggen (depth 100 m), northern Sweden (67°55′09′′N, 18°38′29′′E, 1550 m ASL) in March 2000 and at Juvvasshøe (depth 129 m), southern Norway (61°40′32′′N, 08°22′04′′E, 1894 m ASL) in August 1999. Permafrost thickness at Janssonhaugen is estimated as approximately 220 m. The temperature profiles on Tarfalaryggen and Juvvasshøe show anomalously low geothermal gradients, indicating low heat flow through thick permafrost (∼350 m and ∼380 m respectively). Palaeoclimatic analysis based on inversion modelling of the ground temperature measurements at Janssonhaugen shows near surface warming of 1.5 ± 0.5 °C during the twentieth century. Both the Tarfalaryggen and Juvvasshøe boreholes also reveal thermal anomalies, which reflect a surface warming over the past decades, with a magnitude of approximately 0.5–1.0 °C. Copyright © 2001 John Wiley & Sons, Ltd. RÉSUMÉ L'existence d'un pergélisol ainsi que ses caractères thermiques reflètent la balance entre l'énergie de surface (passée et actuelle) et le flux de chaleur interne de la terre. L'étude des températures du pergélisol constitue ainsi une recherche fondamentale pour détecter les anomalies thermiques dues au réchauffement du vingtième siècle. Trois sondages profonds dans le pergélisol alpin ont été réalisés au ...