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 degrees 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 degrees 55 ' 09 "N, 18 degrees 38 ' 29 "E, 1550 m ASL) in March 2000 and at Juvvasshere (depth 129 m), southern Norway (61 degrees 40 ' 32 "N, 08 degrees 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 Juvvasshoe show anomalously low geothermal gradients, indicating low heat flow through thick permafrost (similar to 350 m and similar to 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 degreesC during the twentieth century. Both the Tarfalaryggen and Juvvasshoe boreholes also reveal thermal anomalies, which reflect a surface warming over the past decades, with a magnitude of approximately 0.5-1.0 degreesC. Copyright (C) 2001 John Wiley sc Sons, Ltd.
