Three deep alpine-permafrost boreholes in Svalbard and Scandinavia

The presence and thermal character of permafrost reflect past and present s urface energy balances plus the heat flux from the Earth's interior. Analys is of permafrost ground temperatures constitutes a key research tool for de tecting thermal anomalies caused by twentieth-century warming. Three deep b oreholes in alpine permafrost were drilled in Svalbard and Scandinavia and form part of the latitudinal transect of mountain permafrost boreholes thro ugh the mountains of Europe established under the EU PACE (Permafrost and C limate in Europe) project. The northernmost borehole in the transect, at Ja nssonhaugen (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 wer e drilled at Tarfalaryggen (depth 100 m), northern Sweden(67 degrees 55 ' 0 9 "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 esti mated 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 respec tively). 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 surfac e warming over the past decades, with a magnitude of approximately 0.5-1.0 degreesC. Copyright (C) 2001 John Wiley sc Sons, Ltd.