Geophysical characteristics of permafrost in the Abisko area, northern Sweden

Research on permafrost in the Abisko area of northern Sweden date from the 1950s. A mean annual air temperature of −3 C in the Abisko mountains (i.e. 1000 m a.s.l.) and −1 C beyond the mountain area at an altitude of around 400 m suggests that both moun− tain and arctic permafrost occur there. Several geophysical surveys were performed by means of resistivity tomography (ERT) and electromagnetic mapping (EM). Wherever pos− sible the geophysical survey results were calibrated by digging tests pits. The results show that permafrost occurs extensively in the mountain areas, especially those above 900 m a.s.l. and also sporadically at lower altitudes. At 400 m a.s.l. permafrost may be up to 30 m thick. Its thickness and extent are determined largely by the very variable local rock and soil con− ditions. Fossil permafrost is also likely to occur in this area.