Relations between slow slope processes and active-layer thickness 1972–2002, Kapp Linné, Svalbard

The active layer has been monitored at 10 sites near Kapp Linné (78°03′42″N 13°37′07″E), Svalbard. The 10 sites differ in elevation, distance from the sea, vegetation cover, substrate, and periglacial processes. The International Permafrost Association's CALM (circumpolar active layer monitoring) standard grids, has been applied. The macroclimate is covered by data from Kapp Linné, for the period 1912 to 2004. Slow slope processes are monitored parallel with the active layer. The mean active layer for the sites varies between 1.13 m and 0.43 m. The variability of the active layer correlates reasonably well with the summer climate, MAAT and DDT-air. The period 1972–1983 had cool summers and since then steadily increasing summer temperatures have been recorded. The active layer follows the same general pattern with good correlation. The slope processes respond clearly to the deeper active layer. The effect is clearest during the last decade when solifluction and creep rates increased significantly. This is explained by the deepening of the active layer and the fact that the summer temperatures during the last decade not only ‘statistically’ show increasing trends but also that the interannual variability is less. This leads to an accumulated, more steady and ‘reliable’ effect upon soil temperatures and the processes within the active layer.

Keywords:

• active layer
• Arctic summer climate
• permafrost
• slope processes
• Svalbard

Acknowledgements

Financial support for the field studies of the project was received from the Swedish Natural Sciences Research Council (NFR G.GU 3445 106–117), the Ymer 80 Fund, The Walter Schytt Fund, The Royal Physiographic Society in Lund, the Swedish Society for Anthropology and Geography, and a generous private donor. Too many people to be individually acknowledged have contributed to the fieldwork – especially field course students. Special thanks are given to to them and especially to the crew at Isfjord Radio station, without whom this study could not have been done.