Short-term changes in thickness and temperature of the active layer in summer in the Kaffiøyra region, NW Spitsbergen, Svalbard

- Short-term permafrost changes in Kaffiøyra, north-western Svalbard were described.
- Both, the thickness and temperature of active layer in polar summer were analysed.
- The ground thaw is exceptionally variable, both temporally and spatially.
- Changes of active layer are highly dynamic in coastal zones of this area.

This article focuses on short-term changes in the thermal conditions and thickness of the active layer during the summer season of 2015, observed in test fields located in the tundra and the beach areas in the Kaffiøyra region Svalbard. The purpose was also to attempt a detailed analysis of short-term relationships between the rate and the dynamic of ground thaw and air temperature, as well as to determine the influence of the local surface features and geological structures on the thaw rate. Active layer thickness in the Kaffiøyra region is considerably diversified both spatially and temporally. Throughout the analysed timeframe average ground temperatures on the beach and in the tundra were above zero and a delayed response of ground temperature to changes in air temperature was generally observed. The increase in the thickness of the active layer on the beach was 0.8 cm per day, whereas in the tundra it averaged 1.3 cm. One essential factor conditioning the short-term variability of the thickness and thermal conditions of an active layer is the activity of contemporary morphogenetic processes, which affect the dynamic of changes in the morphology of permafrost areas and their geological structure. Examples of such changes can be found in coastal zones exposed to tidal activity and undergoing glacial processes. The research demonstrated the substantial influence of local morphology and lithological and geological structures of the active layer on the variable thaw intensity and thickness growth rate in the tundra and beach environments.