CHANGES IN THE DYNAMICS AND THERMAL REGIME OF THE PERMAFROST AND ACTIVE LAYER OF THE HIGH ARCTIC COASTAL AREA IN NORTH-WEST SPITSBERGEN, SVALBARD

摘要

In this paper changes in the active layer of the high arctic coastal area in north-west Spitsbergen, Svalbard are described. Analysis includes both the ground thawing depth and its near-surface thermal structure. The study was conducted on the Kaffi?yra Plain (Svalbard) at several fixed sites, which represent places typical of the region: a sandy beach, a tundra plain and a moraine ridge. The results show that in recent years, at two measurement points a significantly deeper thawing was observed. In 1996–2012 on the beach and on the moraine the trend of active layer thickness change was +1.3 cm yr~(-1) and +2.5 cm yr~(-1), respectively. Generally, in the years 2008–2012 the mean thickness of the active layer in the Kaffi?yra region increased by 3% to 6%. Even at the spatially close sites, within similar environments, there are significant differences in the thickness of the active layer. Measurements show that significant changes also occurred in the thawed ground temperature. Mean values of the observed near-surface temperature in recent years (2007–2011) were higher by more than 1.0°C, in comparison to the mean in the late 1970s.