Variability of temperature and thickness of permafrost active layer at coastal sites of Svalbard

We present the variability of the thermal state and thickness of permafrost active layer at the raised marine beaches in Svalbard. The investigations were carried out using direct probing, thaw tube, ground temperature and radar soundings at Holocene strand plains 10-20 m a.s.l. in Fuglebergsletta (SW Spitsbergen) and at the shore of Kinnvika Bay (Nordaustlandet). Their results were compared to those obtained at other coastal sites in Svalbard. The ground temperature measurements were conducted in 2009 on August, recognized as the standard month for the maximum thawing during the last decade. The studied sites are typical for close to extreme active layer conditions on Svalbard. In Hornsund, the thawing depth exceeded 2 m, while in Kinnvika the active layer was thinner than 1 m. In Svalbard, the depth of thawing decreases generally from south to north and from the open sea coast to the central parts of islands. These differences are the consequence of diverse climatic conditions strongly determined by the radiation balance modified by a number of regional (e.g. ocean circulation) and local (e.g. duration of snow deposition) conditions.