Permafrost temperatures and active layer thickness in Svalbard during 2017/2018

This is chapter 10 of the State of Environmental Science in Svalbard (SESS) report 2019 (https://sios-svalbard.org/SESS_Issue2).

Permafrost temperature presented in this report, including the first full year of ground temperature data from the Hornsund area, indicate that the north-south gradient present in air temperatures is also present in ground temperatures in Svalbard. Permafrost temperatures are warmest in Hornsund in the south, intermediate in Barentsburg and Kapp Linne in the central part, and lowest around Ny-Ålesund in the northern part and in the centrally located Adventdalen area. The ground is warmest near the coasts (e.g. Kapp Linne and Hornsund) and in areas with thicker snow cover during winter (e.g. Endalen and Bayelva). Mean annual ground temperatures measured at the depth of zero annual amplitude varied from ‑1.2°C (Hornsund, 12 m depth) to ‑5.1°C (Breinosa and Old Auroral Station, 10 m depth). During the 2017-2018 hydrological year, the duration of active-layer freeze-back in Svalbard varied from 2 days at Breinosa to 151 days at Endalen. Active-layer thickness ranged in summer 2018 between 64 cm (Breinosa) and 463 cm (Hornsund).