The influence of surface characteristics, topography and continentality on mountain permafrost in British Columbia
- 1Ministry of Forest, Land and Natural Resources Operation of British Columbia, 1044 Fifth Avenue, Prince George, BC V2L 5G4, Canada
- 2Department of Geosciences, University of Fribourg, Chemin du Musee 4, 1700 Fribourg, Switzerland
- 3Department of Geography and Environmental Studies, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
- 4Glaciology, Geomorphodynamics and Geochronology, Department of Geography, University of Zurich, Winterthurerstr 190, 8057 Zurich, Switzerland
Abstract. Thermal and surface offsets describe mean annual ground temperature relative to mean annual air temperature, and for permafrost modelling they are often predicted as a function of surface characteristics and topography. As macroclimatic conditions influence the effectiveness of the underlying processes, knowledge of surface- and topography-specific offsets is not easily transferable between regions, limiting the applicability of empirical permafrost distribution models over areas with strong macroclimatic gradients.
In this paper we describe surface and thermal offsets derived from distributed measurements at seven field sites in British Columbia. Key findings are (i) a surprisingly small variation of the surface offsets between different surface types; (ii) small thermal offsets at all sites (excluding wetlands and peat); (iii) a clear influence of the micro-topography at wind exposed sites (snow-cover erosion); (iv) a north–south difference of the surface offset of 4 °C in vertical bedrock and of 1.5–3 °C on open (no canopy) gentle slopes; (v) only small macroclimatic differences possibly caused by the inverse influence of snow cover and annual air temperature amplitude. These findings suggest that topoclimatic factors strongly influence the mountain permafrost distribution in British Columbia.