Ninth International Conference on Permafrost ... - IARC Research

Mapping and Modeling the Distribution of Permafrost in the Nordic CountriesBernd Etzelmüller, Herman Farbrot, Ole HumlumUniversity of Oslo, NorwayHanne Christiansen, Håvard JuliussenThe University Centre in Svalbard, NorwayKetil IsaksenNorwegian Meteorological Institute, NorwayThomas V. SchulerNorwegian Water and Energy Directorate and University of Oslo, NorwayRune S. ØdegårdUniversity College of Gjøvik, NorwayHanne RidefeltUniversity of Uppsala, SwedenIntroductionIn the Nordic countries (Norway including Svalbard,Sweden, Finland, and Iceland) permafrost is widespreadand ranges from continuous permafrost in Svalbard, towidespread discontinuous permafrost in high-mountainregions of Iceland and the Scandes, to isolated patches relatedto palsas, especially in Iceland and northern Scandinavia.Numerous studies exist, especially in Norway and Svalbard,addressing the distribution and thermal regime of permafrost.Here we present the status of permafrost mapping for theNordic countries, present a map including new boreholeinformation, and draw lines to actual monitoring programmes(TSP NORWAY – Thermal state of permafrost IPY project)and numerical modeling projects (CRYOLINK).The Regional Nordic Permafrost MapAs a basis, a simple climate-permafrost relationshiphas been used to generate a permafrost map of the Nordiccountries (Fig. 1). The approach used the relation of griddedmean annual air temperature (1961–90, MAAT) values topermafrost existence, not considering snow conditionsand topographic heterogeneity (Etzelmüller et al. 2007).The resulting permafrost distribution was compared withobservations in the different regions in Norway, Sweden,and Iceland (e.g., Isaksen et al. 2002, Heggem et al. 2005,Farbrot et al. 2008, Ridefelt et al. in press, Etzelmüller etal. 2007). All validation showed that the general permafrostpattern is well reproduced, indicating a decrease in thelower permafrost limit from west to east in Scandinavia. InIceland, a southwards increase in altitude of the permafrostlimit is due to more maritime and snow-rich conditions insoutheastern Iceland.Borehole Information – The TSP NORWAYProjectBoreholes for ground thermal monitoring exist especiallyin Norway and Iceland. The deepest boreholes down to 130 mFigure 1. Left: Map of mean annual air temperatures, indicating permafrost distribution in the Nordic countries. This study uses this map asa basis. Information about local permafrost mapping and ground temperature recordings will be added. Right: Projected ground temperaturesand active layer depth on Jansonhaugen, Svalbard. A 1D heat-flow model was calibrated based on borehole temperatures, and forced bymonthly air temperatures generated from the Hadley Center 1B scenario, down-scaled to Longyearbyen (REGCLIM, e.g., Hanssen-Baueret al. 2005).The initialization and calibration was based on ground temperature measurements in a borehole (100 m) and extrapolation withdepth. Left inlet: Start condition and simulated temperature at end of simulation run. Upper right: Temperature development in variousdepths. Lower left: Modeled active layer thickness development.71