Ninth International Conference on Permafrost ... - IARC Research

Greenland Permafrost Temperature SimulationsR.P. DaanenGeophysical Institute, University of Alaska Fairbanks, Fairbanks, AlaskaV.E. RomanovskyGeophysical Institute, University of Alaska Fairbanks, Fairbanks, AlaskaS.S. MarchenkoGeophysical Institute, University of Alaska Fairbanks, Fairbanks, AlaskaJ.H. ChristensenDanish Meteorological Institute, Copenhagen, DenmarkM. StendelDanish Meteorological Institute, Copenhagen, DenmarkT. Ingeman-NielsenTechnical University of Denmark, Copenhagen, DenmarkIntroductionTourism in Greenland has increased in recent years andhas put more stress on infrastructure. Expansion of airstripsand roads to accommodate increased travel in conjunctionwith climate warming (IPCC 2001, ACIA 2004) requires anassessment of permafrost in the area. Complex topographyand coastal configurations are key characteristics of theAlaskan and Greenland regions on which this study willfocus. This requires high-resolution simulation of climateas well as permafrost distribution. We used a numericalsimulation model called GIPL 2.1 (Tipenko & Romanovsky2001, Sergeev et al. 2003) for simulating spatially distributedground temperatures over Greenland.ResultsThe permafrost in this country is dominated by areas offrozen bedrock with pockets of sediments and organic matter.For this study, we split the simulation in two categories:bedrock simulations and sediment simulations. Snow istreated the same for sediment areas and bedrock areas, andtaken from HIRHAM snow water equivalent predictions. Itwas corrected for a constant density (0.15 gr/cm 3 ) and showsa fairly close fit for some of the observed years in the datasetfrom Illulisat (Fig. 1).Observed and simulated snow depth in IlulisatFigure 2 shows the temperature distribution in bedrockmaterial over entire Greenland at a 25 km resolution. The firstimage is the result of a ten-year-average ground temperaturefrom 1955 till 1965 for a depth of 2 m; the second image isfor the same depth at the end of the simulation period from2065 till 2075.The simulation data does not show a large differenceover the simulation period. In bedrock, the temperaturefluctuation between summer and winter are larger then inthe sediment, due to a lack of ice or liquid water that buffersthe temperature fluctuation. Figure 3 shows the active layerdepth for the beginning of the simulation period and the endof the simulation period.For sediment we find cooler average temperatures due tothe thermal offset in the organic materials in the upper soillayers. In addition, there is a larger quantity of liquid waterpresent and a larger amount of ice in the winter. The resultsfor the sediment simulations are given in Figure 4 for the 2m temperature and in Figure 5 for the active layer depth.DiscussionThe data provided in this abstract are average data over tenyears and show little change over the simulation period from1950 till 2075. Even the higher spatial resolution simulatedin this study is relatively coarse when comparing it with theheterogeneity of the landscape.2001501005009/15/659/15/669/15/679/14/689/14/699/14/709/14/719/13/729/13/739/13/749/13/759/12/769/12/779/12/789/12/799/11/809/11/819/11/829/11/83-50Observed Simulated 3Figure 1. Observed and simulated snow depth for the Illulisatregion.Figure 2. Bedrock temperature distribution at 2 m depth.55