Permafrost modeling in the Mackenzie River valley: transient aspects of climate change

1. Permafrost modeling in the Mackenzie River valley:transient aspects of climate change Researchers: F. Wright, C. Duchesne, M. Côté, M. Nixon and E. Roberts Natural Resources Canada Geological Survey of Canada January 2003

2. Research objectives • To acquire and synthesize fundamental permafrost-engineering field data. • To develop analytical and numerical methods describing climate-driven transient aspects of the ground thermal regime. • To apply GIS-based analysis techniques to generate predictions of the time-dependent responses of permafrost to climate change scenarios at local and regional scales. January 2003

3. Area of interest January 2003

4. Impact/Relevance • Support engineering design of proposed oil/gas production and delivery systems. • Enhanced capability for: • terrain evaluation • project planning • route selection • Improved knowledge-base for development of adaptation strategies and/or remedial measures. January 2003

5. Conceptual model of climate-permafrost relations • Assume dominance of conductive heat transfer processes • The influence of snow cover is implicit in the buffer layer • Assumes a uniform substrate January 2003

6. Data sources Interpolated mean annual air temperature: DDT & DDF Vegetation Cover: N-factors & Moisture content Surficial Geology: Thermal conductivities January 2003

7. Equilibrium distribution of permafrost Baseline climate 2°C warming 4°C warming January 2003

8. Transient aspect of ground thermal response • Timing of the ground thermal response to climate change depends on the physical and thermal characteristics of the terrain: • Insulating properties of vegetation and snow cover • Thermal conductivity and heat capacity • Frozen water content • Finite-element modeling can be used to generate time-dependent predictions of climate change on ground thermal conditions. 200 years ?? 30 years ?? January 2003

9. Site scale investigation • Degree to which ground temperature profiles diverge from an ideal state of equilibrium • Consistency between different sites with respect to this divergence • Establishment of input values for initial and boundary conditions January 2003

10. GIS-based transient modeling solution Stand-alone finite-element ground thermal model is linked to the GIS at both the model input and output stages. GIS inputs: Time-dependant GIS-based outputs: January 2003

11. Identification of terrain impacts • Magnitude of the expected impacts controlled by the physical and thermal properties of the sediments. • Evaluation of model predictions of changes in ground thermal state vs potential impacts on terrain: • Relating expected temperature changes to temperature-dependent sensitivities of different terrain types. • Relation of excess ice content and sediment compactability to subsidence potential. January 2003

12. Users and partners • Engineering firms: Colt Geomatic Solutions Ltd • preparation for pipeline engineering in the Mackenzie Valley • Territorial government departments: DOT, RWED • Support associated transportation routes • Territorial organisations : MVLWB • Information base to support policy development and decision-making • Federal government: CCRS, Northern POL • Integrated Assessment Model on Climate Change: impact of permafrost change on the carbon balance • Geocomplexity of Mackenzie Beaufort Hydrocarbon Development Region January 2003

13. Summary of goals • Completed: • GSC steady-state model of permafrost characteristics • Database development at a regional scale • Analysis and synthesis of field data • GIS input interface for the transient model • In progress: • Database development at a local scale • GIS output interface for the transient model • Impact assessment, predicting permafrost changes in 30, 50 and 100 year time frames, at both local and regional scales January 2003