CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Duchesne, C.; Ednie, M.; Wright, J.; and Côté, M.
Date : 2007.
Title : Ground thermal modeling in the Mackenzie River valley: from database development to practical application.
Publication : Yellowknife 2007. Annual Conference of the Geological Association of Canada - Mineralogical Association of Canada. May 23-25, 2007. Yellowknife, Northwest Territories, Canada.
Issue :
Page(s) :
Abstract
It is generally accepted that the earth is currently experiencing a period of global climatic warming. In permafrost terrain, warming of the ground in response to increasing atmospheric temperatures will lead to a general deepening of the annual thaw (active) layer, and to partial or complete thawing of permafrost where ground temperatures are currently close to 0°C. To increase our understanding of the distribution and rate of change of permafrost conditions, the GSC has developed a physically-based ground thermal modeling capability at 1 km and 30 m spatial resolution within the broader Mackenzie River valley (north of 60°N). The model is constructed on a digital representation of the landscape, derived from conventional map data of surficial geology and vegetation cover, satellite imagery, and digital elevation models, which serve as the basis for the assignment of appropriate parameter values at grid locations within the study area. The TTOP analytical relation has been implemented as a GIS-resident model for predicting the occurrence and thickness of permafrost under conditions of thermal equilibrium. Results indicate that equilibrium temperatures (at the top of permafrost) range from about –0.5 to +2°C in the vicinity of the Alberta/NWT border to colder than –10°C at the northern edge of Richards Island and Tuktoyaktuk Peninsula. While TTOP serves as a useful scoping tool for rapid assessment of the spatial distribution and thickness of permafrost, recently a more sophisticated finite-element model (T-ONE) was implemented. It supports detailed investigations of the linkages between climate and the ground thermal state (e.g. permafrost thickness, active layer development and the formation of taliks) and is utilized for rigorous assessments of the potential impacts of progressive climate warming in permafrost landscapes. GIS-based mapping of T-ONE solutions facilitates prediction of the transient (time-dependent) response of ground temperatures to changing atmospheric temperatures and/or altered surface conditions. The model employs reconstructions of historic climates (from circa 1700 AD to present day) and scenarios for future climate warming based on GCM outputs. Currently, the GSC ground thermal modeling capability is being applied to practical issues related to the viability of northern transportation systems, and the assessment of terrain stability along the propose Mackenzie Gas Pipeline right-of-way.
Bibliography of Canadian Geomorphology