Permafrost

Surface- coupled 3-D Permafrost Model for Impact Assessment on
Building Foundations in Northern Canada due to Permafrost
Degradation
Fuqun Zhou 1 ,Aining Zhang 1 ,Robert Li 2
(1.Canada Centre for Remote Sensing, Natural Resources Canada, 615 Booth Street, Ottawa, Ontario,
Canada, K1A 0E9; 2 Noetix Research Inc., Canada)
Abstract: In many Canadian northern communities, the stability of building foundation
systems relies on the strength of the underlying permafrost. Building deterioration due to the
loss of this strength/stability would profoundly affect human well-being and economic activities
in the communities. The effects of permafrost degradation due to climate warming observed in
recent decades are of major concern in northern Canada, both to the public and to decision
makers. The Intergovernmental Panel on Climate Change (IPCC) projects that by 2100, air
temperature will increase globally by 1.4°-5.8°C based on a range of greenhouse gas emission
scenarios. Moreover, temperature increases in the North will be greater than the global average.
There is consensus among earth scientists that air temperature increases in this century will
accelerate permafrost degradation, thereby exacerbating impacts on foundation systems with
serious socio-economic consequences for northern communities.
In order for public and decision makers to take adequate and timely adaptation actions to
minimize potential damages, the following scientific and social questions need to be addressed:
(1) How much permafrost degradation will take place due to climate change under different
greenhouse gas emission scenarios and in different northern communities in Canada? (2) What
will be the impacts of permafrost degradation on community foundation systems? (3) What will
be the costs of the impacts with or without adaptation? (4) What are the timeframes within
which adaptation action is required in order to minimize the costs?
To improve our understanding of future permafrost degradation, of the associated
vulnerability of community infrastructure, and of the timeframes, options and potential costs for
adaptation, a surface- coupled 3-Dimensional geothermal model has been developed.
The model has two integrated components. One component is the surface model which
deals with energy and water balances of the ground surface, including snow dynamics, and the
other component is the ground model which manages the coupled heat and water transfers
under the ground surface. The two components are fully coupled through heat and water flux.
The model uses Finite Element Method and is three– dimensional to take account of
building’s effects on energy and water balances. In particular, the model modifies incoming
solar radiation and precipitation distributions surrounding and underneath a building by
modeling building’s dimensions and orientation as part of the energy and water balance
processes, and the model is purely driven by climate variables.
The model has been used for simulation of geothermal dynamics with climate change
scenarios at Inuvik community of the Northwest Territories of Canada. Assessment of the
permafrost degradation and its impacts on and costs to community building foundation systems
for adaptation is under investigation. The paper will present the theory and validation of the
model, and some geothermal simulation results.
Keywords: Climate Warming, Permafrost Degradation, 3-D Geothermal Modeling, Impact
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