Numerical modelling of permafrost dynamics under climate change and evolving ground surface conditions: application to an instrumented permafrost mound at Umiujaq, Nunavik (Québec), Canada

Numerical simulations were carried out based on a conceptual cryohydrogeological model of a permafrost mound near Umiujaq, Nunavik (Québec), Canada, to assess the impacts of climate warming and changes in surface conditions on permafrost degradation. The 2D model includes groundwater flow, advective...

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Bibliographic Details
Main Authors: Julie Perreault (11192300), Richard Fortier (5470091), John W. Molson (11192303)
Format: Other Non-Article Part of Journal/Newspaper
Language:unknown
Published: 2021
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Online Access:https://doi.org/10.6084/m9.figshare.15062738.v1
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Summary:Numerical simulations were carried out based on a conceptual cryohydrogeological model of a permafrost mound near Umiujaq, Nunavik (Québec), Canada, to assess the impacts of climate warming and changes in surface conditions on permafrost degradation. The 2D model includes groundwater flow, advective-conductive heat transport, phase change and latent heat. Changes in surface conditions which are characteristic of the site were represented empirically in the model by applying spatially- and temporally-variable ground surface temperatures derived from linear regressions between monitored surface and air temperatures. After reaching a transient steady-state condition close to present-day conditions, the simulations were then extended to 2100 under hypothetical climate warming scenarios and using imposed changes in surface conditions consistent with observed on-site evolution. The simulations show that the development of a thermokarst pond and shrubification respectively induce ground warming of up to 0.5°C and 1.5°C, upward migration of the permafrost base by up to 2 and 4 m, and a decrease in the lateral permafrost extent of 1 and 7 m, relative to a reference case without changes in surface conditions. Feedback from permafrost degradation which drives changes in ground surface conditions should be included in future numerical modelling of permafrost dynamics.