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

• Main Authors: Perreault, Julie, Fortier, Richard, Molson, John W.
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: Taylor & Francis 2021
• Subjects: Evolutionary Biology; FOS Biological sciences; 59999 Environmental Sciences not elsewhere classified; FOS Earth and related environmental sciences; Ecology; 69999 Biological Sciences not elsewhere classified; Inorganic Chemistry; FOS Chemical sciences; Canada; Nunavik; Umiujaq; permafrost; Thermokarst
• Online Access: https://dx.doi.org/10.6084/m9.figshare.15062738; https://tandf.figshare.com/articles/journal_contribution/Numerical_modelling_of_permafrost_dynamics_under_climate_change_and_evolving_ground_surface_conditions_application_to_an_instrumented_permafrost_mound_at_Umiujaq_Nunavik_Qu_bec_Canada/15062738

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.