Parameter sensitivity analysis of a two-dimensional cryo-hydrogeological numerical model of degrading permafrost near Umiujaq (Nunavik, Canada)

Parameter sensitivity analysis of a two-dimensional cryo-hydrogeological numerical model of degrading permafrost near Umiujaq (Nunavik, Canada)

A calibrated field-scale numerical model of groundwater flow and permafrost degradation has been used in a sensitivity analysis of permafrost thaw on thermal and hydraulic parameters. The two-dimensional cryo-hydrogeological model was developed using the HEATFLOW-SMOKER code applied to the Umiujaq f...

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Bibliographic Details
Published in:Hydrogeology journal Vol. 28; no. 3; pp. 905 - 919
Main Authors: Albers, Britt M. C., Molson, John W., Bense, Victor F.
Format: Journal Article
Language:English
Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2020
Springer Nature B.V
Subjects:
Aquatic Pollution
Bedrock
Canada
Computer simulation
Earth and Environmental Science
Earth Sciences
Flow system
Geology
Geophysics/Geodesy
Gravel
Groundwater
Groundwater flow
Groundwater velocity
Heat
Heat exchange
Heat flux
Heat transfer
Heat transport
Hydraulic properties
Hydraulics
Hydrogeology
Hydrogeology of a cold-region watershed near Umiujaq (Nunavik
Hydrology/Water Resources
Mathematical models
Numerical models
Parameter sensitivity
Parameters
Permafrost
Pests
Profiles
Sand
Sand & gravel
Sensitivity analysis
Soil degradation
Summer
Temperature dependence
Temperature profile
Temperature profiles
Thermodynamic properties
Two dimensional analysis
Two dimensional models
Waste Water Technology
Water Management
Water Pollution Control
Water Quality/Water Pollution
Nunavik Quebec Canada
Canada
Canada
Permafrost
PEST
Parameter sensitivity
Groundwater flow
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Description
Summary:A calibrated field-scale numerical model of groundwater flow and permafrost degradation has been used in a sensitivity analysis of permafrost thaw on thermal and hydraulic parameters. The two-dimensional cryo-hydrogeological model was developed using the HEATFLOW-SMOKER code applied to the Umiujaq field site in Nunavik, Quebec, Canada, and includes coupled groundwater flow and advective–conductive heat transport with latent-heat and temperature-dependent thermal and hydraulic properties. Model sensitivity was evaluated by using the PEST code to systematically vary selected thermal and hydraulic parameters, and was quantified with respect to three system output variables or ‘targets’: subsurface temperature, groundwater velocity and ground-surface heat flux. PEST-derived model sensitivities were similar for all targets which contained subsurface temperature profiles, while sensitivities were slightly higher when only summer conditions were considered as the target compared to a full year of data. This trend was attributed to greater heat exchange at the ground surface during the summer months, leading to a more active groundwater flow system and greater feedback to the thermal regime. For all targets, the hydraulic and thermal parameters of the shallow layers (fine sand and marine silt, respectively) as well as the parameters defining the ground-surface heat exchange layer, were more sensitive compared to the deeper layers (coarse sand and gravel, and unfractured bedrock). Sensitivities were also among the highest for the ground-surface heat flux target. High model sensitivity to these parameters highlights the importance of detailed site characterization in the near-surface zone for more realistic simulations of permafrost dynamics.
ISSN:1431-2174
1435-0157
DOI:10.1007/s10040-020-02112-2