Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 22, 3295-3309, 2018
https://doi.org/10.5194/hess-22-3295-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
13 Jun 2018
On the appropriate definition of soil profile configuration and initial conditions for land surface–hydrology models in cold regions
Gonzalo Sapriza-Azuri1, Pablo Gamazo1, Saman Razavi2,3,4, and Howard S. Wheater2,3,4 1Departamento del Agua, Centro Universitario Regional Litoral Norte, Universidad de la República, Salto, Uruguay
2Global Institute for Water Security, University of Saskatchewan, Saskatoon, SK, Canada
3School of Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada
4Department of Civil and Geological Engineering, University of Saskatchewan, Saskatoon, SK, Canada
Abstract.

Arctic and subarctic regions are amongst the most susceptible regions on Earth to global warming and climate change. Understanding and predicting the impact of climate change in these regions require a proper process representation of the interactions between climate, carbon cycle, and hydrology in Earth system models. This study focuses on land surface models (LSMs) that represent the lower boundary condition of general circulation models (GCMs) and regional climate models (RCMs), which simulate climate change evolution at the global and regional scales, respectively. LSMs typically utilize a standard soil configuration with a depth of no more than 4 m, whereas for cold, permafrost regions, field experiments show that attention to deep soil profiles is needed to understand and close the water and energy balances, which are tightly coupled through the phase change. To address this gap, we design and run a series of model experiments with a one-dimensional LSM, called CLASS (Canadian Land Surface Scheme), as embedded in the MESH (Modélisation Environmentale Communautaire – Surface and Hydrology) modelling system, to (1) characterize the effect of soil profile depth under different climate conditions and in the presence of parameter uncertainty; (2) assess the effect of including or excluding the geothermal flux in the LSM at the bottom of the soil column; and (3) develop a methodology for temperature profile initialization in permafrost regions, where the system has an extended memory, by the use of paleo-records and bootstrapping. Our study area is in Norman Wells, Northwest Territories of Canada, where measurements of soil temperature profiles and historical reconstructed climate data are available. Our results demonstrate a dominant role for parameter uncertainty, that is often neglected in LSMs. Considering such high sensitivity to parameter values and dependency on the climate condition, we show that a minimum depth of 20 m is essential to adequately represent the temperature dynamics. We further show that our proposed initialization procedure is effective and robust to uncertainty in paleo-climate reconstructions and that more than 300 years of reconstructed climate time series are needed for proper model initialization.
Citation: Sapriza-Azuri, G., Gamazo, P., Razavi, S., and Wheater, H. S.: On the appropriate definition of soil profile configuration and initial conditions for land surface–hydrology models in cold regions, Hydrol. Earth Syst. Sci., 22, 3295-3309, https://doi.org/10.5194/hess-22-3295-2018, 2018.

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Short summary
Arctic and subarctic regions are amongst the most susceptible regions on Earth to climate change. There, models require a proper representation of the interactions between climate and hydrology. Typically these model represent the soil with shallow depths, whereas for cold regions, deep soil is needed. To address this, we run model experiments to characterize the effect of soil depth and temperature soil initialization. Our results demonstrate that 20 m of soil profile is essential.
Arctic and subarctic regions are amongst the most susceptible regions on Earth to climate...
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