On the Arctic near-surface permafrost and climate sensitivities to soil and snow model formulations in climate models

Paquin, Jean-Philippe; Sushama, Laxmi

doi:10.1007/s00382-014-2185-6

Cited by 47 publications

(64 citation statements)

References 51 publications

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“…Moreover, the effect of model parameter uncertainty has not been considered in previous work, and only soil types from "look-up tables" and peat soils were compared (Paquin and Sushama 2015). The effect of the climate conditions used to spin-up has also not been analysed.…”

Section: Introductionmentioning

confidence: 99%

“…The presence of significant non-stationarity in climate and hydrology (Razavi et al 2015) further challenges the process of model initialization and necessitates the availability of long historical records in order to include past non-stationarity that may affect the present state and flux 20 variables. Due to this non-stationarity, it may be inadvisable to initialize a model by recycling the historical records (i.e., repeating the simulation over the same period multiple times and using the final model state of one run as the initial state of the next run), as implemented in Troy et al, (2012) or Paquin and Sushama, (2015), since there is a warming trend in temperature which results in warmer and warmer soil states after each cycle.…”

Section: Introductionmentioning

confidence: 99%

“…There are however examples of how the spatial distribution of permafrost is improved by including deeper soil configurations in a LSM. For example, Paquin and Sushama (2015), applied the Canadian RCM, which uses Canadian Land Surface Scheme (CLASS) (Verseghy, 1991) as the LSM, for the arctic region, and by considering a 65 m deep soil configuration with a spin-up period of 200 years through recycling the 1970-1999 period, they improved spatial distribution 5 of permafrost in cold regions. Zhang et al (2003Zhang et al ( , 2006Zhang et al ( , and 2008 used a thermal soil model that includes soil water balance and showed the importance of considering deep soil configurations.…”

Section: Introductionmentioning

confidence: 99%

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On the Appropriate Definition of Soil Profile Configuration and Initial Conditions for Land Surface-Hydrology Models in Cold Regions

Sapriza-Azuri¹,

Gamazo²,

Razavi³

et al. 2017

Preprint

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Abstract. Arctic and sub-arctic 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, the 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 15 typically utilize a standard soil configuration with a depth of no more than 4 meters, 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, 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 20 depth under different climate conditions and in the presence of parameter uncertainty, and (2) develop a methodology for temperature profile initialization in permafrost regions, where the system has an extended memory, by the use of paleorecords 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 that the adequate depth of soil profile in an LSM varies for warmer and colder conditions and is sensitive to model parameters and the uncertainty 25 around them. In general, however, we show that a minimum of 20 meters of soil profile is essential to adequately represent the temperature dynamics. Our results also indicate the significance of model initialization in permafrost regions and our proposed spin-up method requires running the LSM over more than 300 years of reconstructed climate time series.Hydrol. Earth Syst. Sci. Discuss., https://doi

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Appropriate Definition of Soil Profile Configuration and Initial Conditions for Land Surface-Hydrology Models in Cold Regions

Sapriza-Azuri¹,

Gamazo²,

Razavi³

et al. 2017

Preprint

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“…Recent developments in permafrost physics such as including soil freezing, organic soil properties, improved snow schemes, more realistic soil depths and physical impacts of mosses and lichens (Gouttevin et al, 2012;Lawrence et al, 2008;Ekici et al, 2014;Paquin and Sushama, 2015;Chadburn et al, 2015a, b;Porada et al, 2016) mean that the rate of permafrost thaw is now more realistic in many of the land surface components of ESMs. Adding a vertical representation of soil carbon is now required to enable a representation of permafrost carbon in ESMs (Tian et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

A vertical representation of soil carbon in the JULES land surface scheme (vn4.3_permafrost) with a focus on permafrost regions

2017

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Abstract. An improved representation of the carbon cycle in permafrost regions will enable more realistic projections of the future climate-carbon system. Currently JULES (the Joint UK Land Environment Simulator) -the land surface model of the UK Earth System Model (UKESM) -uses the standard four-pool RothC soil carbon model. This paper describes a new version of JULES (vn4.3_permafrost) in which the soil vertical dimension is added to the soil carbon model, with a set of four pools in every soil layer. The respiration rate in each soil layer depends on the temperature and moisture conditions in that layer. Cryoturbation/bioturbation processes, which transfer soil carbon between layers, are represented by diffusive mixing. The litter inputs and the soil respiration are both parametrized to decrease with increasing depth. The model now includes a tracer so that selected soil carbon can be labelled and tracked through a simulation. Simulations show an improvement in the large-scale horizontal and vertical distribution of soil carbon over the standard version of JULES (vn4.3). Like the standard version of JULES, the vertically discretized model is still unable to simulate enough soil carbon in the tundra regions. This is in part because JULES underestimates the plant productivity over the tundra, but also because not all of the processes relevant for the accumulation of permafrost carbon, such as peat development, are included in the model. In comparison with the standard model, the vertically discretized model shows a delay in the onset of soil respiration in the spring, resulting in an increased net uptake of carbon during this time. In order to provide a more suitable representation of permafrost carbon for quantifying the permafrost carbon feedback within UKESM, the deep soil carbon in the permafrost region (below 1 m) was initialized using the observed soil carbon. There is now a slight drift in the soil carbon ( < 0.018 % decade −1 ), but the change in simulated soil carbon over the 20th century, when there is little climate change, is comparable to the original vertically discretized model and significantly larger than the drift.

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“…Other model studies have quantified present and future Arctic permafrost extent and active layer thickness (ALT) (Sushama et al 2006(Sushama et al , 2007Paquin and Sushama 2015). In particular the Paquin and Sushama (2015) study singularly used the single precision CRCM5 to investigate its sensitivity to soil depth, organic matter and snow conductivity formulations for simulating contemporary near-surface permafrost, using column depths of 3.5 and 65 m.…”

Section: Introductionmentioning

confidence: 99%

The reliability of single precision computations in the simulation of deep soil heat diffusion in a land surface model

Harvey

Verseghy

2015

Clim Dyn

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of single precision. There is thus a clear danger of using single precision in some climate model applications, in particular any scientifically meaningful study of deep soil permafrost must at least use double precision. In addition, climate modelling teams might well benefit from paying more attention to numerical precision and roundoff issues to offset the potentially more frequent numerical anomalies in future large-scale parallel climate applications.

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On the Arctic near-surface permafrost and climate sensitivities to soil and snow model formulations in climate models

Cited by 47 publications

References 51 publications

On the Appropriate Definition of Soil Profile Configuration and Initial Conditions for Land Surface-Hydrology Models in Cold Regions

On the Appropriate Definition of Soil Profile Configuration and Initial Conditions for Land Surface-Hydrology Models in Cold Regions

A vertical representation of soil carbon in the JULES land surface scheme (vn4.3_permafrost) with a focus on permafrost regions

The reliability of single precision computations in the simulation of deep soil heat diffusion in a land surface model

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