Continuum sea ice rheology determined from subcontinuum mechanics

Taylor, Paul D.; Feltham, D. L.; Sammonds, Peter; Hatton, Deborah D.

doi:10.1029/2005jc002996

Cited by 8 publications

(9 citation statements)

References 21 publications

(35 reference statements)

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“…[70] Moreover, the deformation rates estimated by both models agree with the observations at large spatial scales (100-300 km), suggesting that all the variability regarding sea ice deformation below such scales is missing in both models, regardless of their high resolution ($10 km grid size). This is consistent with the conclusions of Taylor et al [2006] who suggested that the adoption of isotropic, continuum rheology at sub-100 km resolutions is not useful for a more detailed prediction of ice dynamics.…”

Section: Scaling Properties Of Sea Ice Deformationsupporting

confidence: 91%

Evaluation of high‐resolution sea ice models on the basis of statistical and scaling properties of Arctic sea ice drift and deformation

et al. 2009

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[1] Sea ice drift and deformation from models are evaluated on the basis of statistical and scaling properties. These properties are derived from two observation data sets: the RADARSAT Geophysical Processor System (RGPS) and buoy trajectories from the International Arctic Buoy Program (IABP). Two simulations obtained with the Louvain-la-Neuve Ice Model (LIM) coupled to a high-resolution ocean model and a simulation obtained with the Los Alamos Sea Ice Model (CICE) were analyzed. Model ice drift compares well with observations in terms of large-scale velocity field and distributions of velocity fluctuations although a significant bias on the mean ice speed is noted. On the other hand, the statistical properties of ice deformation are not well simulated by the models: (1) The distributions of strain rates are incorrect: RGPS distributions of strain rates are power law tailed, i.e., exhibit ''wild randomness,'' whereas models distributions remain in the Gaussian attraction basin, i.e., exhibit ''mild randomness.'' (2) The models are unable to reproduce the spatial and temporal correlations of the deformation fields: In the observations, ice deformation follows spatial and temporal scaling laws that express the heterogeneity and the intermittency of deformation. These relations do not appear in simulated ice deformation. Mean deformation in models is almost scale independent. The statistical properties of ice deformation are a signature of the ice mechanical behavior. The present work therefore suggests that the mechanical framework currently used by models is inappropriate. A different modeling framework based on elastic interactions could improve the representation of the statistical and scaling properties of ice deformation.Citation: Girard, L., J. Weiss, J. M. Molines, B. Barnier, and S. Bouillon (2009), Evaluation of high-resolution sea ice models on the basis of statistical and scaling properties of Arctic sea ice drift and deformation,

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Section: Scaling Properties Of Sea Ice Deformationsupporting

confidence: 91%

Evaluation of high‐resolution sea ice models on the basis of statistical and scaling properties of Arctic sea ice drift and deformation

et al. 2009

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“…Taylor et al . [] took a somewhat different approach: they calculated relative floe motion using the kinematic model of UM but calculated sea ice stress from a consideration of the deformation of the ice in the leads separating the floes and using the mean stress theorem to calculate the large‐scale sea ice stress from the integral of edge tractions. This approach allowed an investigation of the scale‐dependence of sea ice rheology and the (restrictive) conditions under which the ice cover could be considered isotropic.…”

Section: The Anisotropic Modelmentioning

confidence: 99%

“…Wilchinsky and Feltham [] generalized the Taylor et al . [] approach to calculate the anisotropic sea ice stress associated with an idealized sea ice cover consisting of closely interlocking, diamond‐shaped ice floes delineated by slip lines. This underlying anisotropic tiling of the sea ice cover is supported by observations (Figure ) and was also shown to emerge through discrete element simulations of the sea ice [ Wilchinsky et al ., ].…”

Section: The Anisotropic Modelmentioning

confidence: 99%

Impact of a new anisotropic rheology on simulations of Arctic sea ice

2013

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[1] A new rheology that explicitly accounts for the subcontinuum anisotropy of the sea ice cover is implemented into the Los Alamos sea ice model. This is in contrast to all models of sea ice included in global circulation models that use an isotropic rheology. The model contains one new prognostic variable, the local structure tensor, which quantifies the degree of anisotropy of the sea ice, and two parameters that set the time scale of the evolution of this tensor. The anisotropic rheology provides a subcontinuum description of the mechanical behavior of sea ice and accounts for a continuum scale stress with large shear to compression ratio and tensile stress component. Results over the Arctic of a standalone version of the model are presented and anisotropic model sensitivity runs are compared with a reference elasto-visco-plastic simulation. Under realistic forcing sea ice quickly becomes highly anisotropic over large length scales, as is observed from satellite imagery. The influence of the new rheology on the state and dynamics of the sea ice cover is discussed. Our reference anisotropic run reveals that the new rheology leads to a substantial change of the spatial distribution of ice thickness and ice drift relative to the reference standard visco-plastic isotropic run, with ice thickness regionally increased by more than 1 m, and ice speed reduced by up to 50%.

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“…In particular, the elastic-decohesive (Schreyer et al 2006;Sulsky and Paterson 2011) and the elasto-brittle (Girard et al 2011) models focus on the process of the crack formation and corresponding weakening of the sea ice without explicitly addressing their postfailure dynamics. In order for an isotropic model to be able to represent the effect of anisotropically distributed leads, the model resolution should be much smaller than the dimensions of the leads, which is generally not the case, and the rheology of sea ice should be isotropic with known scale dependence (Feltham 2008, supplemental appendix C; Taylor et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Rheology of Discrete Failure Regimes of Anisotropic Sea Ice

Wilchinsky

Feltham

2012

Journal of Physical Oceanography

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A rheological model of sea ice is presented that incorporates the orientational distribution of ice thickness in leads embedded in isotropic floe ice. Sea ice internal stress is determined by coulombic, ridging and tensile failure at orientations where corresponding failure criteria are satisfied at minimum stresses. Because sea ice traction increases in thinner leads and cohesion is finite, such failure line angles are determined by the orientational distribution of sea ice thickness relative to the imposed stresses. In contrast to the isotropic case, sea ice thickness anisotropy results in these failure lines becoming dependent on the stress magnitude. Although generally a given failure criteria type can be satisfied at many directions, only two at most are considered. The strain rate is determined by shearing along slip lines accompanied by dilatancy and closing or opening across orientations affected by ridging or tensile failure. The rheology is illustrated by a yield curve determined by combining coulombic and ridging failure for the case of two pairs of isotropically formed leads of different thicknesses rotated with regard to each other, which models two events of coulombic failure followed by dilatancy and refreezing. The yield curve consists of linear segments describing coulombic and ridging yield as failure switches from one lead to another as the stress grows. Because sliding along slip lines is accompanied by dilatancy, at typical Arctic sea ice deformation rates a one-day-long deformation event produces enough open water that these freshly formed slip lines are preferential places of ridging failure.

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Continuum sea ice rheology determined from subcontinuum mechanics

Cited by 8 publications

References 21 publications

Evaluation of high‐resolution sea ice models on the basis of statistical and scaling properties of Arctic sea ice drift and deformation

Evaluation of high‐resolution sea ice models on the basis of statistical and scaling properties of Arctic sea ice drift and deformation

Impact of a new anisotropic rheology on simulations of Arctic sea ice

Rheology of Discrete Failure Regimes of Anisotropic Sea Ice

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