Abstract
Abstract. This paper presents a first implementation of a new rheological model for sea ice on geophysical scales. This continuum model, called Maxwell elasto-brittle (Maxwell-EB), is based on a Maxwell constitutive law, a progressive damage mechanism that is coupled to both the elastic modulus and apparent viscosity of the ice cover and a Mohr–Coulomb damage criterion that allows for pure (uniaxial and biaxial) tensile strength. The model is tested on the basis of its capability to reproduce the complex mechanical and dynamical behaviour of sea ice drifting through a narrow passage. Idealized as well as realistic simulations of the flow of ice through Nares Strait are presented. These demonstrate that the model reproduces the formation of stable ice bridges as well as the stoppage of the flow, a phenomenon occurring within numerous channels of the Arctic. In agreement with observations, the model captures the propagation of damage along narrow arch-like kinematic features, the discontinuities in the velocity field across these features dividing the ice cover into floes, the strong spatial localization of the thickest, ridged ice, the presence of landfast ice in bays and fjords and the opening of polynyas downstream of the strait. The model represents various dynamical behaviours linked to an overall weakening of the ice cover and to the shorter lifespan of ice bridges, with implications in terms of increased ice export through narrow outflow pathways of the Arctic.
Highlights
The formation of ice bridges is a common phenomenon in the Amundsen Gulf, Bering Strait and many narrow passages of the Canadian Arctic Archipelago (Sodhi, 1977)
Dumont et al (2009) were able to simulate the formation of ice arches in both idealized and realistic representations of Nares Strait using a dynamic elastic–viscous–plastic (EVP) model (Hunke, 1997), the ice mechanics component of which is based on the VP rheology and elliptical yield curve of Hibler (1979)
It is important to note that here, “no-flow” or, as later mentioned, “flow stoppage” is not defined as a zero drift speed but rather as a drift velocity on the order of that associated with strictly elastic deformations within an undamaged ice cover
Summary
The formation of ice bridges is a common phenomenon in the Amundsen Gulf, Bering Strait and many narrow passages of the Canadian Arctic Archipelago (Sodhi, 1977). Dumont et al (2009) were able to simulate the formation of ice arches in both idealized and realistic representations of Nares Strait using a dynamic elastic–viscous–plastic (EVP) model (Hunke, 1997), the ice mechanics component of which is based on the VP rheology and elliptical yield curve of Hibler (1979). This rheological framework typically does not account for uniaxial or biaxial (i.e., pure) tensile strength (see Fig. 2, stress states 0 and 1). In the case of Dumont et al (2009), stable ice bridges and flow stoppage were obtained by decreasing the ellipticity of the yield curve below its original value (2; Hibler, 1979) to increase the shear and uniaxial compressive strength of the ice (see Fig. 2, stress state 3), which increases its cohesive strength. Rasmussen et al (2010) performed numerical simulations of the sea ice www.the-cryosphere.net/11/2033/2017/
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