Author(s): Robert S. Pritchard

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Abstract: Mathematical characteristics are derived for quasi-steady, anisotropic plasticity models where ice and mixed layer inertia are neglected. These models are appropriate for resolving daily-averaged ice motions. The focus here is on the mathematical properties of sea ice dynamics models; there are no numerical simulations. Stress characteristics depend on yield surface shape defined by φ = 0. The directions of these characteristics are at angle κ to the x-axis The system of equations is hyperbolic (two real characteristic directions), parabolic (one direction), or elliptic (no directions) depending on whether the discriminant is positive, zero, or negative. The system can behave differently at different locations depending on the stress state σ. Velocity characteristics satisfy a similar equation if φ is replaced by the appropriate potential function ψ, and are coincident if a normal flow rule is assumed (ψ = φ). We believe that leads form along characteristic lines. This relationship has been confirmed in a few cases for isotropic models by comparing satellite images with simulated results. It is expected to remain valid for anisotropic model results.

DOI:

Year: 2008