Analytical modeling of glacier dynamics
Identifieur interne : 002D34 ( Main/Merge ); précédent : 002D33; suivant : 002D35Analytical modeling of glacier dynamics
Auteurs : D. B. Bahr [États-Unis]Source :
- Mathematical geology [ 0882-8121 ] ; 1996.
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- Pascal (Inist)
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Abstract
Flow velocities and stresses within a glacier are determined by inverting known surface velocities with a specified glacier geometry. The surface velocities depend only weakly on the unknown velocities at the bed ofa glacier, so the inversion is ill-posed and unstable. This instability causes both numerical computation errors and data errors to grow dramatically with depth, usually masking the actual velocity and stress solutions. To control the numerical errors, an analytical modeling scheme is presented which modifies the method of mean weighted residuals (used in finite element techniques). The resulting scheme impairs convergence by producing power-series solutions, but in an advantageous trade-off, the coefficients to the power series can be determined analytically rather than numerically. This leads to arbitrary order analytical power-series solutions to the internal stress state of glaciers. The symbolic power-series solutions can be evaluated at any point in the glacier with negligible round-off and discretization errors. Analytical model accuracy is confirmed with known stress solutions for several widely used constitutive relations for ice.
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