Numerical Modeling of Ice Sheet Dynamics

• Main Author: Souček, Ondřej
• Other Authors: Martinec, Zdeněk, Málek, Josef, Ivins, Erik R.
• Format: Other/Unknown Material
• Language: English
• Published: Univerzita Karlova, Matematicko-fyzikální fakulta 2010
• Subjects: Dronning Maud Land; Antarc*; Antarctica; Ice Sheet
• Online Access: http://hdl.handle.net/20.500.11956/25546

Title: Numerical modeling of ice sheet dynamics Author: Ondřej Souček Department: Department of Geophysics, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: Prof. RNDr. Zdeněk Martinec, DrSc. Supervisor's e-mail address: [e-mail] Abstract: The main topic of the presented thesis is the numerical modeling of large-scale ice-sheet evo- lution over several glacial cycles. For this purpose a "Shallow Ice Approximation" (SIA) is traditionally adopted, a scaling approximation utilizing the fact that the vertical-to-horizontal aspect ratio in ice sheets is typically a small parameter allowing for a perturbation expansion of the governing equations with respect to this parameter. We present a formulation of the boundary value problem for a polythermal ice sheet based on the rational thermodynamics of mixtures and derive its "shallow-ice" form. We then provide a novel SIA-I algorithm for iterative improvement of the SIA and thoroughly test its performance in a series of benchmarks including the ISMIP-HOM benchmark and a realistic simulation for the Dronning Maud Land region, Antarctica. The SIA-I algorithm is implemented to an evolutionary thermo-mechanical numerical ice-sheet model and this model is tested in the SIA regime in two EISMINT benchmarks, EISMINT - Effect of. Title: Numerical modeling of ice sheet dynamics Author: Ondřej Souček Department: Department of Geophysics, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: Prof. RNDr. Zdeněk Martinec, DrSc. Supervisor's e-mail address: [e-mail] Abstract: The main topic of the presented thesis is the numerical modeling of large-scale ice-sheet evo- lution over several glacial cycles. For this purpose a "Shallow Ice Approximation" (SIA) is traditionally adopted, a scaling approximation utilizing the fact that the vertical-to-horizontal aspect ratio in ice sheets is typically a small parameter allowing for a perturbation expansion of the governing equations with respect to this parameter. We present a formulation of the boundary value problem for a polythermal ice sheet based on the rational thermodynamics of mixtures and derive its "shallow-ice" form. We then provide a novel SIA-I algorithm for iterative improvement of the SIA and thoroughly test its performance in a series of benchmarks including the ISMIP-HOM benchmark and a realistic simulation for the Dronning Maud Land region, Antarctica. The SIA-I algorithm is implemented to an evolutionary thermo-mechanical numerical ice-sheet model and this model is tested in the SIA regime in two EISMINT benchmarks, EISMINT - Effect of. Katedra geofyziky Department of Geophysics Faculty of Mathematics and Physics Matematicko-fyzikální fakulta