Application of a continuum-mechanical model for the flow of anisotropic polar ice to the EDML core, Antarctica

• Published in: Journal of glaciology Vol. 54; no. 187; pp. 631 - 642
• Main Authors: Seddik, Hakime, Greve, Ralf, Placidi, Luca, Hamann, Ilka, Gagliardini, Olivier
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.01.2008; International Glaciological Society
• Subjects: Earth, ocean, space; Exact sciences and technology; External geophysics; Geophysics. Techniques, methods, instrumentation and models; Snow. Ice. Glaciers; polar regions; Queen Maud Land; Antarctica; glaciology; rheology; textures; Mechanical model; anisotropy; Polycrystal; Ice flow; digital simulation; drill cores; Polar Cap; Ice crystals; ice sheets; one-dimensional models; microstructures; Continuum mechanics; Polar region
• ISSN: 0022-1430; 1727-5652
• DOI: 10.3189/002214308786570755

We present an application of the newly developed CAFFE model (Continuum-mechanical, Anisotropic Flow model based on an anisotropic Flow Enhancement factor) to the EPICA ice core at Kohnen Station, Dronning Maud Land, Antarctica (referred to as the EDML core). A one-dimensional flow model for the site is devised, which includes the anisotropic flow law and the fabric evolution equation of the CAFFE model. Three different solution methods are employed: (1) computing the ice flow based on the flow law of the CAFFE model and the measured fabrics; (2) solving the CAFFE fabric evolution equation under the simplifying assumption of transverse isotropy; and (3) solving the unrestricted CAFFE fabric evolution equation. Method (1) demonstrates clearly the importance of the anisotropic fabric in the ice column for the flow velocity. The anisotropic enhancement factor produced with method (2) agrees reasonably well with that of method (1), even though the measured fabric shows a girdle structure (which breaks the transverse isotropy) in large parts of the ice core. For method (3), we find that the measured fabric is reproduced well by the model down to ∼2100 m depth. Systematic deviations at greater depths are attributed to the disregard of migration recrystallization in the model.