A microstructure-based parameterization of the effectivetransverse isotropic elasticity tensor of snow, firn, and porous ice

Kavitha Sundu,Henning Loewe

doi:10.5194/egusphere-egu21-2129

Abstract

&lt;p&gt;Effective elastic properties of snow, firn, and porous ice are key for&lt;br&gt;various applications and influenced by ice volume fraction and&lt;br&gt;different types of anisotropy. The geometrical anisotropy of the ice-matrix created by temperature gradient metamorphism in low-density&lt;br&gt;snow and firn and the crystallographic anisotropy commonly created&lt;br&gt;upon deformation in high-density, porous ice. Towards a quantitative-distinction of the impact of the different anisotropies on elasticity,&lt;br&gt;we derived a parametrization for the effective elasticity tensor over&lt;br&gt;the entire range of volume fractions as a function of density and&lt;br&gt;geometrical anisotropy. We employed FEM simulations on 395 X-ray&lt;br&gt;tomography microstructures of Lab, Alpine, Arctic, and Antarctic&lt;br&gt;samples. We employed an empirical two-parameter modification of the&lt;br&gt;anisotropic Hashin Shtrikman bounds to obtain a closed-form&lt;br&gt;parametrization accounting for density, anisotropy, and the correct&lt;br&gt;limiting behavior for bubbly ice. We compare our prediction to&lt;br&gt;previous parametrizations derived in limited density regimes and we&lt;br&gt;utilize the Thomson parameter to compare the geometrical-elastic&lt;br&gt;anisotropy to the crystallographic-elastic anisotropy of&lt;br&gt;monocrystalline ice. Our results suggest that a coupled treatment of&lt;br&gt;geometrical and crystallographic effects would be beneficial for a&lt;br&gt;careful interpretation of acoustic measurements in deep firn.&lt;/p&gt;

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