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| Titel |
Study of a temperature gradient metamorphism of snow from 3-D images: time evolution of microstructures, physical properties and their associated anisotropy |
| VerfasserIn |
N. Calonne, F. Flin, C. Geindreau, B. Lesaffre, S. Rolland du Roscoat |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 6 ; Nr. 8, no. 6 (2014-12-05), S.2255-2274 |
| Datensatznummer |
250116388
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| Publikation (Nr.) |
 copernicus.org/tc-8-2255-2014.pdf |
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| Zusammenfassung |
| We carried out a study to monitor the time evolution of microstructural and
physical properties of snow during temperature gradient metamorphism: a snow
slab was subjected to a constant temperature gradient in the vertical
direction for 3 weeks in a cold room, and regularly sampled in order to
obtain a series of three-dimensional (3-D) images using X-ray microtomography. A large set of
properties was then computed from this series of 3-D images: density,
specific surface area, correlation lengths, mean and Gaussian curvature
distributions, air and ice tortuosities, effective thermal conductivity, and
intrinsic permeability. Whenever possible, specific attention was paid to
assess these properties along the vertical and horizontal directions, and an
anisotropy coefficient defined as the ratio of the vertical over the
horizontal values was deduced. The time evolution of these properties, as
well as their anisotropy coefficients, was investigated, showing the
development of a strong anisotropic behavior during the experiment. Most of
the computed physical properties of snow were then compared with two
analytical estimates (self-consistent estimates and dilute beds of spheroids)
based on the snow density, and the size and anisotropy of the microstructure
through the correlation lengths. These models, which require only basic
microstructural information, offer rather good estimates of the properties
and anisotropy coefficients for our experiment without any fitting
parameters. Our results highlight the interplay between the microstructure
and physical properties, showing that the physical properties of snow
subjected to a temperature gradient cannot be described accurately using only
isotropic parameters such as the density and require more refined
information. Furthermore, this study constitutes a detailed database on the
evolution of snow properties under a temperature gradient, which can be used
as a guideline and a validation tool for snow metamorphism models at the
micro- or macroscale. |
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