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| Titel |
A general treatment of snow microstructure exemplified by an improved relation for thermal conductivity |
| VerfasserIn |
H. Löwe, F. Riche, M. Schneebeli |
| 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 ; 7, no. 5 ; Nr. 7, no. 5 (2013-09-24), S.1473-1480 |
| Datensatznummer |
250085161
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| Publikation (Nr.) |
 copernicus.org/tc-7-1473-2013.pdf |
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| Zusammenfassung |
| Finding relevant microstructural parameters beyond density is a
longstanding problem which hinders the formulation of accurate
parameterizations of physical properties of snow. Towards a remedy,
we address the effective thermal conductivity tensor of snow via
anisotropic, second-order bounds. The bound provides an explicit
expression for the thermal conductivity and predicts the relevance
of a microstructural anisotropy parameter Q, which is given by an
integral over the two-point correlation function and unambiguously
defined for arbitrary snow structures. For validation we compiled a
comprehensive data set of 167 snow samples. The set comprises
individual samples of various snow types and entire time series of
metamorphism experiments under isothermal and temperature gradient
conditions. All samples were digitally reconstructed by
micro-computed tomography to perform microstructure-based
simulations of heat transport. The incorporation of anisotropy via
Q considerably reduces the root mean square error over the usual
density-based parameterization. The systematic quantification of
anisotropy via the two-point correlation function suggests a
generalizable route to incorporate microstructure into snowpack
models. We indicate the inter-relation of the conductivity to other
properties and outline a potential impact of Q on dielectric
constant, permeability and adsorption rate of diffusing species in
the pore space. |
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