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| Titel |
Thermal conductivity of snow measured by three independent methods and anisotropy considerations |
| VerfasserIn |
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. 1 ; Nr. 7, no. 1 (2013-02-06), S.217-227 |
| Datensatznummer |
250017414
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| Publikation (Nr.) |
 copernicus.org/tc-7-217-2013.pdf |
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| Zusammenfassung |
| The thermal conductivity of snow determines the temperature gradient, and by
this, it has a direct effect on the rate of snow metamorphism. It is
therefore a key property of snow. However, thermal conductivities measured
with the transient needle probe and the steady-state, heat flux plate differ.
In addition, the anisotropy of thermal conductivity plays an important role
in the accuracy of thermal conductivity measurements. In this study, we
investigated three independent methods to measure snow thermal conductivity
and its anisotropy: a needle probe with a long heating time, a guarded heat
flux plate, and direct numerical simulation at the microstructural level of
the pore and ice structure. The three methods were applied to identical snow
samples. We analyzed the consistency and the difference between these
methods. As already shown in former studies, we observed a distinct
difference between the anisotropy of thermal conductivity in small rounded
grains and in depth hoar. Indeed, the anisotropy between vertical and
horizontal thermal conductivity components ranges between 0.5–2. This can
cause a difference in thermal conductivity measurements carried out with
needle probes of up to –25 % to +25 % if the thermal conductivity is
calculated only from a horizontally inserted needle probe. Based on our
measurements and the comparison of the three methods studied here, the direct
numerical simulation is the most reliable method, as the tensorial components
of the thermal conductivity can be calculated and the corresponding
microstructure is precisely known. |
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