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| Titel |
Modeling the thermal dynamics of the active layer at two contrasting permafrost sites on Svalbard and on the Tibetan Plateau |
| VerfasserIn |
J. Weismüller, U. Wollschläger, J. Boike, X. Pan, Q. Yu, K. Roth |
| 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 ; 5, no. 3 ; Nr. 5, no. 3 (2011-09-19), S.741-757 |
| Datensatznummer |
250002602
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| Publikation (Nr.) |
 copernicus.org/tc-5-741-2011.pdf |
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| Zusammenfassung |
Employing a one-dimensional, coupled thermal and hydraulic numerical model,
we quantitatively analyze high-resolution, multi-year data from the active
layers at two contrasting permafrost sites. The model implements heat
conduction with the de Vries parameterization, heat convection with water and
vapor flow, freeze-thaw transition parameterized with a heuristic
soil-freezing characteristic, and liquid water flow with the Mualem-van
Genuchten parameterization. The model is driven by measured temperatures and
water contents at the upper and lower boundary with all required material
properties deduced from the measured data. The aims are (i) to ascertain the
applicability of such a rather simple model, (ii) to quantify the dominating
processes, and (iii) to discuss possible causes of remaining deviations.
Soil temperatures and water contents as well as characteristic quantities like
thaw depth and duration of the isothermal plateau could be reproduced. Heat
conduction is found to be the dominant process by far at both sites, with
non-conductive transport contributing a maximum of some 3% to the mean
heat flux at the Spitsbergen site, most of the time very much less, and
practically negligible at the Tibetan site. Hypotheses discussed to explain
the remaining deviations between measured and simulated state variables
include, besides some technical issues, infiltration of snow melt, dry
cracking with associated vapor condensation, and mechanical soil expansion in
detail. |
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