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| Titel |
Transient thermal modeling of permafrost conditions in Southern Norway |
| VerfasserIn |
S. Westermann, T. V. Schuler, K. Gisnås, B. Etzelmüller |
| 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. 2 ; Nr. 7, no. 2 (2013-04-25), S.719-739 |
| Datensatznummer |
250017962
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| Publikation (Nr.) |
 copernicus.org/tc-7-719-2013.pdf |
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| Zusammenfassung |
| Thermal modeling is a powerful tool to infer the temperature regime of the
ground in permafrost areas. We present a transient permafrost model, CryoGrid
2, that calculates ground temperatures according to conductive heat transfer
in the soil and in the snowpack. CryoGrid 2 is forced by operational air
temperature and snow-depth products for potential permafrost areas in
Southern Norway for the period 1958 to 2009 at 1 km2 spatial
resolution. In total, an area of about 80 000 km2 is covered. The
model results are validated against borehole temperatures, permafrost
probability maps from "bottom temperature of snow" measurements and
inventories of landforms indicative of permafrost occurrence. The validation
demonstrates that CryoGrid 2 can reproduce the observed lower permafrost
limit to within 100 m at all validation sites, while the agreement between
simulated and measured borehole temperatures is within 1 K for most sites.
The number of grid cells with simulated permafrost does not change
significantly between the 1960s and 1990s. In the 2000s, a significant
reduction of about 40% of the area with average 2 m ground temperatures
below 0 °C is found, which mostly corresponds to degrading permafrost
with still negative temperatures in deeper ground layers. The thermal
conductivity of the snow is the largest source of uncertainty in CryoGrid 2,
strongly affecting the simulated permafrost area. Finally, the prospects of
employing CryoGrid 2 as an operational soil-temperature product for Norway
are discussed. |
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