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| Titel |
Modelling borehole temperatures in Southern Norway – insights into permafrost dynamics during the 20th and 21st century |
| VerfasserIn |
T. Hipp, B. Etzelmüller, H. Farbrot, T. V. Schuler, S. Westermann |
| 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 ; 6, no. 3 ; Nr. 6, no. 3 (2012-05-23), S.553-571 |
| Datensatznummer |
250003591
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| Publikation (Nr.) |
 copernicus.org/tc-6-553-2012.pdf |
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| Zusammenfassung |
| This study aims at quantifying the thermal response of mountain permafrost
in southern Norway to changes in climate since 1860 and until 2100. A
transient one-dimensional heat flow model was used to simulate ground
temperatures and associated active layer thicknesses for nine borehole
locations, which are located at different elevations and in substrates with
different thermal properties. The model was forced by reconstructed air
temperatures starting from 1860, which approximately coincides with the end
of the Little Ice Age in the region. The impact of climate warming on
mountain permafrost to 2100 is assessed by using downscaled air
temperatures from a multi-model ensemble for the A1B scenario. Borehole
records over three consecutive years of ground temperatures, air
temperatures and snow cover data served for model calibration and
validation. With an increase of air temperature of ~1.5 °C over
1860–2010 and an additional warming of ~2.8 °C until 2100, we
simulate the evolution of ground temperatures for each borehole location. In
1860 the lower limit of permafrost was estimated to be ca. 200 m lower than
observed today. According to the model, since the approximate end of the
Little Ice Age, the active-layer thickness has increased by 0.5–5 m and
>10 m for the sites Juvvasshøe and Tron, respectively. The most
pronounced increases in active layer thickness were modelled for the last
two decades since 1990 with increase rates of +2 cm yr−1 to +87 cm yr−1 (20–430%). According to the A1B climate scenario,
degradation of mountain permafrost is suggested to occur throughout the 21st century at most of the sites below ca. 1800 m a.s.l. At the
highest locations at 1900 m a.s.l., permafrost degradation is likely to occur
with a probability of 55–75% by 2100. This implies that mountain
permafrost in southern Norway is likely to be confined to the highest peaks
in the western part of the country. |
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