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| Titel |
Impacts of mean annual air temperature change on a regional permafrost probability model for the southern Yukon and northern British Columbia, Canada |
| VerfasserIn |
P. P. Bonnaventure, A. G. Lewkowicz |
| 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. 3 ; Nr. 7, no. 3 (2013-06-19), S.935-946 |
| Datensatznummer |
250017977
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| Publikation (Nr.) |
 copernicus.org/tc-7-935-2013.pdf |
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| Zusammenfassung |
| Air temperature changes were applied to a regional model of permafrost
probability under equilibrium conditions for an area of nearly 0.5 × 106 km2 in the southern Yukon and northwestern British Columbia,
Canada. Associated environmental changes, including snow cover and
vegetation, were not considered in the modelling. Permafrost extent increases
from 58% of the area (present day: 1971–2000) to 76% under a −1 K
cooling scenario, whereas warming scenarios decrease the percentage
of permafrost area exponentially to 38% (+ 1 K), 24% (+ 2 K), 17% (+ 3 K), 12% (+ 4 K) and 9% (+ 5 K) of the area. The morphology of
permafrost gain/loss under these scenarios is controlled by the surface
lapse rate (SLR, i.e. air temperature elevation gradient), which varies
across the region below treeline. Areas that are maritime exhibit SLRs
characteristically similar above and below treeline resulting in low
probabilities of permafrost in valley bottoms. When warming scenarios are
applied, a loss front moves to upper elevations (simple unidirectional
spatial loss). Areas where SLRs are gently negative below treeline and
normal above treeline exhibit a loss front moving up-mountain at different
rates according to two separate SLRs (complex unidirectional spatial loss).
Areas that display high continentally exhibit bidirectional spatial loss in
which the loss front moves up-mountain above treeline and down-mountain
below treeline. The parts of the region most affected by changes in MAAT (mean annual air temperature)
have SLRs close to 0 K km−1 and extensive discontinuous permafrost,
whereas the least sensitive in terms of areal loss are sites above the treeline
where permafrost presence is strongly elevation dependent. |
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