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| Titel |
The influence of climate and hydrological variables on opposite anomaly in active-layer thickness between Eurasian and North American watersheds |
| VerfasserIn |
H. Park, J. Walsh, A. N. Fedorov, A. B. Sherstiukov, Y. Iijima, T. Ohata |
| 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 (2013-04-04), S.631-645 |
| Datensatznummer |
250017955
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| Publikation (Nr.) |
 copernicus.org/tc-7-631-2013.pdf |
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| Zusammenfassung |
| This study not only examined the spatiotemporal variations of active-layer
thickness (ALT) in permafrost regions during 1948–2006 over the terrestrial
Arctic regions experiencing climate changes, but also identified the
associated drivers based on observational data and a simulation conducted by
a land surface model (CHANGE). The focus on the ALT extends previous studies
that have emphasized ground temperatures in permafrost regions. The Ob,
Yenisey, Lena, Yukon, and Mackenzie watersheds are foci of the study. Time
series of ALT in Eurasian watersheds showed generally increasing trends,
while the increase in ALT in North American watersheds was not significant.
However, ALT in the North American watersheds has been negatively anomalous since
1990 when the Arctic air temperature entered into a warming phase. The
warming temperatures were not simply expressed to increases in ALT. Since
1990 when the warming increased, the forcing of the ALT by the higher annual
thawing index (ATI) in the Mackenzie and Yukon basins has been offset by the combined
effects of less insulation caused by thinner snow depth and drier soil
during summer. In contrast, the increasing ATI together
with thicker snow depth and higher summer soil moisture in the Lena
contributed to the increase in ALT. The results imply that the soil thermal
and moisture regimes formed in the pre-thaw season(s) provide memory that
manifests itself during the summer. The different ALT anomalies between
Eurasian and North American watersheds highlight increased importance of
the variability of hydrological variables. |
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