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| Titel |
Monitoring of active layer dynamics at a permafrost site on Svalbard using multi-channel ground-penetrating radar |
| VerfasserIn |
S. Westermann, U. Wollschläger, J. Boike |
| 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 ; 4, no. 4 ; Nr. 4, no. 4 (2010-11-08), S.475-487 |
| Datensatznummer |
250001898
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| Publikation (Nr.) |
 copernicus.org/tc-4-475-2010.pdf |
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| Zusammenfassung |
Multi-channel ground-penetrating radar is used to investigate the late-summer
evolution of the thaw depth and the average soil water content of the thawed
active layer at a high-arctic continuous permafrost site on Svalbard, Norway.
Between mid of August and mid of September 2008, five surveys have been
conducted in gravelly soil over transect lengths of 130 and 175 m each. The maximum thaw
depths range from 1.6 m to 2.0 m, so that they are among the deepest
thaw depths recorded in sediments on Svalbard so far. The thaw depths increase by
approximately 0.2 m between mid of August and beginning of September and
subsequently remain constant until mid of September. The thaw rates are
approximately constant over the entire length of the transects within the
measurement accuracy of about 5 to 10 cm. The average volumetric soil
water content of the thawed soil varies between 0.18 and 0.27 along the
investigated transects. While the measurements do not show significant
changes in soil water content over the first four weeks of the study, strong
precipitation causes an increase in average soil water content of up to 0.04
during the last week. These values are in good agreement with
evapotranspiration and precipitation rates measured in the vicinity of the
the study site. While we cannot provide conclusive reasons for the detected
spatial variability of the thaw depth at the study site, our measurements
show that thaw depth and average soil water content are not directly
correlated.
The study demonstrates the potential of multi-channel ground-penetrating
radar for mapping thaw depth in permafrost areas. The novel non-invasive
technique is particularly useful when the thaw depth exceeds 1.5 m, so
that it is hardly accessible by manual probing. In addition, multi-channel
ground-penetrating radar holds potential for mapping the latent heat content
of the active layer and for estimating weekly to monthly averages of the
ground heat flux during the thaw period. |
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