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| Titel |
Temporal stereophotogrammetric analysis of retrogressive thaw slumps on Herschel Island, Yukon Territory |
| VerfasserIn |
H. Lantuit, W. H. Pollard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 5, no. 3 ; Nr. 5, no. 3 (2005-05-30), S.413-423 |
| Datensatznummer |
250002490
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| Publikation (Nr.) |
 copernicus.org/nhess-5-413-2005.pdf |
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| Zusammenfassung |
| The western Canadian Arctic is identified as an area of potentially
significant global warming. Thawing permafrost, sea level rise, changing sea
ice conditions and increased wave activity will result in accelerated rates
of coastal erosion and thermokarst activity in areas of ice-rich permafrost.
The Yukon Coastal Plain is widely recognized as one of the most ice-rich and
thaw-sensitive areas in the Canadian Arctic. In particular, Herschel Island
displays extensive coastal thermokarst. Retrogressive thaw slumps are a
common thermokarst landform along the Herschel Island coast that have been
increasing in both frequency and extent have in recent years due to increased
thawing of massive ground ice and coastal erosion. The volume of sediment and
ground ice eroded by retrogressive slump activity and the potential release
of climate change related materials like organic carbon, carbon dioxide and
methane are largely unknown. The remote setting of Herschel Island, and the
Arctic in general, make direct observation of this type of erosion and the
analysis of potential climate feedbacks extremely problematic. Remote sensing
provides possibly the best solution to this problem. This study looks at two
retrogressive thaw slumps located on the western shore of Herschel Island and
using stereophotogrammetric methods attempts to (1) develop the first
three-dimensional geomorphic analysis of this type of landform, and (2)
provide an estimation of the volume of sediment/ground ice eroded through
back wasting thermokarst activity. Digital Elevation Models were extracted
for the years 1952, 1970 and 2004 and validated using data collected in the
field using Kinematic Differential Global Positioning System. Estimates of sediment
volumes eroded from retrogressive thaw slumps were found to vary greatly. In
one case the total volume of material lost for the 1970–2004 period was
approximately 1560000m3. The estimated volume of sediment alone was
360000m3. The temporal analysis of the DEMs suggest that second generation
retrogressive thaw slump activity within the floor of a large polycyclic
retrogressive thaw slump is possible. |
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