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| Titel |
Observations of enhanced thinning in the upper reaches of Svalbard glaciers |
| VerfasserIn |
T. D. James, T. Murray, N. E. Barrand, H. J. Sykes, A. J. Fox, M. A. King |
| 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. 6 ; Nr. 6, no. 6 (2012-11-20), S.1369-1381 |
| Datensatznummer |
250003872
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| Publikation (Nr.) |
 copernicus.org/tc-6-1369-2012.pdf |
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| Zusammenfassung |
| Changes in the volume and extent of land ice of the Svalbard archipelago have
been the subject of considerable research since their sensitivity to changes
in climate was first noted. However, the measurement of these changes is
often necessarily based on point or profile measurements which may not be
representative if extrapolated to a whole catchment or region. Combining
high-resolution elevation data from contemporary laser-altimetry surveys and
archived aerial photography makes it possible to measure historical changes
across a glacier's surface without the need for extrapolation. Here we
present a high spatial resolution time-series for six Arctic glaciers in the
Svalbard archipelago spanning 1961 to 2005. We find high variability in
thinning rates between sites with prevalent elevation changes at all sites
averaging −0.59 ± 0.04 m a−1 between 1961–2005. Prior to 1990,
ice surface elevation was changing at an average rate of −0.52 ± 0.09 m a−1
which decreased to −0.76 ± 0.10 m a−1 after 1990.
Setting the elevation changes against the glaciers' altitude distribution
reveals that significant increases in thinning rates are occurring most
notably in the glaciers' upper reaches. We find that these changes are
coincident with a decrease in winter precipitation at the Longyearbyen
meteorological station and could reflect a decrease in albedo or dynamic
response to lower accumulation. Further work is required to understand fully
the causes of this increase in thinning rates in the glaciers' upper
reaches. If on-going and occurring elsewhere in the archipelago, these
changes will have a significant effect on the region's future mass balance.
Our results highlight the importance of understanding the climatological
context of geodetic mass balance measurements and demonstrate the difficulty
of using index glaciers to represent regional changes in areas of strong
climatological gradients. |
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