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| Titel |
Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR |
| VerfasserIn |
L. Liu, C. I. Millar, R. D. Westfall, H. A. Zebker |
| 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. 4 ; Nr. 7, no. 4 (2013-07-18), S.1109-1119 |
| Datensatznummer |
250017990
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| Publikation (Nr.) |
 copernicus.org/tc-7-1109-2013.pdf |
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| Zusammenfassung |
| Despite the abundance of rock glaciers in the Sierra Nevada of California,
USA, few efforts have been made to measure their surface flow. Here we use
the interferometric synthetic aperture radar (InSAR) technique to compile
a benchmark inventory describing the kinematic state of 59 active rock
glaciers in this region. In the late summer of 2007, these rock glaciers
moved at speeds that range from 14 cm yr−1 to
87 cm yr−1, with a regional mean value of 53 cm yr−1.
Our inventory reveals a spatial difference: rock glaciers in the southern
Sierra Nevada moved faster than the ones in the central Sierra Nevada. In
addition to the regional mapping, we also conduct a case study to measure the
surface flow of the Mount Gibbs rock glacier in fine spatial and temporal
detail. The InSAR measurements over this target reveal (1) that the spatial
pattern of flow is correlated with surface geomorphic features and
(2) a significant seasonal variation of flow speed whose peak value was
48 cm yr−1in the fall of 2007, more than twice the minimum value
observed in the spring of 2008. The seasonal variation lagged air
temperatures by three months. Our finding on the seasonal variation of
surface speed reinforces the importance of a long time series with high
temporal sampling rates to detect possible long-term changes of rock glacier
kinematics in a warming climate. |
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