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| Titel |
A ten-year record of supraglacial lake evolution and rapid drainage in West Greenland using an automated processing algorithm for multispectral imagery |
| VerfasserIn |
B. F. Morriss, R. L. Hawley, J. W. Chipman, L. C. Andrews, G. A. Catania, M. J. Hoffman, M. P. Lüthi, T. A. Neumann |
| 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. 6 ; Nr. 7, no. 6 (2013-12-12), S.1869-1877 |
| Datensatznummer |
250085188
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| Publikation (Nr.) |
 copernicus.org/tc-7-1869-2013.pdf |
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| Zusammenfassung |
| The rapid drainage of supraglacial lakes introduces large pulses of
meltwater to the subglacial environment and creates moulins, surface-to-bed
conduits for future melt. Introduction of water to the subglacial system has
been shown to affect ice flow, and modeling suggests that variability in
water supply and delivery to the subsurface play an important role in the
development of the subglacial hydrologic system and its ability to enhance
or mitigate ice flow. We developed a fully automated method for tracking
meltwater and rapid drainages in large (> 0.125 km2)
perennial lakes and applied it to a 10 yr time series of ETM+ and MODIS
imagery of an outlet glacier flow band in West Greenland. Results indicate
interannual variability in maximum coverage and spatial evolution of total
lake area. We identify 238 rapid drainage events, occurring most often at
low (< 900 m) and middle (900–1200 m) elevations during periods of
net filling or peak lake coverage. We observe a general progression of both
lake filling and draining from lower to higher elevations but note that the
timing of filling onset, peak coverage, and dissipation are also variable.
Lake coverage is sensitive to air temperature, and warm years exhibit
greater variability in both coverage evolution and rapid drainage. Mid-elevation
drainages in 2011 coincide with large surface velocity increases
at nearby GPS sites, though the relationships between ice-shed-scale dynamics
and meltwater input are still unclear. |
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