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| Titel |
Glacial lake outburst floods from Kyagar Glacier, Karakoram, P. R. China |
| VerfasserIn |
Christoph Haemmig, Matthias Huss, Hansrudolf Keusen, Josef Hess, Urs Wegmuller, Zhigang Ao, Wubuli Kulubayi |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073062
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| Zusammenfassung |
| Kyagar Glacier is located in the Karakoram Mountains in the southwest of Xinjiang Uygur
Autonomous Region, P.R. China. The glacier tongue entirely blocks the riverbed of the upper
Shaksgam Valley and impounds a glacial lake at 4750 m a.s.l., which was the source of
several violent and disastrous Glacial Lake Outburst Floods (GLOF) over the past decades.
The spontaneous floods are a threat to over 1 mio. inhabitants in the floodplains of the
Yarkant River.
A GLOF early warning system, combining satellite remote sensing and two terrestrial
observation and warning stations at Kyagar Lake and 200 km downstream, was implemented
in 2011 and 2012. The stations provide daily images based on automatic cameras, water level
measurements, and are equipped with weather sensors to monitor local climate. We discuss
the GLOF early warning system and present first measurement series of melt-water runoff
and meteorological conditions from one of the remotest regions of the Karakoram
mountains.
The ongoing project also elaborates scenario-based forecasts of future glacier lake
developments, considering the ice-flow dynamics of Kyagar Glacier as well as surface
mass-balance response to climate change. Comparison of two high-resolution Digital
Elevation Models (DEMs) for the ice dam show surface lowering rates of more
than 4 m a-1 between 2002 and 2011 leading to a significant reduction in lake
volume and hence, a decreasing GLOF hazard potential. Glacier melt modelling using
climate scenarios indicates a rapid retreat of the glacier tongue over the next decades.
However, two DEMs covering the entire glacier for 2000-2008 show small elevation
changes in the accumulation area and even a slight mass gain in the central part. This
is supported by the observation of a moderate ice-flow speed-up in this region.
This pattern is typical for surge-type glaciers and is consistent with the numerous
documented glacier surges in the Karakoram. Furthermore, the displacement rate of the
glacier surface between 2011 and 2012 is analyzed based on feature tracking of
synthetic aperture radar images in high temporal and spatial resolution. We present an
integrative analysis of recent changes in mass-balance and ice-flow dynamics of
Kyagar Glacier. These assessments are crucial for estimating the future GLOF hazard
potential of Kyagar Glacier Lake and improving risk management in the floodplain. |
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