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| Titel |
Synchronous glacier surge events observed in the West Kunlun Shan, Xinjiang, China |
| VerfasserIn |
Tom Chudley, Ian Willis |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138016
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| Publikation (Nr.) |
 EGU/EGU2017-908.pdf |
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| Zusammenfassung |
| High Mountain Asia is a major centre of glacier surge activity, but the precise surge
mechanisms in the region are poorly understood. Satellite-based studies in the region
describe unusual surge characteristics that appear to be explained poorly by either
of the two classic surge mechanisms (hydrological and thermal surging) firmly
established in the literature. Here, we present a record of surging in a ∼40 x 60 km zone
of the West Kunlun Shan (WKS), Xinjiang, a poorly researched range ∼250 km
northeast of the Karakoram. We use a combination of historic satellite imagery and
cross-correlation feature tracking to expand the record of surging in the region and assess
surge dynamics.
We use the 1972—2016 Landsat satellite record to observe a total of 9 surge active phases
in the past four decades. Of these, 2 occur prior to 2000, but the remaining 7 display a highly
unusual near-synchronous surge onset in the 2006—2008 period. This synchronous surge
behaviour has not previously been reported for discrete unconnected glaciers. Additionally,
the surge characteristics showed similar surge characteristics to those observed in the
Karakoram, notably low peak velocities (2—3 m day−1) reminiscent of thermal surges and
short active phase periods (∼2-5 years) reminiscent of hydrological surges. We suggest that
such observations are indicative of surging via a ‘hydro-thermodynamic’ mechanism,
recently proposed for the Basin-C outlet of Austfonna, Svalbard. In this mechanism, high
surface melt rates can raise the temperature of cold-based ice over relatively short
timescales compared to thermal surges by rapidly transmitting energy to the base,
facilitating enhanced flow by ice deformation. This hypothesis is supported by
meteorological data, which show that the 2006-2008 period was marked by a series
of all-time highs in seasonal temperatures in southern Xinjiang, suggesting that
high surface melt is a valid mechanism by which these surges could have initiated. |
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