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| Titel |
Seasonal and annual mass balances of Mera and Pokalde glaciers (Nepal Himalaya) since 2007 |
| VerfasserIn |
P. Wagnon, C. Vincent, Y. Arnaud, E. Berthier, E. Vuillermoz, S. Gruber, M. Ménégoz, A. Gilbert, M. Dumont, J. M. Shea, D. Stumm, B. K. Pokhrel |
| 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 (2013-11-19), S.1769-1786 |
| Datensatznummer |
250085182
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| Publikation (Nr.) |
 copernicus.org/tc-7-1769-2013.pdf |
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| Zusammenfassung |
| In the Everest region, Nepal, ground-based monitoring programmes were started
on the debris-free Mera Glacier (27.7° N, 86.9° E;
5.1 km2, 6420 to 4940 m a.s.l.) in 2007 and on the small Pokalde
Glacier (27.9° N, 86.8° E; 0.1 km2, 5690 to
5430 m a.s.l., ~ 25 km north of Mera Glacier) in 2009. These glaciers
lie on the southern flank of the central Himalaya under the direct influence
of the Indian monsoon and receive more than 80% of their annual
precipitation in summer (June to September). Despite a large inter-annual
variability with glacier-wide mass balances ranging from −0.67 ± 0.28 m w.e. in
2011–2012 (Equilibrium-line altitude (ELA) at ~ 5800 m a.s.l.) to +0.46 ± 0.28 m w.e.
in 2010–2011 (ELA at ~ 5340 m a.s.l.), Mera Glacier has been shrinking at a moderate mass balance
rate of −0.08 ± 0.28 m w.e. yr−1 since 2007. Ice fluxes measured
at two distinct transverse cross sections at ~ 5350 m a.s.l. and ~ 5520 m
a.s.l. confirm that the mean state of this glacier over the last one
or two decades corresponds to a limited mass loss, in agreement with
remotely-sensed region-wide mass balances of the Everest area. Seasonal mass
balance measurements show that ablation and accumulation are concomitant in
summer which in turn is the key season controlling the annual glacier-wide
mass balance. Unexpectedly, ablation occurs at all elevations in winter due
to wind erosion and sublimation, with remobilised snow potentially being
sublimated in the atmosphere. Between 2009 and 2012, the small Pokalde
Glacier lost mass more rapidly than Mera Glacier with respective mean
glacier-wide mass balances of −0.72 and −0.23 ± 0.28 m w.e. yr−1.
Low-elevation glaciers, such as Pokalde Glacier, have been usually preferred
for in-situ observations in Nepal and more generally in the Himalayas, which
may explain why compilations of ground-based mass balances are biased toward
negative values compared with the regional mean under the present-day
climate. |
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