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| Titel |
Four decades of glacier variations at Muztagh Ata (eastern Pamir): a multi-sensor study including Hexagon KH-9 and Pléiades data |
| VerfasserIn |
N. Holzer, S. Vijay, T. Yao, B. Xu, M. Buchroithner  , T. Bolch |
| 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 ; 9, no. 6 ; Nr. 9, no. 6 (2015-11-10), S.2071-2088 |
| Datensatznummer |
250116867
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| Publikation (Nr.) |
 copernicus.org/tc-9-2071-2015.pdf |
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| Zusammenfassung |
| Previous in situ measurements have indicated a slight mass gain at Muztagh
Ata in the eastern Pamir, contrary to the global trend. We extend these
measurements both in space and time by using remote sensing data and present
four decades of glacier variations in the entire mountain massif. Geodetic
mass balances and area changes were determined at glacier scale from stereo
satellite imagery and derived digital elevation models (DEMs). This includes
Hexagon KH-9 (year 1973), ALOS-PRISM~(2009), Pléiades (2013) and Landsat
7 ETM+ data in conjunction with the SRTM-3 DEM (2000). In addition, surface
velocities of Kekesayi Glacier, the largest glacier at Muztagh Ata, were
derived from amplitude tracking of TerraSAR-X images (2011). Locally, we
observed strong spatial and temporal glacier variations during the last four
decades, which were, however, on average not significant for the entire
massif. Some south-west-exposed glaciers fluctuated or advanced, while
glaciers with other aspects rather experienced continuous shrinkage. Several
glaciers such as Kekesayi indicate no measurable change at their frontal
position, but clear down-wasting despite mostly thick debris coverage at low
altitudes. The surface velocity of this debris-covered glacier reach up to
20 cm per day, but the lowest part of the tongue appears to be stagnant. The
low velocity or even stagnancy at the tongue is likely one reason for the
down-wasting. On average, the glaciers showed a small, insignificant
shrinkage from 274.3 ± 10.6 km2 in 1973 to
272.7 ± 1.0 km2 in 2013 (−0.02 ± 0.1 % a−1).
Average mass changes in the range of −0.03 ± 0.33 m w.e. a−1
(1973–2009) to −0.01 ± 0.30 m w.e. a−1 (1973–2013) reveal
nearly balanced budgets for the last 40 years. Indications of slightly
positive rates after 1999 (+0.04 ± 0.27 m w.e. a−1) are not
significant, but confirmed by measurements in the field. |
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