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Titel |
Trends in timing and magnitude of flow in the Upper Indus Basin |
VerfasserIn |
M. Sharif, D. R. Archer, H. J. Fowler, N. Forsythe |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 4 ; Nr. 17, no. 4 (2013-04-19), S.1503-1516 |
Datensatznummer |
250018853
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Publikation (Nr.) |
copernicus.org/hess-17-1503-2013.pdf |
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Zusammenfassung |
River flow is a reflection of the input of moisture and its transformation
in storage and transmission over the catchment. In the Upper Indus Basin
(UIB), since high-altitude climate measurement and observations of glacier
mass balance are weak or absent, analysis of trends in magnitude and timing
in river flow provides a window on trends and fluctuations in climate and
glacier outflow. Trend analysis is carried out using a Mann–Kendall
nonparametric trend test on records extending from 1960 to 1998. High-level
glacial catchments show a falling trend in runoff magnitude and a declining
proportion of glacial contribution to the main stem of the Indus. Elsewhere
annual flow has predominantly increased with several stations exhibiting
statistically significant positive trends. Analysis of timing using spring
onset date (SOT) and centre of volume date (CoV) indicated no clear trends –
in direct contrast to what has been observed in western North America. There
is, however, a consistent relationship between CoV and annual runoff volume.
A consistently positive correlation was also found between SOT and CoV for
all the stations, implying that initial snowpack conditions before the onset
of runoff influence timing throughout the season. The results of the
analysis presented here indicate that the magnitude and timing of streamflow
hydrograph is influenced both by the initial snowpack and by seasonally
varied trends in temperature. The study contributes to the understanding of
the links between climate trends and variability and river runoff and
glacier mass balance and runoff. The Upper Indus Basin is predominantly
influenced by winter precipitation; similar trend analysis applied to
summer-monsoon-dominated catchments of the central Himalaya is recommended. |
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