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| Titel |
Technical Note: Glacial influence in tropical mountain hydrosystems evidenced by the diurnal cycle in water levels |
| VerfasserIn |
S. Cauvy-Fraunié, T. Condom, A. Rabatel, M. Villacis, D. Jacobsen, O. Dangles |
| 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. 12 ; Nr. 17, no. 12 (2013-12-04), S.4803-4816 |
| Datensatznummer |
250086014
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| Publikation (Nr.) |
 copernicus.org/hess-17-4803-2013.pdf |
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| Zusammenfassung |
| Worldwide, the rapid shrinking of glaciers in response to ongoing climate
change is modifying the glacial meltwater contribution to hydrosystems in
glacierized catchments. Determining the influence of glacial runoff to
streams is therefore of critical importance to evaluate potential impact of
glacier retreat on water quality and aquatic biota. This task has challenged
both glacier hydrologists and ecologists over the last 20 yr due to both
structural and functional complexity of the glacier–stream system interface.
Here we propose quantifying the diurnal cycle amplitude of the streamflow
to determine the glacial influence in glacierized catchments. We performed
water-level measurements using water pressure loggers over 10 months at 30 min
time steps in 15 stream sites in 2 glacier-fed catchments in the
Ecuadorian Andes (> 4000 m a.s.l.) where no perennial snow cover
is observed outside the glaciers. For each stream site, we performed
wavelet analyses on water-level time series, determined the scale-averaged
wavelet power spectrum at 24 h scale and defined three metrics, namely the
power, frequency and temporal clustering of the diurnal flow variation. The
three metrics were then compared to the percentage of the glacier cover in
the catchments, a metric of glacial influence widely used in the literature.
As expected, we found that the diurnal variation power of glacier-fed
streams decreased downstream with the addition of non-glacial tributaries.
We also found that the diurnal variation power and the percentage of the
glacier cover in the catchment were significantly positively correlated.
Furthermore, we found that our method permits the detection of glacial signal in
supposedly non-glacial sites, thereby revealing glacial meltwater
resurgence. While we specifically focused on the tropical Andes in this
paper, our approach to determine glacial influence may have potential
applications in temperate and arctic glacierized catchments. The measure of
diurnal water amplitude therefore appears as a powerful and cost-effective
tool to understand the hydrological links between glaciers and
hydrosystems better and assess the consequences of rapid glacier shrinking. |
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