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| Titel |
The Global Network of Isotopes in Rivers (GNIR): integration of water isotopes in watershed observation and riverine research |
| VerfasserIn |
J. Halder, S. Terzer, L. I. Wassenaar, L. J. Araguas-Araguas, P. K. Aggarwal |
| 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 ; 19, no. 8 ; Nr. 19, no. 8 (2015-08-05), S.3419-3431 |
| Datensatznummer |
250120780
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| Publikation (Nr.) |
 copernicus.org/hess-19-3419-2015.pdf |
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| Zusammenfassung |
| We introduce a new online global database of riverine water stable isotopes
(Global Network of Isotopes in Rivers, GNIR) and evaluate its longer-term data holdings. Overall, 218 GNIR river
stations were clustered into three different groups based on the seasonal
variation in their isotopic composition, which was closely coupled to
precipitation and snowmelt water runoff regimes. Sinusoidal fit functions
revealed phases within each grouping and deviations from the sinusoidal
functions revealed important river alterations or hydrological processes in
these watersheds. The seasonal isotopic amplitude of δ18O in
rivers averaged 2.5 ‰, and did not increase as a
function of latitude, like it does for global precipitation. Low seasonal
isotopic amplitudes in rivers suggest the prevalence of mixing and storage
such as occurs via lakes, reservoirs, and groundwater. The application of a
catchment-constrained regionalized cluster-based water isotope prediction
model (CC-RCWIP) allowed for direct comparison between the expected isotopic
compositions for the upstream catchment precipitation with the measured
isotopic composition of river discharge at observation stations. The
catchment-constrained model revealed a strong global isotopic correlation
between average rainfall and river discharge (R2 = 0.88) and the study
demonstrated that the seasonal isotopic composition and variation of river
water can be predicted. Deviations in data from model-predicted values
suggest there are important natural or anthropogenic catchment processes
like evaporation, damming, and water storage in the upstream catchment. |
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