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| Titel |
What can flux tracking teach us about water age distribution patterns and their temporal dynamics? |
| VerfasserIn |
M. Hrachowitz, H. Savenije, T. A. Bogaard, D. Tetzlaff, C. Soulsby |
| 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. 2 ; Nr. 17, no. 2 (2013-02-07), S.533-564 |
| Datensatznummer |
250017708
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| Publikation (Nr.) |
 copernicus.org/hess-17-533-2013.pdf |
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| Zusammenfassung |
The complex interactions of runoff generation processes underlying the
hydrological response of streams remain not entirely understood at the
catchment scale. Extensive research has demonstrated the utility of tracers
for both inferring flow path distributions and constraining model
parameterizations. While useful, the common use of linearity assumptions,
i.e. time invariance and complete mixing, in these studies provides only
partial understanding of actual process dynamics. Here we use long-term
(<20 yr) precipitation, flow and tracer (chloride) data of three
contrasting upland catchments in the Scottish Highlands to inform integrated
conceptual models investigating different mixing assumptions. Using the
models as diagnostic tools in a functional comparison, water and tracer
fluxes were then tracked with the objective of exploring the differences
between different water age distributions, such as flux and resident water
age distributions, and characterizing the contrasting water age pattern of
the dominant hydrological processes in the three study catchments to
establish an improved understanding of the wetness-dependent temporal
dynamics of these distributions.
The results highlight the potential importance of partial mixing processes
which can be dependent on the hydrological functioning of a catchment.
Further, tracking tracer fluxes showed that the various components of a
model can be characterized by fundamentally different water age
distributions which may be highly sensitive to catchment wetness history,
available storage, mixing mechanisms, flow path connectivity and the
relative importance of the different hydrological processes involved. Flux
tracking also revealed that, although negligible for simulating the runoff
response, the omission of processes such as interception evaporation can
result in considerably biased water age distributions. Finally, the modeling
indicated that water age distributions in the three study catchments do have
long, power-law tails, which are generated by the interplay of flow path
connectivity, the relative importance of different flow paths as well as by
the mixing mechanisms involved. In general this study highlights the
potential of customized integrated conceptual models, based on multiple
mixing assumptions, to infer system internal transport dynamics and their
sensitivity to catchment wetness states. |
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