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| Titel |
A case study on the use of appropriate surrogates for antecedent moisture conditions (AMCs) |
| VerfasserIn |
G. A. Ali, A. G. Roy |
| 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 ; 14, no. 10 ; Nr. 14, no. 10 (2010-10-11), S.1843-1861 |
| Datensatznummer |
250012439
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| Publikation (Nr.) |
 copernicus.org/hess-14-1843-2010.pdf |
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| Zusammenfassung |
| While a large number of non-linear hillslope and catchment rainfall-runoff
responses have been attributed to the temporal variability in antecedent
moisture conditions (AMCs), two problems emerge: (1) the difficulty of
measuring AMCs, and (2) the absence of explicit guidelines for the choice of
surrogates or proxies for AMCs. This paper aims at determining whether or
not multiple surrogates for AMCs should be used in order not to bias our
understanding of a system hydrological behaviour. We worked in a small
forested catchment, the Hermine, where soil moisture has been measured at
121 different locations at four depths on 16 occasions. Without making any
assumption on active processes, we used various linear and nonlinear
regression models (i.e. linear, quadratic, cubic, exponential, logarithmic
and logistic) to evaluate the point-scale temporal relations between actual
soil moisture contents and selected meteorological-based surrogates for
AMCs. We then mapped the nature of the "best fit" model to identify (1)
spatial clusters of soil moisture monitoring sites whose hydrological
behaviour was similar, and (2) potential topographic influences on these
behaviours. Two conclusions stood out. Firstly, it was shown that the sole
reference to AMCs indices traditionally used in catchment hydrology, namely
antecedent rainfall amounts summed over periods of seven or ten days, would
have led to an incomplete understanding of the Hermine catchment dynamics.
Secondly, the relationships between point-scale soil moisture content and
surrogates for AMCs were not spatially homogeneous, thus revealing a mosaic
of linear and nonlinear catchment "active" and "contributing" sources whose
locations were seldom controlled by surface terrain attributes or the
topography of a soil-confining layer interface. These results represent a
step forward for the Hermine catchment as they point towards depth-specific
processes and spatially-variable triggering conditions that are not
controlled by topography. Further investigations are, however, necessary in
order to derive general guidelines for the choice of the best surrogates for
AMCs in a catchment. |
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