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| Titel |
Assessment of the indirect calibration of a rainfall-runoff model for ungauged catchments in Flanders |
| VerfasserIn |
Niels De Vleeschouwer, Valentijn R. N. Pauwels |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078152
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| Zusammenfassung |
| Abstract
In this research the potential of discharge-based indirect calibration of the Probability
Distributed Model (PDM), a lumped rainfall-runoff (RR) model, is examined for six selected
catchments in Flanders. The concept of indirect calibration indicates that one has to estimate
the calibration data because the catchment is ungauged. A first case in which indirect
calibration is applied is that of spatial gauging divergence: Because no observed discharge
records are available at the outlet of the ungauged catchment, the calibration is carried out
based on a rescaled discharge time series of a very similar donor catchment. The latter is
selected out of a catchment population on the basis of a dissimilarity measure which takes
in account the mutual catchment distance and differences in drainage area, land
topography, soil composition and land cover. Both a calibration in the time domain and
the frequency domain (a.k.a. spectral domain) are carried out. Furthermore, the
case of temporal gauging divergence is considered: Limited (e.g. historical or very
recent) discharge records are available at the outlet of the ungauged catchment.
Additionally, no time overlap exists between the forcing and discharge records. Therefore,
only an indirect spectral calibration can be performed in this case. To conclude
also the combination case of spatio-temporal gauging divergence is considered. In
this last case only limited discharge records are available at the outlet of a donor
catchment. Again the forcing and discharge records are not contemporaneous which
only makes feasible an indirect spectral calibration. The post calibration model
performance is assessed using four indicators: the Pearson correlation coefficient (R), the
relative absolute bias (BIASn), the relative Root Mean Square Error (RMSEn) and the
Nash- Sutcliffe coefficient (NS). The modelled discharge time series are found to be
acceptable in all three considered cases. In the case of spatial gauging divergence,
indirect temporal calibration results in a slightly better model performance than
indirect spectral calibration. Furthermore, indirect spectral calibration in the case of
temporal gauging divergence leads to a better model performance than indirect spectral
calibration in the case of spatial gauging divergence. Finally, the combination of
spatial and temporal gauging divergence does not necessarily lead to a worse model
performance compared to the separate cases of spatial and temporal gauging divergence. |
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