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| Titel |
Regional water balance modelling using flow-duration curves with observational uncertainties |
| VerfasserIn |
I. K. Westerberg, L. Gong, K. J. Beven  , J. Seibert, A. Semedo, C.-Y. Xu, S. Halldin |
| 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 ; 18, no. 8 ; Nr. 18, no. 8 (2014-08-14), S.2993-3013 |
| Datensatznummer |
250120433
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| Publikation (Nr.) |
 copernicus.org/hess-18-2993-2014.pdf |
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| Zusammenfassung |
Robust and reliable water-resource mapping in ungauged basins requires
estimation of the uncertainties in the hydrologic model, the regionalisation
method, and the observational data. In this study we investigated the use of
regionalised flow-duration curves (FDCs) for constraining model predictive
uncertainty, while accounting for all these uncertainty sources. A
water balance model was applied to 36 basins in Central America using
regionally and globally available precipitation, climate and discharge data
that were screened for inconsistencies. A rating-curve analysis for 35
Honduran discharge stations was used to estimate discharge uncertainty for
the region, and the consistency of the model forcing and evaluation data was
analysed using two different screening methods. FDCs with uncertainty bounds
were calculated for each basin, accounting for both discharge uncertainty
and, in many cases, uncertainty stemming from the use of short time series,
potentially not representative for the modelling period. These uncertain
FDCs were then used to regionalise a FDC for each basin, treating it as
ungauged in a cross-evaluation, and this regionalised FDC was used to
constrain the uncertainty in the model predictions for the basin.
There was a clear relationship between the performance of the local model
calibration and the degree of data set consistency – with many basins with
inconsistent data lacking behavioural simulations (i.e. simulations within
predefined limits around the observed FDC) and the basins with the highest
data set consistency also having the highest simulation reliability. For the
basins where the regionalisation of the FDCs worked best, the uncertainty
bounds for the regionalised simulations were only slightly wider than those
for a local model calibration. The predicted uncertainty was greater for
basins where the result of the FDC regionalisation was more uncertain, but
the regionalised simulations still had a high reliability compared to the
locally calibrated simulations and often encompassed them. The regionalised
FDCs were found to be useful on their own as a basic signature constraint;
however, additional regionalised signatures could further constrain the
uncertainty in the predictions and may increase the robustness to severe
data inconsistencies, which are difficult to detect for ungauged basins. |
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