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| Titel |
Calibration analysis for water storage variability of the global hydrological model WGHM |
| VerfasserIn |
S. Werth, A. Güntner |
| 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. 1 ; Nr. 14, no. 1 (2010-01-11), S.59-78 |
| Datensatznummer |
250012146
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| Publikation (Nr.) |
 copernicus.org/hess-14-59-2010.pdf |
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| Zusammenfassung |
| The aim of this study is to provide an improved global simulation of continental
water storage variations by calibrating the WaterGAP Global Hydrology Model (WGHM)
for 28 of the largest river basins worldwide. Five years (January 2003–December 2007) of
satellite-based estimates of the total water storage changes from the GRACE
mission were combined with river discharge data in a multi-objective calibration
framework that uses the most sensitive WGHM model parameters. The uncertainty
and significance of the calibration results were analysed with respect to errors
in the observation data. An independent simulation period (January 2008–December 2008) was
used for validation. The contribution of single storage compartments to the total
water budget before and after calibration was analysed in detail. A multi-objective
improvement of the model states was obtained for most of the river basins, with
mean error reductions of up to 110 km3/month for discharge and up to 24 mm of
a water mass equivalent column for total water storage changes, such as for the
Amazon basin. Errors in the phase and signal variability of seasonal water mass
changes were reduced. The calibration is shown to primarily affect soil water
storage in most river basins. The variability of groundwater storage variations
was reduced on a global scale after calibration. Structural model errors were
identified from a small contribution of surface water storage including wetlands
in river basins with large inundation areas, such as the Amazon or the Mississippi.
Our results demonstrate the value of both the GRACE data and the multi-objective
calibration approach for improving large-scale hydrological simulations, and they
provide a starting-point for improving model structures. The integration of
complimentary observation data to further constrain the simulation of single
storage compartments is encouraged. |
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