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| Titel |
Spatio-temporal precipitation error propagation in runoff modelling: a case study in central Sweden |
| VerfasserIn |
J. Olsson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 6, no. 4 ; Nr. 6, no. 4 (2006-07-11), S.597-609 |
| Datensatznummer |
250003609
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| Publikation (Nr.) |
 copernicus.org/nhess-6-597-2006.pdf |
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| Zusammenfassung |
| The propagation of spatio-temporal errors in precipitation estimates to
runoff errors in the output from the conceptual hydrological HBV model was
investigated. The study region was the Gimån catchment in central
Sweden, and the period year 2002. Five precipitation sources were
considered: NWP model (H22), weather radar (RAD), precipitation gauges
(PTH), and two versions of a mesoscale analysis system (M11, M22). To define
the baseline estimates of precipitation and runoff, used to define seasonal
precipitation and runoff biases, the mesoscale climate analysis M11 was
used. The main precipitation biases were a systematic overestimation of
precipitation by H22, in particular during winter and early spring, and a
pronounced local overestimation by RAD during autumn, in the western part of
the catchment. These overestimations in some cases exceeded 50% in terms
of seasonal subcatchment relative accumulated volume bias, but generally the
bias was within ±20%. The precipitation data from the different
sources were used to drive the HBV model, set up and calibrated for two
stations in Gimån, both for continuous simulation during 2002 and for
forecasting of the spring flood peak. In summer, autumn and winter all
sources agreed well. In spring H22 overestimated the accumulated runoff
volume by ~50% and peak discharge by almost 100%, owing to both
overestimated snow depth and precipitation during the spring flood. PTH
overestimated spring runoff volumes by ~15% owing to overestimated
winter precipitation. The results demonstrate how biases in precipitation
estimates may exhibit a substantial space-time variability, and may further
become either magnified or reduced when applied for hydrological purposes,
depending on both temporal and spatial variations in the catchment. Thus,
the uncertainty in precipitation estimates should preferably be specified as
a function of both time and space. |
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