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| Titel |
The index-flood method in a Bayesian perspective: sensitivity to regional heterogeneity |
| VerfasserIn |
A. Viglione, E. Gaume, L. Gaal, G. Blöschl, J. Szolgay |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022772
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| Zusammenfassung |
| In regional flood frequency analysis, the commonly used index-flood method assumes that
the frequency distribution of flood peaks for different sites in an homogeneous region is the
same, provided that the discharge series are rescaled using a site-specific scale factor. This
scale factor (index flood) is subsequently related to catchment characteristics to permit
estimation of flood quantiles at ungauged sites within the region. In this work, a Monte Carlo
Markov Chain (MCMC) approach is used to jointly estimate the parameters of the flood
frequency distribution and the parameters relating them to catchment characteristics.
The Bayesian approach allows accounting for the uncertainty associated to the
estimated parameters and associating confidence intervals to the estimated flood
frequency curves at ungauged sites. The consistency of the computed confidence
intervals is verified through simulations of artificial sets of samples by counting in how
many cases the quantile confidence interval includes the underlying parent flood
frequency distribution. The limits of the method and its robustness when it is used on
heterogeneous regions are checked simulating sets of samples characterized by different
degree of heterogeneity, both in terms of the relation of the index-flood to catchment
characteristics and in terms of variability of the underlying parent distribution. |
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