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| Titel |
Characterising the space–time structure of rainfall in the Sahel with a view to estimating IDAF curves |
| VerfasserIn |
G. Panthou, T. Vischel, T. Lebel, G. Quantin, G. Molinié |
| 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. 12 ; Nr. 18, no. 12 (2014-12-11), S.5093-5107 |
| Datensatznummer |
250120559
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| Publikation (Nr.) |
 copernicus.org/hess-18-5093-2014.pdf |
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| Zusammenfassung |
| Intensity–duration–area–frequency (IDAF) curves are increasingly demanded for characterising
the severity of storms and for designing hydraulic structures. Their computation requires
inferring areal rainfall distributions over the range of space scales and timescales that are the most
relevant for hydrological studies at catchment scale. In this study, IDAF curves are computed for
the first time in West Africa, based on the data provided by the AMMA-CATCH Niger network,
composed of 30 recording rain gauges having operated since 1990 over a 16 000 km2 area
in south-western Niger. The IDAF curves are obtained by separately considering the time (intensity–duration–frequency, IDF) and
space (areal reduction factor, ARF) components of the extreme rainfall distribution. Annual
maximum intensities are extracted for resolutions between 1 and 24 h in time and from point
(rain gauge) to 2500 km2 in space. The IDF model used is based on the concept of scale
invariance (simple scaling) which allows the normalisation of the different temporal resolutions
of maxima series to which a global generalised extreme value (GEV) is fitted. This parsimonious framework allows one to use the
concept of dynamic scaling to describe the ARF. The results show that coupling a simple scaling in
space and time with a dynamical scaling that relates to space and time allows one to satisfactorily model the
effect of space–time aggregation on the distribution of extreme rainfall. |
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