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| Titel |
Change of extreme rainfall indexes at Ebro River Basin |
| VerfasserIn |
J. L. Valencia, A. M. Tarquis, Antonio Saá-Requejo, J. M. Gascó |
| 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 ; 12, no. 7 ; Nr. 12, no. 7 (2012-07-05), S.2127-2137 |
| Datensatznummer |
250010979
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| Publikation (Nr.) |
 copernicus.org/nhess-12-2127-2012.pdf |
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| Zusammenfassung |
Extreme rainfall events are a serious concern for regional hydrology and
agriculture in the Ebro River Basin. Repeated anomalous rainfall in recent
decades has had a devastating impact on this region, both socially and
economically. Some studies developed in Italy and USA have shown that there
is a change in seasonal patterns and an increasing frequency of extreme
rainfall events, whereas other studies have pointed out that no global
behaviour could be observed in monthly trends due to high climatic
variability. The aim of this work is to test which of these scenarios is the
case for the Ebro River Basin.
For this purpose, 14 meteorological stations were selected based on
the length of the rainfall series and the climatic classification to obtain
a representative untreated dataset from the river basin. Daily rainfall
series from 1957 to 2002 were obtained from each meteorological station.
First, classical climatic indexes were analysed with an autoregressive test
to study possible trends in rainfall. The results can be explained following
the evolution of the NAO and WeMO indexes, which indicate that the initial
period should be subdivided in two periods (1957–1979 and 1980–2002) to
assume stationarity and to analyse the rainfall distribution functions.
The general results obtained in this study for both sub-periods, through the
generalised Pareto distribution (GPD) parameters and the maximum expected
return values, do not support the results previously obtained by other
authors that affirm a positive trend in extreme rainfall indexes and point
to a slight reduction indicated by others. Three extreme precipitation
indexes show negative statistical significant trends. GPD-scale parameters
decrease except for only one rain gauge, although this decrease is only
statistically significant for two rain gauges. Another two locations show
statistical significance decreased for maximum expected return values. |
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