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| Titel |
Droughts and floods over the upper catchment of the Blue Nile and their connections to the timing of El Niño and La Niña events |
| VerfasserIn |
M. A. H. Zaroug, E. A. B. Eltahir, F. Giorgi |
| 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. 3 ; Nr. 18, no. 3 (2014-03-31), S.1239-1249 |
| Datensatznummer |
250120319
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| Publikation (Nr.) |
 copernicus.org/hess-18-1239-2014.pdf |
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| Zusammenfassung |
| The Blue Nile originates from Lake Tana in the Ethiopian Highlands and
contributes about 60–69% of the main Nile discharge. Previous studies
investigated the relationship of sea surface temperature (SST) in the Pacific
Ocean (Niño 3.4 region) to occurrence of meteorological and hydrological
droughts in the Nile Basin. In this paper we focus on the dependence of
occurrence of droughts and floods in the upper catchment of the Blue Nile on
the timing of El Niño and La Niña events. Different events start at
different times of the year and follow each other, exhibiting different
patterns and sequences. Here we study the impact of these timing and temporal
patterns on the Blue Nile droughts and floods. The comparison between the
discharge measurements (1965–2012) at the outlet of the upper catchment of
the Blue Nile and the El Niño index shows that when an El Niño event
is followed by a La Niña event, there is a 67% chance for occurrence
of an extreme flood. Furthermore, we also found that 83% of El Niño
events starting in April–June resulted in droughts in the upper catchment of
the Blue Nile. Although the current study is limited by the reduced number of
samples, we propose that observations as well as global model forecasts of
SST during this season could be used in seasonal forecasting of the Blue Nile
flow. |
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