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| Titel |
Predicting East African spring droughts using Pacific and Indian Ocean sea surface temperature indices |
| VerfasserIn |
C. Funk, A. Hoell, S. Shukla, I. Bladé, B. Liebmann, J. B. Roberts, F. R. Robertson, G. Husak |
| 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 (2014-12-10), S.4965-4978 |
| Datensatznummer |
250120552
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| Publikation (Nr.) |
 copernicus.org/hess-18-4965-2014.pdf |
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| Zusammenfassung |
| In eastern East Africa (the southern Ethiopia, eastern Kenya and southern
Somalia region), poor boreal spring (long wet season) rains in 1999, 2000,
2004, 2007, 2008, 2009, and 2011 contributed to severe food insecurity and
high levels of malnutrition. Predicting rainfall deficits in this region on
seasonal and decadal time frames can help decision makers implement disaster
risk reduction measures while guiding climate-smart adaptation and
agricultural development. Building on recent research that links more
frequent East African droughts to a stronger Walker circulation, resulting
from warming in the Indo–Pacific warm pool and an increased east-to-west sea
surface temperature (SST) gradient in the western Pacific, we show that the
two dominant modes of East African boreal spring rainfall variability are
tied to SST fluctuations in the western central Pacific and central Indian
Ocean, respectively. Variations in these two rainfall modes can thus be
predicted using two SST indices – the western Pacific gradient (WPG) and
central Indian Ocean index (CIO), with our statistical forecasts exhibiting
reasonable cross-validated skill (rcv ≈ 0.6). In contrast, the
current generation of coupled forecast models show no skill during the long
rains. Our SST indices also appear to capture most of the major recent
drought events such as 2000, 2009 and 2011. Predictions based on these
simple indices can be used to support regional forecasting efforts and land surface
data assimilations to help inform early warning and guide climate outlooks. |
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