Seasonal prediction of East African rainfall

2014 ◽  
Vol 35 (10) ◽  
pp. 2698-2723 ◽  
Author(s):  
Chia-Jeng Chen ◽  
Aris P. Georgakakos
Keyword(s):  
Seasonal Prediction ◽  
East African ◽  
African Rainfall

scholarly journals Reconciling Theories for Human and Natural Attribution of Recent East Africa Drying

2017 ◽  
Vol 30 (6) ◽  
pp. 1939-1957 ◽  
Author(s):  
Andrew Hoell ◽  
Martin Hoerling ◽  
Jon Eischeid ◽  
Xiao-Wei Quan ◽  
Brant Liebmann
Keyword(s):  
Global Warming ◽  
East Africa ◽  
Decadal Variability ◽  
Coupled Model ◽  
Western Pacific ◽  
East African ◽  
Coupled Models ◽  
Central Pacific ◽  
Model Simulations ◽  
African Rainfall

Abstract Two theories for observed East Africa drying trends during March–May 1979–2013 are reconciled. Both hypothesize that variations in tropical sea surface temperatures (SSTs) caused East Africa drying. The first invokes a mainly human cause resulting from sensitivity to secular warming of Indo–western Pacific SSTs. The second invokes a mainly natural cause resulting from sensitivity to a strong articulation of ENSO-like Pacific decadal variability involving warming of the western Pacific and cooling of the central Pacific. Historical atmospheric model simulations indicate that observed SST variations contributed significantly to the East Africa drying trend during March–May 1979–2013. By contrast, historical coupled model simulations suggest that external radiative forcing alone, including the ocean’s response to that forcing, did not contribute significantly to East Africa drying. Recognizing that the observed SST variations involved a commingling of natural and anthropogenic effects, this study diagnosed how East African rainfall sensitivity was conditionally dependent on the interplay of those factors. East African rainfall trends in historical coupled models were intercompared between two composites of ENSO-like decadal variability, one operating in the early twentieth century before appreciable global warming and the other in the early twenty-first century of strong global warming. The authors find the coaction of global warming with ENSO-like decadal variability can significantly enhance 35-yr East Africa drying trends relative to when the natural mode of ocean variability acts alone. A human-induced change via its interplay with an extreme articulation of natural variability may thus have been key to Africa drying; however, these results are speculative owing to differences among two independent suites of coupled model ensembles.

The relationship between Indian Ocean sea–surface temperature and East African rainfall

2005 ◽  
Vol 363 (1826) ◽  
pp. 43-47 ◽  
Author(s):  
Emily Black
Keyword(s):  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Southern Oscillation ◽  
Sea Surface ◽  
East African ◽  
African Rainfall ◽  
The Pacific ◽  
The Indian Ocean ◽  
The Relationship

Knowledge of the processes that control East African rainfall is essential for the development of seasonal forecasting systems, which may mitigate the effects of flood and drought. This study uses observational data to unravel the relationship between the Indian Ocean Dipole (IOD), the El Niño Southern Oscillation (ENSO) and rainy autumns in East Africa. Analysis of sea–surface temperature data shows that strong East African rainfall is associated with warming in the Pacific and Western Indian Oceans and cooling in the Eastern Indian Ocean. The resemblance of this pattern to that which develops during IOD events implies a link between the IOD and strong East African rainfall. Further investigation suggests that the observed teleconnection between East African rainfall and ENSO is a manifestation of a link between ENSO and the IOD.

scholarly journals The observed and modelled influence of the Madden-Julian Oscillation on East African rainfall

2014 ◽  
Vol 22 (3) ◽  
pp. 459-469 ◽  
Author(s):  
Emily Hogan ◽  
Ann Shelly ◽  
Prince Xavier
Keyword(s):  
Madden Julian Oscillation ◽  
East African ◽  
African Rainfall

ENSO signals in East African rainfall seasons

2000 ◽  
Vol 20 (1) ◽  
pp. 19-46 ◽  
Author(s):  
Matayo Indeje ◽  
Fredrick H.M. Semazzi ◽  
Laban J. Ogallo
Keyword(s):  
East African ◽  
African Rainfall
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