Abstract
Ethiopian decadal climate variability is characterized by application of singular value decomposition to gridded rainfall data over the period 1901–2007. Two distinct modes are revealed with different annual cycles and opposing responses to regional and global forcing. The northern zone that impacts the Nile River and underlies the tropical easterly jet has a unimodal rainy season that is enhanced by Atlantic Multidecadal Oscillation warm phase. This rainfall mode is linked with the Atlantic zonal overturning circulation and exhibits 10–12-year cycles through much of the twentieth century. The southern zone has a bimodal rainy season that is enhanced by Pacific Decadal Oscillation cool phase and the southern meridional overturning circulation. Multiyear wet and dry spells are characterized by sympathetic responses in the near-equatorial trough extending from Central America across the African Sahel to Southeast Asia. The interaction of Walker and Hadley cells over Africa appears to be a key feature that modulates Ethiopian climate at decadal frequency through anomalous north–south displacement of the near-equatorial trough.
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The author thanks Arba Minch University, Ethiopia for stimulating this research.
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Jury, M.R. Ethiopian decadal climate variability. Theor Appl Climatol 101, 29–40 (2010). https://doi.org/10.1007/s00704-009-0200-3
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DOI: https://doi.org/10.1007/s00704-009-0200-3