Summary
Tropical North African climate variability is investigated using a Sahel rainfall index and streamflow of the Nile River in the 20th century. The mechanisms that govern tropical North Africa climate are diagnosed from NCEP reanalysis data in the period 1958–1998: spatially – using composite and correlation analysis, and temporally – using wavelet co-spectral analysis. The Sahelian climate is characterised by a decadal rhythm, whilst the mountainous eastern and equatorial regions exhibit interannual cycles. ENSO-modulated zonal circulations over the Atlantic/Pacific sector are important for decadal variations, and create a climatic polarity between South America and tropical North Africa as revealed through upper-level velocity potential and convection patterns. A more localised N–S shift in convection between the Sahel and Guinea coast is associated with the African Easterly Jet.
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Yeshanew, A., Jury, M. North African climate variability. Part 2: Tropical circulation systems. Theor. Appl. Climatol. 89, 37–49 (2007). https://doi.org/10.1007/s00704-006-0243-7
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DOI: https://doi.org/10.1007/s00704-006-0243-7