El Niño years are associated with above-normal rains in East Africa and subnormal in southern Africa (Fig 1)(1). During the 1997-98 El Niño eastern Africa (mainly Kenya, Somalia and Ethiopia) was particularly wet. Also the African Easterly Jet (AEJ) at 2-3 km altitude and ~15° N is enhanced, whilst the upper-level Tropical Easterly Jet (TEJ) at about 10° N is lessened.
Fig 1. Rainfall anomalies during October-December during the first year of an El Niño event (composite based on data between 1857-1994). Source: Climate Diagnostics Center.
(1) Thiaw, W.M. and V. Kumar, 1999. Atmospheric response to ENSO in he continental tropics and the 1997-8 El Nino. Preprints to the 11th Conf. on Appl. Climatol., Dallas, Texas (Amer. Meteor. Soc.), 327-330.