Mechanisms of East African rainfall variability

Empirical Orthogonal Function (EOF) analysis is used to identify meteorological modes which contribute to East African rainfall variability and to delineate East Africa into rainfall homogeneous regions. The meteorological mode operating during the October-December season accounted for most of the variance (;Temporal and spatial variability of sea-surface temperatures (SSTs) are investigated using EOF analysis for the domain 40;In the Atlantic, an eastward propagation of SST anomalies was evident while within the Indian Ocean SST anomalies appeared to propagate westward. However, the Indian Ocean lags the Atlantic Ocean. There was a significant correlation (;The regional SSTs series showed fluctuations being in-phase throughout the tropical and southeastern Atlantic Ocean and the west-central Indian Ocean. The SST fluctuations within these areas were almost in-phase and were also in-phase with East African rainfall. Their association is attributed to fluctuations of time scales of 2-2.5, 3-3.5 and 5-6 years.;The above normal rainfall in East Africa is associated with below normal southwest monsoon flow which is associated with less upwelling leading to above normal (warming) SSTs over North Indian Ocean and the Arabian Sea. Also, the tropical region east of 50...