Jun 15, 2004

East African Rainfall Anomaly Patterns in Association with El Niño/Southern Oscillation

Henry K. Ntale and Thian Yew Gan
Journal of Hydrologic Engineering
  • Applies harmonic analysis to El Niño Southern Oscillation (ENSO) composites of the 6-month Standardized Precipitation Index (SPI) and rainfall anomalies for the 1900–1996 period, using 90% confidence limits established from bootstrap resampling
  • Finds that ENSO responses in East African rainfall are region and season dependent, and the influence of El Niño is stronger and opposite that of La Niña
  • Results show that, among five regions of unique ENSO responses identified, northeastern (R4) and southern Tanzania (R5) seem to have the most consistent ENSO responses
  • Finds that R5 experiences positive (negative) response under La Niña (El Niño) influence during January and June of the post-ENSO year
  • Results show that Southern Uganda and much of the Lake Victoria basin show some significant positive ENSO response for November, December, and January