Simulating the connections of ENSO and the rainfall regime of East Africa and the upper Blue Nile region using a climate model of the Tropics

• Main Authors: Zaroug, M. A. H. (Author), Giorgi, F. (Author), Coppale, E. (Author), Abdo, G. M. (Author), Eltahir, Elfatih A. B. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Civil and Environmental Engineering (Contributor), Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences (Contributor)
• Format: Article
• Language: English
• Published: Copernicus GmbH, 2018-08-07T12:12:21Z.
• Subjects: Article
• Online Access: Get fulltext

 We simulate the observed statistical relationship between ENSO and the rainfall regime of the upper Blue Nile using the tropical-band version of the regional climate model RegCM4 (or Reg-TB). An ensemble of nine simulations for the 28-year period 1982-2009 is completed to investigate the role of ENSO in modulating rainfall over the upper Blue Nile catchment. Reg-TB shows a good skill in simulating the cli- matology of temperature, outgoing long-wave radiation pat- terns as well as related atmospheric circulation features dur- ing the summer season (i.e. the rainy season over the Blue Nile catchment). The model also succeeds in reproducing the observed negative correlation between Pacific SST and rain- fall anomalies over the Blue Nile catchment, and in particular the association of droughts over the Blue Nile with El Niño events that start in April-June. We thus propose that observa- tions and model forecasts of Pacific SST during this season could be used in seasonal forecasting of summer rainfall over the upper Blue Nile region.