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

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 ENS...

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Bibliographic Details
Main Authors: Zaroug, M. A. H., Giorgi, F., Coppale, E., Abdo, G. M., Eltahir, Elfatih A. B.
Other Authors: Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Format: Article
Published: Copernicus GmbH 2018
Online Access:http://hdl.handle.net/1721.1/117290
https://orcid.org/0000-0002-6148-7997
Description
Summary: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.