The Impact of the El-Niño Southern Oscillation Precipitation and the Surface Temperature over the Upper Blue Nile Region

Abstract

Precipitation is a climatic variable influenced by global weather parameter like, sea surface temperature from Pacific Ocean. Its effect in turn has an impact on crop production and other precipitation related results (add reference).  In this research work, we have studied the impact of the El Niño-Southern Oscillation (ENSO) on surface temperature and precipitation over selected regions of Upper Blue Nile. We applied Pearson correlation analysis on the precipitation and sea surface temperature above the parts of Upper Blue Nile with monthly Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) anomaly and from four ENSO regions over the Equatorial Pacific Ocean. We have found that the Niño 4 region is a better matching region for the selected location of the Upper Blue Nile out of the four ENSO regions in the equatorial Pacific Ocean. Moreover, the Niño 4 region shows a negative correlation with precipitation and a positive correlation with temperature over Upper Blue Nile. Further evaluations of the relationships between precipitation and temperature with Niño 4 including the Atlantic oscillation, were conducted. Precipitation and temperature are partially correlated with Niño 4 and the Atlantic oscillation however, precipitation was limited to a few months. The seasonal dependence of precipitation and temperature on the strength of El Niño and La Niña events in the Niño 4 region were evaluated over the Upper Blue Nile. Results show   the temperature is maximum over the Upper Blue Nile region during the El Niño period and reverses for the La Niña events. Precipitation is reduced during the El Niño period and increases during the La Niña period.