Tropical Oceans Thermodynamic and Atmospheric Modulations over Southern Ethiopian Climate, Water Resource and Vegetation Variability

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Addis Ababa University


Singular value decomposition, correlation and composite analyses were used to investigate the tropical oceans thermodynamic and atmospheric modulations over the southern Ethiopian climate, water resource and vegetation variability. Significant association is found between them using the 50 years ocean and climate dataset from 1951 to 2000 and vegetation data that range from 1981 to 2000.Both climate and vegetation dataset are obtained from international centers. River discharge flow and water level dataset are obtained from the Ethiopian Water Resource. The study reveals the strong association between Tropical oceans thermodynamic and atmospheric circulation and climate, hydrology and vegetation over Southern Ethiopia. The tropical oceans sea surface temperature anomalies contribute 50% to the short rain season (SON) of rainfall over Ethiopia but a very small contribution to the long rain season (MAM) of the rainfall variability over the area. These tropical oceans also have contributions for the vegetation variability to 51.6% during the SON and 44.8% during the MAM seasons and for the water level variability to a 53% and 58% during the short and long rainfall seasons of the southern Ethiopia, respectively. The Tropical oceans heat content contributions also revealed with its 85.6% during the September through December season but with a very small contribution during the March through May season. The wet minus dry composite patterns of sea surface temperature and atmospheric analyses explain during the regional and global atmospheric dynamics together with the Tropical oceans modulation cause the climate, hydrology and vegetation variability. The correlation explains that tropical Indian Ocean is strongly correlated with the short rains of Ethiopia having a 99% confidence level and r=0.640 correlation coefficient. A 90-99% confidence level association except the MAM season is demonstrated by the Atlantic ocean and also the tropical pacific ocean is seen correlated more strongly than the other tropical oceans, particularly the December through February SST anomaly has a strong association with the short rains over Ethiopia



Southern Ethiopian Climate