Singular value decomposition, correlation and composite analyses were used to investigate therntropical oceans thermodynamic and atmospheric modulations over the southern Ethiopian climate,rnwater resource and vegetation variability. Significant association is found between them using thern50 years ocean and climate dataset from 1951 to 2000 and vegetation data that range from 1981 torn2000.Both climate and vegetation dataset are obtained from international centers. River dischargernflow and water level dataset are obtained from the Ethiopian Water Resource. The study revealsrnthe strong association between Tropical oceans thermodynamic and atmospheric circulation andrnclimate, hydrology and vegetation over Southern Ethiopia. The tropical oceans sea surfacerntemperature anomalies contribute 50% to the short rain season (SON) of rainfall over Ethiopia butrna very small contribution to the long rain season (MAM) of the rainfall variability over the area.rnThese tropical oceans also have contributions for the vegetation variability to 51.6% during thernSON and 44.8% during the MAM seasons and for the water level variability to a 53% and 58%rnduring the short and long rainfall seasons of the southern Ethiopia, respectively. The Tropicalrnoceans heat content contributions also revealed with its 85.6% during the September throughrnDecember season but with a very small contribution during the March through May season. Thernwet minus dry composite patterns of sea surface temperature and atmospheric analyses explainrnduring the regional and global atmospheric dynamics together with the Tropical oceans modulationrncause the climate, hydrology and vegetation variability. The correlation explains that tropicalrnIndian Ocean is strongly correlated with the short rains of Ethiopia having a 99% confidence levelrnand r=0.640 correlation coefficient. A 90-99% confidence level association except the MAMrnseason is demonstrated by the Atlantic ocean and also the tropical pacific ocean is seen correlatedrnmore strongly than the other tropical oceans, particularly the December through February SSTrnanomaly has a strong association with the short rains over Ethiopia