Space-time variability of rainfall over Tropical South America

variability.Monthly rainfall data spanned 40 years (1951-90) at around one hundred sites eastern Andes mountain in the contiguous Tropical South America is analysed through PCA and MTM spectral analysis. Of particular interest in this investigation is the identification of regions that appears to have strong and consitent low-frequency variability -time scales beyond the annual cycle. Two major recurrent and persistent precipitation patterns separetly for ENOS events and the Interdecadal variability are found, and it is demostrate the sencitivity of eastern South America precipitation to low-frequency