Two ENSO episodes with reversed impacts on the regional precipitation of the northeastern South America

diagnostic analyses of two enso episodes observed during 1954-55 (la ni？a) and 1972-73 (el ni？o) over tropical pacific ocean are reported. these years were marked by reversed impact on the regional precipitation observed over the northeastern south america. the observational results showed that, in the pacific ocean, the la ni？a stayed well configured during both summer and autumn of 1954-55, however the el ni？o presented its mature phase during summer of 1972-73 and an abrupt decline during autumn of 1973. on the other hand, the large-scale oceanic and atmospheric patterns related to the intertropical atlantic sst gradient, created dynamic conditions that modulated the positioning of itcz in the equatorial atlantic and regulated significantly the rainfall anomalies observed in the northeastern south america, overcoming the effect of the enso mode observed in the tropical pacific.