Relação entre duração dos eventos de El Niño com as condições do Atlântico Tropical e a precipitação no Ceará

Abstract

This paper investigates how El Niño events of different durations affect the atmospheric circulation over the Tropical North Atlantic (TNA) region, what are the consequences of these alterations in the sea surface temperature (SST) interannual variability and what are the responses, in terms of precipitation anomalies, over Ceará. Composite analyses of oceanographic and atmospheric variables were made for 18 El Niño years, divided between events of short and long duration. Events that lasted longer resulted in positive SST anomalies in the TNA region, leading to an interhemispheric gradient of SST anomalies in the Tropical Atlantic and below normal precipitation anomalies over Ceará. On the other hand, the alterations in the atmospheric circulation on TNA, during years of short duration El Niño, have not shown to be as intense as those in years of long duration El Niño. This resulted in SST anomalies on TNA close to zero and consequently, the interhemispheric gradient of SST anomalies was not observed. The near normal precipitation anomalies composites are consistent with the no formation of a SST anomalies gradient.