Variabilidade da temperatura da superfície do oceano Pacífico equatorial e sua correlação com a chuva do Nordeste do Brasil

Abstract

The impact of variability in Sea Surface Temperature (SST) in the equatorial Pacific Ocean on the spatial distribution of rainfall over the Northeast has been the subject of study for many years. Historically, research results have shown that in El Niño (La Niña) years, a pattern prevails that hinders (facilitates) the formation of rain over the Northeast region of Brazil (NEB). This work aimed to investigate the existence of a warming trend in the surface of the Equatorial Pacific Ocean (Niño 3.4) and whether there is a difference in the SST anomaly pattern over the Niño 3.4 region calculated through a fixed (recent) climatology compared to the Oceanic Niño Index (ONI), which uses a moving climatology. Furthermore, it was investigated whether the correlation of precipitation over northeastern Brazil with SST anomaly series calculated using the two methods would produce a different signal and consequently distinct impacts. Monthly global SST field data and precipitation data at grid points in the NEB region were used to perform the analysis. The results revealed a positive trend in the series with fixed climatology and a slightly negative trend in the series with moving climatology. An increase in the intensity of El Niño and a temporal extension of La Niña were noted, impacting the sea surface temperature in the Niño 3.4 region. With these results, it is hoped to provide support for climate monitoring activities and climate modeling and forecasting studies. The findings can help to better understand climate variability in the NEB region.