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Correlations between the tropical atlantic trade winds and precipitation in northeastern Brazil

1982; Wiley; Volume: 2; Issue: 1 Linguagem: Inglês

10.1002/joc.3370020104

2374-7412

James C. Chung,

Marine and coastal ecosystems

Abstract Surface wind and sea surface temperature data for the tropical Atlantic Ocean for the period 1911‐1972 are analysed in relation to the precipitation at Quixeramobim, Ceará in northeastern (NE) Brazil. Stratified correlations between the March‐April‐May Quixeramobim rainfall and the December, January, February, and March values of SST, and u ‐ and v ‐components of surface wind are presented for the tropical Atlantic. The implications of the correlations are that the months preceding an abnormally dry rainy season in NE Brazil are characterized by a strengthened South Atlantic trade flow and a North Atlantic circulation slightly weaker than normal. Cold SST anomalies are found in the South Atlantic and warm anomalies in the North Atlantic, suggesting a wind‐induced change in surface mixing or in evaporation from the surface. The divergence over the South Atlantic is seen to be stronger and more extensive preceding a dry season, and the equatorial convergence appears to be compressed northward and also strengthened. This northward compression is concluded to be responsible for the lack of rainfall in Ceará.