Tropical Atlantic sea surface temperature variability and its relation to El Niño-Southern Oscillation

摘要: Past analyses of tropical Atlantic sea surface temperature variability have suggested a dipole behavior between the northern and southern tropics, across Intertropical Convergence Zone (ITCZ). By analyzing an improved 43-year (1950-1992) record SST (Smith et al., 1996) other data derived from Comprehensive Ocean-Atmosphere Data Set (COADS), it is shown that regions north south ITCZ are statistically independent each at seasonal to interannual timescales dominating data, confirming conclusions Houghton Tourre (1992). Some does develop weakly during boreal spring season, when there tendency for anomaly west Angola be opposite in North Atlantic. It further corre- lated with Pacific E1 Nifio-Southern Oscillation (ENSO) several regions. The ma- jor region affected area NE trades 40oW along 10oN - 20oN extending into Caribbean. There, about 50-80% anomalous associ- ated ENSO, warmings occurring 4-5 months after mature phases warm events. An analysis local flux fields COADS shows ENSO-related occur as result reductions trade wind speeds, which turn reduce latent sensible heat losses over ques- tion, well cooling due entrainment. This ENSO connection best developed following most frequent season maximum anomalies Pacific. A secondary covariability occurs edge mean position appears associated northward migrations At- lantic occur. Although easterly winds intensified western equatorial response events, they do not produce strong changes SST. Contrary expectations studies based on dynamics, these teleconnected give rise significant correlations Gulf Guinea ENSO. As teleconnection sequence matures, SE low latitudes follow de- velopment precede by appearance weak negative off stronger positive eastward Brazil 15o-30oS.