Tropical Atlantic sea surface temperature variability and its relation to El Nifio-Southern Oscillation
Abstract. Past analyses of tropical Atlantic sea surface temperature variability have suggested a dipole behavior between the northern and southern tropics, across the Intertropical Convergence Zone (ITCZ). By analyzing an improved 43-year (1950-1992) record of SST [Smith et al., 1996] and other dat...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.557.2800 http://www.o3d.org/abracco/Atlantic/atlantic_enso/enfield_mayer_1997.pdf |
| Summary: | Abstract. Past analyses of tropical Atlantic sea surface temperature variability have suggested a dipole behavior between the northern and southern tropics, across the Intertropical Convergence Zone (ITCZ). By analyzing an improved 43-year (1950-1992) record of SST [Smith et al., 1996] and other data derived from the Comprehensive Ocean-Atmosphere Data Set (COADS), it is shown that the regions north and south of the ITCZ are statistically independent of each other at the seasonal to interannual timescales dominating the data, confirming the conclusions of Houghton and Tourre [1992]. Some dipole behavior does develop weakly during the boreal spring season, when there is a tendency for SST anomaly west of Angola to be opposite of that in the tropical North Atlantic. It is further shown that tropical Atlantic SST variability is corre-lated with Pacific E1 Nifio-Southern Oscillation (ENSO) variability in several regions. The ma-jor region affected is the North Atlantic area of NE trades west of 40øW along 10øN- 20øN and extending into the Caribbean. There, about 50-80 % of the anomalous SST variability is associ-ated with the Pacific ENSO, with Atlantic warmings occurring 4-5 months after the mature phases of Pacific warm events. An analysis of local surface flux fields derived from COADS data shows that the ENSO-related Atlantic warmings occur as a result of reductions in the surface NE |
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