How ubiquitous is the dipole relationship in tropical Atlantic sea surfacetemperatures?

Several kinds of analysis are applied to sea surface temperature anomalies (SSTA) (1856-1991) to determine the degree to which SSTA of opposite sign i n the tropical North and South Atlantic occur. Antisymmetric ("dipole") con figurations of SSTA on basin scales are not ubiquitous in the tropical Atla ntic. Unless the data are stratified by both season and frequency, inherent dipole behavior cannot be demonstrated. Upon removing the global El Nino-S outhern Oscillation signal in SSTA (which is symmetric between the North an d South Atlantic) from the data, the regions north or south of the Intertro pical Convergence Zone have qualitatively different temporal variabilities and are poorly correlated. Dipole configurations do occur infrequently (12- 15% of the time), but no more so than expected by chance for stochastically independent variables. Nondipole configurations that imply significant mer idional SSTA gradients occur much more frequently, nearly half of the time. Cross-spectral analysis of seasonally averaged SSTA indices for the North and South Atlantic show marginally significant coherence with antisymmetric phase in two period bands: 8-12 years for the boreal winter-spring and 2.3 years for the boreal summer-fall. Antisymmetric coherence is optimal for a small subregion west of Angola in the South Atlantic, with respect to SSTA of basin scale in the tropical North Atlantic. Dipole variability, even wh ere optimal, explains only a small fraction of the total variance in tropic al Atlantic SSTA (< 7%).