Atmosphere–Ocean Coupled Variability in the South Atlantic

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Abstract
The climate variability of the South Atlantic region is determined from 40 yr (1953–92) of Comprehensive Ocean–Atmosphere Data Set monthly sea surface temperature (SST) and sea level pressure (SLP) data using the empirical orthogonal function (EOF) and the singular value decomposition (SVD) analysis methods. The EOF method is applied to each field separately, whereas the SVD method is applied to both fields simultaneously. The significance of the atmosphere–ocean interaction is revealed by a strong resemblance between individual (EOF) and coupled (SVD) modes of SST and SLP. The three leading modes of coupled variability on interannual and interdecadal timescales are discussed in some detail. The first coupled mode, which accounts for 63% of the total square covariance, represents a 14–16-yr period oscillation in the strength of the subtropical anticyclone, accompanied by fluctuations of a north–south dipole structure in the SST. The atmosphere–ocean coupling is strongest during the southern summe... Abstract The climate variability of the South Atlantic region is determined from 40 yr (1953–92) of Comprehensive Ocean–Atmosphere Data Set monthly sea surface temperature (SST) and sea level pressure (SLP) data using the empirical orthogonal function (EOF) and the singular value decomposition (SVD) analysis methods. The EOF method is applied to each field separately, whereas the SVD method is applied to both fields simultaneously. The significance of the atmosphere–ocean interaction is revealed by a strong resemblance between individual (EOF) and coupled (SVD) modes of SST and SLP. The three leading modes of coupled variability on interannual and interdecadal timescales are discussed in some detail. The first coupled mode, which accounts for 63% of the total square covariance, represents a 14–16-yr period oscillation in the strength of the subtropical anticyclone, accompanied by fluctuations of a north–south dipole structure in the SST. The atmosphere–ocean coupling is strongest during the southern summe...