South Atlantic’s Surface Circulation: A Note

SSTs of the South Atlantic suggest there is a side by side surface circulation with north-ward cold water to the east and southward warm water to the west. Then logic predicts that both currents should be stronger in the southern hemisphere summer than in winter in order to maintain the heat balance, because the upper 100 m of the water column absorbs more solar energy in summer, especially at lower latitudes. This prediction is confirmed by the seasonal variation of the deflection angle of the sea surface isotherms in the middle of the ocean, measured counterclockwise from the east, which are highest in summer and lowest in winter. It is assumed that the stronger the north/south component of a current is, the greater the deflection is of the isotherm from constant latitude.