Sarmiento, J. L., 1986: On the north and tropical Atlantic heat balance. Journal of Geophysical Research, 91 (C10), 11,677-11,689.

Abstract: The heat balance deduced from a three-dimensional, seasonally driven primitive equation model of the North Atlantic is described and compared with observations. The greatest response to the seasonal forcing occurs in the region between ~5 degrees N and 10 degrees N, where the northward heat transport goes from a minimum of <0 in summer, when the North Equatorial Countercurrent dominates the surface flow and the Brazil Current is at a minimum, to a maximum of >1.4 x 10¹⁵ W in the winter, when the Brazil Current and northward Ekman transport are at a maximum. Elsewhere in the tropics and subtropics the range in transport is smaller. In the northern hemisphere (~12 degrees to 32 degrees N), there is a signficant semiannual component due to Ekman transport. The large seasonal changes in heat storage in the tropics are caused primarily by transport divergence rather than surface heat flux. In the annual mean, the equatorial region has a large surface heat flux gain associated primarily with the conversion of ~6 x 10⁶ m³ s^-1 of northward geostrophic flow with theta < 20 degrees C in the southern hemisphere, to a surface Ekman flow with theta ~ 27 degrees C in the northern hemisphere. The seasonal variation in heat storage within the subtropical and subpolar gyres is due almost entirely to the surface heat flux. However, seasonal variations in Ekman transport do lead to a relatively large annual cycle in northward heat transport (e.g., 0.5 x 10¹⁵ W to 0.9 x 10¹⁵ W at ~35 degrees N), with maximum transport occuring during the summer when the southward Ekman transport is at a minimum. A comparison of the model results with heat storage estimates shows that the model and data agree very well in the tropics but that at higher latitudes the model underestimates the seasonal variations because of inadequate vertical penetration of heating during periods of warming.