Toggweiler, J. R., and B. Samuels, 1993: New radiocarbon constraints on the upwelling of abyssal water to the ocean's surface. In The Global Carbon Cycle. Berlin; Heidelberg: Springer-Verlag, 333-366.

Abstract: The output from seven different ocean model simulations is compared on the basis of the delta ¹⁴C difference between North Pacific deep water and Antarctic surface water. This set of models produces a range of North Pacific-Antarctic delta ¹⁴C differences between -173% and -108%, all but the smallest of which are substantially larger than the actual pre-bomb difference, -80 to -110%. Predicted values are highly correlated with the quantity of mid-depth water which flows out of the Pacific to the south. A circulation in which most of the Antarctic bottom water flows back out of the basin at mid-depth produces the smallest North Pacific-Antarctic delta ¹⁴C differences, whereas a circulation in which all the inflow of bottom water upwells through the thermocline produces tha largest and least realistic differences. According to the models, upwelled abyssal water becomes entrained into the wind-driven convergence of thermocline water toward the equator. When it reaches the surface it spreads to the north and south, producing a delta ¹⁴C minimum along the equator. A detailed analysis of both pre-bomb and post-bomb delta ¹⁴C data indicates that the oldest water in the tropical Pacific is actually found south of the equator and is associated with the upwelling off Peru, not the upwelling along the equator. Toggweiler et al. (1991) trace the low-delta ¹⁴C signal in the Peru upwelling to deep water raised to the surface around Antarctica which is pushed northward into the thermocline by circumpolar winds. According to the models, even a small amount of abyssal water upwelling through the thermocline (~3x10⁶ m³ s^-1) leaves a characteristic signal in the surface delta ¹⁴C distribution which is not observed. One is left with the general conclusion that there is very little upwelling associated with a top-to-bottom thermohaline circulation in the world ocean. Virtually all the upwelling of abyssal water to the ocean's surface occurs around Antarctica where it is mainly wind-forced. The implications of this conclusion for the carbon cycle are discussed.