Rapid changes in ocean circulation and atmospheric radiocarbon ...

• Main Authors: Stocker, Thomas F., Wright, Daniel
• Format: Text
• Language: unknown
• Published: American Geophysical Union 1996
• Subjects: 530 Physics; North Atlantic; Southern Ocean
• Online Access: https://dx.doi.org/10.48350/158216; https://boris.unibe.ch/158216/

A latitude-depth, coupled global ocean-ice-atmosphere model is extended to include a simple biosphere component. A physically reasonable adjustment of runoff into the North Atlantic is invoked to achieve a transient response to glacial meltwater perturbations, which closely resembles the Younger Dryas climate event. We then investigate the evolution of the isotopic ratio of atmospheric radiocarbon, Δ14C, due to the rapid changes of deep ocean circulation. When the North Atlantic branch of the conveyor belt circulation is interrupted, the oceanic uptake of radiocarbon is reduced, resulting in an increase of atmospheric Δ14C by about 35 ‰. The reduction of ventilation in the North Atlantic is partly compensated by an increase of the 14C ratios of the biosphere, the Southern Ocean, and the upper ocean above 1000 m depth. A plateau of the 14C year/calendar year relation can be generated at the time of the rapid reinitiation of deep ocean ventilation which begins coincident with the major temperature increase and ...