A global diagnostic of interior ocean ventilation

Ventilation is the process by which water is transferred from the surface mixed layer to the interior ocean. Ventilation anomalies as the result of climate variability may impact the atmosphere in remote regions where the flow returns to the mixed layer. From the Lagrangian analysis of monthly-mean ocean fields of a numerical model constrained by observed climatologies, we show that 324 Sv of mixed layer water travel throughout the interior ocean for periods longer than 12 months, leading to an average volume replacement time of roughly 125 yr. We evaluate the connections established on a global scale, with an appropriate mapping of the ventilation and corresponding obduction regions, and highlight the role of the Antarctic Circumpolar Current as a main receptacle of the water masses formed throughout the world ocean.