On the role of mesoscale eddies in ventilation of the Southern Ocean

This study examines the role of mesoscale eddies in the along-isopycnal ventilation of the Southern Ocean below the mixed layer, using idealized and comprehensive eddy-permitting numerical simulations. The comprehensive simulations of idealized age and "Boundary Impulse Response" tracers are carried out using a new Southern Ocean Offline Tracer Model (SOOTM). The importance of eddies in this setting is quantified by contrasting sensitivity runs with and without mesoscale eddies. These simulations are further interpreted using Lagrangian particle trajectories in an idealized model of the Southern Ocean, which allows examination of the pathways, time- and length scales that govern the ventilation. In particular, the results outline the importance of the western Atlantic sector for the eddy-driven subduction.