Demons in the North Atlantic: Variability of Deep Ocean Ventilation

Translation of atmospheric forcing variability into the ocean interior via ventilation is an important aspect transient climate change. On a seasonal timescale in subtropics, this translation mediated by so-called “Demon” that prevents access to all except late-winter mixed-layer water. Here, we use eddy-permitting numerical circulation model investigate similar process operating on longer (interannual) timescales subpolar North Atlantic. We find variations are their interior, with year-to-year changes mixed layer depth being critical factor. The signature persistent strong driving deep layers preferentially ventilated when ceased. Susceptibility effect depends location and density subduction—with rate at which newly water escapes its region subduction crucial