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