How subsurface and double-core anticyclones intensify the winter mixed-layer deepening in the Mediterranean Sea

Abstract. The mixed layer is the uppermost of ocean, connecting atmosphere to subsurface ocean through atmospheric fluxes. It subject pronounced seasonal variations: it deepens in winter due buoyancy loss and shallows spring while heat flux increases restratifies water column. A mixed-layer depth (MLD) modulation over this cycle has been observed within mesoscale eddies. Taking advantage numerous Argo floats deployed trapped large Mediterranean anticyclones last decades, we reveal for first time at a 10 d temporal scale, free smoothing effect composite approaches. analysis 16 continuous MLD series inside 13 long-lived fine scale brings light importance eddy pre-existing vertical structure setting by Extreme anomalies up 330 m are when connects with anticyclonic core, greatly accelerating deepening. sometimes does not achieve such connection but homogenizes another layer, then forming multi-core anticyclone restratification. An restratification delay always observed, reaching more than 2 months 3 out series. column starts restratify outside anticyclones, keeps deepening cooling core longer time. These new elements provide keys understanding vertical-structure formation evolution.