The spatio-temporal variability of such heat and CO 2 uptake and storage is dependent on various physical mechanisms from both ocean surface and subsurface perspectives. Intuitively, air-sea heat and momentum fluxes generate and modulate sea surface temperature (SST) anomalies, which in turn, provide feedback to these fluxes (Park et al., 2005). In addition, studies have also observed and examined a reemergence mechanism of SST anomalies from one winter to another, without maintaining through the summer in between (Alexander & Deser, 1995;Deser et al., 2003;Hanawa & Sugimoto, 2004). Such reemergence has been linked to the presence of mode waters capped underneath the seasonal thermocline and characterized by a substantial volume of thermostad or pycnostad (a layer with low temperature or density gradients) distributed broadly in the ocean interior (Hanawa & Talley, 2001;Speer & Forget, 2013). The dynamical nature of mode waters is thus often