Reassessing the Role of the Indo‐Pacific in the Ocean's Global Overturning Circulation

Abstract

Surface buoyancy fluxes in the Southern and North Atlantic Oceans are presumed to disproportionately influence the ocean's residual global overturning circulation (GOC) with respect to those in the Indo‐Pacific. Here, this assumption is challenged through an assessment of global buoyancy transport in the Community Earth System Model 1.0, which reveals that the steady state GOC is equally constrained by surface buoyancy flux everywhere. Further, an unacknowledged aspect of the GOC is demonstrated: it transports buoyancy from where it is gained at the surface, predominately in the Indo‐Pacific, to where it is lost, predominately in the Atlantic and Southern Oceans. This global buoyancy transport requires zonal structure in the GOC, linking the Atlantic and Indo‐Pacific within the Southern Ocean, asymmetry and interbasin coupling absent from many conceptual descriptions of overturning dynamics. These results compel a more nuanced appreciation for an Indo‐Pacific influence in GOC evolution.

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