Surface heating steers planetary-scale ocean circulation

Gyres are central features of large-scale ocean circulation and involved in transporting tracers such as heat, nutrients, carbon-dioxide within across basins. Traditionally, the gyre is thought to be driven by surface winds quantified via Sverdrup balance, but it has been proposed that buoyancy fluxes may also contribute forcing. Through a series eddy-permitting global model simulations with perturbed forcing, relative contribution wind stress heat flux forcing investigated, focusing on subtropical gyres. In addition strength being linearly proportional stress, shown strongly impacted variations (specifically, its meridional gradient) through rearrangement ocean's structure. On shorter timescales ($\sim$ decade), anomalies magnitude gradient perturbation, up $\sim 0.15\,\mathrm{Sv}$ anomaly induced per $\mathrm{W}\,\mathrm{m}^{-2}$ change flux. longer than decade, response perturbations becomes non-linear feed back onto structure fluxes. These interactions complicate development buoyancy-driven theory for gyres complement relation. The flux-forced underscore importance steering circulation.