Deep‐Ocean Circulation in the Southwest Pacific Ocean Interior: Estimates of the Mean Flow and Variability Using Deep Argo Data

Abstract The spatial structure and time variability of the global deep‐ocean circulation are poorly understood due to limited sampling below 2,000‐m depth. A Deep Argo array deployed in 2016 has significantly increased oceanic measurements from the ocean surface to near the sea floor in the Southwest Pacific Basin interior. Deep Argo profiles collected between 2016 and 2019 show that 4.3–4.7 Sv between 1,500 and 4,800 m, relative to 4,800 m, of the Deep Western Boundary Current flowing along the Tonga Kermadec Ridge is redirected southward over the abyssal plain between the Tonga Kermadec Ridge and the East Pacific Rise. The southward recirculation of the Deep Western Boundary Current exhibits seasonality that may be influenced by Ekman pumping.