Aditya Narayanan: East Australian Current modulates gating between the Tasman Front and the Poleward Extension via heat transport
The East Australian Current System (EAC) is a western boundary current in the South Pacific that is responsible for driving rapid ocean warming in the Tasman Sea. We use a global eddy permitting ocean model across the period 1970–2018 to reveal long term variability in transport of volume and heat. We reveal the regional controls on the gating of volume and heat across the poleward extension and the eastward flow associated with the Tasman Front. The upstream jet has grown more stable, allowing for greater poleward penetration, driving long term warming in the Southwestern Tasman Sea and the raising of steric height that is associated with an erosion of the Tasman Front. This further reinforces the gating of the flow of heat poleward at the expense of the eastward flow. In contrast, the Southeastern Tasman Sea shows no overall trend in heat content. Regional changes to wind stress curl ultimately drive the long-term variability in the Tasman Sea, with poleward heat transport playing an additional role as a control of regional circulation and the gating of flow.