Local and non-local energy transfers in eddy-mean flow interactions along the Indonesian throughflow.

How local energy conversion and non-local redistribution jointly shape eddy activity along the Indonesian Throughflow (ITF) remains unclear. Using long-term, eddy-resolving ocean model output, we diagnose exchanges among mean and eddy kinetic and available potential energy along the ITF and its adjacent basins. The results reveal a marked change in the dominant energy pathway. At the Pacific entrance and along the western ITF, eddies gain energy primarily through barotropic conversion associated with the sheared mean current. Farther downstream, baroclinic conversion becomes more prominent near the Indian Ocean exit, where horizontal density contrasts favor the transfer of mean available potential energy into eddy energy. Local conversion alone does not explain these regional patterns. Non-local kinetic energy transfer diverges in the Pacific source region and converges along the western pathway, consistent with energy redistribution toward the Sulawesi Sea. Near the Indian Ocean exit, non-local potential energy transfer accompanies enhanced baroclinic conversion. Together, these findings show how local eddy generation and non-local energy redistribution vary along the ITF, from a predominantly shear-associated kinetic energy pathway upstream to a more prominent potential energy pathway downstream. This study provides the quantification of inhomogeneous local versus non-local eddy-mean flow interactions along the entire ITF pathway, providing a fundamental insight for understanding mixing in this climatically and biologically critical oceanic region.