Ocean Energy Pathways: A Multiscale Perspective

Abstract

Ocean circulation is maintained by mechanical and thermodynamical fluxes across its boundaries, primarily imposed by winds and buoyancy forcing at large scales, yet its kinetic energy (KE) is distributed across a vast range of scales and depths. This review synthesizes current understanding of these multiscale pathways from an ocean physics perspective, emphasizing recent progress enabled by scale-aware diagnostics. We summarize global KE spectra, highlighting prominent mesoscale and gyrescale peaks, and a pronounced spectral gap separating them, with implications for parameterizations. Framed using a spatially local, scale-dependent KE budget, we discuss wind work; potential energy (PE) generation and baroclinic release; and KE transfer across gyrescale, mesoscale, and submesoscale ranges. We also examine the unresolved problem of mesoscale KE sinks: A significant upscale mesoscale cascade must ultimately be arrested by processes such as wind damping, bottom drag, loss of balance, and/or submesoscale pathways. Emerging research directions include balanced–unbalanced flow decomposition, conversion and cascade of PE, and coupled ocean–atmosphere feedbacks across scales relevant to climate variability.