A global internal tide modeling framework for improving satellite observations of fine-scale ocean circulation

Small-scale oceanic eddies and filaments mediate the vertical exchange of heat and carbon within the global ocean. The Surface Water and Ocean Topography (SWOT) mission resolves these features through wide-swath interferometry, but internal tides often mask these observations. Non-phase-locked internal tides present special difficulty because they vary with the evolving ocean background. We show that this chaotic variability can be predicted. We use a data-assimilative ocean forecast model to resolve the mesoscale environment and separate tidal signals from the broader circulation. The model captures the organized structure of these incoherent waves in the independent SWOT measurements. Correcting for the total (phase-locked plus non-phase-locked) internal tide signal reduces the error by 59% relative to current empirical methods. These findings show that non-phase-locked internal tides become predictable when the evolving ocean state is explicitly modeled. Our framework allows wide-swath altimetry to more accurately map climatically important fine-scale dynamics in the ocean.