Regional Studies of Internal Tides from Altimetry

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OCE-0623540Intellectual MeritInternal waves generated by the surface tide are a potential source of energy for vertically mixing the deep ocean. To date, analysis of altimetry data has provided gross global scale maps of energy lost from the surface tide, as well as a qualitative picture of low-mode internal tides propagating in the open ocean. However, many important questions remain, especially with regard to the processes, rate and spatial distribution of energy loses from the internal tide. An analysis of the internal tide at a suite of regions in the world ocean will be conducted using the generalized inversion of a primitive-equation model to assimilate satellite altimetry data. The main goal is to study the generation, propagation, and dissipation of the internal tide at sites which differ in topography (island arcs, mid-ocean ridges, and abyssal plains), position relative to the critical latitude, and proximity to the continental shelf, and assess the impact of mesoscale and seasonal variability on harmonic constants inferred from altimetry. Intercomparison of a range of different sites, including mapping of low-mode internal tide energy fluxes, and analysis of residuals in the data assimilation solutions, will permit the generalization of inferences based on relatively sparse in situ measurements of the tides and mixing, and help to elucidate mechanisms for the dissipation of the internal tides.Broader ImpactsTidally driven mixing is poorly if at all represented in the current generation of ocean climate models, and this study will be directly relevant to researchers who are developing energetically consistent parameterizations for ocean mixing. The detailed maps of the internal tide will also provide a second-order tidal correction for altimetry obtained by the multiple missions now in orbit which are currently used to study mesoscale and longer-term processes. In addition, the computational tools refined and developed in this study will be useful in the creation of regional ocean prediction systems that utilize data-assimilative methodologies.