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Breaking Internal Waves and Ocean Diapycnal Diffusivity

Recent analyses of downscaled Internal Wave (IW) fields from an internal-wave-admitting global simulation into higher-resolution regional configurations have shown a significantly improved fit of the simulated IW spectra to the empirical Garrett-Munk spectrum. The global simulation, known as LLC4320, is based on the Massachusetts Institute of Technology general circulation model (MITgcm), forced by both astronomical tidal potential and surface atmospheric processes.

We utilize this dynamically downscaled ocean simulation to scrutinize the dynamics of IW-breaking and wave-turbulence cascade. Our exploration reveals that the wavefield in the high-resolution regional domain is dominated by a well-resolved spectrum of low-mode IWs, predictable through employing a Galerkin method to solve the associated Sturm-Liouville problem

Given that LLC4320 employed a variant of the KPP parameterization in which the normal background component had been essentially eliminated, we have investigated whether the remaining components, particularly those associated with internal wave shear, can account for the physical origins of the background depth dependence of diapycnal diffusivity. Finally, we propose a novel tentative approach to enhance the KPP parameterization. This approach shows promise in refining our understanding of diapycnal diffusivity and offers valuable insights for improving ocean circulation models.

Host: Aleksandra Elias Chereque
Event series  Brewer-Wilson Seminar Series