Atmosphere Ocean Science Friday Seminar

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Isopycnal tracer mixing via an energy backscatter parameterization

Speaker: Matt Pudig

Location: Warren Weaver Hall 1314

Date: Friday, January 31, 2025, 4 p.m.

Synopsis:

 

Mesoscale eddies are a dominant driver of mixing in the ocean, with a substantial preference to mix properties along rather than across isopycnals. In coarse resolution ocean models these eddies are unresolved; their diffusive mixing effects are parameterized by downgradient diffusion in the along-isopycnal direction, often with a prescribed diffusivity coefficient that is constant in space and time. In eddy-permitting ocean models these eddies become increasingly resolved, but in the absence of any additional parameterization they may have too little energy. A recent parameterization that tracks subgrid kinetic energy and reinjects (or backscatters) energy into the resolved flow has shown great promise at parameterizing both the partially resolved eddy momentum and buoyancy fluxes at these eddy-permitting resolutions. However, it is currently not well understood whether such backscatter schemes effectively parameterize the isopycnal eddy tracer fluxes as well. In this talk I will discuss the beginnings of my current project examining a backscatter scheme in an idealized primitive equation ocean model where passive tracers are included in order to measure isopycnal diffusivities, with a focus on the mathematical machinery used to measure these diffusivities.