Eddies in the ocean
Mesoscale eddies in the ocean, sometimes referred to as the oceanic equivalent of atmospheric storms, derive their energy from the large-scale flow mainly through baroclinic instability processes. These processes are parameterized in climate models with down-gradient parameterizations using eddy diffusivities. In geostrophic turbulence, eddies then tend to transfer their energy upscale in an inverse cascade. But ultimately, this energy has to be dissipated and it is largely unknown how and where.
Our scientists specifically assess one important pathway to dissipation, the spontaneous emission of gravity waves by the quasi-balanced flows, and analyze drifter and float data to estimate eddy production and Lagrangian mixing from observations, models and theory.
Specific research questions in Area L are:
- How is the balanced flow dissipated in the ocean, and how important is the route to dissipation via spontaneous wave generation?
- What are the limits and validities of the eddy diffusion model and how can we quantify and parameterize the effects of mesoscale eddies in an energy-consistent way?
Blender, R., & Badin, G. (2017).Construction of Hamiltonian and Nambu Forms for the Shallow Water Equations. Fluids 2017, 2 (2), doi:10.3390/fluids2020024.
Blender, R., & Badin, G. (2017). Viscous dissipation in 2D fluid dynamics as a symplectic process and its metriplectic representation. The European Physical Journal Plus, 132(3), 137.
Li, Q., Lee, S., & Griesel, A. (2016). Eddy Fluxes and Jet-Scale Overturning Circulations in the Indo–Western Pacific Southern Ocean. Journal of Physical Oceanography, 46(10), 2943-2959.