Deterministic model of the eddy dynamics for a midlatitude ocean model
Résumé
Mesoscale eddies, although being on the scales of O (20–100km), have a disproportionate role in shaping the mean stratification, which varies on the scale of O (1000km). With the increase in computational power, we are now able to partially resolve the eddies in basin-scale and global ocean simulations, a model resolution often referred to as mesoscale permitting. It is well-known, however, that due to grid-scale numerical viscosity, mesoscale-permitting simulations have less energetic eddies and consequently weaker eddy feedback onto the mean flow. In this study, we run a quasi-geostrophic model at mesoscale-resolving resolution in a double gyre configuration and formulate a deterministic closure for the eddy rectification term of potential vorticity (PV), namely, the eddy PV flux divergence. Our closure successfully reproduces the spatial patterns and magnitude of eddy kinetic and potential energy diagnosed from the mesoscale-resolving model. One novel point about our approach is that we account for non-local eddy feedbacks onto the mean flow by solving the ‘sub-grid’ eddy PV equation prognostically in addition to the mean PV.
Domaines
Océanographie
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[15200485 - Journal of Physical Oceanography] Deterministic model of the eddy dynamics for a midlatitude ocean model-1.pdf (4.29 Mo)
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