Fig. 1

Stages in the oceanic general circulation from planetary scale forcing to microscale dissipation and mixing: climate forcing by wind stress and air-sea buoyancy flux; balanced flow dynamics (e.g., mostly geostrophic and hydrostatic); submesoscale transitional dynamics; and microscale flows with only a weak influence from Earth’s rotation, a mostly unbalanced momentum dynamics with large accelerations, and an approximate equivalence of vertical and horizontal lengths scales, \(h \sim \ell\). The Rossby and Froude numbers, Ro and Fr, start from very low values at the planetary scale, pass through \(\mathcal {O}(1)\) values within the submesoscale regime, and end up with large values at the microscale