Abstract
A reduced-order semi-analytic model of multiple zonal jets in the Southern Ocean is proposed based on the statistical approach and scale decomposition. By introducing two dominant scales in the vorticity equation, the model describes the large-scale and mesoscale dynamics using the explicit momentum dissipation in the horizontal and vertical directions. For validation and physical insights, the results of the reduced-order model are compared with solutions of two eddy-resolving ocean models: (i) a realistic primitive-equation HYCOM (HYbrid Coordinate Ocean Model) simulation of the Southern Ocean and (ii) an idealized quasi-geostrophic model of a shear-driven channel flow.
•There is a scale separation in vorticity spectrum of the Southern Ocean.•The large- and small-scale components are described by a semi-analytical model.•The large-scale flow is derived by wind and dissipated via bottom friction.•Zonal jets result from balance of beta term, vertical stretching and dissipation.•Zonal jets are coupled to the background flow through eddy viscosity.
