Zonal Jets in Wide Baroclinically Unstable Regions: Persistence and Scale Selection

摘要: Abstract Extremely persistent, equivalent barotropic zonal jets are observed in statistically steady quasigeostrophic two-layer beta-plane turbulence. Flows forced by an imposed unstable vertical shear, horizontally uniform over domains several tens of Rossby radii wide. Damping is surface drag, small-scale mixing, and for some runs, radiative relaxation. When dissipation weak, emerge with a meridional scale related to beta the equilibrated eddy energy level as suggested Rhines. Spinup behavior suggests priori prediction this will be difficult. The conversion also cannot determined priori, while upscale transfer important, (reverse) cascading ranges any significant extent do not occur. Time scales considerably longer than those simply model parameters prominent. choices doubly periodic boundary conditions spatially homogeneous forcing emphasize that low-frequency du...