Two idealized, three-dimensional, analytical models of middepth meridional overturning in a basin with a Southern Hemisphere circumpolar connection are described. In the first, the overturning circulation can be understood as a “pump and valve” system, in which the wind forcing at the latitudes of the circumpolar connection is the pump...
A simple theory is presented for steady geostrophic circulation of a stratified fluid in a rectangular basin with a circumpolar connection. The interior flow obeys the β-plane Sverdrup vorticity balance, and the circulation is closed by geostrophic boundary currents. The circulation is forced by surface thermal gradients and wind-driven Ekman...
A reduced-gravity model is presented of the warm-water branch of the middepth meridional overturning circulation in a rectangular basin with a circumpolar connection. The model describes the balance between production of warm water by Ekman advection across the circumpolar current, dissipation of warm water by eddy fluxes southward across the...
The vertical structure of coastal-trapped disturbances in several idealized models of a stably stratified lower atmosphere is examined. The vertical structure and phase speeds of the trapped modes depend on the resting stratification and the height of the orographic step. The presence of a stable layer above the boundary layer...
The influence of localized regions of intensified vertical mixing on the stratification and circulation in a large-scale ocean model is investigated with idealized numerical experiments. Numerical solutions are obtained of a closed-basin, single-hemisphere ocean model based on the planetary geostrophic equations. Mesoscale eddy effects are minimized, and vertical mixing at...
The diffusivity dependence of internal boundary layers in solutions of the continuously stratified, diffusive
thermocline equations is revisited. If a solution exists that approaches a two-layer solution of the ideal thermocline
equations in the limit of small vertical diffusivity kᵥ, it must contain an internal boundary layer that collapses
to...
A recently proposed reduced-gravity model of the warm-water branch of the middepth meridional overturning circulation in a rectangular basin with a circumpolar connection is extended to include time dependence. The model describes the balance between gain of warm water through northward Ekman advection across the circumpolar current, loss of warm...
The growth of linear disturbances to stable and unstable time-periodic basic states is analyzed in an asymptotic
model of weakly nonlinear, baroclinic wave–mean interaction. In this model, an ordinary differential equation
for the wave amplitude is coupled to a partial differential equation for the zonal-flow correction. Floquet vectors,
the eigenmodes...