Movies using the MIT General Circulation Model

A hundred days of 2km resolution of an idealized ocean surface boundary layer (with submesoscale fronts and eddies) mesoscale eddy interaction problem. This problem is forced with cooling and heating at the surface to generate the surface boundary layer, and temperature restoring at the sides to generate an eddy field. Note the smaller scale instabilities within the surface boundary layer. A movie zooming in on one such instability is here.

This movie shows how the mixed-layer instabilities are involved in a Rossby adjustment problem of an initially-resting density front, with parameters appropriate for the ocean mixed layer. This movie shows the same adjustment occurring on top of stable density stratification. This movie and this movie show the effects of adding a diurnal cycle of heating and cooling at the ocean surface (they differ in parameterization of the small-scale turbulence). This movie shows plan views.

Movies using the Hallberg Isopycnal Model

Side views of a calculation of an idealized Ocean with steady winds and restoring to a surface density profile (similar to Cox & Bryan '84). First, a 2 degree spin-up (0-500 yrs). After 500 years at 2 degrees, a 1 degree model was run for 100 yrs (500-600 yrs). Then a relatively viscous, 100-year 0.5 degree run ensued (600-700 yrs). Afterwards, 50 years at 0.5 degrees and a lower viscosity were calculated (700-750). Years 750-775 were calculated at 0.2 degrees with strong eddies. Quicktime. Only the 0.2 degree segment 750-775 years: Quicktime.

Monthly-means resolved mass transport (i.e., no diffusive fluxes plotted) superimposed on potential vorticity (shown only where the pot. density layer is more than ~1 m thick) for the Cox & Bryan-like model. Watch the time in the upper left closely, the snapshot interval changes during major transitions. Quicktime. Only the 0.2 degree segment 750-775 years: Quicktime.

Monthly-means of resolved mass transport (i.e., no diffusive fluxes plotted) superimposed on monthly-means of potential thickness (1/pot. vorticity) for the Cox & Bryan-like model. Quicktime. Only the 0.2 degree segment 750-775 years: Quicktime.

Snapshots of resolved mass transport (i.e., no diffusive fluxes plotted) superimposed on snapshots of layer thickness for the Cox & Bryan-like model. Quicktime. Only the 0.2 degree segment 750-775 years: Quicktime.

Focusing on the formation of mode water by fluxes out of the mixed layer near the separation of the western boundary current: Quicktime.

Formation of MODE water when resolution is sufficient to resolve eddies: Quicktime.

Movies using my barotropic turbulence code

These two models have the same viscosity in the basin interior, but the right-hand one has increased viscosity in a thin layer near the boundary. This layer is able to control the circulation strength, sith the help of eddy fluxes delivering vorticity from the interior. (a plot of potential vorticity)! Movie.

Good parameterization! These two calculations have different viscosities, but very similar time-mean flows. I call these solutions homoparic, for same mean. Movie.

These calculations have the same viscosity, but the larger basins have an opposing wind forcing in the northern region. Their circulation strength is reduced by the addition of this region. Movie.

The double-gyre on the left is started from rest, while the one on the right is started with an initial condition which breaks the initial symmetry between the southern gyre and the northern gyre. Note how the symmetric, resting initial condition run at first resembles the single-gyre in the middle, and then after the symmetry is broken (by numerical errors) it begins to resemble the solution with symmetry-breaking initial conditions. Thus, the symmetric state is unstable, and the sinuous modes which break the symmetry are very important in the control of the circulation strength. Movie.

The situtation is quite different with slip boundary conditions. Here, the middle two-gyre solution has a subtropical boundary current which dominates and overshoots ito the subpolar region. Only the right-hand solution, a slip, double-gyre solution, has an important inter-gyre eddy flux of vorticity. Movie.