For macOS.  Available on the Apple App Store

Idealized 1- and 2-layer general circulation models of planetary atmospheres, and a stellar tachocline, on a sphere, solved by a variety of methods. Direct Statistical Simulation (DSS) by cumulant expansions is implemented. Results can be compared to those obtained by direct numerical simulation (DNS) performed either on a spherical geodesic grid, or with a pure spectral (not pseudospectral) algorithm.  Details can be found here.

Fluid fields such as vorticity, zonal velocity, and enstrophy density may be visualized. Energy, angular momentum, and other quantities are calculated and displayed at regular intervals. Statistics such as the second cumulant of the vorticity, power spectra, and time lines of zonal means, are also calculated as the flow evolves.

Quick Start: Click the “Add” button to create a new model. Select “Model” to choose a prototypical model. (Model parameters can be edited in the Models table.) Select “Solution” to choose a solution method. Then click anywhere in the black portion of the screen to start a run; click again to stop it. Click on the sphere to display the two-point correlation function (second cumulant) with one of the two points being the selected cell.