Barotropic vorticity equation

Summary

The barotropic vorticity equation describes a two-dimensional, non-divergent flow on a rotating planet. It says that the absolute vorticity of each fluid column is carried along unchanged. It is the simplest member of the family of quasi-geostrophic equations, with one unknown, the stream function. It describes Rossby waves, and it was the model used in the first successful numerical weather forecast in 1950.