The special case of turbulence in which the scales of the turbulent velocities in two dimensions (often the horizontal plane) are much larger than in the third dimension, and the horizontal eddies can be treated separately from the vertical. In consequence, the equations of geophysical fluid dynamics can be formulated in especially simple and productive forms for applications to atmospheric and oceanic flows. Applications include especially study of large-scale atmospheric and oceanic disturbances, the general circulation, and climate change. See Also two-dimensional eddies.