Two-dimensional model
From Glossary of Meteorology
two-dimensional model
A mathematical model of the atmosphere that simulates variations of concentration with two spatial coordinates (usually vertical and latitudinal) as a function of time.
Since the prevailing winds tend to move zonally (around circles of latitude), variations in chemical concentrations tend to be less pronounced in that coordinate, and the simplification resulting from using a zonally averaged model leads to a considerable saving in computation time.