Main Page | See live article | Alphabetical index Fluid flow is often decomposed into mean and deviation from the mean, where the averaging can be done in either space or time. The mean flow is then obviously the field of means for all individual grid points. In the atmospheric sciences, the mean flow is taken to be the purely zonal flow of the atmosphere which is driven by the temperature contrast between equator and the poles. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.