The earth's atmosphere is always in motion, and as the winds blow over the surface of this globe, they maintain a “layer of frictional influence” or atmospheric boundary layer that extends from the surface to heights typically of the order of one kilometer. The atmosphere receives much of its heat and virtually all of its water vapor through turbulent transfer processes in the boundary layer. Furthermore, most atmospheric pollutants are released in the boundary layer, and the quality of our daily environment (we allliveinside the boundary layer!) depends strongly on the mixing capabilities of whatever turbulence happens to be around us.