Turbulent Diffusion in the Atmosphere

This chapter deals with an approach towards a physical description of the spreading of pollution in a turbulent atmosphere. We may witness this phenomenon quite commonly by, e.g., following the smoke of a chimney or the steam emerging from a power plant. It is remarkable that the equations to quantify atmospheric turbulence reveal close similarities with the formalism provided by the Fick’s diffusion laws. This is not only true for passive constituents (like smoke or moisture) but also for the turbulent diffusion of heat and momentum. Modelling of atmospheric turbulences, however, is still based on two conceptions which describe the same phenomenon from different perspectives. The development of an all-embracing view has thus remained a challenging task for the future.