The random force theory: Application to meso- and large-scale atmospheric diffusion

The physical basis for the random force theory of atmospheric diffusion is briefly reviewed. The random force equation has usually been introduced as an atmospheric analogy to Brownian motion. Here it is derived by assuming a type of Rayleigh friction in the Lagrangian equations of atmospheric motion. Consequences, including the Lagrangian correlation and spectrum, the particle-particle intercorrelation, and cluster and plume dispersion and meandering, are derived and compared with atmospheric observations. The characteristic time-scale of atmospheric diffusion is shown to be governed by the Coriolis effect, a result in good agreement with meso- and large-scale observations.