An algebraic expression for the eddy diffusivity in the residual layer

Ln this paper the problem of the theoretical derivation of a parameterization for the eddy diffusivity in the Residual Layer (RL), the nearly adiabatic remainent of the day time boundary layer, where the dispersion of contaminants occurs in condition of decaying turbulence is addressed The model makes use of the three-dimensional dynamical equation for the classical statistical diffusion theory. The starting point is the Heisenberg's elementary decaying turbulence theory. The main assumption is related to the identification of a frequency, lying in the inertial energy transfer among eddies of different size. The novelty in this study is the derivation of an algebraic formulation for the eddy diffusivity in the RL.