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In this work, eddy diffusivity is derived from the energy spectra for the stable and convective regimes in the planetary boundary layer. The energy spectra are obtained from a spectral model for the inertial subrange that considers the anomalous behavior of turbulence. This spectrum is expressed as a function of the Hausdorff fractal dimension. The diffusivity eddies are employed in a classical Eulerian dispersion model, where the derivatives are of integer order and in fractional dispersion model, where the derivatives are of fractional order. The eddy diffusivity proposed considers the anomalous nature of geophysical turbulent flow. The results obtained with the fractional and classic dispersion models using the eddy diffusivity proposed is satisfactory when compared with the experimental data of the Prairie Grass and Hanford experiments in a stable regime, and the Copenhagen experiment in a convective regime. [ABSTRACT FROM AUTHOR]

The present work develops a model for the turbulent velocity spectra that considers the anomalous behaviour of the turbulent flow. The β -model assumes that the standard Kolmogorov phenomenology is valid only in active turbulence regions, and it proposes an expression for the turbulent velocity spectra in the inertial subrange that is a function of the Hausdorff fractal dimension. From this idea, expressions are obtained for the components of the turbulent velocity spectra that describe the turbulence that exists in geophysical turbulence above the ocean and in very stable situations in the planetary boundary layer where intermittent turbulence occurs. With these spectra, the main parameters used in dispersion models are obtained, that is, the eddy diffusivity and the Lagrangian time scale. The eddy diffusivity is used in an Eulerian dispersion model to estimate the concentration of contaminants in the stable boundary layer. The results obtained are compared with experimental data and other models in the literature. [ABSTRACT FROM AUTHOR]