Employing Eddy Diffusivities to Simulate the Contaminants Dispersion for a Shear Dominated-Stable Boundary Layer

For the convective planetary boundary layer there is a large number of mathematical models to describe the transport and the dispersion of contaminants. Generally, the turbulent parameterizations that are utilized in such models are well known and statistical quantities as eddy diffusivities, dispersion parameters, velocity variances, and time scales are represented by a convective similarity theory originated from a physical system in a state of quasi-equilibrium. Differently, in comparison with the convective boundary layer, the number of turbulent parameterizations employed in a dispersion model for a shear dominated stable boundary layer (SBL) is quite reduced. One of the major problems concerning to the shear dominated SBL is the determination of its height. This particular vertical depth is a relevant quantity to describe the processes that govern the SBL development. It is important to note that the SBL height has a significant influence on the mixing properties. Furthermore, the inhomogeneous character associated with the turbulence in the SBL becomes difficult the derivation of eddy diffusivities and dispersion parameters. Nonetheless, the local similarity theory (LST) allied to the spectral Taylor statistical diffusion theory allows to construct local expressions for the turbulence parameters in a shear dominated SBL. Therefore, in the present study we employ the LST and the turbulent velocity spectra, in the Taylor statistical diffusion theory to derive eddy diffusivities for a shear dominated SBL. This new formulation is used in a bidimensional Eulerian dispersion model to simulate the observed contaminant concentrations in the classical Hanford experiment