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- Author or Editor: C. Mangia x
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Abstract
A new formulation for the lateral dispersion parameter is presented. The model is valid for unstable atmospheric conditions and based on the turbulent kinetic energy spectra and Taylor diffusion theory. It has been tested and compared, through an experimental dataset, with other formulations taken from the literature. The statistical evaluation shows that the proposed σ y parameterization is suitable for application in advanced air quality regulatory models.
Abstract
A new formulation for the lateral dispersion parameter is presented. The model is valid for unstable atmospheric conditions and based on the turbulent kinetic energy spectra and Taylor diffusion theory. It has been tested and compared, through an experimental dataset, with other formulations taken from the literature. The statistical evaluation shows that the proposed σ y parameterization is suitable for application in advanced air quality regulatory models.
Abstract
An integral parameterization of the dispersion coefficients σ y and σ z in a shear–buoyancy-driven atmospheric boundary layer is developed by using a model for the frequency spectrum of eddy energy. The formulation relies on Taylor classical diffusion theory and further developments by Pasquill. The statistical independence of Fourier components for distant frequencies allows the specification of the turbulent kinetic energy spectrum as the sum of a buoyancy- and a shear-produced part. For both components the dispersion parameters are described in terms of the frequency of spectral peak and dissipation function. In this way they are directly related to energy-containing eddies that are most responsible for turbulent transport of any scalars in an atmospheric boundary layer generated by mechanical and thermal forcing mechanisms. As a consequence, the resulting dispersion parameters are more general than those found in the literature, because they do not utilize measurements of turbulent dispersion as most parameterizations do and provide a formulation valid for the whole unstable regime. The formulations are compared with field diffusion data, along with other schemes. The new parameters are well suited for application in air pollution modeling under unstable conditions.
Abstract
An integral parameterization of the dispersion coefficients σ y and σ z in a shear–buoyancy-driven atmospheric boundary layer is developed by using a model for the frequency spectrum of eddy energy. The formulation relies on Taylor classical diffusion theory and further developments by Pasquill. The statistical independence of Fourier components for distant frequencies allows the specification of the turbulent kinetic energy spectrum as the sum of a buoyancy- and a shear-produced part. For both components the dispersion parameters are described in terms of the frequency of spectral peak and dissipation function. In this way they are directly related to energy-containing eddies that are most responsible for turbulent transport of any scalars in an atmospheric boundary layer generated by mechanical and thermal forcing mechanisms. As a consequence, the resulting dispersion parameters are more general than those found in the literature, because they do not utilize measurements of turbulent dispersion as most parameterizations do and provide a formulation valid for the whole unstable regime. The formulations are compared with field diffusion data, along with other schemes. The new parameters are well suited for application in air pollution modeling under unstable conditions.
