A dispersion model for the estimation of crosswind integrated concentrations in the surface-based inversion is proposed.The generalized forms of eddy diffusivity with spatial dependence in both horizontal and vertical...A dispersion model for the estimation of crosswind integrated concentrations in the surface-based inversion is proposed.The generalized forms of eddy diffusivity with spatial dependence in both horizontal and vertical directions and vertical height-dependent wind speed are considered.In view of the computational limitation associated with numerical models for Dirac-delta function,the source term is expressed as a limiting case of normal distribution.The accuracy of the employed numerical scheme to solve the resulting partial differential equation with appropriate physically relevant boundary conditions is checked with those obtained from the respective analytical solutions available in literature for the particular forms of eddy diffusivity and wind speed.Concentrations computed from the proposed model are found close to those obtained from analytical models.The concentrations obtained from the proposed model are evaluated for the generalized functional forms of eddy diffusivity(Degrazia and Moraes,1992;Degrazia et al.,2001)and diabatic logarithmic profile as well as power-law profile of wind speed with the observations from Hanford(Doran et al.,1984)and Copenhagen(Gryning and Lyck,1984)diffusion experiments in stable and unstable conditions,respectively.Majority of the cases i.e.,64%and 96%are predicted in factor of two to observations in both stable and unstable conditions,respectively.展开更多
文摘A dispersion model for the estimation of crosswind integrated concentrations in the surface-based inversion is proposed.The generalized forms of eddy diffusivity with spatial dependence in both horizontal and vertical directions and vertical height-dependent wind speed are considered.In view of the computational limitation associated with numerical models for Dirac-delta function,the source term is expressed as a limiting case of normal distribution.The accuracy of the employed numerical scheme to solve the resulting partial differential equation with appropriate physically relevant boundary conditions is checked with those obtained from the respective analytical solutions available in literature for the particular forms of eddy diffusivity and wind speed.Concentrations computed from the proposed model are found close to those obtained from analytical models.The concentrations obtained from the proposed model are evaluated for the generalized functional forms of eddy diffusivity(Degrazia and Moraes,1992;Degrazia et al.,2001)and diabatic logarithmic profile as well as power-law profile of wind speed with the observations from Hanford(Doran et al.,1984)and Copenhagen(Gryning and Lyck,1984)diffusion experiments in stable and unstable conditions,respectively.Majority of the cases i.e.,64%and 96%are predicted in factor of two to observations in both stable and unstable conditions,respectively.
