Most of the air quality dispersion models used for regulatory applications are based on K-diffusion formulations. In this paper, two turbulent parameterisations for dispersion models in the atmospheric boundary layer are evaluated with experimental data. The first scheme is based on a similarity approach and provides wind and eddy diffusivity profiles on the basis of a diagnostic PBL model. The second one provides an eddy diffusivity profile based on the Taylor statistical diffusion theory and on the spectral properties of turbulence. The two parameterisations have been included in a numerical grid model and tested with the Copenhagen data set. Results show tha: i) the dispersion model with both turbulent schemes, produces a good fitting of the measured ground-level concentration data for all the experimental conditions considered; ii) there are no significant differences between the two schemes in the range of experimental data - the profiles are close to each other in the lower layers while they show larger differences in the layer above the surface layer. Therefore, both parameterisations give a realistic description of the dispersion processes in the lower PBL, and can be used for short range air pollution models and ground level concentrations.
Evaluation of wind and turbulent parameterisations for short range air pollution modeling
RIZZA U;MANGIA C;
2006
Abstract
Most of the air quality dispersion models used for regulatory applications are based on K-diffusion formulations. In this paper, two turbulent parameterisations for dispersion models in the atmospheric boundary layer are evaluated with experimental data. The first scheme is based on a similarity approach and provides wind and eddy diffusivity profiles on the basis of a diagnostic PBL model. The second one provides an eddy diffusivity profile based on the Taylor statistical diffusion theory and on the spectral properties of turbulence. The two parameterisations have been included in a numerical grid model and tested with the Copenhagen data set. Results show tha: i) the dispersion model with both turbulent schemes, produces a good fitting of the measured ground-level concentration data for all the experimental conditions considered; ii) there are no significant differences between the two schemes in the range of experimental data - the profiles are close to each other in the lower layers while they show larger differences in the layer above the surface layer. Therefore, both parameterisations give a realistic description of the dispersion processes in the lower PBL, and can be used for short range air pollution models and ground level concentrations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
