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