Analysis and Simulation of Local Circulations and Air Pollution Over a Coastal, Complex Site

Abstract

Field surveys have been done in the La Spezia complex site and a scale model of the area in a hydrodynamic tank has been built in order to both analyze the dynamic and thermodynamic structure of the air flow and to study air pollutants dispersion. Results from the field experiments made it possible to describe relevant meteorological processes such as formation of sea and land breezes, evolution of the diurnal and nocturnal inversion and others. The physical model proved to simulate the air flow of the site in satisfactory agreement with the observations. Hence, it was also operated to simulate dispersion of air pollutants under different air flow regimes. In spite of the high scale factors, the hydraulic model gave realistic simulations of the hourly average ground level concentration caused by the local thermal power plant. The physical model was then complemented by a Gaussian model in order to simulate the seasonal air pollution trend. The parameterization of the Gaussian climatological model was done by taking into account the results from the field experiments. Validation of the model through comparison with measured values over eight seasons showed that the adopted parameterization was relevant to the achievement of a satisfactory agreement with the observations and that the Gaussian model could integrate the physical model in the establishment of air quality strategies in the considered area.