Experimental and numerical study of a near-field pollutants dispersion campaign in a stratified surface layer

In order to study pollutants dispersion in a stably stratified surface layer at small scales, a field experiment program is being conducted on the site 'SIRTA' in the southern suburb of Paris. Data analysis is made on turbulence and concentration measurements during an IOP (Intensive Observation Period). Turbulence is characterized to be strongly anisotropic in a stable surface layer. Forest to the north of experiment field induces a strong wind directional shear between 3 m and 30 m levels and a wind speed decrease. Concentration measurements are influenced by plume meandering effect which occurs usually in a stable condition. Numerical simulation in RANS mode with a canopy model enables to reproduce qualitatively the observed wind rotation and the shelters effect on turbulence kinetic energy, but there is still difference in values between measurements and simulation results which can be partly explained by the uncertainty on the inlet profiles.