About the behaviour of the SAFE_AIR II atmospheric dispersion numerical model during low wind conditions

Abstract: The SAFE_AIR II modelling system (Simulation of Air pollution From Emissions _ Above Inhomogeneous Regions, Version II) has been implemented at the Department of Physics of the University of Genova (Italy) to simulate dispersion of air pollutants over complex terrain. A test case has been performed in order to point out the importance of meteorological input on model results. Three different configurations have been chosen in order to initialize the model: i) surface and upper air data; ii) surface data only; iii) upper air data only. The behaviour of SAFE_AIR II, driven by different meteorological data pre-processing, has been investigated by means of the simulation of a hypothetical emission above a real complex orography (Florence outskirts, Italy) under low wind real meteorological conditions. The influence of the meteorological input was very relevant to the model outputs, more relevant than the dispersion scheme used.