Mesoscale Flow and Pollutants Transport Modelling in North-East Sicily

Abstract

The area around Milazzo, a city located on a narrow peninsula, north-east Sicily, is heavily polluted by the presence of power plants and refinery. In this work, the atmospheric pollution levels resulting from two circulation regimes are simulated. First, westerly synoptic winds are considered, as the most likely meteorological conditions (Graziani et al., 1997). Then, a less frequent but most dangerous situation with southerly winds is examined. In this meteorological condition, weak winds can develop that may favour the accumulation of pollutants in the most populated area of the city of Milazzo. The RAMS model (version 3b) is used to calculate the flow, in its non-hydrostatic configuration, due to the highly complex terrain. RAMS is initialised and nudged with data from ECMWF model and a multiple nested grid configuration is selected to solve both local flow and large scale circulation over the Mediterranean. The time-dependent RAMS output is used to drive the Lagrangian particle model MONTECARLO, written in terrain following co-ordinates. In the model, buoyancy of hot emissions in convective conditions is taken into account. Non-reactive SO₂ sources are only considered. Both meteorological and concentration model outputs are compared with observations performed during the 1996 Spring campaign (Cerutti et al., 1996).