The RAMS-CALMET-CALGRID modelling system to assess seasonal ozone pollution: a five-month application over Tuscany region

The LaMMA laboratory implemented the RAMS-CALMET-CALGRID integrated modelling system to assess ozone pollution at a regional scale. The system is based on the RAMS meteorological forecasting model and the CALGRID photochemical grid dispersion model. In the present study a comprehensive application of RAMS-CALMET-CALGRID has been carried out on a seasonal basis over Tuscany region, Italy. The study area is 184x224 Km2 wide, made of a 45x55x12 3-D computational grid, with a horizontal resolution of 4 Km. The modelling system has been applied in a long term mode on a five-month long (May to September 2002) time period, which can be certainly reckoned as the most original part of the work. As a matter of fact, a number of strong modifications in the original CALGRID code proved to be necessary to let the model run continuously all over the five months of simulation. The SAPRC-90 "lumped" chemical mechanism developed by Carter has been used to lump all VOCs involved in the O3 formation and removal processes in the atmosphere. Concerning emission data, all point, line and area sources within the whole region were provided by the regional emission inventory. As far as initial and boundary conditions are concerned, they have been provided as outputs by the CAMx dispersion model applied by CESIRICERCA in the framework of a project aimed at evaluating atmospheric pollution over Italy. Eventually ozone 1-hour concentrations estimated by CALGRID have been compared with observations provided by the major stations of ozone regional monitoring network, showing a good accuracy degree being performed.