Mesoscale Modeling with MM5 for the PATH Study (Pollutants in the Atmosphere and their Transport over Hong Kong)

The PATH Study is a modelling and field-work project which took place between September 1996 and June 1998. Its aim was to produce an air quality modelling system that could be used by the Hong Kong Government for guidance on decisions involving emissions control and planning policy. The validated system consists of a prognostic meteorological model (MM5), a prognostic air-chemistry model (SAQM), an emissions inventory package (EMS-95), and a Graphical User Interface (GUI) for display of results and preparation of input for new simulations. Meteorological fields from simulations of eleven case studies (chosen to address photochemical and particle issues) can be used to re-run the air chemistry model under different emission scenarios.

This talk provides an overview of the Study and presents results from several case-study simulations with MM5, carried out on two-way nested grids with spacings of 13.5, 4.5, 1.5 and 0.5 km. The dense observing network for Hong Kong allows a quantitative assessment of the model performance. The limitations of several statistical indicators are discussed.