A meso-scale plume dispersion model. Preliminary evaluation in a heterogeneous area

A plume dispersion model for meso-γ-scale applications is developed. The model is formulated with the aim to study plume spreading in moderately complex terrain. An eddy diffusivity analogue is used in order to facilitate future inclusion of chemical transformations. The full diffusivity tensor, obtained from a second-order closure turbulence model, is used to described the dispersion process. The model is driven with simulated meteorological fields, obtained by means of a second-order turbulence closure model. An initial model evaluation has been undertaken using model predictions for an area featuring horizontally inhomogeneous dispersion conditions. Comparison with measurements, as well as with predictions of several other model types for distances out to 40 km, shows that the model is able to describe realistically plume widths and concentration in areas with strongly varying dispersion conditions. Non-negligible errors in plume position were however found for all models compared.