Including the Urban Canopy Layer in a Lagrangian Particle Dispersion Model

Abstract In this study we introduce a novel extension of an existing Lagrangian particle dispersion model for application over urban areas by explicitly taking into account the canopy layer. As commonly done, original uses zero-plane displacement as lower boundary condition, while reaches to ground. To achieve this, spatially-averaged parametrizations flow and turbulence characteristics are created fitting functions observational numerical data. The extended is verified with respect basic assumptions (well-mixed condition) its behaviour investigated unstable/neutral/stable atmospheric stabilities. A sensitivity shows that newly introduced parameters characterizing impact output less than previously parameters. Comparing concentration predictions Basel Urban Boundary Layer Experiment—where concentrations were measured near roof level—shows modified performs slightly better model. More importantly, can also be used treat surface sources (traffic) assess within (pedestrian level). small improvement level suggests parametrized profiles realistically represent environment on average.