Dispersion from ground-level sources in a shoreline urban area

A simple Gaussian dispersion model was used to interpret the ground-level concentrations measured in the experiment. The model uses expressions for plume spreads that depend on meteorological information at a height of 50 m from the surface. The vertical spread of the plume is limited to the height of the shear generated boundary layer. The height of this boundary layer is proportional to σw/N, where σw is the standard deviation of the vertical velocity fluctuations, and N is the Brunt-Vaisala frequency of the stable layer capping the surface-based convective layer. This result is based on indirect evidence: model performance improves significantly when vertical plume spread is limited to this height.