A PDF micromixing model of dispersion for atmospheric flow. Part II: application to convective boundary layer

The Lagrangian stochastic probability density function (PDF) model developed by Cassiani et al. [Atmos. Environ. (2005) Part 1] is extended to the atmospheric convective boundary layer. The model is applied to simulate concentration statistics and PDF generated by passive releases from point and line sources in the convective boundary layer. A dynamical time-expandable grid is implemented, which optimises the computational resources required for dispersion simulations in atmospheric flow. A parameterised formulation for the micromixing time scale in convective conditions is derived. Model concentration statistics including mean field, fluctuations and concentration PDF are tested with four water tank experiments