A Lagrangian dispersion model with a stochastic equation for the temperature fluctuations

Abstract

A new plume rise scheme for the Lagrangian stochastic model SPRAYWEB is developed and tested. The plume rise scheme is based on a stochastic differential equation for the potential temperature fluctuations coupled with the equations for the wind velocity fluctuation components. The new approach is tested against measured data from a water tank experiment (Weil et al., 2002). The results are discussed in terms of statistical indices and scatter plots. For the sake of comparison, the new scheme's performance is compared with the algorithm used in SPRAYWEB formerly proposed by Anfossi et al. (1993) which doesn't account for the temperature fluctuations. The results obtained with the novel plume rise scheme are generally satisfactory. A better agreement is found for the vertical standard deviation with respect to the results given by the Anfossi et al. (1993) scheme.