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This note describes the three dimensional Lagrangian particle dispersion model PDM, currently in use at JRC Environment Institute, Ispra site, and ENVIROWARE srl.PDM is a computer code, written in FORTRAN, for the simulation of the atmospheric dispersion of inert pollutants.
The scheme for simulating the vertical motion of particles under convective conditions, driven by vertical turbulence, is described first. For this motion a modified version of the one -dimension skewed homogeneous model by Hurly and Physick (1993) is developed. This developed vertical model, named 'quasi-homogeneous skewed model', partially takes into account the inhomogeneity of vertical turbulence, still skewed inhomogeneous models (Luhar and Britter, 1989).
Willis and Deardorff water tank experiments are used to evaluate the quasi-homogeneous formulation. The comparison of model results with experimental data in terms of particle spatial distribution shows the capability of the model to verify the "well-mixed condition", the fundamental test a Lagrangian particle model has to satisfy.
The vertical scheme introduced is then incorporated in the three-dimensional model PDM. Meteorological variables are input as three dimensional fields on a terrain influenced co-ordinates grid system. The displacement of particles along the horizontal direction is solved by the linear Langevin equation.
The three dimensional concentration is reconstructed from particle space distribution through a kernel density estimator whose parameters are determined as functions of particles age and relative position. The use of this kernel reduces the number of particles required to characterize the emission.
The performance of the three dimensional model is evaluated with Karlsruhe and Copenhagen tracerfield experiments under convective conditioned, indicating that realistic three dimensional simulations can be obtained in the cases considered.
The fast execution time and the limited number of input data requ requ

Additional information

Authors: BIANCONI R, Enviroware Srl;MOSCA S, Enviroware Srl;GRAZIANI G, JRC
Bibliographic Reference: EUR 17721 EN (1999)
Availability: Available from OOPEC Sales agents
Record Number: 199910439 / Last updated on: 1999-03-19
Original language: en
Available languages: en