In this study, the effect of seasonal variation on air flow and pollutant dispersion characteristics was numerically investigated. A three-dimensional urban canopy model with unit aspect ratio (H/D = 1) was used to calculate surface temperature distribution in the street canyon. Four representative time events (1000 LST, 1300 LST, 1600 LST and 2000 LST) during typical clear summer and winter da...

a computer program was developed to predict the dispersion of gas pollutant in the atmosphere. this program relies on puff method, and in order to consider the wind shear effects, the program has the ability to consider the complete dynamic and unsteady atmospheric conditions. plume rise of hot pollutants due to buoyancy effects was also considered. the program has the capacity to perform the r...

Within this project, Meteo-France is in charge of evaluating the transport of the patch of pollution at the sea surface and the atmospheric dispersion of the chemical substance linked to its evaporation. A modelling system has been settled, which consists of the coupling of two models: The first one, MOTHY, is Meteo-France operational drift forecast system in case of marine pollution. It is a t...

[1] We estimate the average time required for intercontinental transport of atmospheric tracers based on simulations with the global chemical tracer model MOZART-2 driven with NCEP meteorology. We represent the average transport time by a ratio of the concentration of two tracers with different lifetimes. We find that average transport times increase with tracer lifetimes. With tracers of 1and ...

The stochastic trajectory-based (Lagrangian) approach has gained increasing importance and sophistication in atmospheric transport and dispersion modelling over the last few decades. State-of-the-art Lagrangian particle dispersion model (LPDMs) are used to compute trajectories of a large number of ‘marked’ particles and numerically simulate the dispersion of a pollutant (passive tracer) in the ...

This paper focuses on the transient analysis of nonlinear dispersion of a pollutant ejected by an external source into a laminar flow of an incompressible fluid in a channel. The influence of density variation with pollutant concentration is approximated according to the Boussinesq approximation, and the nonlinear governing equations of momentum and pollutant concentration are obtained. The pro...

The eleven nuclear power plants in operation, under construction and a well-planned plant in the east coast of China generally use seawater for reactor cooling. In this study, an oceanic dispersion assessment system based on a database of tidal harmonic constants is developed. This system can calculate the tidal current without a large computational cost, and it is possible to calculate real-ti...