Keywords: air pollution, atmospheric dispersion modelling, numerical advection schemes, analytic solution, advection equation, time splitting
Testing of numerical advection schemes and splitting techniques used in pollution dispersion modelling on an analytic solution
In the real nature the processes of pollutants advection, their release in and removal from the atmosphere take place simultaneously. In dispersion modelling, these processes are considered separately, one after another within a time step, which causes the generation of some specific errors. Two types of numerical advection schemes, typical Eulerian and semi-Lagrangian one, are considered. The numerical results are compared to the stationary analytic solution of the 1D advection equation with incorporation of emission and deposition. Several approaches to reduce the errors of the numerical solutions are discussed. Analytic solutions for the air concentration and deposition for some characteristic cases (different emission and deposition space distributions) are prepared in a shape, convenient to be used as a kit for testing the advection schemes and splitting techniques.