A PSEUDO-NON-TIME-SPLITTING METHOD IN AIR-QUALITY MODELING

This paper presents a pseudo-non-time-splitting (PN) method that combi nes the different processes in air quality modeling, such as advection , diffusion, and emission,with chemical reaction computations. The pur pose is to reduce the errors generated by the time-splitting method by taking the advantage of the fact that the integration time steps in t he chemical reaction computation are much smaller than those used in o ther processes. An example of a cosine hill rotation with chemical rea ctions is used to demonstrate this new method. We show that the PN met hod produces results with similar accuracy to those from the conventio nal time-splitting method but consumes about 20% less execution CPU ti me. (C) 1996 Academic Press, Inc.