Dp. Chock et al., TRAJECTORY-GRID - AN ACCURATE SIGN-PRESERVING ADVECTION-DIFFUSION APPROACH FOR AIR-QUALITY MODELING, Atmospheric environment, 30(6), 1996, pp. 857-868
We propose a new method, called the trajectory-grid (T-G) approach, wh
ich contains a fully Lagrangian advection scheme coupled with an Euler
ian diffusion scheme, to remove the numerical problems associated with
the advection equation in air quality modeling. This method is sign p
reserving, mass conserving, and very accurate. The method assigns the
spatial locations of points on a given concentration profile to a set
of concentration pulses; then tracks the pulse positions as they move
downwind undergoing diffusion and reactions. Multigrid nesting can be
conveniently accounted for by increasing the number density of concent
ration pulses in given areas in the modeling domain. The method can al
so serve as a tool to test the validity of the observation-based model
s. While the execution time may be comparable to that of the Accurate
Space Derivative scheme, the advection step of the method is highly am
enable to multiply-parallel processing.