Set up a 3-D horizontal and vertical particle run with 500 particles and
a 6-h snapshot simulation from the initial
28.5N, 80.7W source location at 10 m with a continuous emission. Use
a 0.01 degree resolution grid (reduce the grid span if needed to conserve memory),
the 12 km NAM meteorological data and set the particle dump output interval to
6 hours. Turn back on source labeling and color contour outlines in the
Concentration Display menu and execute the display. The concentration output (below, top left) clearly shows a noisy pattern indicating
too few particles were defined.
Run the simulation again with
5000 particles and the results will be smoother
(below, top right). Now rerun the simulation with 50,000 particles (make
sure the maximum number of particles is greater than 50,000), and the concentration pattern
shows much more structure (below, bottom left).
These large 3-D particle simulations can take quite some time to run, but if the model is re-run with the much quicker default
scenario but using 2500 Top-hat-horizontal particle vertical (500 particles is
not enough in this case), the results (below, bottom right) cover similar areas as the
50,000 3D-particle simulation.
||2500 Top-hat Particles
The Concentration / Display Options / Particle menu (right) has options to show snapshot
particle distributions, assuming that the particle dump option was set in
the Advanced / Configuration Setup / Concentration menu before running the
particle simulation. Horizontal, vertical, and cross-sectional
views are available. Rerun the 50,000 particle
simulation to produce a PARDUMP particle dump file. Then choose the particle vertical cross
section and the graphic is drawn automatically based upon the particle distribution.
Another option is to view the concentration values directly on
the grid without any interpolation through the Concentration / Display Options / Pointer Select
tab. This option will draw the entire concentration domain. Click on the initial map domain image with the left
mouse button to display the concentrations. The grid span option in
the initial concentration grid setup menu should be adjusted to optimize the view region.