Documentation of the Evaluation of CALPUFF and Other Long ...

Figure 6‐3a. Distribution of the observed PMCH tracer concentrations (pgm ‐3 ) 24 (top right),
36 (top right), 48 (bottom left) and 60 (bottom right) hours after the release.
6.2 MODEL CONFIGURATION AND APPLICATION
6.2.1 Experimental Design
The objectives of the LRT model evaluation using the ETEX field study database was somewhat
different than the other three tracer test evaluations. In the GP80, SRL75 and CAPTEX tracer
test LRT model evaluations, one major objective was an evaluation of the CALPUFF LRT
dispersion model using two different sets of meteorological inputs, one based on the CALMET
diagnostic wind model and the other using the MMIF WRF/MM5 pass‐through tool. However,
in the ETEX LRT model tracer test evaluation an objective was to use the same meteorological
inputs in all of the LRT dispersion models. This approach is similar to the one taken by Chang
and co‐workers (2003) who conducted an evaluation of three Lagrangian puff models
(HPAC/SCIPUFF, VLSTRACK, and CALMET/CALPUFF). While all three puff models are based on a
Gaussian puff formulation, these models varied significantly in terms of the level of
sophistication of their technical formulation. Chang and co‐workers (2003) proposed a
framework to perform an objective and meaningful evaluation when such models vary
significantly in their formulation. A primary focus of their model evaluation framework
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