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

compact discs, which were used to obtain the hourly surface observations. The following
surface stations were used for each of the field experiments:
Table 3‐1. Surface meteorological monitoring sites used in the GP80 CALMET modeling.
State City
Arkansas Fort Smith
Illinois Springfield
Kansas Dodge City, Topeka, Wichita
Missouri Columbia, Kansas City, Springfield, St. Louis
Nebraska Grand Island, Omaha, North Platte
Oklahoma Oklahoma City, Tulsa
Texas Amarillo, Dallas‐Fort Worth, Lubbock, Wichita Falls
Twice daily upper‐air meteorological soundings came from the second set of compact discs, the
Radiosonde Data for North America. The following stations were used for each of the field
experiments:
Table 3‐2. Radiosonde monitoring sites used in the GP80 CALMET modeling.
State City
Arkansas Little Rock
Illinois Peoria
Kansas Dodge City, Topeka
Missouri Monett
Nebraska Omaha, North Platte
Oklahoma Oklahoma City
Texas Amarillo
Consistent with the August 2009 Clarification Memorandum, some of the CALPUFF/CALMET
sensitivity tests utilized CALMET simulations using prognostic meteorological model output as
the first‐guess wind field for CALMET and then perform the CALMET STEP1 procedures to apply
diagnostic effects to the wind fields. CALMET then uses the surface and upper air observations
in the objective analysis (OA) phase that blends the meteorological observations with the STEP1
wind field to produce the STEP2 wind field. This method is often referred to as the “hybrid”
method.
The terrain and GIS land use data on the original CALPUFF CD were used to define gridded land
use data for each field experiment. These data are defined with a resolution of 1/6° latitude
and 1/4° longitude. The program PRELND1.EXE, also provided on the CD, was run to extract the
data from the GIS data base and map the data to the meteorological domain for each field
experiment. The program ELEVAT.EXE (also provided on the CD) was used to process the raw
terrain data into average gridded terrain data. The file of terrain and geophysical parameters
required by CALMET was constructed from the output files generated by ELEVAT and PRELND1
with additional required records inserted manually to create the final forms of the file for GP80
tracer experiment.
One of the primary purposes of the GP80 experiment was to demonstrate the efficacy of
perfluorocarbons as tracers in atmospheric dispersion field studies.
Perfluoromonomethylcyclohexane (PMCH) and perfluorodimethylcyclohexane (PDCH) were
released during this experiment. For the 1998 EPA CALPUFF evaluation report and the current
analyses, the PDCH emission rate was used in the CALPUFF evaluation since the monitoring
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