Table of Contents - The Atmospheric Studies Group at TRC

Section 9: CALPUFF
1 IBYEAR integer Beginning year for which data in this set is valid (YYYY)
2 IBJUL integer Beginning Julian day for which data in this set is valid (JJJ)
3 IBHOUR Integer Beginning hour for which data in this set is valid (HH)
4 IBSEC Integer Beginning second for which data in this set is valid (SSSS)
5 IEYEAR integer Ending year for which data in this set is valid (YYYY)
6 IEJUL integer Ending Julian day for which data in this set is valid (JJJ)
7 IEHOUR Integer Ending hour for which data in this set is valid (HH)
8 IESEC Integer Ending second for which data in this set is valid (SSSS)
Next "NSTA" OZCONC real array Ozone concentration (ppb) at each ozone station (in the
same order as the station coordinates in the time-invariant
records; missing value indicator is 9999.)
9.10 User-Specified Chemical Transformation Rate Data File (CHEM.DAT)
If chemical conversion is to be considered by CALPUFF, the user must specify a variable in the control
file, MCHEM, which determines how chemical transformation rates are computed. The options for
MCHEM are:
0 = chemical transformation is not modeled
1 = the MESOPUFF II chemical scheme is used to compute transformation rates
2 = user-specified 24-hour cycles of transformation rates are used
3 = the RIVAD/ARM3 chemical scheme is used to compute transformation
If MCHEM is set equal to 2, CALPUFF reads a formatted user-prepared data file with 24-hour diurnal
cycles of transformation rates k 1 , k 2 , k 3 . The nature of the equilibrium relationship assumed between
pollutants 4 and 5 (e.g., HNO 3 and NO − 3) precludes the use of a user-specified conversion rate between
these pollutants. If NO 3 is being modeled, the NH 4 NO 3 dissociation constant is determined as a function
of temperature and relative humidity.
A sample user-specified CHEM.DAT file is shown in Table 9-39. The CHEM.DAT file uses a control
file format (see Section 9.1). All text outside the delimiters (!) is considered as user comment information
and is echoed back but otherwise ignored by the input module. Each data line consists of a delimiter
followed by the species name, 24 conversion rates, and a terminating delimiter. The data may extend
over more than one line. The line being continued must end with a comma. The control file format
allows the use of repetition factors (e.g., 3 * 1.0 instead of 1.0, 1.0, 1.0). The order in which the species
are entered in the file is not important. However, the file must end with an input group terminator (i.e.,
!END).
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