Table of Contents - The Atmospheric Studies Group at TRC

Section 9: CALPUFF
9.3 Point Source Emissions File With Arbitrarily Varying Emissions (PTEMARB.DAT)
The PTEMARB.DAT file contains point source emissions data for sources with detailed, arbitrarily
varying emissions parameters. In the PTEMARB.DAT file, values for the stack parameters and emission
rates can be specified for each time step in the run. Plume rise is computed within the CALPUFF model
for each source.
PTEMARB.DAT is a free-formatted ASCII data file (see Table 9-16 for an example). Multiple files may
be provided if groups of sources possess very different time-variability. For example, group 1 may
require hourly data records for the entire simulation period, while group 2 may produce emissions for
only a few weeks during the simulation. Using a second file for group 2 is more economical to prepare
because a single data record can be used to prescribe a long period with no (or constant) emissions. Each
such file must cover the entire modeling period, no source may appear in more than one file, and the
species list must be identical among these files.
The data in the PTEMARB.DAT file are independent of the horizontal and vertical grid systems being
used in the model. The horizontal coordinates are specified for a particular map projection and datum,
and CALPUFF converts these coordinates to the map projection and datum used in the modeling grid.
Header records of the PTEMARB.DAT file (see Table 9-17) contain the coordinate definitions, number
of sources, starting and ending time periods of data in the file, the time zone, and a list of the emitted
species and the corresponding molecular weights.
The PTEMARB.DAT file contains two types of data records. A set of time-invariant records (see Table
9-18) are read after the header records. These records specify the time-invariant source parameters,
including the source coordinates, stack height, diameter, momentum flux factor, and building data for
sources subject to building downwash. The vertical momentum flux factor may be either 1.0 (full vertical
momentum flux), or 0.0 (no vertical momentum). Use 0.0 to simulate the effect of stack structures like
rain hats. A set of time-varying data follows (see Table 9-19). The time-varying records contain the
stack temperature, exit velocity, initial plume size ( y and z ), and emission rate for each species.
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