United States
Environmental Protection
Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S8-83-015 July 1983
Project Summary
COMPLEX/PFM Air Quality
Model User's Guide
D. G. Strimaitis, J. S. Scire, and A Bass
A user's guide has been assembled
to describe the purpose, design, and
operation of the COMPLEX/PFM air
quality modeling system. The system
combines the features of the Potential
Flow Model (PFM) with those of the
EPA COMPLEX I and COMPLEX II
models to produce a potential flow
complex terrain model for routine
application.
Potential flow dispersion calculations
may be selected as an option within
COMPLEX/PFM. When this option is
selected, the model requires hourly
wind speed and temperature profiles
to calculate hourly mixing heights,
hourly plume rise using a layered-
plume-rise equation, and hourly values
of the critical dividing streamline height
A preprocessor is provided to inter-
polate hourly profile data from morning
and evening radiosonde data. Potential
flow calculations are made whenever
the plume lies above the dividing
streamline height provided that the
surface stability class is D, E, or F.
COMPLEX I calculations are performed
whenever the plume lies below the
dividing streamline height and COM-
PLEX It calculations are made when-
ever the surface stability class is A, B,
or C.
This Project Summary was developed
by EPA's Environmental Sciences Re-
search Laboratory, Research Triangle
Park. NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Potential flow theory was applied to the
problem of predicting pollutant concen-
trations on significant terrain features.
This approach produced the modeling
system described in this manual. Two
classes of meteorological conditions are
often associated with the likelihood of
large ground-level concentrations on ele-
vated terrain features: (1) low wind speed
and stable cases, and (2) moderate or high
wind speed and neutral or slightly stable
cases. The first class of conditions gen-
erally leads to high concentrations through
direct plume impingement or terrain block-
ing. The second class promotes high con-
centrations because the plume is forced to
pass close to the terrain surface Physical
mechanisms relevant to this class of con-
ditions include terrain-induced alteration
of the plume centerline trajectory and
kinematic constraints on horizontal and
vertical dispersion. Potential flow theory is
particularly useful in modeling concen-
trations produced by the second class
of conditions.
The objective of this user's guide was to
generalize the PFM code to a complete
modeling system. That modeling system
is COMPLEX/PFM. The PFM calculations
made by this model are applicable to bluffs
and ellipsoidal terrain shapes. The host
model, EPA COMPLEX contains the struc-
ture for handling point sources, the hourly
simulation of concentrations, and averag-
ing and reporting air pollutant concen-
tration statistics. The host model also
provides pollutant concentration algo-
rithms for impingement situations and
strongly corrective situations.
Major Model Features
COMPLEX/PFM is a modified version
of COMPLEX I/COMPLEX II, which con-
tains the PFM algorithm option If the PFM
option is not invoked the model performs
COMPLEX I (22.5° crosswind sector av-
eraging and Gaussian vertical spread based
on o^ computations for stability classes
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five and six (E, F), and COMPLEX II
(bivariate Gaussian spread based on
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Hourly
Surface
[Meteorological
V Data I
RAMMETor CRSTER Meteoro-
logical Preprocessor Program
Twice
Daily Mixing
Height Data
Twice
Daily Wind
and Temperature
Profiles (TDF 5600
TAPE)
\
i
READ56 Profile Scanning
Program
Twice
Daily Wind'*
and Temperature
Profiles lUsej
Format) fL.
i
*
User Edit and Reformat
Program
/Card Format
I Meteorological
I Data
User Edit
Program
PROFIL Mixing Height
and Profile Interpolation
Program
/Source, Receptor
I and Control Card
I Input
I PFM Table \
I
SETUP
Reformating
Program
\
COMPLEX/PFM Dispersion
Model
J Binary PFM\
y Table I
Predicted
Concentration
Statistics .
Figure 1, The COMPLEX/PFM Modeling System
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D. G. Strimaitis, J. S, Scire. and A. Bass are with Environmental Research &
Technology, Inc., Concord, MA 01742.
John F. Clarke is the EPA Project Officer (see below).
The complete report, entitled "COMPLEX/PFM Air Quality Model User's Guide,"
(Order No. PB 83-200 626; Cost: $13.00, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
PS 0000329
uc£iE^VlR PROTECTION AGENCY
KESIUN b LIBRARY
230 S DEARBORN STREET
CHICAGO IL 60604
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