United States
Environmental Protection
Environmental Sciences Research
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
models to  produce a potential flow
complex terrain model for routine
  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).

  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

five  and six (E,  F), and  COMPLEX  II
(bivariate Gaussian  spread based  on 
            V   Data    I
               RAMMETor CRSTER Meteoro-
               logical Preprocessor Program
Daily Mixing
Height Data
 Daily Wind
and Temperature
 Profiles (TDF 5600
READ56 Profile Scanning
 Daily Wind'*
and Temperature
Profiles lUsej
   Format) fL.
                                                                    User Edit and Reformat
  /Card Format
  I Meteorological
  I     Data
                       User Edit
                                                                            PROFIL Mixing Height
                                                                           and Profile Interpolation
                                                /Source, Receptor
                                                I  and Control Card
                                                I	Input
                                                                                                         I PFM Table \

                                             COMPLEX/PFM Dispersion
                                                                       J Binary PFM\
                                                                        y   Table    I
                                                     Statistics .
Figure 1,    The COMPLEX/PFM Modeling System

    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
Center for Environmental Research
Cincinnati OH 45268
Postage and
Fees Paid
EPA 335
Official Business
Penalty for Private Use $300
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