United States
Environmental Protection
Agency
Atmospheric Sciences
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S8-86/010 May 1986
&EPA Project Summary
TUPOS—A Multiple Source
Gaussian Dispersion
Algorithm Using On-Site
Turbulence Data
t>. Bruce Turner, Thomas Chico, and Joseph A. Catalano
TUPOS and its postprocessor,
TUPOS-P, form a Gaussian model
which resembles MPTER but offers sev-
eral technical improvements. TUPOS
estimates dispersion directly from fluc-
tuation statistics at plume level and cal-
culates plume rise and partial penetra-
tion of the plume into stable layers
using vertical profiles of wind and tem-
perature. The model user is thus re-
quired to furnish meteorological infor-
mation for several heights above
ground in a separate input file.
TUPOS can be used for short-term
(hours to days) impact assessment of
inert pollutants from single or multiple
sources and can be expected to have
greatest accuracy for locations within
10 km of the source. Although TUPOS
will make computations for receptors
having any ground-level elevation, it is
not intended as a complex terrain
model, but rather as a model for calcu-
lations over flat or gently rolling terrain.
TUPOS will optionally treat buoyancy-
induced dispersion but does not in-
clude building down-wash, deposition,
or fumigation.
The maximum number of point
sources and the maximum number of
receptor locations are easily adjusted at
the time of program compilation and
have no specific limit. The program is
initially configured to handle 25 sources
and 180 receptors.
Output from TUPOS consists primar-
ily of tape or disk concentration files,
which are then analyzed and summa-
rized by the postprocessor, TUPOS-P.
An hourly concentration file is automat-
ically created by TUPOS; the user has
the option of creating a partial concen-
tration file.
This Project Summary was devel-
oped by EPA's Atmospheric Sciences
Research 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 infor-
mation at back).
Introduction
TUPOS and its postprocessor,
TUPOS-P, form a Gaussian model
which resembles MPTER but offers sev-
eral technical improvements. TUPOS
estimates dispersion directly from fluc-
tuation statistics at plume level and cal-
culates plume rise and partial penetra-
tion of the plume into stable layers
using vertical profiles of wind and tem-
perature. In order to do this adequately,
considerable knowledge of the variation
of meteorology in the vertical dimen-
sion must be known.
Information must be furnished by the
user for each simulated hour at several
levels for the five variables: ambient air
temperature, wind direction, wind
speed, standard deviation of wind az-
imuth, and standard deviation of wind
elevation angle. These parameters are
interpolated vertically for calculating
plume rise, dilution, plume dispersion,
and transport. This profile information
must be provided in sufficient detail so
that linear interpolation between levels
is reasonable. One of the levels speci-
fied must be that of the mixing height.
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Source parameters are physical stack
height above ground, stack top inside
diameter, stack gas temperature, stack
gas exit velocity, and pollutant emission
rate. As an option, values for three vari-
ables: stack gas temperature, stack gas
exit velocity, and emission rate can be
entered hourly.
Optional features of the TUPOS com-
puter code include:
• Stack downwash, buoyancy-
induced dispersion, and gradual
plume rise;
• Terrain adjustment as a function of
stability category; and
• An optional program-generated
polar coordinate grid, with sector
size and azimuth spacing entered
as input.
Output from TUPOS consists primar-
ily of tape or disk concentration files
which are then analyzed and summa-
rized by the postprocessor, TUPOS-P.
An hourly concentration file is automat-
ically created by TUPOS; the user has
the option of creating a partial concen-
tration file.
By making the number of sources and
receptors easily adjustable at the time
of compilation and by removing func-
tions that are largely bookkeeping to the
postprocessor, the TUPOS system
should be easily adaptable to computer
systems with small core storage.
Discussion
TUPOS is a Gaussian plume steady-
state model using measured (or in-
ferred) turbulence data {wind fluctua-
tion standard deviations) as part of the
meteorological input. It is a useful short-
term (hours to days) algorithm to evalu-
ate the effects of multiple point sources
in the near field (within 10 km). It is the
intent of the authors that TUPOS be ap-
plied to sources from which the effluent
is dominated by buoyancy or momen-
tum (not heavier than air releases). Only
simple terrain adjustments are made; it
is not expected that plume impaction be
considered. The model includes the fol-
lowing optional computational features
in common with MPTER:
• Stack downwash,
• Buoyancy-induced dispersion,
• Gradual plume rise, and
• Terrain adjustment as a function of
stability category.
Although TUPOS will make computa-
tions for receptors having any ground-
level elevation, it is not intended as a
complex terrain model, but rather as a
model for calculations over flat or gen-
tly rolling terrain. TUPOS will optionally
treat buoyancy-induced dispersion but
does not include building downwash,
deposition, or fumigation.
Modeling features unique to TUPOS
include:
• Layer-by-layer plume rise and
• Partial plume penetration above
the mixing height.
TUPOS retains limitations typical of
Gaussian plume models including:
• No consideration of nonlinear pol-
lutant removal or chemical reac-
tions,
• No consideration of spatial varia-
tion in meteorology, and
• No consideration of increased hori-
zontal dispersion due to wind direc-
tion shear through the vertical ex-
tent of plumes.
Also, TUPOS has no provision for calcu-
lating the effects from area or line
source emissions.
Emission Data
The following information is required
for each point source:
• East and north coordinates of the
point source (user units),
• Pollutant emission rate (g/s),
• Physical stack height (m),
• Stack gas temperature (K),
• Stack inside diameter (m), and
• Stack gas exit velocity (m/s).
The east-north coordinate system can
be provided in any consistent units.
Also, the stack ground-level elevation is
required if the terrain adjustment option
is used.
Receptor Data
The user has the option of designing
his or her own receptor grid or instruct-
ing TUPOS to generate a polar coordi-
nate receptor grid. In either case, the
location (user length units) and, if the
terrain adjustment option is used, the
ground-level elevation (user height
units) are required for input. Addition-
ally, for the user-supplied receptors, the
receptor height above ground (m) must
be given.
Meteorological Data
Hourly meteorological data are re-
quired for specific levels. The user may
prepare the data in the format specified,
or data prepared by the Meteorological
Processor for Dispersion Analyses,
(MPDA-1) may be used. The hourly me-
teorological data needed for the compu-
tations are as follows:
• Year,
• Julian day,
• Hour,
• Number of vertical levels,
• Level number corresponding to the
mixing height,
• Stability category,
• Height above ground of each level
(m),
• Ambient air temperature at each
level (K),
• Wind direction at each level (de-
grees),
• Wind speed at each level (m/s),
• Standard deviation of the azimuth
angle (radians) at each level, and
• Standard deviation of the elevation
angle (radians) at each level.
There are four stability categories in
TUPOS: unstable, day-time neutral,
nighttime neutral, and stable desig-
nated 1 to 4, respectively. These can be
defined using the ratio of Monin-
Obukhov length to mixing height. (The
stability category is contained in the
output from MPDA-1.)
It is assumed that the variation of me-
teorological parameters with height is
provided in sufficient detail such that
linear interpolation with height between
levels yields reasonable values. Any in-
formation required for a height below
the height of the lowest level is as-
signed the value of the lowest level,
Similarly, any information required foi
a height above the height of the highest
level is assigned the value of the highest
level.
Output primarily consists of tape oi
disk files, which are then analyzed anc
summarized by a separate postproces
sor, TUPOS-P. An hourly concentratior
file is automatically created by TUPOS
the user has the option of creating a par
tial concentration file. For convenience
a brief summary of the simulation i
printed; however, the user is encour
aged to exercise the postprocesso
TUPOS-P to obtain a detailed listing c
the results.
Conclusions and Recommenda
tions
A computer code, TUPOS, is provide
to make dispersion calculations. Th
dispersion parameters are charactei
ized in terms of the wind fluctuatio
statistics at plume height. Plume rise i
calculated layer-by-layer and provision
are included for estimating the amour
of material that penetrates above th
mixing height. Extensive comparisor
of calculated values with field measun
ments have not been made. The mod
produces an output file of calculate
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hourly concentrations that can conve-
niently be processed with a companion
code, TUPOS-P. Evaluation of this
model by those having appropriate data
sets is encouraged.
Thomas Chico and Joseph Catalano are with Aerocomp, Inc., Costa Mesa, CA
92626; the EPA author Bruce Turner (also the EPA Project Officer, see below) is
with the Atmospheric Sciences Research Laboratory, Research Triangle Park,
NC 27711.
The complete report, entitled "TUPOS—A Multiple Source Gaussian Dispersion
Algorithm Using On-Site Turbulence Data," (Order No. PB 86-181 310/AS;
Cost: $16.95, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Atmospheric Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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Environmental Protection
Agency
Center for Environmental Research
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EPA/600/S8-86/010
CHIC^O
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