United States
Environmental Protection
Agency
Environmental Sciences
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S3-84-038 Apr 1984
&EPA Project Summary
EPA Complex Terrain Model
Development: Description of a
Computer Data Base from Small
Hill Impaction Study No. 1
Cinder Cone Butte, Idaho
Lawrence E. Truppi and George C. Holzworth
As part of the U.S. Environmental Pro-
tection Agency's effort to develop and
demonstrate a reliable model of at-
mospheric dispersion emissions in ir-
regular mountainous terrain, the
Complex Terrain Model Development
Program was initiated. The first phase,
a comprehensive tracer field study, was
carried out on Cinder Cone Butte, Idaho,
during the autumn of 1980. Eighteen
quantitative tracer experiments were
conducted, each lasting 8 hr at night or
early morning. The main tracer gas was
sulfur hexafluoride; a second tracer,
Freon 13B1, was used in 10 of the 18 ex-
periments. Averaged meteorological
data were recorded from six towers near
and on the slopes of the hill. Data con-
sisted of direct and derived measures of
temperature, wind, turbulence, solar
and net radiation, and nephelometer
coefficient of scattering. Hourly values
of tracer gas concentrations were de-
tected by a network of approximately
100 samplers located on the slopes of
the hill.
This report serves as a user's guide to
the data files of meteorological pa-
rameters and tracer concentrations to
encourage constructive feedback and to
promote additional applications and
utilizations of various dispersion
models. The system used to collect the
data, the operational procedures used to
run the system, and its performance
record are described. Tables of tracer
gas release data have been included to
assist in any modeling effort. All me-
teorological and tracer concentration
data have been edited and recorded on
magnetic tape. These data are now
available, upon request, at the National
Computer Center, Research Triangle
Park, North Carolina, either as tape
copies or by interactive computer
access.
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 infor-
mation at back}.
Introduction
The extensive development of energy
resources, especially in the mountainous ter-
rain of the western United States, has gen-
erated concern about the resulting impact on
air and water quality. Even in relatively sim-
ple situations, reliable calculations of at-
mospheric transport and diffusion are
difficult to produce. In complex terrain,
mathematical modeling is difficult because
the physical processes are more complicated
and meteorological measurements are less
"representative" than in level terrain settings.
The U.S. Environmental Protection Agency
(EPA) responded to this problem by the
Complex Terrain Model Development
(CTMD) Program, a major program to de-
velop and demonstrate reliable models of at-
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mospheric dispersion for emissions in
mountainous terrain.
An early step in the development of this
program was the convening of a workshop
on problems in modeling atmospheric disper-
sion over complex terrain. Following recom-
mendations of the workshop report, EPA's
CTMD Program involves a coordinated ef-
fort in mathematical model development,
field experimentation, and scaled physical
modeling. The Program's basic objective is
the production of practical models with
demonstrated reliability.
Initially, the CTMD Program has focused
on stable plume impaction/interaction with
elevated terrain. This phenomenon was
singled out because of the likelihood of
relatively high concentrations and because
models that are in use have been challenged
extensively. Stable plume interaction has
been studied first in relatively simple terrain
settings and subsequently in more complex
situations.
EPA's prime contractor for carrying out
the CTMD program is Environmental Re-
search and Technology, Inc. (ERT). EPA's
Fluid Modeling Facility (FMF) and the Na-
tional Oceanographic and Atmospheric Ad-
ministration's Wave Propogation Laboratory
(WPL) have provided sophisticated measure-
ment capabilities. A comprehensive tracer
field study was carried out on Cinder Cone
Butte (CCB), near Boise, Idaho, during the
autumn of 1980 (Small Hill Impaction Study
No. 1, SHIS #1). Based on those data,
several models of plume impaction have
been tested and some relatively new model-
ing concepts have been introduced.
This report describes the data collected in
the tracer field study on CCB and publicizes
their availability. These data offer a wealth
of information for model development/test-
ing, which is continuing in the EPA Program.
Procedure
This report describes the setting of CCB,
the experimental approach, and the follow-
ing data archived on magnetic tape in seven
sets of data files:
• Tower (six) wind and temperature mea-
surements (unaltered but flagged), solar
and net radiation at one location, and
nephelometer data;
• Tower wind data refined by applied
quality assurance procedures;
• Tracer gas concentrations;
• Winds based on pilot balloon data;
• Winds, temperatures, and moisture
measured from tethersondes;
• Winds, temperatures, and moisture
measured from balloon-borne mini-
sondes and
• The modelers' archive of derived wind
and temperature values at tracer release
locations and measured tracer concen-
trations (tracer values in this file differ
from those in data file 3; here averages
of co-located samplers, reanalyzed sam-
ples, and 10-min samples during a given
hour are taken).
In the first set of data files, the neph-
elometer measurements were taken at three
locations near the top of CCB. These data
(5-min averages of backscatter are listed with
Tower B data. A preliminary evaluation of
these measurements indicates that they are
qualitatively useful for determining when and
where plume impact occurs. Although hdar
measurements (by WPL) and extensive pho-
tography were made of the oil fog plumes,
those data are not available for publication
at this time. Pertinent scaled physical model-
ing studies by EPA's FMF are being pub-
lished as they become available.
Two tracer gases, SF6 and Freon, were
released at different heights from the boom
of a mobile crane. The mobility of the release
system resulted in a higher number of suc-
cessful hours per test (normally six or seven
hours out of eight) in which significant tracer
concentrations were recorded on the hill.
The release system upwind of the hill could
not be aligned in only one experiment (212)
because of variable wind patterns.
The SF6 and Freon tracer gases were
stored in individual compressed gas cylinders
kept at ground level. Flexible Tygon tubing,
approximately 100 m long, led from the gas
cylinders to different release heights on the
crane boom. For the first nine experiments
(201 to 209), the tracer release tube was at-
tached to the smoke generator platform at
the smoke release height but from 0.5 m to
1 m away, horizontally. For the last nine ex-
periments (210 to 218), the tracer release
tube was on a separate pulley system in-
dependent of the smoke generator platform
and about 1 m away, horizontally, from the
smoke release. The gas flow was monitored
by separate rotameters on the SF6 and Freon
cylinders, and each cylinder's weight loss
was monitored by a separate electronic
digital scale.
Tracers were sampled by means of ap-
proximately 100 individual battery-operated
samplers capable of either 10-min of 1-h se-
quential operation. Each sampler contained
12 individual pumps, each of which intermit-
tently filled a Tedlar bag during the sampling
period. Thus, each sampler could take se-
quential 1-h samples over a 12-h period or
sequential 10-min samples over a 2-h period.
Normally, 1-1 bags were used for both hourly
and 10-min samples. Except for samples
taken from reflection masts (described
below), all samples were taken at 1 m above
ground level. Seventy of the samplers were
fixed in location, whereas 10 moveable sam-
plers were placed on either the NW or SE
side of the hill, depending on the prevailing
wind direction. Of these 80 samplers, typi-
cally 60 were used for 1-h average samples
and 20 were used for 10-min average sam-
ples. Another 20 samplers were used for
reflection masts for background ambient air
samples and for co-located samplers.
Air samples on a reflection mast were
drawn in from 3 m and 6 m (in addition to
the normal 1-m height) and also at an uphill
site equal in elevation to the 6-m height. The
purpose of this sampling strategy was to
determine if the tracer gas would "reflect"
off the surface as predicted by some disper-
sion models. Four of these reflection masts
were used during Cases 203 to 218. Nor-
mally, the 3-m height was sampled on only
one of the reflection masts; the other masts
were sampled at 6 m and 1 m, in addition
to the uphill site.
Results
Meteorological Data Tape Files
Two sets of tower meteorological data
files are recorded on one tape. The first set
of files, numbers 1 to 323, are edited but un-
corrected data.
The second set of files, numbers 324 to
612, are derived from the same wind speed
and direction observations as set number
one, except that the data have been cor-
rected to account for audited misalignment
of wind sets, for consistent errors in instru-
ment calibration, for noncosine response of
the wind component propeller sensors, and
for the effect of tower wakes on wind
speeds.
Wind speed and directions from the Cli-
matronics F460 cup-and-vane anemometers
were corrected for erroneous calibration,
misalignment to true north, and mean non-
linearity in vane response. Wind speeds and
directions derived from the UVW propeller
anemometers were corrected for noncosine
response, misalignment to true north, and
consistent calibration efforts that were
greater than the resolution of the measure-
ment provided by the data acquisition sys-
tem. In addition, corrections were applied to
wind speeds derived from both types of wind
instruments to account for tower wakes.
These corrections resulted in substantially
improved correspondence between speed
and direction data from the two types of
wind sets. Data tape files are located at the
National Computer Center, Environmental
Research Center, Research Triangle Park,
North Carolina on Sperry UNIVAC 1100/83
systems magnetic tape, nine track, odd par-
ity, ASCII-quarter word mode, density 6250
BPI, tape number 004700. UNIVAC users or
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users of interactive computer access may
assign the tape with the UNIVAC Executive
Control Language statement, @ASG,T
CTML*CCB,U9S//////Q,004700. Copies of
the tape can be produced and translated into
formats acceptable to any computer using
nine track tape drives.
Tracer Gas Concentrations Data
Tape Files
Tracer concentrations are stored on 18
tape files, one for each experiment,
numbered 613 to 630, following the cor-
rected meteorological tower data on tape
number 004700. Each record has observed
concentrations of SF6 and Freon 13B1 de-
tected by one sampler in the network in a
sequential 1-hr period or a sequential 10-min
period. Included in each tape record are
values of quality (flags), gas chromatograph
identification, sampler location, sampling
start and end times, Tedlar bag identifica-
tion, analysis date and time, and values of
gas chromatography response and attenua-
tion. Tracer gas release data are presented
in the text of the document, consisting of
emission rates, times of release, and loca-
tion and heights of release. To supplement
the tracer gas concentration data, calibration
data observed on the gas chromatograph in-
struments during all experiments are in-
cluded on the data tape on eight files, 631
to 638, immediately following the tracer gas
tape files. There are eight tape files, one for
each gas chromatograph employed in tracer
gas analysis. Each record in the files iden-
tifies the instrument, the date of calibration,
the calibration gas concentration, and the
resulting gas chromatograph response.
Pilot Balloon Data Tape Files
North American Weather Consultants
operated pilot balloon systems from the up-
wind of two locations about 1.3 km NW and
SE of the CCB center. Wind profiles were
derived from double theodlite measurements
of trajectories from pilot balloons or mini-
sonde balloons released approximately once
an hour. Of 27 data tape files, 9 contain wind
profiles for 9 days preceding the days of
tracer gas release and 18 contain data from
experiments 201 to 218. Files are numbered
639 to 665 following the gas chromatography
calibrations data on tape number 004700.
Data records contain computed wind speed
and direction at 30 sec intervals after release.
Tethersonde and Minisonde Data
Tape Files
North American Weather Consultants
operated tethersonde and minisonde sys-
tems from the same two locations NW 7nd
SE of CCB. The tethersonde was operated
in an ascent-descent sequence yielding pro-
files of temperature, pressure, relative
humidity, mixing ratio, wind speed, and
direction once an hour to a height of at least
200 m above local terrain. Release times
were scheduled 30 min after the pilot balloon
soundings to obtain wind profiles every half
hour. Minisonde flights were conducted
when wind speeds were too high to allow
tethersonde operation, or when the tether-
sonde system was not working. The mini-
sonde was operated as a free release balloon
sounding to obtain profiles of temperature,
wet bulb temperature, and pressure and was
sometimes tracked as a pilot balloon for wind
profiles.
Of 17 tape files, 10 contain tethersonde
data and 7 contain minisonde data. Files are
numbered 666 to 675 for tethersonde data
and 676 to 682 for minisonde data on tape
number 004700, immediately following the
pilot balloon data files.
Modelers' Data Base Tape Files
The modelers' data archive contains
observed 1 -hr average tracer gas concentra-
tion data, tracer release information, and
meteorological variables and derived pa-
rameters estimated at release height for each
of the hours when either SF6 or Freon tracer
was released. The method of estimating
meteorological data appropriate to the re-
lease heights of the tracer gases relies on
assumptions and procedures described in the
text.
Data are stored at the National Computer
Center, Environmental Research Center,
Research Triangle Park, North Carolina on
the Sperry UNIVAC 1100/83 system's mag-
netic tape, nine track, odd parity, ASCII-
quarter word mode, density 6250 BPI, tape
number 002689. UNIVAC users or users of
interactive computer access may assign the
tape with UNIVAC Executive Control Lan-
guage statement, @ASG,T CTML*CCBTR,
U9S//////Q,002689. Copies of the tape can
be produced and translated into formats ac-
ceptable to any computer using nine track
tape drives.
There are four tape files. File no. 1 con-
tains a chronological listing of SF6 tracer
release data and associated meteorological
parameters for the eighteen experiments. File
no. 2 contains SF6 concentrations recorded
by the network of samplers during the re-
leases described in file no. 1. Similarily, file
no. 3 and file no. 4 document the release and
detection of the Freon gas tracer.
Conclusion
This report describes the data collected in
the tracer field study at Cinder Cone Butte,
Idaho and illustrates the availability of the
data to encourage additional applications in
utilization and testing various dispersion
models. Data are arranged on magnetic tape
files so that identification and acquisition is
easily accomplished by any user with interac-
tive computer access to the UNIVAC com-
puter at the National Computer Center,
Research Triangle Park, North Carolina or
with access to any computer capable of
reading standard nine-track magnetic tape.
The report describes the instruments used
to collect the data, the operational pro-
cedures used to run the collection system,
and the performance record of the system.
The EPA authors Lawrence E. Truppi and George C. Holzworth are on
assignment from the National Oceanic and Atmospheric Administration,
Department of Commerce, to the Environmental Sciences Research Laboratory,
Research Triangle Park. NC 27711
The complete report, entitled "EPA Complex Terrain Model Development:
Description of a Computer Data Base from Small Hill Impaction Study No. 1
Cinder Cone Butte, Idaho,"(Order No. PB84-161 439; Cost $13.00, subject to
changel will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA authors can be contacted at:
Environmental Sciences Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
if U S GOVERNMENT PRINTING OFFICE, 1984 — 759-015/7639
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Environmental Protection
Agency
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