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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