Overview of the Ozark Isoprene Experiment (OZIE)
99-412
Thomas Pierce
NOAA/Air Resources Laboratory, EPA (MD-80), Research Triangle Park, NC 27711 (on assignment
to the National Exposure Research Laboratory, U.S. Environmental Protection Agency)
Michael Koerber
Lake Michigan Air Directors Consortium, 2250 E Devon Avenue, Des Plaines, Illinois 60018
Alex Guenther
Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado
80307
Steven King
Department of Air, Illinois Environmental Protection Agency, Springfield, Illinois 62794-9276
Steven Lengerich
Indiana Department of Environmental Management, Indianapolis, Indiana 46206-6015
Jay Turner
Environmental Engineering Program, Washington University, St. Louis, Missouri 63130-4899
ABSTRACT
Ozone modeling studies, such as those performed for the Ozone Transport Advisory Group (OTAG),
have raised concerns about extremely high isoprene concentrations (> 50 ppbv) that have been
predicted over the Ozark Plateau in southern Missouri. In response to these concerns, a collaborative
study was undertaken involving participants from AMEREN, U.S. Department of Army at Fort
Leonard Wood, Lake Michigan Air Directors Consortium, National Center for Atmospheric Research,
Purdue University, U.S. Environmental Protection Agency, Washington State University, Washington
University (St. Louis), and the states of Illinois, Indiana, and Missouri. The Ozark Isoprene
Experiment (OZIE) took place during July 1998 and included measurements of isoprene from the
surface and aloft at several locations stretching from northeastern Oklahoma to southern Indiana
Measurements were made along a balloon tethered to nearly 1000 m, surface footprint sites at five
locations upwind of the balloon, surface sites in Illinois and Indiana, and from an aircraft flying at
heights ranging from 300 to 1000 m over southern Illinois, southern Indiana, and southern Missouri.
Preliminary analysis of the data indicates that daytime surface isoprene concentrations ranged from 1
to 36 ppbv, and isoprene concentrations measured at 600 m ranged from 0.4 to 6 ppbv. Conditions
were favorable for the emission of isoprene, with daytime maximum temperatures exceeding 32°C on
at least four days during the two-week study period. This paper provides an overview of the study
design and describes measurements taken during the experiment.
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NERL-RTP-O-644
TECHNICAL REPORT DATA
1 REPORT NO.
60Q/A-99/045_
4 TITLE AND SUBTITLE
Overview of the Ozark isoprene experiment (OZIE)
5 REPORT DATE
6 PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Thomas E. Pierce, et al.
8 PERFORMING ORGANIZATION REPORT NO
9 PERFORMING ORGANIZATION NAME AND ADDRESS
Atmospheric Modeling Division
National Exposure Research Laboratory
U S. Environmental Protection Agency
79 T.W. Alexander Drive, MD-80
Research Triangle park, NC 27711
10 PROGRAM ELEMENT NO
11 CONTRACT/GRANT NO
12 SPONSORING AGENCY NAME AND ADDRESS
NATIONAL EXPOSURE RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U S ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NC 27711
13 TYPE OF REPORT AND PERIOD COVERED
14 SPONSORING AGENCY CODE
15 SUPPLEMENTARY NOTES
16 ABSTRACT
Ozone modeling studies, such as those performed for the Ozone Transport Advisory
Group (OTAG), have raised concerns about extremely high isoprene concentrations (>
50 ppbv) that have been predicted over the Ozark Plateau in southern Missouri In
response to these concerns, a collaborative study was undertaken involving
participants from AMEREN, U.S Department of Army at Fort Leonard Wood, Lake
Michigan Air Directors Consortium, National Center for Atmospheric Research, Purdue
University, U.S Environmental Protection Agency, Washington State University,
Washington University (St. Louis), and the states of Illinois, Indiana, and
Missouri The Ozark Isoprene Experiment (OZIE) took place during July 1998 and
included measurements of isoprene from the surface and aloft at several locations
stretching from northeastern Oklahoma to southern Indiana Measurements were made
along a balloon tethered to nearly 1000 m, surface footprint sites at five locations
upwind of the balloon, surface sites in Illinois and Indiana, and from an aircraft
flying at heights ranging from 300 to 1000 m over southern Illinois, southern
Indiana, and southern Missouri. Preliminary analysis of the data indicates that
daytime surface isoprene concentrations ranged from 1 to 36 ppbv, and isoprene
concentrations measured at 600 m ranged from 0.4 to 6 ppbv. Conditions we-re
favorable for the emission of isoprene, with daytime maximum temperatures exceeding
32°C on at least four days during the two-week study period This paper provides an
overview of the study design and describes measurements taken during the experiment
17
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19 SECURITY CLASS (This Report)
Unclassified
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INTRODUCTION
Air quality modeling studies have demonstrated the important role of biogenic volatile organic
compounds (VOCs) in producing ozone near rural and urban areas. u Recognizing the need for
accurate biogenic VOC emission inventories for air quality simulation modeling, efforts have been
undertaken to develop emission inventories at the appropriate spatial (<20 1cm) and temporal (hourly)
scales. 3 Annual biogenic VOCs emissions for the contiguous United States are estimated to exceed
that of anthropogenic VOCs (30 Tg versus 21 Tg, where Tg = lO g). The most abundant biogenic
VOC is isoprene, with estimated annual emissions of 17 Tg. 5 Figure 1 shows that isoprene emissions
estimated with the Biogenic Emissions Inventoiy System (BEIS2) are highest over the Ozark Plateau
region of the central United States, and photochemical models using these emission estimates have
predicted that isoprene concentrations may be as high as 100 ppbv over this region. Concerns have
been raised because these large modeled isoprene values have not been corroborated with observed
data.
Because of the lack of isoprene measurements in this region and to address these concerns, a number of
organizations from the academic, private, state, and federal sector collaborated in the Ozark Isoprene
Experiment (OZIE) during the summer of 1998. Key participants and their responsibilities during
OZW are listed in Table 1. The overall goal of OZIE was to provide spatial and temporal
measurements of isoprene during meteorological conditions conducive to high isoprene emissions.
Surface measurements were made near forested areas in Indiana, Illinois, and Missouri. Elevated
measurements were made using tethered balloons and an aircraft above the surface sites, and in
Missouri up to five more surface sites were positioned upwind of the balloon. Other measurements
collected in some locations included speciated VOCs, isoprene oxidation products, carbonyls, and
meteorology. These data should help in evaluating isoprene emission estimates for this region and in
evaluating isoprene concentrations simulated with photochemical grid models. The tethered balloon
flux measurement technique 6 will be used to estimate landscape scale (5 - 50 krn 2 ) isoprene fluxes. The
purpose of this paper is to provide a brief overview of the field experiment.
SITE DESCRIPTIONS
As summarized in Table 2, measurements during OZIE were taken from eastern Oklahoma to southern.
Indiana, with much of the study’s focus on south-central Missouri. Surface measurements were made
near forested areas in Indiana, Illinois, and Missouri as shown in Figure 2. Elevated measurements
were made using tethered balloons and an aircraft above the surface sites, and in Missouri up to five
more surface sites were positioned upwind of the balloon. These five surface sites were located in the
emissions “footprint” of the tethered balloon at the primary site in Ft. Leonard Wood, Missouri 1 and at
individual sites in different forest types in southern Illinois (Giant City State Park> and in southern
Indiana (Morgan-Monroe State Forest). The ground-based sites are expected to characterize near-
surface conditions in these portions of the study domain Speciated VOC and some meteorological
data were collected at all of these sites. The aloft measurements are expected to provide some
information about the vertical profile of isoprene concentrations The tethered balloon measurements
included speciated VOC and carbonyl data The aircraft made grab samples of VOC and transects of
ozone across the study area Further descriptions of each site are given below
Illinois surface site
The Illinois Environmental Protection Agency (TEPA) operated a surface measurement site in Jackson
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County in Giant City State Park (37°4T N, 89°14’ W), which is located about 13 km south of
Carbondale, Illinois. Approximately 33% of Jackson County is forested, and oak (a high isoprene
emitter) comprises about 20% of the forested area. The site was located in a small (-4600 m 2 )
clearing, with forests located to the south and southwest. VOCs were sampled via stainless steel
canisters, and gas chromatographic (GC) analysis was performed by IEPA personnel. A total of 40
samples were collected on fourteen days. Many (13 out of 40) of the hourly samples were collected at
2 p.m. CDT, and all of the samples were taken during daylight hours between 6 a.m. and 8 p.m. Two
samples were taken during the early morning transition period (6 a.m. - 8 a.m.), and two samples were
taken during the evening transition period (6 p.m. - 8 p.m.). Preliminary analysis of the Illinois data
indicates a mean isoprene concentration of 7 ppbv, ranging from I to 15 ppbv.
The VOC sampler used dunng the experiment is a manual passive grab sampling device designed
around a critical orifice and a back flow pressure regulator. When attached to a certified clean
evacuated canister, about a 1-hour sample is collected at a steady flow rate of about 60 cc/minute. Just
under atmospheric pressure is reached at the end of the sampling period. A check valve allows flow in
one direction to the evacuated canister, which protects the collected sample until the green handled
valve on the grab sampling device and the valve on the canister are manually closed.
Meteorological data for the Illinois site are available from the Southern Illinois University Climate
Network (ICN) site, located about 11 km northwest of Giant City State Park. Measured parameters
include temperature, wind speed and direction, solar radiation, soil temperature, soil moisture, dew
point temperature, precipitation, pressure and relative humidity. Additional meteorological data are
available from a National Atmospheric Deposition Program site located at the University of Illinois
Dixon Springs Agricultural Center, which is approximately 50 km southeast of Giant City State Park.
Indiana surface site
The Indiana Department of Environmental Management (IDEM) operated a surface measurement site
in Monroe County within the Morgan-Monroe State Forest (39°19’ N, 86°23’ 1W), which is located
about 50 km south of Indianapolis. Approximately 48% of Monroe County is forested, and - 27% of
the forestcd land consists of oak. The surface measurement site was located in a small clearing near
the Indiana University astronomical observatory. The secondary balloon was flown from a small
clearing next to the observatory on July 13, 1998. The total clearing for the observatory is
approximately 40 m x 60 m. The open area north of the observatory is approximately 40 m x 30 m.
The trees surrounding the clearing are about 15 m in height The observatory is a one-story building
with two telescope domes extending approximately 5 m above the building. The building is fenced,
generally 3 m from the walls, plus an open area about 10 m x 10 m, which is used for vehicle access.
The canister sampler was located inside the fence and outdoor power was provided. The sampler,
which is similar to the Illinois design, was inside a small enclosure approximately 1 m 3 . Probe height
was about 3 m above the ground. VOC samples were taken via stainless steel canisters, and GC
analysis was performed by IDEM personnel. A total of 25 samples were collected on 13 days.
Slightly more than half (56%) of the hourly samples were taken at 2 p.m EST, and all the samples
were taken between 10 a.m. and 5 p.m. EST. Preliminary analysis of the Indiana data indicates a mean
isoprene concentration of 6 ppbv, ranging from 2 to 15 ppbv
Missouri surface “footprint” sites
Washington University, under contract to AMEREN, operated three sets of isoprene emission
“footprint” measurement sites: (1) within Ft. Leonard Wood in Pulaski County, (2) within the Mark
Twain National Forest near Willow Springs in Howell County, and (3) within the Sinkin Creek
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wilderness area in the Mark Twain National Forest near the border of Dent and Iron County. The
surface measurements were made within a 10 - 15 km 2 “footprint” area upwind of the tethered balloon
site. VOC samples were taken via stainless steel canisters and carbonyl samples via cartridges, with
GC analysis performed by Washington State University. A total of 92 samples were collected during
nine days. Most of the measurements were taken during daylight hours, with 62% of the
measurements being made between 12 p.m. and 3 p.m. CDT. About one-fourth (24%) of the
measurements were made during the morning (6- 8 a.m.) and evening (6 - 9 p.m.) transitional periods.
Preliminary analysis of the surface data indicates a mean isoprene concentration of 12 ppbv, ranging
from 2 to 36 ppbv.
Surface meteorological data were collected at the tethered balloon site by the National Center for
Atmospheric Research (NCAR). Measured parameters included photosynthetically active radiation
(PAR), temperature, and relative humidity. The Department of the Defense operates a low-level
SODAR at Ft. Leonard Wood, which can provide vertical wind proflEes. Ft. Leonard Wood also has
additional meteorological monitoring data as part of a State of Missouri Prevention of Significant
Deterioration (PSD) permit. These data are being archived by the State of Missouri Department of
Natural Resources
Tethered balloons
The National Center for Atmospheric Research (NCAR) primarily operated a tethered balloon system
at Ft. Leonard Wood, Missouri. NCAR also deployed smaller balloon systems at two other sites in
southeastern Missouri (Sinkin Creek and Willow Springs), the Illinois surface site, the Indiana surface
site, and in northeastern Oklahoma. Three to six samplers were deployed at heights ranging to 1000 m
along the tether of each balloon, including one at ground level. Samples were collected on solid
adsorbent traps and transported to Boulder, CO for analysis using GC-mass spectrometry/atomic
emission detection (MSIAED) and GC-flame ionization detection (FID) Targeted compounds
included isoprene and its oxidation products (methyl vinyl ketone and methacrolein). Approximately
25 flights were made during nine different days. Meteorological data collected aloft at the balloon sites
included temperature and relative humidity measured with each sampler package. Data from NCAR
should be submitted to the preliminary data archive for internal study review during the spring of 1999.
Aircraft
R. Jacko (Purdue University) operated a Cessna (1210) twin engine aircraft and collected ozone, VOC,
and carbonyl concentration data. The aircraft was based in West Lafayette, Indiana, and took VOC and
carbonyl grab samples over the surface sites at Ft. Leonard Wood, Giant City State Park, and Morgan-
Monroe State Forest. Grab samples were typically taken at a height of— 600 m. VOC samples were
analyzed by the IEPA, and carbonyl samples were analyzed by the Wisconsin Department of Natural
Resources. A total of2l VOC/carbonyl samples were collected on seven days. Preiiminary analysis
indicates a mean isoprene concentration of 2 ppbv, ranging from 0 4 to 6 ppbv.
A typical flight plan during the experiment consisted of the following
(1) West Lafayette to Study AreaS Depart at 1000 CDT and fly “dolphin” maneuvers between 150 -
600 m above ground level (agi) at a ground speed of—’70 ms’ Make Continuous measurements of
ozone concentration
(2) Study Area Arrive Ft. Leonard Wood at 1215 CDT, land, refuel, takeoff, and take a grab sample
Then fly to Giant City State Park (1440-1500 CDT) and Morgan-Monroe State Forest (1620-1640
CDT) Grab sampling was made while flying a “race track” pattern centered mostly upwind, but
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enclosing the surface Site of interest (Ft. Leonard balloon/surface footprint site, Illinois surface site,
and Indiana surface site). Approximate dimensions of the “race track” were about 10 km long and
5 km across. The flight level was — 00 m.
(3) Study Area to West Lafayette: Depart area over final surface site and resume “dolphin” maneuvers.
Return to base about 1830 CDT.
FIELD STUDY OPERATIONS
Beginning July 1, 1998, a daily conference call was held for the purpose of identifying intensive
sampling days. The call occurred at 11:00 am CDT (noon EDT) on a special conference line
established by USEPA. The calls began with a brief review of meteorological conditions in the study
area. Meteorologists from the states of Illinois, Indiana, and Missouri provided this review. Each
study participant then reported on his/her readiness for sampling. USEPA and LADCO, along with the
field personnel, then determined whether intensive sampling should be performed the following day.
A status recording was updated each day, and study participants were given an e-mail update on a daily
basis. The decision to conduct intensive sampling the following day was based on the forecasted
weather conditions and the readiness of the study participants. The preferred sampling conditions
consisted of sunny skies and high temperatures (> 30°C), generally associated with a region of high
pressure. Over a several day period, these conditions favored the build-up of regional ozone
concentrations and the degradation of visibility. However, these conditions were also conducive to
thunderstorms, which occasionally altered sampling schedules by the tethered balloon and aircraft
crews. In addition, sampling at Ft. Leonard Wood had to be coordinated closely with the Department
of Army who was actively engaged in artillery, aircraft, and small-arms training exercises near the
surface “footprint” and tethered balloon sites.
METEOROLOGICAL CONDITIONS
A summary of the meteorological conditions in southern Missouri, southern Illinois, and southern
Indiana during OZIE is provided below.
July 6-12, 1998
Dunng the early part of the week, clouds and showers associated with a stationary warm front covered
much of the study area. Field personnel and equipment were in place by Wednesday (July 8). On
Thursday (July 9), although forecasted conditions were less than desirable (chance of showers,
northerly winds, and maximum temperatures around 30°C), a decision was made to proceed with a test
sampling day. On Friday through Sunday, clouds and showers continued to affect parts of the study
area. Because of this, and temperatures less than —28°C and northerly flow from a high pressure
system located over the Great Lakes, no more special sampling was conducted this week
July 13-19, 1998
The continued period of unsettled weather hampered field operations as the small balloon system was
scheduled to sample near the Indiana and Illinois sites during the early part of the week. However, a
decision was made to proceed with balloon and ground-based sampling at these sites, regardless of
weather conditions, because of the balloon’s limited availability in Indiana and Illinois. On Monday
(July 13), the weather improved slightly with clearing skies and temperatures reaching about 30°C,
although the winds were easterly. Special sampling continued on Tuesday (July 14), although
conditions began to deteriorate due to an intense upper level low pressure system Clouds and showers
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associated with the upper level low affected the eastern part of the study area, which produced
generally poor sampling conditions for the small balloon. By Thursday (July 16), skies began to clear
in the western part of the study area (around Ft. Leonard Wood) and temperatures reached 30°C.
Limited special sampling was conducted on Thursday. Conditions further improved on Friday (July
17), but the flow remained northerly. Given the similarity of these marginal conditions to previous
sampling days and the forecast for ideal conditions (temperatures up to 37°C, southerly flow, and clear
skies) for several days beginning on Saturday (July 18), a decision was made to delay any special
sampling until the weekend. On Saturday, the upper level ridge began to build over the study area.
Skies were generally clear, winds were southerly, and maximum temperatures approached 35 °C. With
an outlook for continued favorable conditions for the next several days, a 5-day period of special
sampling began on Saturday. On Sunday (July 19), maximum temperatures increased slightly and
approached 37°C.
July 20-26, 1998
The upper level ridge remained in place into the early part of the last week of the study, as the very hot
weather persisted on Monday (July 20) and Tuesday (July 21). These days were similar to Sunday
(July 19), with sunny skies, southerly winds, and maximum temperatures of —37°C. These conditions
continued into Wednesday, but by late in the day, a weak cold front began to sag down from the north,
bringing welcome relief from the heat. The 5-day penod of special sampling ended on Wednesday
(July 22). On Thursday and Friday, there were clouds arid showers associated with the front over much
of the study area and maximum temperatures were only —27°C
QUALITY ASSURANCE AND DATA MANAGEMENT
Several quality assurance procedures were implemented during the field program. Intercomparisons
were performed between the various VOC measurements. A footpnrit sampler was located beside a
near-surface tethersonde cartridge. In addition, tethersonde cartridges were located beside the Indiana
and Illinois VOC samplers, when the small balloon made measurements at these locations.
Comparisons were also made between the aircraft and the tethersonde, as the highest tethersonde
cartridge was flown at approximately the same elevation (—800 in) as the aircraft grab sample In
addition, three sets of canister samples were di’rculated between the three surface VOC sampling
groups to provide for analytical intercompairson
Several on-ground program audits and one aloft intercomparison were performed for the Jacko aircraft
The on-ground audits were conducted on April 29 by IEPA, May 15 by WDNR; August 13 by [ EPA
and WDNR; September 15 by ]DEM; September 18 by WDNR; and September28 by IEPA. The aloft
intercomparison was conducted on July 1, 1998 with an aircraft operated by the State of Wisconsin.
The initial level of data validation is the responsibility of each measurement group. These groups are
submitting their data to an internal data archive in flat ASCII or EXCEL computer files for further
review and intercomparison by the OZIE study team Afler the team completes its review during the
fall of 1999, the data will be made available to the public via anonymous ftp.
FUTURE PLANS
In the short term, analysis and quality assurance of the VOC and carbonyl data collected during OZIE
will continue By the spring of 1999, the tethersonde data will be available for review by the OZIE
study group. Further analysis will be performed on the data to see if inferred isoprene flux values
agree with the isoprene emission fluxes estimated with inventories such as BEIS2 In addition,
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LADCO and USEPA/ORD are each planning to model the July 1998 period with photochemical grid
models, and to compare the model predictions of isoprene with isoprene observed during the study. It
is hoped that additional collaboration will take place with groups involved with the Texas Isoprene
Experiment (TXIE) and the Program for Research on Oxidants: PHotochemistry, Emissions, and
Transport (PROPHET) study in northern Michigan, both of which made isoprene measurements during
the summer of 1998.
Further information on OZIE may be obtained from http://www.epa.govfasmdnerllozie / of by
contacting pierce. tom( epa. gov .
ACKNOWLEDGEMENTS AND DISCLAIMER
The authors gratefully acknowledge the hard work and contributions made by all of the OZIE study
participants. in particular, we would like to recognize Ken Anderson from AMEREN; Pam Brooks
from Illinois EPA; Balvant Pate! from Indiana DEM; Bill Baugh, Jennifer Zabel, Gabrielle Petron, and
Jim Greenberg from National Center for Atmospheric Research; Bob Jacko from Purdue University;
Chris Geron from USEPAJORD; Brian Long from Washington University in St. Louis; and, Lee
Bamesburger, Brian Lamb, Hal Westberg, Gene. Aliwine, and Brian Hopkins from Washington State
University We also appreciate the assistance of Roiy McCarthy and Steve Thurman at Ft. Leonard
Wood’s Environmental Office.
This paper has been reviewed in accordance with the U.S. Environmental Protection Agency’s peer and
administrative review policies and has been approved for presentation and publication. Mention of
trade names or commercial products does not constitute endorsement or recommendation for use.
REFERENCES
1. Trainer, M.; William, E.; Parrish, D ; et al. Nature 1987, 329, 705-707.
2 Chameides, W.; Lindsay, R.; Richardson, J.; et al. Science 1988, 241, 1473-1475.
3. Pierce, T., C. Geron, L Bender; et al J Geophys Res 1998, 103, 25611-25629.
4. Nizich, S.; Misenheimer, D.; Perce, 1.; eta!. National Air Pollutant Emission Trends. 1900 - 1995,
EPA-454/R-96-007, U.S Environmental Protection Agency, Research Triangle Park, 1996, 74 pp
5. Pierce, T.; Dudek, M. In Proceedings of the A WMA Emission Inventory Specialty Conference; New
Orleans, Louisiana, 1996; pp 309-326.
6. Guenther, A., Zimmerman, P.; Klinger, L; et al ,J. Geop/iys Res 1996, 101, 1345-1359
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Table 1. Key participants and their responsibility during the Ozark Isoprene Experiment (OZIE).
Organization
Responsibility
USEPAJORD/NTERL
NCAR; USEPA/ORD/NRMRL
Bob Jacko & Associates; LADCO
Illinois EPA
Indiana DEM
Missouri DNR;
U.S. Army (Ft Leonard Wood)
AMEREN; Washington State University;
Washington University (St. Louis)
Project coordination
Tethered balloons; land characterization
Aircraft measurements
Surface VOC measurements
Surface VOC measurements
Missouri site coordination; meteorological data
archival
Surface ( tt footpnnt”) VOC measurements
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Table 2. Measurements taken during the Ozark Isoprene Experiment (OZIE).
Site
Measurements
Sampling frequency
Ft. Leonard Wood, Missouri
Surface VOC (5 sites)
Surface meteorology (1 site)
Tethered balloon
Aircraft
— 3 per day, 13 days
Hourly
—3 per day, 13 days
Special study days
Sinkin Creek, Missouri
Surface VOC (4 sites)
Tethered balloon
4 per day, 1 day
4 per day, 1 day
Willow Springs, Missouri
Surface VOC (5 sites)
Tethered balloon
4 per day, 1 day
4 per day, 1 day
Giant City State Park, Illinois
Surface VOC
Surface ozone
Surface meteorology
Aircraft
i-S per day, 13 days
Continuous, hourly
Continuous, hourly
One observation on special
study days
Morgan-Monroe State Forest,
Indiana
Surface VOC
Surface meteorology
Aircraft
__________________________
1-3 per day, 13 days
Continuous, hourly
One observatton on special
study days
Table 3. Measurements taken from the B. Jacl co aircraft operated dunng the Ozark Isoprene
Experiment (OZIE)
Parameter
Manufacturer/model
Resolution
Accu racy
Ozone
TECO 49*
2 ppm
10%
Latitude/longitude
Apollo 61 8c
0.01 mm
0.8 km
Altitude
Loran encoder set
against Cessna altimeter
10 ft
20 ft
Air speed
On-board Cessna
5 kts
5%
Ozone recorder
Rustrak
0.1 ppb
1%
VOC
Canister-based
Carbonyls
Cartridge-based
sThe TECO 49 was specially modified for use in aircraft. It updated analog output every 8 seconds, instead of the usual 20
seconds The full-scale response time was 24 seconds, instead of the usual 60 seconds The analyzer was supplied by Mel
Schuchardt (Illinois EPA).
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Figure 1. Gridded isoprene emissions estimated for July 12, 1995 (20 GMT) at a 36 km resolution
using a version of BEIS2 developed for the Community Multiscale Model for Air Quality
(CMAQIMode1s-3). Meteorological conditions on this day in the OZIE domain were similar to those
observed during July 18-22, 1998.
116.55779
87.418
58.279
29.139
- 0.000
molesis
PAVE
bq
MCNC
July 12.1995 20 :00 :00
Min=O.000 at (8,1). Max=1 16.557 at (26,39)
1
85
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Figure 2. The Ozark Isoprene Experiment (OZIE) study area.
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