United States Office of Air Quality EPA-450/4-79-008c
Environmental Protection Planning and Standards September 1979
Agency Research Triangle Park NC 27711
_
c/EPA Study of the Nature
of Ozone, Oxides of
Nitrogen, and Nonmethane
Hydrocarbons in Tulsa,
Oklahoma
Volume III
Data Analysis and
Interpretation
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EPA-450/4-79-008C
Study of the Nature of Ozone,
Oxides of Nitrogen, and Nonmethane
Hydrocarbons in Tulsa, Oklahoma
Volume III
Data Analysis and Interpretation
by
W.C. Eaton, M.L Saeger, W.D. Bach,
J.E. Sickles, II, and C.E. Decker
Research Triangle Institute
Research Triangle Park, N.C. 27709
Contract No. 68-02-2808
EPA Project Officer: Norman C. Possiel, Jr.
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, N.C. 27711
September 1979
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This report was furnished to the Environmental Protection Agency by Research
Triangle Institute, Research Triangle Park, North Carolina, in fulfillment of Con-
tract No. 68-02-2808. The contents of this report are reproduced herein as received
from Research Triangle Institute. The opinions, findings, and conclusions expressed
are those of the author and not necessarily those of the Environmental Protection
Agency. Mention of company or product names is not to be considered as an
endorsement by the Environmental Protection Agency.
This report is issued by the U.S. Environmental Protec-
tion Agency to report technical data of interest to a
limited number of readers. Copies are available free
of charge to Federal employees, current contractors and
grantees, and nonprofit organizations - in limited quan-
tities - from the Library Services Office (MD-35),
Research Triangle Park, North Carolina 27711; or, for
a fee, from the National Technical Information Service,
5285 Port Royal Road, Springfield, Virginia 22161.
Publication No. 450/4-79-008c
ii
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CONTENTS
Figures v
Tables . viii
Acknowledgments xi
1.0 INTRODUCTION 1
1.1 Background 1
1.2 Research Objectives 2
1.2.1 Objectives of the Field Measurements Program 2
1.2.2 Objectives of the Data Analysis and Interpretation
Effort 2
1.3 Analysis Approach and Report Organization 2
2.0 PRINCIPAL FINDINGS AND CONCLUSIONS 5
3.0 DATA ANALYSIS AND INTERPRETATION 9
3.1 Meteorological Analysis 9
3.1.1 Meteorological Representativeness of Tulsa,
Summer 1977 9
3.1.2 Air Transport and Vertical Structure 15
3.2 Examination of Mean Monthly Pollutant Distributions 19
3.2.1 Ozone 19
3.2.2 Oxides of Nitrogen 26
3.2.3 Nonmethane Hydrocarbons 30
3.3 Discussion of Stratified Data Base 31
3.3.1 Introduction 31
3.3.2 Urban and Nonurban Ozone 32
3.3.3 Urban and Nonurban Oxides of Nitrogen 40
3.4 Statistical Relationship of Ozone to Other Parameters .... 43
3.5 Analysis and Interpretation of the Hydrocarbon Data
Base 51
3.5.1 Background 51
3.5.2 Comparison of Nonmethane Hydrocarbons at
Various Sites 53
3.5.3 Comparison of Classes of Hydrocarbons 55
3.5.4 Comparison of Individual Hydrocarbon Compounds .... 56
3.5.5 Variation in Hydrocarbon Content by Day of
the Week 62
3.5.6 Hydrocarbon Content of Samples Taken During
Aircraft Low-Pass Operations 63
3.5.7 Distributions of Hydrocarbons From South
to North at the Surface and Aloft 67
3.5.8 Correlation between NMHC by Sum of Species
and by Continual Chromatography 70
111
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CONTENTS (continued)
3.5.9 Comparison of Hydrocarbons from GC/FID
and GC/Mass Spectrometry Studies 72
3.6 Analysis and Interpretation of Aircraft Data 74
3.6.1 Analysis Approach 74
3.6.2 Background Ozone Concentrations on the Aircraft
Flights 74
3.6.3 Analysis of the Horizontal Traverses 77
3.6.4 Analysis of Vertical Spiral Profiles 81
3.6.5 Comparison of Aircraft and Ground-Based
Ozone Measurements 82
4.0 ANALYSIS OF CASE STUDY DAYS 87
4.1 Introduction 87
4.2 July 21 through 25, 1977: Case Study 90
4,2.1 Introduction 90
4.2.2 Overview of the Case Study Period 91
4.2.3 Analysis of July 21, 1977 112
4.2.4 Analysis of July 22 and 23, 1977 115
4.2.5 Analysis of July 24 and 25, 1977 118
4.3 July 28 through 30, 1977: Case Study 120
4.3.1 Introduction 120
4.3.2 Overview of the Case Study Period 121
4.3.3 Analysis of July 28, 1977 . 137
4.3.4 Analysis of July 29, 1977 139
4.3.5 Analysis of July 30, 1977 141
4.4 August 2-5, 1977: Case Study 144
4.4.1 Introduction 144
4.4.2 General Description of the Case Study 145
4.4.3 Analysis of August 2, 1977 163
4.4.4 Analysis of August 3, 1977 164
4.4.5 Analysis of August 4, 1977 166
4.4.6 Analysis of August 5, 1977 167
4.5 September 2 and 3, 1977: Case Study 168
4.5.1 Introduction 168
4.5.2 General Description of the Case Study 191
4.5.3 Analysis of September 2, 1977 195
4.5.4 Analysis of September 3, 1977 202
5.0 REFERENCES : 209
APPENDIXES
A. Mesoscale Air Parcel Trajectories A-l
B. Synoptic Scale Air Parcel Trajectories B-l
C. Mixing Depth and Atmospheric Stability Parameters
Parameters for Case Study Days C-l
IV
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LIST OF FIGURES
Figure Page
1.1 Map of Tulsa, Oklahoma, and vicinity; locations of ground
monitoring sites 3
3.1 Arriving synoptic trajectories associated with low
and high concentrations of ozone 18
3.2 Mean monthly diurnal ozone for sites in the Tulsa area 21
3.3 Mean monthly diurnal ozone for urban- and nonurban-
influenced days at the Vera site 34
3.4 Mean monthly diurnal ozone for common urban-influenced
days in July, August, and September 37
3.5 Frequency distribution of nonmethane hydrocarbon con-
centrations 54
4.1 United States surface weather maps for July 20-26, 1977 92
4.2 Synoptic scale trajectories for case study period
July^ 21-25, 1977 96
4.3 Mesoscale trajectories for case study period July 21-
25, 1977 98
4.4 Forward air parcel trajectories for case study period
July 21-25, 1977 100
4.5 Diurnal variation of temperature for the period
July 21-25, 1977 105
4.6 Diurnal variation of solar radiation for the period
July 21-25, 1977 105
4.7 Diurnal variations of NO and N0_ for the period July 21-
25, 1977 7 106
4.8 Diurnal variation of ozone for the period July 21-25,
1977 107
4.9 Ozone concentration/distance plots for July 21, 1977 114
4.10 Ozone concentration/distance plots for July 22, 1977 117
4.11 United States surface weather maps for July 27-31, 1977 122
4.12 Synoptic scale trajectories for case study period
July 28-30, 1977 125
4.13 Mesoscale trajectories for case study period July 28-30,
1977 126
4.14 Forward air parcel trajectories for case study period
July 28-30, 1977 127
4.15 Diurnal variation of temperature for the period July 28-30,
1977 130
4.16 Diurnal variation of solar radiation for the period
July 28-30, 1977 130
4.17 Diurnal variations of NO and NO- for the period
July 28-30, 1977 7 131
4.18 Diurnal variation of ozone for the period July 28-30,
1977 132
4.19 Ozone concentration/distance plots for July 28, 1977 138
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LIST OF FIGURES (continued)
Figure
4.20 Ozone concentration/distance plots for July 30, 1977 142
4.21 United States surface weather maps for August 1-6, 1977. . . . 146
4.22 Synoptic scale trajectories for case study period
August 2-5, 1977 149
4.23 Mesoscale trajectories for case study period August 2-5,
1977 151
4.24 Forward air parcel trajectories for case study period
August 2-5, 1977 152
4.25 Diurnal variation of temperature for the period August 2-5,
1977 156
4.26 Diurnal variation of solar radiation for the period
August 2-5, 1977 156
4.27 Diurnal variation of NO and N02 for the period
August 2-5, 1977 157
4.28 Diurnal variation of ozone for the period August 2-5,
1977 158
4.29 United States surface weather maps for September 1-4,
1977 169
4.30 Synoptic scale trajectories for case study period
September 2-3, 1977 171
4.31 Mesoscale trajectories for case study period
September 2-3, 1977 172
4.32 Forward air parcel trajectories for case study period
September 2-3, 1977 173
4.33 Diurnal variation of temperature for the period
September 2-3, 1977 175
4.34 Diurnal variation of solar radiation for the period
September 2-3, 1977 175
4.35 Diurnal variation of NO and NOa for the period
September 2-3, 1977 176
4.36 Diurnal variation of ozone for the period
September 2-3, 1977 177
4.37 Tulsa Flight T09, September 2, 1977. AM transport
pattern 179
4.38 Tulsa Flight T10, September 2, 1977. PM transport
pattern 180
4.39 Tulsa Flight T09, September 2, 1977. Vertical
spiral, Liberty Mounds, 0529-0601 CST 181
4.40 Tulsa Flight T09, September 2, 1977. Horizontal
traverse, ozone concentration 182
4.41 Tulsa Flight T09, September 2, 1977. Vertical
spiral, central business district, 0733-0800 CST 183
4.42 Tulsa Flight T10, September 2, 1977. Horizontal
traverse, ozone concentration 184
4.43 Tulsa Flight T10, September 2, 1977. Vertical
spiral, Ramona, 1401-1435 CST 185
VI
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LIST OF FIGURES (continued)
Tulsa Flight Til, September 3, 1977. Vertical spiral,
Liberty Mounds, 0526-0554 CST 186
Tulsa Flight Til, September 3, 1977. Horizontal
traverse, ozone concentration 187
Tulsa Flight Til, September 3, 1977. Vertical
spiral, central business district, 0723-0746 CST 188
Tulsa Flight T12, September 3, 1977. Horizontal
traverse, ozone concentration 189
Tulsa Flight T12, September 3, 1977. Vertical
spiral, Ramona, 1408-1439 CST 190
Ozone concentration/distance plots for morning
of September 2, 1977 199
Ozone concentration/distance plots for the afternoon
of September 2, 1977 201
Ozone concentration/distance plots for September 3, 1977 . . . 207
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LIST OF TABLES
Table Page
3.1 Average daily temperature 9
3.2 Average maximum and minimum temperatures 10
3.3 Days with extreme temperatures 10
3.4 Relative humidity 10
3.5 Precipitation 11
3.6 Days with measureable precipitation 11
3,7 Clear days and sunshine 12
3.8 Prevailing wind direction and average wind speed 12
3.9 Anticyclone frequency and duration 12
3.10 Daily average temperature 13
3.11 Average maximum temperature 13
3.12 Average minimum temperature 13
3.13 Precipitation days and amounts 14
3.14 Percentage of possible sunshine 14
3.15 Resultant wind direction/average wind speed 15
3.16 Anticyclone frequency and duration 15
3.17 Sounding analyses; case study days 20
3.18 Mean monthly concentrations (ppm) of NO and NO- 27
3.19 Mean 0600-0900 CDT NO concentrations by month and entire
period for monitoring sites, Tulsa, Oklahoma, 1977 ...... 28
3.20 Urban-influenced days at sites near Tulsa 33
3.21 Average values for ozone, temperature, percent
sunshine, and solar radiation 36
3.22 Average NO, N0?, and NO concentrations on urban-
influenced days common to Sperry, Vera, and Ochelata 41
3.23 Average NO, N0_, and NO concentrations on nonurban-
influenced days at Sperry, Vera, and Ochelata 42
3.24 Summary statistics for pollutant and meteorological
variables by site 44
3.25 Correlations between daily maximum ozone and
meteorological and pollutant variables by site 46
3.26 Results of stepwise regressions by station with daily
maximum ozone as the dependent variable 48
3.27 Results of stepwise regressions by station with
daily maximum ozone as the dependent variable
with wind directions greater than 116°, less than
231° at Post Office 49
3.28 Averages of meteorological and pollutant variables
for different levels of daily maximum ozone by station ... 50
3.29 Number of hydrocarbon samples collected in Tulsa 52
Vlll
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LIST OF TABLES (continued)
Table
3.30 Average sum of hydrocarbon classes at Tulsa sites
for morning samples 57
3.31 Average values for alkenes and alkynes in morning
hydrocarbon samples 58
3.32 Average values for alkanes in morning hydrocarbon
samples 60
3.33 Average 0600 to 0900 CDT hydrocarbon concentrations
by wind direction. Tulsa Post Office site 61
3.34 Average values for aromatics in morning hydrocarbon
samples 62
3.35 Average acetylene concentrations by day of the week 62
3.36 Aircraft hydrocarbons; low pass at Downtown Airport 64
3.37 Post Office site 0500-0800 CST hydrocarbons on days
of Downtown Airport samples 65
3.38 Aircraft hydrocarbons; low pass at Tulsa International
Airport 66
3.39 Hydrocarbon distributions at the surface south, in,
and north of Tulsa 68
3.40 Hydrocarbon distributions at 2,500 ft MSL south, over,
and north of Tulsa 69
3.41 Quantitative comparison of volatile organics by Tenax
GC/MS in ambient air from Liberty Mounds, Tulsa, and
Vera, Oklahoma 73
3.42 Background ozone concentrations of aircraft flights 75
3.43 Summary of afternoon aircraft flight data 79
3.44 Altitude and concentration of maximum ozone during
morning aircraft spirals 82
3.45 Altitude and concentration of maximum ozone during
afternoon aircraft spirals 83
4.1 Monthly averages and standard deviations of selected
parameters 88
4.2 0500 to 0800 CST average concentrations of selected
hydrocarbons and oxides of nitrogen, and distributions
for July 21-25, 1977 110
4.3 0500 to 0800 CST average concentrations of selected
hydrocarbons and oxides of nitrogen, and distributions
for July 28-30, 1977 135
4.4 0500 to 0800 CST average concentrations of selected
hydrocarbons and oxides of nitrogen, and distributions
for August 2-5, 1977 160
4.5 0500 to 0800 CST average concentrations of selected
hydrocarbons and oxides of nitrogen, and distributions
for September 2 and 3, 1977 192
4.6 September 2 hydrocarbon samples 197
4.7 September 3 hydrocarbon samples 204
IX
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ACKNOWLEDGMENTS
This project was conducted by Research Triangle Institute (RTI),
Research Triangle Park, North Carolina, under Contract 68-02-2808 for the
United States Environmental Protection Agency (EPA). The support of this
agency is gratefully acknowledged as is the advice and guidance of the
Project Officer, Mr. Norman C. Possiel, Jr., and other staff members of
the Office of Air Quality Planning and Standards.
Work on this project was performed by staff members of the Systems
and Measurements Division and the Energy, Engineering, and Environmental
Sciences Division of RTI under the direction of Mr. J. J. B. Worth, Group
III Vice President. Mr. C. E. Decker, Manager, Environmental Measurements
Department, was Laboratory Supervisor for the project. Dr. W. C. Eaton
served as Project Leader and was responsible for the coordination of the
program. Staff members who contributed to the preparation of this report
are recognized and listed in alphabetical order: Dr. W. D. Bach, Mr. C. E.
Decker, Mr. F. E. Dimmock, Dr. W. C. Eaton, Mr. W. J. King Jr., Mr. M. L.
Saeger, and Dr. J. E. Sickles II.
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1.0 INTRODUCTION
1.1 BACKGROUND
Anthropogenic emissions of nonmethane hydrocarbons (NMHC) and oxides of
nitrogen (NO ) in the presence of strong solar radiation are involved in a
A
complex sequence of chemical reactions that result in the formation of
ozone. Local meteorological processes such as the diurnal variation of
solar radiation, temperature, and mixing height, as well as the local wind
speed and direction, influence the production and distribution of ozone near
an urban source area. In addition, synoptic-scale meteorological conditions
can lead to transport of ozone over large distances and can contribute to a
higher background ozone concentration.
The highly nonlinear relationships between maximum ozone concentration
and initial concentrations of ozone precursors (NMHC and NO ) have been
demonstrated in smog chamber experiments. This nonlinearity and the large-
scale transport of ozone add to the complexity of developing ozone control
strategies to achieve the ozone National Ambient Air Quality Standard (NAAQS).
The NAAQS for ozone at the time of this study was a maximum 1-hour concentra-
tion of 0.08 ppm, not to be exceeded more than once per year. In 1979 the
NAAQS was revised to permit a maximum ozone concentration of 0.12 ppm, not
to be exceeded more than once per year.
Prior control strategies to meet the NAAQS for ozone involve reducing
emissions of NMHC according to guidelines outlined in Appendix J, Part 51,
Title 40 of the Code of Federal Regulations. The applicability of the
Appendix J approach for all urban areas has been questioned and alternate
methodologies based on photochemical simulation models are being tested.
One such procedure, known as the Empirical Kinetic Modeling Approach, is now
under consideration. This method is described in an EPA document entitled
Uses, Limitations and Technical Basis of Procedures for Quantifying Rela-
tionships between Photochemical Oxidants and Precursors. The validation
of such models requires extensive amounts of ambient air quality data.
Another, more complex model is the SAI (Systems Applications Inc.) photochem-
ical model which computes hourly ozone concentrations across a grid based
upon inputs of precursor emissions, meteorological conditions and air quality
boundary conditions.
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1.2 RESEARCH OBJECTIVES
1.2.1 Objectives of the Field Measurements Program
The principal objective of the field measurements program was to pro-
vide EPA with a high quality data base to be used in testing various photo-
chemical simulation models. The city of Tulsa represents an isolated urban
area, and thus provides an excellent location to observe ozone formation
from an individual urban area. The large urban areas nearest to Tulsa are
Oklahoma City, approximately 160 km (100 mi) to the southwest, and Dallas-
Fort Worth, Texas, approximately 350 km (220 mi) to the south. The eight
stations comprising the surface monitoring network were located to facili-
tate the observation of incoming pollutant transport and the formation of
ozone downwind. The location of the eight surface stations are shown in
Figure 1.1 on a map of the Tulsa area. Upwind and downwind measurements
were also obtained aboard an instrumented aircraft during part of the study.
1.2.2 Objectives of the Data Analysis and Interpretation Effort
The principal objectives of the data analysis and interpretation effort,
presented in this volume, were to: (a) determine the concentrations of
ozone and precursors transported into the Tulsa area; (b) determine the net
production of ozone downwind of Tulsa as a result of urban emissions in
Tulsa; (c) provide insight into the causes of high ozone concentrations
(>0.10 ppm) measured downwind of Tulsa; (d) determine the distance downwind
of Tulsa that maximum ozone concentrations typically occur; (e) investigate
the relative contributions of various source categories to the nonmethane
hydrocarbon concentrations measured in and around Tulsa; and (f) conduct
intensive analyses of selected case study days to relate observed pollutant
concentrations to precursor sources and observed meteorological conditions,
and to provide support for EPA modeling and control strategy efforts.
1.3 ANALYSIS APPROACH AND REPORT ORGANIZATION
This report includes three major sections. Section 2.0 lists the major
conclusions drawn from the analysis and interpretation effort. Section 3.0
presents an analysis of the overall data base and includes the following
sections describing the approaches taken to satisfy the objectives of the
analysis:
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8ARTLESVILLE
STATUTE MILES
0 5
KILOMETERS
0 5
LEGEND' 0
o
10 IS 20 3
10 IS ZQ 25 30 C
si
LOCATION OF GROUND MONITORING SITE
INTERSTATE HIGHWAY
+ 700 M3U
£ LIBERTY MOUNDS
U.S. HIGHWAY
STATE HIGHWAY
Figure 1.1. Map of Tulsa, Oklahoma, and vicinity; locations of
ground monitoring sites.
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3.1 Meteorological Analysis, including an evaluation of the represen-
tativeness of the summer of 1977 to average conditions over the
previous 30-year period;
3.2 Examination of Mean Monthly Pollutant Distributions and the Strat-
ified Data Base;
3.3 Statistical Relationship of Ozone to Other Parameters;
3.4 Analysis and Interpretation of the Hydrocarbon Data Base; and
3.5 Analysis and Interpretation of the Aircraft Data.
In Section 4.0 extensive analyses of 14 specific case study days are pre-
sented that relate observed meteorological conditions to the resulting ozone
distribution. The case study days were grouped into four sets of days:
July 21-25, July 28-30, August 2-5, and September 2 and 3, 1977.
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2.0 PRINCIPAL FINDINGS AND CONCLUSIONS
The principal findings of the data base collected in Tulsa during the
summer of 1977, and the conclusions drawn from the data analysis and inter-
pretation effort are summarized below.
1. The average ozone concentrations measured at Liberty Mounds during
hours 1000 and 1100 CST, of 0.058 ppm in July, 0.061 ppm in August,
and 0.046 ppm in September are assumed to represent the mean
background ozone concentrations in the Tulsa area. The ozone that
resulted in those concentrations was mixed to the surface from
above the height of the nocturnal inversion. Those concentrations
are in good agreement with the mean concentrations (ranging from
0.049 to 0.078 ppm) measured above the nocturnal inversion at
2,500 ft MSL by the aircraft on the morning flights at approxi-
mately 0630 CST.
2. The concentrations of NO measured aboard the aircraft on the
x
morning flights were near the minimum detectable limit of the
instrument, implying that very little NO was transported to the
A
Tulsa area. The NO concentrations at the Liberty Mounds site
rarely exceeded 0.010 ppm throughout the study period, further
suggesting that very little NO was transported to Tulsa.
A
3. The average concentrations of NMHC and NO measured during the
X
0500 to 0800 CST collection period at the Post Office site, located
in the downtown urban area, were 0.534 ppmC and 0.065 ppm, respec-
tively. At the Health Department station, which is located in a
residential area of Tulsa, the mean concentrations of NMHC and NO
during the same 3-hour measurement period were 0.317 ppmC and
0.027 ppm, respectively.
4. Using a technique developed by Kopczynski that relates the
acetylene/NMHC ratio to the percentage of the total NMHC due to
tailpipe emissions, an estimate of the average contribution from
vehicular sources to the NMHC concentrations was found to be
17 percent at Liberty Mounds, 64 percent at the Post Office, and
60 percent at the Health Department.
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5. The level of vehicular traffic (as indicated by acetylene), and
thus the level of vehicular tailpipe emissions, showed a strong
weekday/weekend variation in the city and no pattern of variation
at the southern (generally upwind) site, Liberty Mounds.
6. Downwind transport of urban emissions was evidenced by increased
amounts of acetylene measured in samples collected downwind of
Tulsa between 1300 and 1600 CST, as compared to samples collected
between 0800 and 1100 CST. This effect was most noticeable at the
Sperry site, 16 km north of the central business district of Tulsa.
7. The mean concentration of NO measured at Liberty Mounds between
0500 and 0800 CST was 0.007 ppm. This suggests that urban emis-
sions contributed, on the average, 0.058 and 0.020 ppm of NO at
X
the Post Office and Health Department sites, respectively.
8. Following the 0500 to 0800 CST period the concentrations of NO
measured at the Health Department were generally near the minimum
detectable limit of the instrument. During the afternoon traffic
period the concentration of N02 often increased. At the Post
Office the concentration of NO and N02 often remained high rela-
tive to the Health Department throughout the day. This suggests
that both industrial and traffic-related sources of NO were of a
x
more continuous nature near the central business district Post
Office site than they were near the Health Department site.
9. On days when the Post Office site and the Tulsa Downtown Airport
were downwind of the petrochemical complex, higher than average
concentrations and percentages of low molecular weight alkane
species were generally measured during the 0500 to 0800 CST collec-
tion period at the Post Office and during low approach morning
flights by the aircraft approximately 50 ft above the Downtown
Airport runway. This implies that the petrochemical complex had a
high rate of emissions of low molecular weight alkanes.
10. The mean NMHC/NO ratios during the 0500 to 0800 CST period aver-
A
aged over the study were 10.9/1 at the Post Office, 14.4/1 at the
Health Department, and 45.6/1 at Liberty Mounds. The ratios from
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the urban sites were similar to ratios obtained in Los Angeles
(10.2/1), St. Louis (8.5/1), and El Paso (14.0/1).(2) The NMHC/NO
A
ratio at Liberty Mounds was similar to the ratios obtained at two
predominantly rural sites in Ohio of 53.0/1 at McConnelsville and
C*\
42.0/1 at Wooster/ }
11. The concentrations of the naturally occurring hydrocarbons, a-
pinene, p-pinene, and isoprene, were quite low (usually less than
5 ppbC for the sum of these three compounds and the known inter-
ferents g-xylene and trans-2-pentene).
12. The results of air parcel trajectory analyses investigated for
many of the 14 case study days suggested that the air that produced
the maximum ozone concentrations in the network typically had been
over Tulsa between 1000 and 1200 CST rather than 0500-0800. There
was no significant correlation between the maximum ozone concentra-
tions measured at any of the typically downwind sites and the 0500
to 0800 CST NMHC concentrations measured at either of the two
urban sites.
13. The data from each station were stratified into urban-influenced
(i.e., airflow from Tulsa towards the monitoring site) or nonurban-
influenced categories during the photochemically active portion of
the day. When the northern stations were classified as nonurban-
influenced, the meteorological conditions important for ozone
formation, percent sunshine, solar radiation, and temperature were
often significantly lower than on days of urban influence and the
average ozone concentrations were also lower. The lower ozone
concentrations seem to result from the lack of Tulsa emissions
rather than the lack of sunshine.
14. The very low concentrations of ozone precursors measured at Liberty
Mounds suggest that very little ozone synthesis was possible at
that location. The available data both from the surface and the
aircraft do not provide any strong evidence of direct ozone trans-
port to Liberty Mounds from any urban area other than Tulsa. On
urban-influenced days high ozone concentrations (>0.10 ppm) oc-
curred at Liberty Mounds; on the remaining days, however, the
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ozone synthesis was limited at Liberty Mounds. The ozone increase
measured at Liberty Mounds on most days with southerly winds was
likely due to mixing of ozone from above the height of the noc-
turnal inversion during the midmorning hours.
15. The ozone precursor concentrations measured during the morning
hours at the northern (downwind) sites were generally very low
compared to those measured in the city. Therefore, ozone synthesis
from local sources at the individual sites most likely represents
only a small contribution to the maximum ozone concentrations
measured at those sites.
16. As measured at 770 m (2,500 ft) MSL, the net ozone formation due to
Tulsa emissions was determined by subtracting the mean background
ozone concentration measured on that portion of the horizontal
traverses of each afternoon flight that was not obviously in the
Tulsa urban plume from the maximum ozone concentration measured
during the afternoon horizontal flights. The net ozone formation
determined from the data of the aircraft flights that had distinct
ozone plumes varied from 0.017 ppm (August 26) to 0.116 ppm (Sep-
tember 3).
17. During the study, Sperry, Vera, and Ochelata were all considered
to be simultaneously under urban influence on 39 days. The maximum
ozone concentration in the network was measured at Vera (34 km
downwind) on 49 percent of those days; at Ochelata (48 km downwind)
on 32 percent of those days, and at Sperry (14 km downwind) on
only 8 percent of those days.
18. On 3 of the 4 days that the aircraft measured a distinct ozone
plume, the maximum ozone concentration was measured approximately
48 km (30 mi) north of the center of Tulsa. On the remaining day,
the maximum ozone concentration was measured approximately 32 km
(20 mi) downwind.
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3.0 DATA ANALYSIS AND INTERPRETATION
3.1 METEOROLOGICAL ANALYSIS
3.1.1 Meteorological Representativeness of Tulsa, Summer 1977
In order to assess the climatological normalcy of the summer of 1977
(July, August, and September) in Tulsa, Oklahoma, to insure that the meteoro-
logical conditions were not greatly different from previous summers, a
number of meteorological parameters were examined including temperature,
relative humidity, cloud cover, winds, and high-pressure systems. The data
for this investigation were obtained from the NOAA publications Cliroatologi-
cal Data, National Summary, and Local Climatological Data (LCD) monthly and
annual summaries for the National Weather Service Office at Tulsa Interna-
tional Airport. Unless otherwise indicated, "normal" refers to the 30-year
period from 1941 through 1970. When data were available, a 10-year average
(1968 through 1977) was also determined. Later, the summer of 1977 is
compared climatologically with the summers of 1974, 1975, and 1976, speci-
fically because of the large amount of reliable ozone data available for
those four years.
3.1.1.1 Temperature--
In 1977 the mean daily temperature for each month was above the normal,
but was within one standard deviation of the 10-year and normal mean
(Table 3.1). The third warmest July and August and the warmest September of
the past 10 years were recorded in 1977.
Examination of the average maximum and minimum temperature (Table 3.2)
suggests that the above-average mean temperatures were due to higher minimum
temperatures rather than higher maximum temperatures.
TABLE 3.1. AVERAGE DAILY TEMPERATURE
Month
Jul
Aug
Sep
71 Yr
82.5
81.8
74.0
Means
Normal
82.1
81.4
73.3
Standard Deviation
10 Yr
82.4
80.8
72.4
Normal
3.2
3.0
2.8
10 Yr
2.2
1.9
3.4
1977
84.8
81.7
75.6
-------
TABLE 3.2. AVERAGE MAXIMUM AND MINIMUM TEMPERATURES (°F)
Month
Jul
Aug
Sep
Normal
92.8
92.7
84.8
Maximum
10-Yr Average
93.2
91.9
82.8
1977
95.2
91.4
84.8
Normal
71.4
70.0
61.7
Minimum
10-Yr Average
71.5
69.7
62.0
1977
74.3
72.0
66.4
TABLE 3.3. DAYS WITH EXTREME TEMPERATURES
Temp >90° F
Temp >100° F
Month
Jul
Aug
Sep
Normal
23
21
8
10-Yr Average
24
22
8
1977 Normal
26 <1
21 <1
9 <1
10-Yr Average
4
4
0
1977
4
4
0
3.1.1.2 Relative Humidity--
Relative humidity for the summer of 1977 was compared to the normal for
four different times of the day: 0000, 0600, 1200, and 1800 CST (Table 3.4).
July was found to be normal with respect to relative humidity; however,
August and September were more humid, particularly at noon and 1800. Because
temperatures were above normal, the higher relative humidities of August and
September indicate more moisture than usual in the air.
TABLE 3.4. RELATIVE HUMIDITY
00 CST
Jul
Aug
Sep
12 CST
Jul
Aug
Sep
Normal
73
74
82
Normal
54
54
61
1977
74
77
85
1977
54
61
67
06 CST
Jul
Aug
Sep
18 CST
Jul
Aug
Sep
Normal
83
85
89
Normal
50
50
60
1977
83
86
91
1977
50
57
67
10
-------
TABLE 3.5. PRECIPITATION (INCHES)
Month
Jul
Aug
Sep
90 Yr
3.20
3.22
3.89
Means
Normal
3.51
2.95
4.07
Standard Deviation
10 Yr
2.41
3.36
6.28
Normal
3.3
1.8
2.9
10 Yr
1.9
1.6
5.3
1977
2.00
4.86
5.57
3.1.1.3 Precipitation--
Generally speaking, July 1977 was drier than normal; August, wetter
than normal; and September had about normal rainfall (Table 3.5).
With the exception of August, precipitation for all 3 months fell
within one standard deviation of the mean for both the normal period of
record (1941-1970) and the previous 10 years (1968-1977). August's rainfall
of 4.86 inches was slightly more than one standard deviation above the
normal.
There were 2 more days with measureable precipitation in both August
and September than is normal for those months (Table 3.6).
3.1.1.4 Clear Days
Consistent with the temperature and precipitation data already pre-
sented, July 1977 had a significantly greater number of clear days than
normal--19and a higher than normal percentage of possible sunshine
(Table 3.7). August and September had only 6 clear days and lower than
normal percentages of possible sunshine.
TABLE 3.6. DAYS WITH MEASUREABLE PRECIPITATION
Month Normal 10 Yr Average 1977
Jul 7 67
Aug 7 79
Sep 8 10 10
11
-------
TABLE 3.7. CLEAR DAYS AND SUNSHINE
Clear Days Percent Possible Sunshine
Month
Jul
Aug
Sep
TABLE
Month
Jul
Aug
Sep
Normal 1977 Normal
12 19 72
13 6 72
12 6 65
3.8. PREVAILING WIND DIRECTION AND AVERAGE WIND SPEED
Normal 1977
S/9.3 170°/9.
SSE/9.1 170°/10
SSE/9.3 150°/9.
1977
79
64
60
(mph)
6
.4
8
TABLE 3.9. ANTICYCLONE FREQUENCY* AND DURATIONf
Jul
Aug
Sep
Avg. No. Maximum Minimum
1.8 (19) 3 (42) 0 (6)
1.0 (35) 2 (66) 0 (12)
2.1 (20) 3 (36) 1 (6)
1977
1 (10)
1 (26)
1 (18)
*Number of anticyclones passing within 500 km.
fNumber of hours anticylone center was within 500 km.
3.1.1.5 Winds
During the summer of 1977, the normal south to south-southeasterly
flow prevailed and wind speeds for the period were slightly greater than
normal, particularly in August (Table 3.8).
3.1.1.6 High-Pressure Systems
The tracks of anticyclones were examined for the 10-year period of
1968-1977. High-pressure systems were catalogued when their centers passed
within 500 km of Tulsa. During 1977, only three systems traversed the area
during the 3-month period (Table 3.14). Normally, about five high-pressure
systems would be expected during this period. Also, the amount of time that
the Tulsa area was under the influence of high pressure was significantly
below the average, particularly in July and August (Table 3.15).
12
-------
3.1.1.7 Comparing 1977 to the Three Previous Years--
Because ozone data from a fairly dense network are available for the
period 1974-1977 for the Tulsa area, certain meteorological parameters were
examined in order to identify periods of unusual weather. Table 3.10 shows
that warm months during this period include July 1974, July 1977, and
September 1977. Cool months include August 1974, September 1974, and
September 1975. Examination of average maximum daily temperatures (Table
3.11) and average minimum daily temperatures (Table 3.12) confirms the
selection of these months as somewhat unusual with respect to temperature.
Although there was a considerable amount of scatter in the precipita-
tion data (Table 3.13), only three of the months fell outside one standard
deviation of the normal: August 1974, September 1974, and August 1977.
TABLE 3.10. DAILY AVERAGE TEMPERATURE
Jul
Aug
Sep
Jul
Aug
Sep
Jul
Aug
Sep
Normal
82.1
81.4
73.3
TABLE 3
Normal
92.8
92.7
84.8
TABLE 3.12.
Normal
71.4
70.0
61.7
1974
85.4
78.3
64.7
.11. AVERAGE
1974
97.5
88.6
74.2
1975
81.2
82.2
69.2
1976
81.4
79.7
72.8
1977
84.8
81.7
75.6
MAXIMUM TEMPERATURE
1975
91.6
93.1
80.8
1976
92.7
91.8
84.0
1977
95.2
91.4
84.8
AVERAGE MINIMUM TEMPERATURE
1974
73.2
67.9
55.1
1975
70.7
71.3
57.6
1976
70.1
67.5
61.5
1977
74.3
72.0
66.4
13
-------
TABLE 3.13. PRECIPITATION DAYS AND AMOUNTS
Jul
Aug
Sep
Normal
7 (3.51)
7 (2.95)
8 (4.07)
1974
2 (0.55)
9 (5.30)
10 (11.78)
1975
6 (2.14)
9 (3.52)
9 (3.34)
1976
6 (4.37)
7 (1.17)
7 (2.60)
1977
7 (2.00)
9 (4.86)
10 (5.57)
Each of these months was wetter than normal. Two relatively dry months were
July 1974 and August 1976. As for the number of days with measureable
precipitation, no great departures from normal are noted except for July
1974 when it rained only 2 days. Even September 1974, with 11.78 inches of
total rainfall, had only 10 rain days.
Large deviations from the normal percentage of possible sunshine (Table
3.14) occurred for only 3 months: July 1974 (15 percent above normal),
August 1974 (19 percent below normal), and September 1975 (13 percent below
normal). Generally, July had above normal percentage of sunshine, while
August and September were below normal for the 4-year period.
For the 4-year period, resultant wind directions were within 20° of
normal with the exception of September 1974, which had a definite easterly
flow as opposed to the prevailing south-southeasterly direction normal for
that month (Table 3.15). September 1974 also had abnormally heavy rainfall.
Generally, wind speeds fell within 1 mph of the normal monthly average with
these exceptions: July 1975 (1.7 mph low), September 1975 (1.1 mph low),
September 1976 (1.2 mph low), and August 1977 (1.3 mph high).
Jul
Aug
Sep
TABLE 3.14.
Normal
72
72
65
PERCENTAGE
1974
87
53
57
OF POSSIBLE
1975
69
70
52
SUNSHINE
1976
79
75
58
1977
79
64
60
14
-------
TABLE 3.15. RESULTANT WIND DIRECTION/AVERAGE WIND SPEED (mph)
Normal
Jul
Aug
Sep
S/9
SSE/9
SSE/9
.3
.1
.3
1974
190/9
170/9
100/8
.6
.6
.5
1975
190/7.
180/9.
140/8.
6
4
2
1976
200/9
150/9
150/8
.4
.4
.1
1977
170/9
170/10
150/9
.6
.4
.8
TABLE 3.16. ANTICYCLONE FREQUENCY AND DURATION (hours)
1974
Jul
Aug
Sep
2
2
3
(24)
(53)
(20)
1975
2
1
3
(25)
(54)
(18)
1976
2
0
2
(24)
(34)
1977
1
1
1
(10
(26)
(18)
Analysis of high-pressure systems passing within 500 km of Tulsa indi-
cates that 1977 had an unusually low number of high-pressure systems (Table
3.16) and that their influence was comparatively short-lived. For the
period, August seemed to have fewer occurrences of high-pressure systems,
but their effect was longer lasting. September had more anticyclones, but
they were rather fast moving.
3.1.2 Air Transport and Vertical Structure
3.1.2.1 Mesoscale Transport
Hourly average wind speed and direction were compiled for the Liberty
Mounds, Post Office, Skiatook, and Wynona stations and combined with the
hourly wind speed and direction reported at Tulsa International Airport.
These data were used to help define the characteristics of the airflow about
the study area. Of principal interest were the air parcel trajectories
associated with daily maximum ozone concentration and the movement of air
out of the urban Tulsa area when precursor emissions were greatest.
Hourly wind data were tabulated for those five locations during the
period 0600 to 1900 CST each day and were normalized to a 50-m altitude
using the power law wind profile equation
15
-------
V(Z)/V(Z0)=(Z/Z0)P ,
where z_ is the altitude of the measurement. To account for difference in
surface roughness, p = 2/7 was used at the urban locations while p = 1/7 was
(2)
used at the rural locations . The wind direction was held constant as
altitude changed.
Both analyses used the time-space weighted interpolation first developed
(2)
arnes and modi
function of the form
(2) (3)
by Barnes and modified by Bach . The interpolation uses a weight
exp {- (r2/4k2 + t2/4v2)} ,
when r is the distance from the point in question to an observation and t is
the time difference between the observation and the analysis time. Specif-
ically, k = 12.7 km and v = 1 hour were used in this analysis. In all
cases, only those observations for which
(r/2k)2 + (t/2v)2 <8
were used. Each component of the wind was interpolated independently.
3.1.2.1.1 Air parcel trajectoriesAir parcel movements were computed
at half-hourly time increments for periods up to 6 hours using interpolated
wind speed at the beginning of the time step. Trajectories were plotted for
the air parcels arriving at four sampling sites at the time the daily maximum
hourly 03 was measured. The sites chosen were (a) the site of the maximum
03; (b) Liberty Mounds, Post Office, and Vera; and (c) Wynona when the
system maximum 0% occurred at one of the previous sites. The trajectories
are plotted on maps showing the sampling sites, the 03 concentrations present
at the arrival time of the trajectory, the date and time of arrival, and an
outline of the Tulsa city limits. Appropriate trajectories are shown in
case study analysis; all are shown in Appendix A.
3.1.2.1.2 Urban plume analysesThe urban plume analyses depict the
6-hour movement of air initially over Tulsa at 0600, 0900, 1200, and 1500
CST on each case study day. The urban area was characterized by a cross-
hatched quadrilateral covering the city. The vertices of the area were
moved in half-hourly increments at the speed and direction of the local wind
vector interpolated from the wind observations. The movement of the area
16
-------
plume is shown in the figures for hourly increments for up to 6 hours, or
until one vertex was out of the map area. The sequence of cross-hatched
areas depicts the time that a given area was affected by the air initially
over the Tulsa urban area at the given start hour. Those figures are pre-
sented with the case study analyses.
The distortion of the area indicates the divergence, vorticity, and
deformation of the analyzed wind fields. Over-plotting of successive hourly
position indicates slower moving, stagnating conditions. Occasionally, the
area tends to collapse into a single line, suggesting that two parcels oc-
cupy the same space at the same time. That physically unrealistic condition
probably results from a lack of data or an inhomogeneous wind distribution.
3.1.2.2 Synoptic-Scale Transport--
Synoptic-scale air parcel trajectories were computed for air parcels
arriving at Tulsa and Oklahoma City, Little Rock, and Kansas City. These
trajectories were developed from National Weather Service rawinsonde data,
vertically averaged over the lowest 2 km of the atmosphere, using a technique
(4)
previously described by Bach . The trajectories were computed for arrival
at 0600 and 1600 CST daily and depict the movement of the arriving parcel
over the previous 48 hours. The complete plotted set of trajectories is
given in Appendix B. Specific trajectories are discussed in the case studies.
Because Oklahoma City trajectories are very similar to those for Tulsa, they
were omitted from the plots for clarity of the figures.
The trajectories were stratified by the occurrence of high and low
maximum daily ozone within the measuring network. The criteria for high or
low ozone were developed by plotting the cumulative frequency distribution
of maximum daily ozone on log probability paper. The high values exceed one
standard deviation greater than the mean and the low values are less than
one standard deviation less than the mean.
The plot of the 1600 CST trajectories associated with high and low
ozone is shown in Figure 3.1. The results of this analysis are no different
from similar analyses. Low ozone is found to generally occur with fast-moving
air parcels trajectories while high ozone is found with slow-moving air.
The passage of the air over urban areas seems immaterial to the ozone content
as measured in Tulsa.
17
-------
x:
LU
H-i
Oc&co
CL.O-
HH
cc:
cc
o
..>
r<'
1
13
G
cfl
U
O
CO
CO
03
CO
CD
H CU
!-i C
O O
4J N
O O
cu
U-l
O
Cfl
4-) CO
C
a o
H -H
W 4-1
a, cc
o s-<
C 4-1
t^ c
CD Q)
O
00 C
q o
H U
H £
M bO
M -H
Q)
S-i
bO
18
-------
3.1.2.3 Sounding Analyses--
The vertical distribution of potential temperature and the water vapor
mixing ratio were plotted for each case study day. These distributions were
derived from the 0600 and 1800 CST rawinsonde data taken at Oklahoma City,
160 km southwest of Tulsa.
The potential temperature, 0, is given by
0 = T (1000/p)2/7 ,
where T is the ambient temperature (K) and p is the air pressure (mb). It
represents the entropy of an air parcel and is conserved in adiabatic pro-
cesses. Its vertical gradient, 30/3z, is directly proportional to the
static stability of the air; therefore, the shape of its vertical profile
immediately indicates the stability of the air.
The water vapor mixing ratio, R, is expressed in grams of water vapor
per kilogram of dry air. In adiabatic motion, R is also conserved. Since
water vapor is gaseous and has a ground source, the degree of mixing in the
lower atmosphere should be indicated by the R profile. The mixing depth
should be indicated by the altitude at which the R profile changes from a
nearly constant value to a decreasing value with altitude.
The plotted profiles to 4 km for each case study day and the first
twenty observations in the rawinsonde report are in Appendix C.
Analysis of the morning inversion characteristics and the afternoon
mixing height for case study days are summarized in Table 3-17.
3.2 EXAMINATION OF MEAN MONTHLY POLLUTANT DISTRIBUTIONS
3.2.1 Ozone
3.2.1.1 Variation of Ozone Diurnal Plots by Month--
A mean diurnal curve by month results when monthly average values of
pollutant concentration for each hour of the day are plotted. The graph is
a diurnal composite of all of the days in that month. Comparison of fea-
tures of such graphs for different sites and months gives information on the
urban or rural character of the air at the site and the variation of pollut-
19
-------
TABLE 3.17. SOUNDING ANALYSES; CASE STUDY DAYS
Date
July 21
22
23
24
25
28
29
30
Aug 2
3
4
5
Sept 2
3
Morning
Inversion top*
(m, MSL)
762
595
594
858
1,002
1,045
494
652
518
598
722
727
535
509
Strength!
(°C)
6.1
4.4
5.9
8.2
10.1
4.7
2.9
6.9
2.4
5.2
5.6
5.8
8.0
7.2
Afternoon
mixing depth
(m,MSL)
1,870
1,940
3,030
3,594
3,720
soot
2,140
2,195f
2,910
2,790
2,560
2,580
2,000
2,955
*Altitude at which -dT/dz >6.5°C/km.
tDifference of potential temperature at the inversion top at ground (a
measure of the diabatic heating needed to dissipate the inversion).
^Rawinsonde surface temperature exceeded maximum daily temperature and was
used in the calculation.
ant concentrations from month to month. Figure 3.2 shows the mean diurnal
plots by month for the eight ozone monitoring sites maintained by RTI in the
Tulsa study area.
When the three monthly diurnal ozone plots (July, August, and September
1977) are compared, one feature is immediately evident. The maximum ampli-
tude of the curves decreases from July to August to September for six of the
eight sites. In terms of photochemical production of ozone, this finding is
expected since sunlight intensity and total minutes of sunshine are decreas-
ing from month to month. The two exceptions to this order of ozone amplitudes
are the background site, Liberty Mounds (which has an August diurnal ozone
plot of greater magnitude than that of July), and Skiatook Lake (which has
diurnal plots for July and August that are very similar). At each site the
September diurnal plot was of lowest amplitude for the 3-month period.
20
-------
. 0.16
0.15
0.14
0.13
0.12
0.11
x 0.10
a- 0.09
uj- 0.08
I 0.07
o 0.06
' I ' I ' I ' I ' I ' I ' I ' I '
flVERRGE OZONE BY MONTH LIBERTY MOUNDS
O JULY
D AUGUST
A SEPTEMBER
l l I l i l i l i l i
02 Of 06 08 10 12 14 16 18 20 22
HOUR CCST)
0.16
0.15
0.14
0.13
0.12
0.11
0.10 o
0.09 §
0.08 .m
0.07 -D
0.06 5
0.05
0.04
0.03
0.02
0.01
0.00
ZT
Q.
Q_
LU
O
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
16
15
14
13
12
11
10
09
08
07
06
05
7 I f T ^ I r T r I ' I ' I ' I ' I '
RVERfl&E OZONE B^ MONTH POST OFFICE
OJULY
D AUGUST
A SEPTEMBER
02 04 06 08 10 12 14 16
HOUR COST)
18 20 22
0.16
0.15
0.14
0.13
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
o
rn
Figure 3.2. Mean monthly diurnal ozone for sites in the Tulsa area.
21
-------
0.16
0.15
0.14
0.13
0.12
0.11
5 °-10
a- 0.09
iJ 0.08
I 0.07
o 0.06
'I'I'I'I'I'I^ I T I I '
RVERRGE OZONE BV MONTH HERL.TH DEPARTMENT
O JULY
D AUGUST
A SEPTEMBER
02 04 06 08
10 12 14
HOUR COST")
16 18
22
0.16
0.15
0.14
0.13
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
o
rvi
o
1 I ' I ' I ' I ' I ' I ' I '
flVERR&E OZONE BV MONTH SPERRV
O JULY
D AUGUST
A SEPTEMBER
i i i i i
02 04 06 08 10 12 14 16 18 20 22
HOUR fCST)
0.16
0.15
0.14
0.13
0.12
0.11
0.10
0.09 __
0.08 -m
0.07 -D
0.06 3
0.05
0.04
0.03
0.02
0.01
0.00
Figure 3.2. Mean monthly diurnal ozone for sites in the Tulsa area
(continued).
22
-------
V . 1U
0.15
0.14
0.13
0.12
0.11
£0.10
0-0.09
iJ 0 . 08
i 0.07
o 0.06
0.05
0.04
0.03,
0.02
0.01
n nn
- ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' 1 ' -
~ flVERR&E OZONE B* MONTH SKIRTQOK ~
z_ o JULY _:
. D AUGUST
^_ A SEPTEMBER
PL X^^^^^^^X ~
/^7^ ^^^^r*^ ~
^^z&zx*^^? ^^*^^^
r, 1 , 1 i 1 , I , 1 , 1 , 1 , 1 , 1 , 1 , I ,~
U . ID
0.15
0.14
0.13
0.12
0.11
0.10 o
0.09 §
0.08 .m
0.07 ^
0.06 z.
0.05
0.04
0.03
0.02
0.01
n nn
02 04 06 08 10 12 14 16 18 20 22
HOUR fCST)
1 I I ' I I I I
flVERR&E OZONE BY MONTH VERR
O JULY
D AUGUST
A SEPTEMBER
II l_ I I ._.!_.I I I
02 04 06 08 10 12 14 16 18 20 22
HOUR fCSD
Figure 3.2. Mean monthly diurnal ozone for sites in the Tulsa area
(continued).
23
-------
0.16
0.15
0.1^
0.13
0.12
0.11
0.10
0.09
uJ 0.03
o 0.07
o 0.06
0.05
0.0^
0.03
0.02
0.01
0.00
CL
o.
1 ! ' I ' i ' I ' I ' I ' I ^1 ' I ' 1
flVERfi&E OZONE BY MONTH WYNONR
O JULY
D AUGUST
A SEPTEMBER
1,1,1,1
02 04 06 08 10 12 14 16 18 20 22
HOUR fCST)
0.16
0.15
0.14
0.13
0.12
0.11
0.10 o
0.09 §
o.o8 r1
0.07 -D
0.06 J
0.05
0.04
0.03
0.02
0.01
0.00
0.
0.
O
tvj
O
' I ' I ' I ' 1 ' I '
RVERR&E OZONE BY MONTH OCHELflTR
O JULY
D AUGUST
SEPTEMBER
02 04 06 08 10 12 14 16 18 20 22
HOUR CCST)
Figure 3.2. Mean monthly diurnal ozone for sites in the Tulsa area
(continued).
24
-------
Minimum average values of ozone also fell to lower values from July to
August to September at each site.
The northern sites usually rank in the top five positions of average
diurnal ozone maximum. One exception is the southern site, Liberty Mounds,
which ranks first in maximum ozone in August; however, the concentration was
not much greater than those recorded at the Wynona or Sperry sites. The
urban core site, the Post Office, always ranks last in average maximum ozone
as would be expected for a location with air containing high levels of
ozone-destructive materials such as nitric oxide; this site also attains the
lowest average minimum ozone level.
3.2.1.2 Examination of Ozone Frequency Distributions--
Bar graph representations of frequency distributions of ozone concen-
tration in 0.01-ppm increments for July, August, and September for each site
are given in Volume I of this report. Each bar graph shows the number of
hourly observations for each range and the percentage of all hours for the
month represented by the number of observations.
Several approaches are employed to evaluate and compare the frequency
distributions for the different sites. The first approach is to compare the
percentage of hours that have ozone concentrations greater than the then
existing NAAQS of 0.08 ppm and less than a low value of 0.03 ppm. For the
month of July, four of the five northern sites had a higher percentage of
ozone concentration values greater than 0.08 ppm than either the southern
site or the city sites. The exception is the Skiatook Lake site, which had
only 2.0 percent of its hourly values above 0.08 ppm--the lowest percentage
for all sites for July. The Vera site had the highest (17.5 percent) number
of values in excess of 0.08 ppm. Next in line is Wynona with 14.5 percent;
Sperry is third with 7.5 percent. Values above 0.08 ppm occurred three to
four times more frequently at Vera than at sites in or south of the city.
These findings suggest the influence of the urban plume on the Vera site
since wind direction is generally from the south.
The distribution of values recorded during August generally shows that
the percentage of ozone values above 0.08 ppm declined; furthermore, the
percentage of values below 0.03 ppm increased. The most striking feature of
the August distributions, as compared to those of July, is that the southern
25
-------
site, tiberty Mounds, had the highest percentage of ozone hourly values
greater than the NAAQS with 9.6 percent. Wynona is second at 7.6 percent;
Skiatook Lake is third with 7.0 percent. All sites outside the city had a
greater number of hourly values above 0.08 ppm than did the two city sites.
During September, the frequency of hours when ozone was in excess of
0.08 ppm declined further with respect to the preceding month. The percent-
age of values less than 0.03 ppm generally increased with respect to values
in August. The highest percentage of values above 0.08 ppm in September was
4.4 at Ochelata; second highest was 3.0 at Vera; third highest was 2.0 at
Sperry.
3.2.2 Oxides of Nitrogen
3.2.2.1 General-
Monthly average concentration levels of nitric oxide, NO, are quite low
(7 ppb or less) at seven of the sites in the Tulsa area. Such concentra-
tions are at or below the minimum detectable limit for the analyzers used in
this study. Highest concentrations were recorded at the downtown Post
Office site, which is close to primary NO emitters such as automobile traffic,
railroads, and two petroleum refineries. This site had monthly average NO
concentrations of 0.022, 0.034, and 0.023 ppm for July, August, and September,
respectively. Nitrogen dioxide monthly average concentration values can be
classed in three groups. Highest average values are recorded at the downtown
Post Office site (0.024 to 0.029 ppm); second highest values are recorded at
the Health Department (0.014 to 0.015 ppm) and Sperry (0.008 to 0.01 ppm);
other sites have average monthly values ranging from 0.003 to 0.009 ppm.
Table 3.18 lists the mean monthly values.
The 0600 to 0900 local daylight time monthly average values for NO are
summarized in Table 3.19. This time frame (0500 to 0800 CST) is of interest
since it is during this period that early morning traffic buildup and other
activities associated with a city are at their maximum (with corresponding
maximum levels of oxides of nitrogen emissions). It is also the time during
which photochemical production of ozone begins.
Mean monthly 0600-0900 CDT NO values were greatest at the Tulsa Post
A
Office site, and averaged 0.065 ppm over the 3-month period. As compared to
26
-------
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27
-------
TABLE 3.19. MEAN 0600-0900 CDT NO CONCENTRATIONS BY MONTH AND ENTIRE
X
PERIOD FOR MONITORING SITES, TULSA, OKLAHOMA, 1977
Liberty Mounds
Tulsa Post Office
Tulsa City/County
Health Department
Sperry
Skiatook Lake
Vera
Wynona
Ochelata
July
0.009
0.065
0.019
0.016
0.005
0.006
0.006
0.011
NO ,
x'
August
0.006
0.073
0.028
0.016
0.005
0.012
0.006
0.007
ppm
September
0.005
0.055
0.034
0.020
0.004
0.012
0.004
0.005
Total
period
0.007
0.065
0.027
0.017
0.005
0.011
0.005
0.007
urban sites in other cities , Tulsa's 0600-0900 NO average is not as high
A
as central business district (CBD) locations in Houston (0.156 ppm) or Los
Angeles (0.147 ppm). Its average NO value is similar to that of El Paso
X
(0.067 ppm) or to a composite value for seven sites near the CBD of St.
Louis (0.077 ppm). The second highest 3-month average was 0.027 ppm and was
recorded at the Health Department site. This concentration is of similar
magnitude to those at other suburban sites such as the Ascarte Park site in
El Paso, Texas, which has a mean 0600-0900 value of 0.028 ppm.
3.2.2.2 Monthly Mean Diurnal Behavior of NO and N02
Of the three city sites (Post Office, Health Department, and Sperry),
average hourly levels of NO and N02 were highest at the Post Office site.
All three sites had higher average values than the remaining five sites.
The NO plot for the Post Office shows that there was continual injection of
this pollutant throughout the day. Maximum hourly average values between
0.035 and 0.049 ppm were attained during the morning traffic rush hours of
0500-0800 CST. Values then declined during the morning due to the combined
effects of lessened emissions, reaction of NO with ozone, and transport/
dilution. Early in the afternoon (around 1400) concentrations began to
28
-------
climb; this was most evident during the month of July when an average peak
concentration of 0.037 ppm was attained at 1700. NO values began to fall
off again at about 1600 or 1700 GST as the afternoon traffic diminished.
However, average hourly values remained at 0.010 to 0.030 ppm on into the
evening. Much lower NO values were recorded in the evening at the Health
Department (~0.014 ppm) and Sperry (~0.06 ppm) locations than at the Post
Office site.
At the Liberty Mounds, Skiatook Lake, Vera, and Ochelata sites, the
diurnal curves for each month show values that are quite low for both NO and
N02 (less than 0.012 ppm, with many average hourly values at 0.003 ppm).
The diurnal plots show no regular pattern or curve. For each hourly average
of the 3 months--July, August, and September--N02 concentrations averaged
0.008 ppm or below. A recurrent feature of these curves is that N02 concen-
trations were slightly higher in the early morning hours than during the
daylight hours when good mixing had occurred.
Maximum average hourly values of N02 at Liberty Mounds, as taken from
the diurnal curve, were 0.009, 0.005, and 0.004 ppm for July, August, and
September, respectively. These values are similar to diurnal curve N02
maxima recorded in a previous EPA study at rural sites . Maximum N02
values from a diurnal plot covering the period June 27 through October 31,
1975, were 0.004, 0.003, 0.000 (below minimum detectable limit), and 0.004
at sites near Bradford, Pennsylvania, Creston, Iowa, Wolf Point, Montana,
and DeRidder, Louisiana, respectively.
N02 average values at the Post Office site were fairly high throughout
the day. Values for each month are closely grouped. Maximum values oc-
curred early in the morning between 0700 and 0900 and ranged between 0.026
and 0.038 ppm. During this time NO was being emitted in larger quantities
and was quickly reacting with residual and newly formed ozone to produce
N02. A slight fall-off in N02 values occurred at about midday (1200 to
1300). During this time of high sunlight, NO emissions lessened and N02
photodissociation and other reactions were prevalent. By 1500, N02 levels
had peaked again to a maximum of 0.032 ppm.
The Health Department and Sperry sites each showed a fairly uniform N02
concentration pattern for each month. Values were elevated in the early
29
-------
morning hours (~0.022 ppm at the Health Department site and ~0.012 ppm at
the Sperry site), fell off gradually to a low point at about 1300, and then
slowly climbed to the highest average level for the day later in the evening
(~0.024 ppm at 2000 at the Health Department site and ~0.014 ppm at hour
2100 at the Sperry site).
3.2.3 Nonmethane Hydrocarbons
Total hydrocarbons, nonmethane hydrocarbons, and methane were measured
by use of the Beckman Model 6800 Air Quality Chromatograph at three sites in
the Tulsa area. These sites were the urban core site at the Post Office,
the suburban site at the Tulsa City/County Health Department, and a rural
site, Wynona. Diurnal plots for the total periods of hydrocarbon measure-
ment were constructed and examined. Note that the dates of the measurements
are not identical from site to site.
Mean diurnal concentrations of NMHC were highest at the Tulsa Post
Office. An average maximum value of 0.65 ppmC occurred at 0600 CST; the
minimum value was 0.30 ppmC and occurred during hour 1800. There was a
small increase in NMHC concentration during the day from 1200 to 1400, which
could be attributed to midday vehicular activity in the urban core area of
the city. No similar patterns for this time frame were observed at either
the Health Department or Wynona site. The Health Department NMHC diurnal
did exhibit a steady buildup of hydrocarbons starting at 0.10 ppmC at hour
1300 and maximizing at 0.39 ppmC at hour 1900. Values then fell off to a
minimum point of 0.10 ppmC at hour 0200. Concentrations at the Post Office
and Wynona sites were increasing during evening hours and continued to
increase until early morning. In contrast, the Health Department's concen-
tration values fell off during the evening (after hour 1900) and increased
only slightly in the early morning hours of 0200 through 0700.
The Post Office site NMHC diurnal is similar to that recorded by simi-
lar instrumentation in the St. Louis RAPS network from June through October
(8)
1976 . However, values at the Tulsa site did not fall to as low a point
as at sites in St. Louis.
The NMHC values recorded at the rural site, Wynona, were remarkably
high during the evening hours with a peak value of 0.61 ppmC in the 0500
hour. Between the hour of 0600 and 0700, the NMHC average concentration
30
-------
decreased dramatically (the Post Office site was also decreasing, but less
rapidly). The buildup of NMHC at this site was probably due to a combina-
tion of geogenic and anthropogenic emissions into a space beneath an inver-
sion layer where low wind speeds are prevalent.
3.3 DISCUSSION OF STRATIFIED DATA BASE
3.3.1 Introduction
Of the eight monitoring sites in the RTI Tulsa network, one was to the
south of the city, two were in the city, and five were to the north of the
city. Winds in eastern Oklahoma were generally from the south. Thus, the
southern site was usually exposed to what could be termed nonurban air; the
northern sites were, on many days, exposed to air that had passed over the
Tulsa metropolitan area that could be called urban air. This section of the
report is concerned with the comparison of data for ozone and oxides of
nitrogen (there were too few hydrocarbon samples at northern sites to es-
tablish a stratification) for days that have been divided into urban and
nonurban categories. Such a stratification gives an average picture of the
overall ozone and ozone-precursor spatial and temporal distributions in the
vicinity of Tulsa.
Stratifications were made on a day-by-day basis for the six sites sur-
rounding Tulsa. The two city sites are considered to be always under the
influence of urban air. The primary urban/nonurban stratification was made
on the basis of two major criteria: (1) the average vector wind direction
for the hours 0700 through 1600 CST as measured at the site under considera-
tion and at other sites; and, (2) examination of the afternoon synoptic and
mesoscale trajectories insofar as their temporal and spatial resolution
permits.
To decide what would constitute an urban-influenced day, the following
strategy was used. On a map (U.S. Geological Survey, 1:250,000) two lines
were drawn from the point of location of each site. One line extended from
the site to the eastern border of the city; the other line extended from the
site to Tulsa's western border. The number of degrees (arc) swept out by
these two lines was determined. To account for urban plume broadening and
small variations in wind direction, a 10-degree span was added to the eastern
31
-------
and western limits. This process gave the following degree ranges in which
air parcels would be classified as urban- or nonurban-influenced.
Urban Nonurban
Liberty Mounds 335° - 037° 038° - 334°
Sperry 125° - 218° 219° - 124°
Skiatook Lake 116° - 180° 181° - 115°
Vera 160° - 220° 221° - 159°
Wynona 123° - 166° 167° - 122°
Ochelata 152° - 201° 202° - 151°
By using this scheme, all days were classified as either urban or nonurban.
Table 3.20 summarizes those days classified as urban-influenced.
In particular borderline cases, the individual hours of wind direction
data were examined, and if the morning hours showed consistent direction,
the day was classified accordingly.
3.3.2 Urban and Nonurban Ozone
Mean hourly values of ozone were calculated for each site for the
months July, August, and September for urban and nonurban sets of days.
From these, the mean monthly urban and nonurban diurnal curves were con-
structed for the northern sites, Sperry, Vera, and Ochelata. In each case
there is a significant difference between the urban and nonurban curves.
The urban curve portrays much higher ozone concentrations during the midday
hours than does the curve for nonurban days. This probably reflects the
enhanced ozone production in air parcels that passed over Tulsa. Figure 3.3
shows the mean diurnal curves for urban- and nonurban-influenced days at the
Vera site for July, August, and September. As was also true for Sperry and
Ochelata, the highest average urban or nonurban ozone concentrations at Vera
were recorded in July, followed by August and September. One possibility for
this trend would be the diminishing intensity of solar radiation. A statis-
tical test of significance (t-test) at the 95 percent confidence level
showed that, for individual months and for the 3-month period, the averages
of daily maximum values of ozone for urban days were significantly different
from the average of daily maximum values for nonurban days. Furthermore,
the mean of ozone concentrations during the 4 hours having the highest
average concentrations of ozone was statistically significantly different
32
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TABLE 3.20. URBAN-INFLUENCED DAYS AT SITES NEAR TULSA
July
August
September
July
August
September
July
August
September
July
August
September
July
August
September
July
August
September
Liberty Mounds
1, 27
11, 12, 13, 17, 24, 29
5, 6, 13, 14, 19, 24
Sperry
2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 23, 30
2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 20, 22,
23, 25, 26, 27, 30, 31
1, 2, 3, 4, 8, 11, 12, 16, 17, 18, 20, 21, 22,
23, 26, 30
Vera
2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 23, 24, 28, 30
3, 5, 6, 7, 8, 9, 10, 14, 16, 20, 22, 23, 25, 26
27, 30, 31
1, 2, 3, 4, 8, 12, 16, 17, 18, 20, 21, 22, 23,
26, 30
Ochelata
2, 7, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21,
28, 30
3, 4, 5, 6, 7, 14, 15, 20, 22, 25, 26, 27, 30, 31
1, 2, 3, 8, 12, 16, 17, 18, 20, 21, 22, 23, 26, 30
Skiatook Lake
15, 19
3, 4, 14, 15, 19, 20, 22, 25
1, 2, 3, 8, 11, 16, 20, 21, 22, 26
Wynona
4, 14, 15, 19, 22, 25
1, 11, 16, 20, 21, 22
for the urban and nonurban data sets. Table 3.21 lists the average values
and the number of cases for the 3-month period.
33
-------
I ( I I ( I I I I I I I I I I I I I I I I I 1
VERfl OZONE URBflN/NONURBftN JULY, 1977
O URBAN
D NONURBAN
2 f 6 8 10 12 If 16 18 20 22
HOUR CCST)
o
fvl
O
' I ' I ' I ' I ' I ' I ' I ' I ' ' '
VERfl OZONE URBflN/NONURBftN flUGUST, L977
O URBAN
D NOMURBAN
8 10 12 If 16 18 20 22
HOUR (GST)
Figure 3.3. Mean monthly diurnal ozone for urban and nonurban influenced
days at the Vera site.
34
-------
QL.
Q_
UJ
z
o
o
0.16
0.15
O.H
0.13
0.12
0.11
0.10
0.09
; 0.08
' I ' 1 ' I ' I ' I ' i ' I ' | ' I '
VERfl OZONE URBflN/NONURBRN SEPT.. 1977
O URBAN
D NONURBAN
6 8 10 12 If 16 18 20 22
HOUR CCST)
0.16
0.15
O.H
0.13
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
O.Ot
0.03
0.02
0.01
0.00
o
M
o
Figure 3.3. Mean monthly diurnal ozone for urban and nonurban influenced
days at the Vera site (continued).
-------
TABLE 3.21. AVERAGE VALUES FOR OZONE, TEMPERATURE, PERCENT SUNSHINE,
AND SOLAR RADIATION
Maximum 03, ppm
4-hr mean 03, ppm
Maximum temp, °F
Percent sunshine
Cumulative solar
radiation,
langleys/min
Sperry Vera
Urban Rural Urban Rural
0.080(53) 0.060(34) 0.087(54) 0.061(38)
0.070(54) 0.051(34) 0.077(54) 0.054(38)
93.1(56) 84.6(36) 93.4(54) 84.6(38)
79.3(56) 49.2(36) 79.7(54) 50.3(38)
549(54) 367(35) 559(52) 363(37)
Ochelata
Urban Rural
0.082(42) 0.062(43)
0.073(42) 0.056(45)
92.4(43) 87.5(49)
78.3(43) 58.1(49)
534(42) 426(47)
Because the intensity of sunlight and the temperature are important
factors in the photochemical production of ozone, average values of the
maximum daily temperature, percent sunshine, and cumulative solar radiation
were also compared for urban and nonurban days at the three sites (Table 3.21)
It was found in most cases that the differences in average values for the
meteorological parameters were also statistically significantly different.
On days when the winds at the northern sites were from directions other than
southerly, the averages for maximum temperature, percent sunshine, and
cumulative solar radiation were all lower than their southerly, urban-
influenced counterparts. In a further stratification, when 14 urban-
influenced days at Vera were compared to 12 nonurban days that had similar
cumulative solar radiation, the difference in the average ozone profiles was
still significantly different, yet the meteorological parameters were not.
This finding implies that enhanced concentrations of ozone at the northern
sites are associated with air parcels that have passed over the urban area.
A further comparison was made between the upwind site, Liberty Mounds,
and downwind sites for urban-influenced days that were common to Sperry,
Vera, and Ochelata. Figure 3.4 shows the average monthly diurnal plots of
these common days in July (14 days), August (11 days), and September (14
days). Average hourly ozone concentrations for the same days are shown for
Liberty Mounds (these days are, of course, nonurban days at this site).
Several features of these plots should be noted.
36
-------
I 1 I I I I I I I I I I I I I I I I I I 1 I I
RVE. 03 COMMON URBflN DflYS JULY, 1977
A VERA
SPERRY
* OCHELATA
O LIBERTY MOUNDS
2 4 6 8 10 12 14 16 18 20 22
HOUR (CST)
I'
RVE. 03' COMMON URBflN DflYS flUGUST, 1977
VERA
SPERRY
OCHELATA
LIBERTY WJNDS
10 12 14 16 18 20 22
HOUR CCST)
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
16
15
14
13
12
11
10
09
08
07
06
05
04
03
02
01
00
o
o
z
m
-o
3
Figure 3.4. Mean monthly diurnal ozone for common urban influenced days in
July, August, and September.
37
-------
Q_
Q_
UJ
0.16
0.15
0.14
0.13
0.12
0.11
0.10
0.09
: 0.08
0.07 -
M
O
I ' I ' I ' I ' I ' I ' I ' I ' I ' I '
flVE. 03 COMMON URBflN DflYS SEPT.. 1977
VERA
SPERRY
OCHELATA
LIBERTY MOUNDS
6 8 10 12 H 16 18 20 22
HOUR CCST)
0.16
0.15
0.14
0.13
0.12
0.11
0
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
10 8
o
m
-o
-o
Figure 3.4. Mean monthly diurnal ozone for common urban influenced days in
July, August, and September (continued).
38
-------
For the month of July, the upwind background site, Liberty Mounds,
displayed an average diurnal ozone curve typical of nonurban areas. The
average minimum value was reached in the early morning (0400) and, as the
inversion layer broke up and the combined effects of downward mixing of
ozone from above the inversion and local photosynthesis of ozone occurred,
the concentration rose gradually. The average concentration leveled off at
about hour 1000 and persisted at or near this value until hour 1800. The
average maximum value of 0.064 ppm occurred relatively late in the day at
hour 1600.
In contrast, the diurnal curves for sites to the north of Tulsa show
nighttime and early morning ozone concentrations that are generally lower
and remain lower for a couple of hours longer than those of the background
site (probably a consequence of ozone titration by urban-emitted ozone
scavengers such as NO). At about hour 0600, the ozone concentrations began
to climb at a rate much faster than those of Liberty Mounds and reached peak
values considerably higher and earlier in the day than those of the back-
ground site. The diurnal curve of the urban-influenced site(s) is not
flattened during the midday hours as is that of Liberty Mounds. Average
peak ozone concentrations of 0.085 ppm and 0.099 ppm were reached at hour
1300 at the Sperry and Vera sites, respectively. The Ochelata average peak
was 0.081 ppm and occurred somewhat later (hour 1500). The lag in the time
of the occurrence of maximum ozone at Ochelata was probably a consequence of
the increased travel time required for a given air parcel to reach the
northernmost site.
Figure 3.4 also compares the mean diurnal curves for the 11 urban-
influenced days in August that were common to Sperry, Vera, and Ochelata.
In contrast to the July diurnal curves, the average maximum values are quite
similar. The difference is probably largely due to lower percent sunshine
for August days (74 as compared to 84 for July days) and higher morning wind
speeds for common days in August (11.1 versus 9.2 mph). The Liberty Mounds
curve displays features characteristic of a nonurban site: average concentra-
tions of ozone were higher during the nighttime and predawn hours than are
those of northern sites, and the curve is flatter than those of urban-influ-
enced sites, showing that elevated ozone concentrations persisted longer.
Except for a concentration excursion to 0.075 ppm at hour 1400, the average
39
-------
hourly afternoon values at Liberty Mounds were the lowest of the four sites.
Sperry was next lowest, Ochelata somewhat higher, and Vera was highest.
Figure 3.4 shows that the maximum average ozone attained in the system was
at the Vera site.
The mean diurnal behavior of ozone for the 14 common days of September
is shown in Figure 3.4. Of the four sites, ozone concentrations at Liberty
Mounds were highest during the nighttime hours and lowest during the after-
noon hours. An average maximum of 0.058 ppm occurred at hour 1700. Values
at the urban-influenced downwind sites ascend in the order of Sperry, Vera,
and Ochelata. The closer the site is to the urban area (and its ozone-
destructive emissions) the lower is the average maximum concentration.
Average values of 0.062, 0.068, and 0.070 ppm occurred at hour 1300 at
Sperry, Vera, and Ochelata, respectively. Average morning solar radiation
intensities for common September days was a third less than for July common
days.
For the 3-month period, the average hourly maximum values for ozone for
urban-influenced days at Sperry, Vera, and Ochelata were 0.077, 0.085, and
0.081 ppm, respectively. The average hourly maximum for the same days at
Liberty Mounds was 0.068 ppm. The difference between each of the urban-
influenced averages and the nonurban average is statistically significant at
the 95 percent confidence level. This is to say, the probability that the
difference could have occurred by chance is less than 5 percent.
3.3.3 Urban and Nonurban Oxides of Nitrogen
Concentration values for oxides of nitrogen (NO, N02, NO ) were also
examined for the stratified urban- and nonurban-influenced days. Table 3.22
presents average values for the time intervals 0500 through 0700 CST and
1000 through 1200 CST for urban-influenced days at the Sperry, Vera, and
Ochelata sites. Values from the upwind site, Liberty Mounds, and one of the
city sites, the Post Office, are included for comparison.
In all cases the concentration of NO, NOg, or NO was quite low at the
upwind Liberty Mounds site. The highest average NO concentration attained
X
at this site was 0.010 ppm for early morning hours in July. As expected,
the downtown Post Office site recorded much higher concentrations than
Liberty Mounds during both time periods. The NO, N02, and NO concentra-
A
tions during the 1000-1200 averaging period at the Post Office site were in
all cases somewhat higher than those recorded during the 0500 through 0700 CST
40
-------
TABLE 3.22. AVERAGE NO, N02, AND NO CONCENTRATIONS, ppm, ON
A
URBAN-INFLUENCED DAYS COMMON TO SPERRY, VERA, AND OCHELATA
Liberty Mounds
July
August
September
Post Office
July
August
September
Sperry
July
August
September
Vera
July
August
September
Ochelata
July
August
September
Hours
NO
.001
.002
.003
.033
.054
.049
.006
.007
.014
.001
.004
.002
.004
.002
.000
05, 06,
N02
.009
.003
.004
.033
.031
.033
.015
.012
.010
.006
.009
.010
.009
.007
.006
07 CST
NO
X
.010
.005
.007
.066
.085
.082
.021
.019
.024
.007
.013
.012
.013
.009
.006
Hours
NO
.001
.002
.001
.034
.067
.055
.004
.002
.003
.003
.002
.001
.002
.001
.000
10, 11,
N02
.006
.002
.002
.036
.040
.038
.008
.010
.008
.004
.008
.010
.005
.004
.004
12 CST
NO
X
.007
.004
.003
.070
.107
.093
.012
.012
.011
.007
.010
.011
.007
.005
.004
period in spite of the expected greater mixing due to increased ventilation.
Thus, it seems that when winds are from the south, concentrations of NO in
' ' x
Tulsa are sustained and do not diminish after the morning traffic rush
hours.
The Sperry, Vera, and Ochelata sites recorded NO, N02, and NO concen-
trations that were sharply reduced as compared to those in the city (see
Table 3.22). For the 0500 through 0700 CST time period, relative NO con-
centrations were: Post Office, 1; Sperry, 0.28; Vera, 0.13; and Ochelata, 0.09.
Average oxides of nitrogen values at Ochelata were not significantly different
from those found at the upwind site, yet the ozone values were significantly
41
-------
TABLE 3.23. AVERAGE NO, N02, AND NO CONCENTRATIONS, ppm, ON
NONURBAN-INFLUENCED DAYS AT SPERRY, VERA, AND OCHELATA
Post Office
July
August
September
Sperry
July
August
September
Vera
July
August
September
Ochelata
July
August
September
Hours
NO
.019
.025
.014
.004
.004
.008
.003
.001
.000
.002
.004
.002
05, 06,
NO 2
.031
.022
.020
.008
.008
.007
.006
.005
.005
.004
.008
.009
07 CST
NO
X
.050
.047
.034
.012
.012
.015
.009
.006
.005
.006
.012
.011
Hours
NO
.008
.008
.006
.003
.002
.004
.003
.001
.000
.001
.002
.008
10, 11,
N02
.023
.017
.017
.006
.006
.005
.002
.007
.008
.005
.003
.004
12 CST
NO
X
.031
.025
.023
.009
.008
.009
.005
.008
.008
.006
.005
.012
different. This tends to suggest that the concentrations of ozone attained
at Ochelata are not dependent on NO levels at that site, but rather are
dependent on transport of photochemically active air parcels from the urban
environs.
Table 3.23 presents similar data for nonurban days at Sperry, Vera, and
Ochelata. The average concentrations for the CBD (Post Office) site for
days judged to be nonurban at Sperry are also listed. On the whole, concen-
trations of NO, N02, and NO were lower at each site in comparison to urban
days. In fact, the values were about the same as those determined for nonurban-
influenced days at Liberty Mounds. This suggests that NO was not being
X
transported into the study area at ground level.
An examination of the values of NO, N02, and NO at the Post Office
X
site for the days when the northern sites were classed as nonurban-influenced
(i.e., northerly winds) shows that average values at the Post Office site
42
-------
are lower in the 0500-0700 samples than the average for urban-influenced
days (i.e., southerly winds) and that the concentrations in the 1000-1200
period are lower than in the early morning time frame. This contrast elicits
two comments. First, the bulk of the NO, N02, and NO seems to originate in
A
areas generally to the south of the Post Office site (the greater part of
the urban area and industry ijs located to the south). Second, the sources
of NO to the south are such that their emissions of NO continue throughout
X X
the morning hours. This suggests that continuous vehicular traffic and/or
continuous industrial processes are responsible for an appreciable portion
of the NO measured at the Post Office site during the hours 1000, 1100, and
1200 when winds were southerly.
3.4 STATISTICAL RELATIONSHIP OF OZONE TO OTHER PARAMETERS
In this section, the relationships between daily maximum ozone concentra-
tions and values of various meteorological and pollutant variables measured
in Tulsa are examined. Table 3.24 is a listing of the summary statistics
(mean values, standard deviations, maximum values, and the number of days
used in calculations) for selected pollutant and meteorological variables by
site for the 3-month study period.
Table 3.25 lists the correlations established between values of daily
maximum ozone and various meteorological and pollutant variables. In general,
the correlations are not very high. The strongest correlations are found
with the variables maximum temperature, percent possible sunshine, and solar
radiation. This is, of course, a consequence of the necessity for ultravio-
let radiation in the photochemical formation of ozone.
The values of maximum ozone do not correlate well with 0500-0800 CST
values of NO as measured at either the Health Department or Post Office
A.
site. Correlations are also poor between ozone maximum values and morning
nonmethane hydrocarbon values determined in the city by the automated chrom-
atograph (NMHC) or by summing individual hydrocarbon species (INMHC). The
same can be said for correlations with NO/NO and the ratio of INMHC to NO .
x x
A good correlation between maximum ozone and the 0500-0800 CST average
values mentioned above may not have been expected a priori since trajectory
analyses (Appendix A) suggest that the air parcel in the vicinity of the
43
-------
TABLE 3.24. SUMMARY STATISTICS FOR POLLUTANT AND METEOROLOGICAL
VARIABLES BY SITE
Variable
Daily Maximum 63
mean, ppm
s.d.
max
no . days
% days
03>.08
NO (5-8 CST)
mean, ppm
s.d.
max
no . days
N02 (5-8 CST)
mean , ppm
s.d.
max.
no . days
N0x (5-8 CST)
mean, ppm
s.d.
max.
no . days
NMHC (5-8 CST)
mean , ppm
s.d.
max.
no . days
INMHC (5-8 CST)
mean, ppm
s.d.
max.
no . days
OCH
.072
.019
.114
85
30.6
.001
.002
.006
85
.006
.002
.012
85
.003
.003
.016
85
WYN
.071
.019
.123
86
26.7
.001
.001
.008
87
.005
.003
.011
85
.005
.003
.012
87
.530
.503
1.760
25
Site
VER
.076
.025
.151
92
38.0
.003
.003
.011
77
.008
.003
.015
85
.011
.005
.021
84
SKI
.068
.018
.120
84
26.2
.000
.000
.002
80
.005
.003
.016
88
.005
.003
.017
87
SPE
.072
.021
.135
87
33.3
.007
.008
.056
84
.010
.005
.028
85
.017
.010
.065
87
HD
.066
.020
.124
82
18.3
.011
.019.
.118
81
.017
.009
.043
82
.028
.026
.149
83
.231
.255
1.190
50
.317
.224
1.457
68
PO
.055
.022
.127
81
12.3
.036
.039
.170
79
.028
.010
.048
79
.064
.046
.209
79
.607
.462
3.110
41
.538
.448
3.684
71
LM
.069
.018
.127
92
26.1
.002
.002
.010
88
.005
.004
.019
90
.007
.005
.021
90
.240
.213
1.136
59
Wind Direction
(5-17 CST)
mean, degrees
s.d.
no . days
156
71
87
162
83
81
172
68
89
167
73
82
(continued)
44
-------
TABLE 3.24 (continued)
Variable
Wind Speed
(5-17 CST)
mean , mph
s.d.
max.
no . days
OCR
4.3
2.3
12.2
72
Site
WYN VER SKI
6.9
3.9
18.1
82
SPE HD
8.0
4.4
19.8
88
PO LM
6.1
3.6
16.5
81
Ozone (5-8 CST)
mean, ppm
s.d.
max.
no. days
.027
.009
.052
85
.029
.012
.059
88
.022
.013
.054
85
.022
.010
.046
88
.021
.011
.068
78
.020
.011
.068
78
.012
.008
.037
81
.026
.012
.051
91
45
-------
TABLE 3.25. CORRELATIONS BETWEEN DAILY MAXIMUM OZONE AND
METEOROLOGICAL AND POLLUTANT VARIABLES BY SITE
Variable
Max . temp .
% Sun
Sol. rad.
Dew pt.
WS (HD) (a)
WD (HD) (a)
NO (HD) (b)
NOX (PO)
NOX (LM)
NMSC (HD)
NMHC (PO)
INMHC (HD)
INMHC (PO)
INMHC (LM)
N02/N0 (HD)
N02/NOX (PO)
N02/NOX (LM)
NMHC/NO (HD)
NMHC/NOX (PO)
INMHC/N6 (HD)
INMHC/NOX (PO)
INMHC/NOX (LM)
Ave. sample size
(days) meteoro.
Ave. sample size
(days) pollutants
NMHC sample
size (days)
OCH
.55
.47
.46
.28
-.02
.10
.18
.04
.39
.29
.33
.20
.35
.35
.05
.07
-.03
-.05
.15
-.01
.23
-.05
85
80
45
WYN
.57
.32
.38
.28
-.11
.10
.23
.18
.36
.19
.40
.19
.42
.37
.06
-.02
-.20
-.09
-.01
-.04
.15
-.01
84
75
45
VER
.66
.44
.58
.28
-.06
.19
-.06
.13
.51
.03
-.03
-.02
.10
.24
.31
.08
-.08
-.02
-.15
.02
.03
-.13
90
80
45
Site
SKI
.44
.34
.30
.16
-.13
.09
.17
.11
.24
.29
.37
.15
.37
.31
.07
.00
-.11
.13
.05
-.09
.21
-.04
80
75
40
SPE
.59
.44
.50
.32
-.18
.09
.10
.01
.51
.21
.37
.19
.34
.52
.14
.09
-.07
-.03
.20
-.01
.22
.11
85
80
45
HD
.48
.34
.38
.20
-.29
.01
-.03
,' -.11
.41
.11
.02
.05
.06
.32
.17
.25
-.03
.16
.13
.02
.13
.06
80
75
45
PO
.26
.17
.23
.20
-.49
-.12
.09
-.34
.36
.20
.10
.09
.08
.39
.04
.44
-.05
-.03
.33
-.12
.28
.20
80
75
45
LM
.41
.23
.25
.13
-.19
-.05
.11
-.01
.32
.14
.20
.22
.28
.31
.13
.10
-.12
.04
.20
.05
.30
.04
90
80
45
(a}
^ 'Vector average for the hours 0500-1700 CST.
from 0500 to 0800 CST.
(b) All pollutants averaged
46
-------
maximum ozone site at the time of maximum ozone was upwind of Tulsa during
the period of morning precursor emissions. Mesoscale trajectories show
that, more often, the air parcel present at the northern site at the time of
ozone maxima passed across the city between the hours of 0900 and 1200 CST
and not during the 0500 to 0800 CST period.
Stepwise regressions were also performed. This procedure is commonly
used to indicate which variables out of a large group appear to be the most
important in predicting a given variable (e.g., maximum ozone). The procedure
assumes that a linear relationship exists between the dependent variable and
the independent variable. Table 3.26 lists the results of stepwise regres-
sions with daily maximum ozone as the dependent variable. For example, at
the Sperry site, the most important independent variable in predicting
maximum ozone is maximum temperature; second in importance is wind speed;
third, 2NMHC; and fourth, NO . Maximum temperature (a variable closely
associated with percent sunshine) is the most important variable in pre-
dicting maximum ozone at seven out of eight sites. Anywhere from 38 to 56
percent of the variation in ozone concentration was explained by the inde-
pendent variables checked in the table.
Table 3.27 is similar to the previous table except that the data were
stratified to include only those days having mean wind direction between
116° and 231° as measured at the Health Department site between the hours of
0500 and 1700 CST. In general, the results of the stepwise regression are
similar to those obtained with the nonstratified data base; maximum tempera-
ture ranks first in explaining ozone variation at six of the eight sites.
In contrast to the nonstratified data, variations in ozone at the Post
Office and Health Department sites show an increased dependence on NC-2/NO ,
X
and ZNMHC (each as measured at the Post Office site) and the meteorological
variables wind speed, maximum temperature, and solar radiation as measured
at the Health Department, Tulsa International Airport, and Skiatook, respec-
tively.
Finally, the means of several pollutant and meteorological variables
were calculated for three levels of maximum ozone. The levels chosen were:
low (less than 0.06 ppm); medium (between 0.06 and 0.08 ppm); high (greater
than 0.08 ppm). Table 3.28 is a compilation of the 0500-0800 CST average
47
-------
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-------
TABLE 3.28. AVERAGES OF METEOROLOGICAL AND POLLUTANT VARIABLES FOR
DIFFERENT LEVELS OF DAILY MAXIMUM OZONE BY STATION
Maximum Pollutant Variables
Station
Liberty
Mounds
Post
Office
Health
Department
Sperry
Skiatook
Lake
Vera
Wynona
Ochelata
Ozone
levels
<.06
intermed.
>.08
<.06
intermed.
>.08
<.06
intermed.
>.08
<.06
intermed.
>.08
<.06
intermed.
>.08
<.06
intermed.
>.08
<.06
intermed.
>.08
<.06
intermed.
>.08
NO
(ppm)
.062
.071
.057
.076
.048
.048
.067
.069
.045
.054
.079
.060
.050
.069
.060
.052
.071
.070
.049
.071
.069
.048
.083
.058
N02/N0x
.53
.55
.63
.50
.64
.73
.51
.57
.65
.57
.51
.59
.59
.54
.62
.57
.51
.60
.58
.55
.55
.59
.50
.62
INMHC
ppmC
.378
.526
.741
.545
.508
.584
.547
.557
.516
.397
.554
.696
.382
.585
.726
.420
.715
.537
.338
.507
.787
.380
.573
.687
Meteorological
Wind
speed
(a)
8.4
8.7
6.2
9.6
6.0
4.5
8.6
8.1
4.8
7.9
9.3
6.5
8.2
8.1
6.7
7.4
9.5
7.6
7.2
8.9
6.3
6.9
9.0
7.4
Max.
temp.
(Airport)
84.2
91.6
92.9
88.1
89.5
95.4
85.6
92.2
93.2
82.4
91.8
94.7
85.6
90.6
92.9
82.8
91.0
95.2
83.0
89.2
95.1
81.8
92.5
92.8
Variables
Solar
radiation
(Skiatook)
376
516
513
442
450
584
406
519
527
333
524
563
393
480
536
317
512
586
374
451
558
323
523
537
No. of times vari-
able increased from
low to high level
of max. ozone
No. of times vari-
able decreased from
low to high level
of max. ozone
(a) Speed in mph as measured at Health Department, 0500-1700 average.
50
-------
values of pollutant variables NO , N02/NO , and ZNMHC as measured at the
X X
Post Office site and the meteorological variables wind speed, maximum temper-
ature, and the sum of hourly solar radiation values for the day as measured
at the Health Department, Tulsa International Airport, and Skiatook, respec-
tively. The data show increasing levels of ozone with increasing temperature
and solar radiation and generally higher values of ozone with lower wind
speeds.
3.5 ANALYSIS AND INTERPRETATION OF THE HYDROCARBON DATA BASE
3.5.1 Background
One objective of the Tulsa field monitoring program was acquisition
of a nonmethane hydrocarbon data base for sites upwind of and in the city,
especially for the hours 0500 to 0800 CST (0600 to 0900 CDT), a time frame
important to EPA modeling and control strategy efforts. This data base was
compiled using two methods. One method was to collect hydrocarbon samples,
analyze each sample for 47 individual hydrocarbon species, and sum the
concentrations. Such samples were collected in an integrated fashion by
filling stainless steel containers with air from the station sample manifold
over a 3-hour period. Details of the sampling and gas chromatography analysis
procedures and quality assurance experiments are given in Volume I of this
report; concentrations and sums of individual hydrocarbon species are listed
in Volume II. Samples were collected during hours 0500 to 0800 CST each day
of the study at the southern site, Liberty Mounds, which was generally
upwind of Tulsa, and at the Post Office and Health Department city sites.
During the period of aircraft flights (August 26 through September 17),
additional ground samples were collected at all sites in the system during
the hours 0800 to 1100 CST or 1300 to 1600 CST. Hydrocarbon samples were
also collected by the aircraft during vertical spirals upwind of, over, and
downwind of the city and during low passes over the Tulsa International and
Downtown Airport runways. Table 3.29 summarizes the number of hydrocarbon
samples collected at each site or location.
The second approach to measurement of nonmethane hydrocarbons was
through the use of the Beckman Model 6800 automated chromatograph. This
monitor was in operation at the Health Department site from July 28 through
51
-------
TABLE 3.29. NUMBER OF HYDROCARBON SAMPLES COLLECTED IN TULSA
Site or location
Liberty Mounds
Health Department
Post Office
Sperry
Skiatook Lake
Vera
Wynona
Ochelata
Aircraft, upwind
Aircraft, over city
Aircraft, low pass
Aircraft, downwind
Morning
05 to 08 CST
70
77
78
10
0
0
0
0
24
10
11
0
Midmorning
08 to 11 CST
7
7
7
7
0
0
0
0
0
0
0
0
Afternoon
13 to 16
0
1
1
5
6
6
5
5
0
0
0
12
CST
September 20, at the Post Office site from July 28 through August 26, and at
the Wynona site from August 29 through September 22. Mean monthly diurnal
curves of hourly concentrations of total hydrocarbon, methane, and, by
difference, nonmethane hydrocarbons are presented in Volume I. Hourly
values are listed in Volume II.
In addition to the above samples, five Tenax adsorption cartridges were
collected and analyzed for organic components by gas chromatography/mass
spectrometry. These analyses were qualitative in nature and served several
purposes: to confirm the presence or absence of specific hydrocarbons and
other compounds; to establish the relative order of chromatographic elution
of hydrocarbons; and to quantitatively compare, on a relative basis, the
variation in organic compound content of samples collected upwind of, in,
and downwind of the city of Tulsa.
In this section, comparisons will be made among the measurements of
nonmethane hydrocarbon concentrations (determined by summing individual
species) at the sites in Tulsa as well as in other cities. Concentrations
of selected hydrocarbons and sums of hydrocarbons from Tulsa ground and
aircraft samples will also be interpreted with respect to site location, day
of the week, time of day, distance of the sampling site from Tulsa, altitude,
and influences of sources and meteorological conditions. From this, the
52
-------
average concentration levels of hydrocarbons contained in background air, in
air over the urban area, and in air downwind of the city can be established.
The contribution of various sources can also be assessed.
A quantitative comparison will be made between NMHC as the sum of indi-
vidual hydrocarbons and NMHC as given by the automated chromatograph. A
qualitative comparison will also be made between the hydrocarbon species
measurements and the results of the gas chromatography/raass spectrometry
studies.
3.5.2 Comparison of Nonmethane Hydrocarbons at Various Sites
Values of nonmethane hydrocarbons (obtained by summing values of
individual species) are shown in Figure 3.5 for morning samples at three
Tulsa locations, two St. Louis locations, and one location in Ohio. The St.
(9)
Louis and Ohio distributions are based on data reported by Lonneman.
Listed on the figure are (1) the date and location of the samples and (2) the
average percentage of nonmethane hydrocarbon attributed to vehicular tailpipe
emissions. This was determined by considering acetylene as an indicator of
tailpipe NMHC emissions. An acetylene factor of 15.5 was used in making
these computations. This factor (15.5) is based on experimental work by
Kopczynski et al. and Lonneman in which the total hydrocarbon content
of vehicular emissions in tunnel samples is compared to the acetylene content
of the same sample. In Kopczynski's work, the percentage calculation in-
volves the ratio of estimated vehicular emissions (acetylene concentration
x 15.5) to the observed total nonmethane hydrocarbon concentration.
The distribution of NMHC concentrations at the generally upwind site,
Liberty Mounds, has a median value around 150 ppbC, a value somewhat higher
than that found for the Wilmington, Ohio, site. Wilmington is located in
the Ohio Valley and is within 80 km (50 mi) of the large cities of Cincinnati,
Dayton, and Columbus. The nearest major metropolitan area in the predominant
upwind direction from Liberty Mounds is Dallas-Fort Worth, approximately
400 km (250 mi) away. The average percentage of NMHC attributed to vehicular
exhaust was considerably lower in the Liberty Mounds samples than it was in
the Wilmington samples. Thus, it seems that the hydrocarbon constituents of
the air to the south of Tulsa are, in large part, derived from sources other
53
-------
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than vehicular emissions. In fact, on the average, 74 percent of NMHC at
Liberty Mounds is due to alkanes; only 64.3 percent is due to alkanes at the
downtown Post Office site. This is not surprising since the area south of
Tulsa is dotted with oil fields, natural gas sites, and petrochemical produc-
tion and storage facilities. The nearest such source south of Liberty is a
small refinery ot Okmulgee, approximately 27 km (17 mi) away.
Liberty Mounds also recorded several cases in which the sum of NMHC
exceeded 500 ppbC. On these days, the winds during the hours preceding the
sample were either calm or from the north. The occurrence of higher than
average concentrations of low molecular weight hydrocarbons was noted on
these same days. This suggests that emissions associated with the refinery
complex in Tulsa may have influenced NMHC levels as far south as Liberty
Mounds.
Early morning samples from the Health Department site gave a NMHC dis-
tribution having a median around 250 ppbC. On the average, the acetylene
concentration was 11.8 ppbC and 60 percent of the hydrocarbon burden was
attributable to vehicular emissions. This percentage is similar to Kopczyn-
ski's findings in St. Louis at the Saint Louis University site
The frequency distribution of morning NMHC concentrations at the Post
Office site is bimodal whereas the Health Department, Wilmington, and St.
Louis data show single peak distributions. Two distinct humps are observed;
one is centered around 350 ppbC, the other at about 550 ppbC.
3.5.3 Comparison of Classes of Hydrocarbons
Table 3.30 summarizes by month and for the entire period the average
values of the alkene, alkane, and aromatic classes of hydrocarbons for
morning samples collected at three surface sites.
The generally upwind site, Liberty Mounds, was lowest of the three
sites in average concentration for the alkene (olefin) class for every
month. The inner city site, the Post Office, had average alkene concentra-
tions almost three times higher than those of the background site (ten times
higher if the ethylene concentration, which may have been enhanced by exhaust
from the chemiluminescent ozone monitor, is included). Concentrations at
the Health Department site were about twice as high as those at Liberty
55
-------
Mounds. The average sum of alkanes (paraffins) at the background site was
not greatly different from that of the Health Department site. At the Post
Office site, average alkane, aromatic, and nonmethane hydrocarbon concentra-
tions were significantly higher than at the other two sites.
The percentage of nonmethane hydrocarbons due to vehicular tailpipe
emissions was computed for each sample; averages are given in Table 3.30.
Liberty Mounds was lowest, with an average of only 17 percent. The Health
Department and Post Office sites averaged 60 and 64 percent, respectively.
These percentages represent a maximum value because they were calculated
based on an acetylene factor of 15.5, which was itself derived by Kopczynski
and Lonneman from automobile tunnel samples assumed to be composed 100
percent of vehicular emissions. In Kopczynski's work , a greater number
of hydrocarbons were identified than is the case in the present study. Thus
the concentration of NMHC would have been greater had additional compounds
been analyzed, and the percentage attributed to vehicular exhaust would have
been correspondingly less.
3.5.4 Comparison of Individual Hydrocarbon Compounds
The concentrations of individual hydrocarbons, as expected, show dif-
ferences between background and city sites as did the sums of hydrocarbons.
Table 3.31 lists average values for six alkenes and acetylene. In most
cases, the concentration of an individual compound was lowest at the back-
ground site, Liberty Mounds, and highest at the downtown Post Office site.
Note that no detectable quantities of the naturally emitted compound, p-
pinene, were measured at any of the monitoring stations, ot-pinene eluted
from the chromatographic column at the same time as p-xylene, and thus was
not quantified separately. It is likely, however, that the concentration of
a-pinene was very low. Another naturally occurring compound, isoprene, was
sought in the analysis, but was found to elute at the same time as trans-2-
pentene. The average concentration of trans-2-pentene plus isoprene was
higher in the city samples than in background samples, suggesting that, if
isoprene is truly present, its source is associated with the urban area
emissions. At any rate, the average concentration of trans-2-pentene plus
isoprene was quite low and would not be expected to exert a significant
influence on the ozone production potential of this area.
56
-------
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Table 3.32 lists average values for hydrocarbons classed as alkanes.
This table shows a tendency toward higher concentrations of low molecular
weight alkanes, and quite small or zero concentrations of long-chain hydro-
carbons such as nonane, decane, undecane, and dodecane. For most alkanes,
the concentrations are higher at the city sites than at the background site.
However, the Liberty Mounds samples are, on the average, higher in ethane,
propane, and isobutane than the Post Office site and almost as high in
n-butane. This distribution may perhaps be explained as a combination of
two factors that affected the Liberty Mounds site. First, on those few days
when winds were from the north during the predawn hours, concentrations of
low molecular weight alkanes were elevated; these days are included in the
average. Second, there was a small refinery near the city of Okmulgee,
which is 27 km (17 mi) south of the site, and it may have been a source of
these compounds.
The average morning concentration of almost every alkane in the Post
Office samples was higher than at either of the other sites. It was thought
that measurements made at this site might be influenced by the nearby petro-
chemical refinery complex, which is located about 3 to 5 km south and west
of the Post Office at a direction of 172° to 269°. To investigate this
possibility, samples at the Post Office site were stratified based on average
wind direction for the hours 0400, 0500, and 0600 as measured at the Tulsa
International Airport. Table 3.33 shows that 20 of 76 days had average wind
directions from 172° to 269°. Average concentration values for propane,
isobutane, and butane (each associated with refinery operations or gasoline
storage) are statistically significantly different (based on the t-test)
than are average concentrations on days when winds are from other directions.
The percentage of NMHC due to propane (or butane) is also higher when winds
are from 172° to 269° (refer to Table 3.33). The difference in the average
concentrations of isopentane is not as great as for propane, isobutane, or
butane when stratified days are compared and is not statistically signifi-
cantly different. This might be expected since isopentane is less volatile
and fewer losses from refinery operations would be expected. Furthermore,
isopentane is associated with vehicular tailpipe emissions and gasoline
evaporation. Note that the average concentration of acetylene, a key indi-
59
-------
TABLE 3.32. AVERAGE VALUES, ppbC, FOR ALKANES IN MORNING HYDROCARBON
SAMPLES
Alkane Liberty Mounds
Ethane
Propane
Isobutane
n-Butane
Isopentane
n-Pentane + Cyclopentane
2 , 2-Dimethylbutane
2-Methylpentane
3-Methylpentane
n-Hexane
2 , 4-Dimethy Ipentane
2-Methylhexane
3-Me thy Ihexane
2,2, 4-Trime thy Ipentane
n-Heptane
Methylcyclohexane
2,3, 4-Trime thy Ipentane
2-Methylheptane
3-Me thy Iheptane
n-Octane
n-Nonane
n-Decane
n-Undecane
n-Dodecane
36.4
54.9
11.4
25.7
17.4
36.3
0.0
4.0
9.1
3.1
0.4
1.5
1.0
1.7
0.7
0.5
0.3
2.6
0.4
0.5
0.2
0.0
0.0
0.0
Health Department
26.5
23.1
10.9
26.6
31.3
39.1
0.1
8.5
17.7
5.5
0.6
5.7
4.4
4.8
3.1
2.1
0.3
8.9
1.1
2.0
0.3
0.0
0.0
OoO
Post Office
39.8
38.9
24.8
69.3
58.8
41.5
0.2
11.6
17.7
10.4
1.1
7.9
4.6
8.3
5.1
1.6
0.8
13.8
2.7
2.8
1.2
0.2
0.0
0.0
60
-------
cator of vehicular exhaust, is actually lower when winds are from the direc-
tion of the refinery as compared to other directions.
Six days during the summer had light and variable winds during the
hours just preceding the hydrocarbon sample and were classed as calm. On
these days, the average concentrations of low molecular weight compounds
were much higher than on other measurement days at the Post Office site.
Average morning concentration values for aromatic compounds are given
in Table 3-34. Generally, concentrations of aromatics are higher at the
city sites than at the background site. Benzene concentrations seem to be
quite high, even when compared to values found at one site in the Houston
(12)
area in 1976 , where the aromatic portion of NMHC was often predominant.
The average concentration given for benzene may not be reliable because the
benzene peak eluted near the beginning of the chromatograph in a crowded
region and some of the samples may have suffered interferences from nearby
compounds or baseline effects not compensated for by the computerized data
acquisition system.
TABLE 3.33. AVERAGE 0600 TO 0900 CDT HYDROCARBON CONCENTRATIONS BY WIND
DIRECTION. TULSA POST OFFICE SITE
Average Wind
Direction for
Hours 04, 05,
and 06 at Air-
port (Number
of Cases)
270°-90°(20)
91°-171°(30)
270°-171°(50)
172°-269°(20)
Calm (06)
Propane
(ppbC)*
30.6 (7.0)
30.2 (6.3)
30.4 (6.6)
46.8 (8.7)
65.2 (6.4)
Acetylene
(ppbC)
21.4
15.7
18.0
13.8
32.8
Isobutane Butane Isopentane
(ppbC) (ppbC)* (ppbC)
15.2
19.5
17.8
28.6
68.6
39.6 (8.9)
53.4 (10.3)
47.8 (9.7)
79.8 (13.8)
204.0 (11.8)
43.3
50.0
47.3
56.4
158.1
*Average percentage of sum of NMHC in parentheses.
61
-------
TABLE 3.34. AVERAGE VALUES, ppbC, FOR AROMATICS IN MORNING
HYDROCARBON SAMPLES
Benzene
Toluene
Ethylbenzene
p-Xylene
m-Xylene
o-Xylene
n-Propylbenzene
m-Ethyl toluene
1 ,3,5-Trimethylbenzene
t-Butylbenzene
o-Ethyltoluene
1,2, 4-Trimethylbenzene
1 , 2 , 3-Trimethylbenzene
n-Butylbenzene
Liberty Mounds
15.3
7.3
3.4
0.8
1.4
0.8
3.1
1.0
1.0
0.8
0.8
9.4
1.0
0.9
Health Department
23.8
9.5
5.9
0.9
2.4
1.7
2.1
0.7
0.6
0.1
0.3
11.0
1.0
1.9
Post Office
29.6
13.8
3.9
2.0
4.7
2.9
2.9
1.7
1.8
1.0
1.0
18,5
3.4
5.0
3.5.5 Variation in Hydrocarbon Content by Day of the Week
Samples of nonmethane hydrocarbons taken in & city between the hours of
0500 and 0800 CST (0600 and 0900 CDT) would be expected to show a distinct
variation in constituent composition with the day of the week. Acetylene, a
key indicator of vehicular emissions, would be expected to be higher during
the workdays Monday through Friday and lower on the weekend when traffic
patterns differ. Table 3.35 illustrates the variation in acetylene concen-
tration by day of the week at the southern site, Liberty Mounds, and the two
city sites. The two city sites show a strong weekday/weekend variation; the
southern site, shows no pattern of variation.
TABLE 3.35. AVERAGE ACETYLENE CONCENTRATIONS
BY DAY OF THE WEEK
Site
Post Office
Health Department
Liberty Mounds
No. of
Samples
78
77
70
Acetylene, ppbC
Mon.
25.3
18.6
1.8
Tue.
22.8
14.1
2.1
Wed.
16.7
9.5
1.7
Thur.
22.4
14.6
2.5
Fri.
21.0
13.6
2.4
Sat.
11.2
7.2
2.7
Sun.
9.5
4.0
1.5
62
-------
3.5.6 Hydrocarbon Content of Samples Taken During Aircraft Low-Pass Operations
Table 3.36 summarizes the results of hydrocarbon grab samples collected
during the aircraft morning low-pass operation at the Downtown Airport.
Refer to Figure 1.1 for the location of this airport. Table 3.37 is a
summary of hydrocarbon data for the 0500 to 0800 CST period at the downtown
Post Office site on the same days. The aircraft grab samples were taken
over a brief time span (about 1 minute) as the plane passed low over the
runway. The Post Office samples were collected over a 3-hour period.
However, both samples were taken during the 0500 to 0800 time frame.
Tailpipe emissions (as judged by acetylene concentrations) are common
to both sets of data. As expected, the samples taken at the Downtown Airport
were lower in acetylene than those at the urban core site because the Post
Office (CBD) site is in the vicinity of direct vehicular emissions. Of
particular interest are the airport samples for September 2 and 3, which
were much higher in NMHC than those of the Post Office. Examination of the
individual hydrocarbon data reveals that the major contributors to the
airport totals were the low molecular weight alkanes, especially propane,
butane, and isopentane. Samples taken at the Post Office site were not
nearly so rich in these compounds and had higher values of acetylene. Thus
it seems that sources other than vehicular emissions were responsible for
the elevated values at the Downtown Airport. The petrochemical refinery
complex lies about 8 km to the south of the airport. Wind directions during
the hour preceding the sample on September 2 and 3 were from 170°, a direc-
tion which may allow the refinery to directly affect the Downtown Airport
and yet only marginally affect the Post Office to the northeast. The high
levels may also be partially due to the fact that wind speeds during the
hours preceding the sample were low, reducing the dispersion of hydrocarbons
prior to their transit northward.
Table 3.38 lists values for selected hydrocarbons and sums for samples
collected by the aircraft during low passes over the Tulsa International
Airport runway about 1 hour after the low pass at the Downtown Airport. The
most significant features of these samples, as compared to those at the
Downtown Airport, are the presence of much lower concentrations of hydrocar-
bons, especially alkanes such as propane, n-butane, and isopentane; and
63
-------
TABLE 3.36. AIRCRAFT HYDROCARBONS, ppbC; LOW PASS AT DOWNTOWN AIRPORT
Ethylene
Propane
Acetylene
n-Butane
Propylene
Isopentane
Toluene
m-Xylene
Sum Alkenes
Sum Alkanes
Sum Aromatics
Sum NMHC
Percent Tailpipe
Emissions
Airport Wind
Direction ^a)
Wind Speed, mph(a)
8-26
Friday
0809 CST
6.0
59.1
2.0
92.3
9.9
67.5
8.4
1.4
20.7
436.1
62.9
521.7
6
180°
19.6
9-02
Friday
0817 CST
28.8
256.5
19.6
536.8
33.9
333.5
59.7
8.6
78.9
2124.3
219.8
2442.6
12
170°
6.9
9-03
Saturday
0757 CST
24.4
90.9
10.4
236.0
30.6
177.0
74.9
14.0
72.4
1071.9
192.1
1346.8
12
170°
9.2
9-16
Friday
0715 CST
21.8
69.3
28.0
88.0
15.3
65.0
14.7
5.0
39.1
527.2
61.2
655.5
66
180°
3.5
9-17
Saturday
0754 CST
5.0
45.9
1.4
75.6
7.2
48.5
6.9
1.1
13.8
333.2
41.5
389.9
6
180°
17.3
(a)
For the 1-hour period preceding the sample.
64
-------
TABLE 3.37. POST OFFICE SITE 0500-0800 CST HYDROCARBONS,
ppbC; ON DAYS OF DOWNTOWN AIRPORT SAMPLES
Ethylene
Propane
Acetylene
n-Butane
Propylene
Isopentane
Toluene
m-Xylene
Sum Alkenes
Sum Alkanes
Sum Aromatics
Sum NMHC
Percent Tailpipe
Emissions
Airport Wind
Direction (a)
Wind Speed, mph(a)
8-26
Friday
48.2
40.5
29.2
53.2
6.9
47.0
4.9
3.7
57.3
312.2
166.2
564.9
80
173°
13.8
9-02
Friday
62.2
50.7
30.0
60.4
14.4
70.0
13.3
9.6
79.8
419.6
110.7
640.1
73
170°
3.5
9-03
Saturday
37.4
20.4
12.0
40.0
6.3
47.0
15.1
5.6
51.0
230.4
73.5
366.9
51
calm
1.2
9-16
Friday
59.0
54.0
45.4
112.0
18.9
111.5
21.0
9.6
85.3
638.9
100.9
870.5
81
170°
3.1
9-17
Saturday
33.6
21.3
7.6
21.2
3.0
18.5
4.2
1.3
46.4
204.3
57.7
314.8
37
167°
12.7
(a)
(b)
Average for hours 0400, 0500, and 0600.
Calm for two of three hours.
65
-------
TABLE 3.38. AIRCRAFT HYDROCARBONS, ppbC; LOW PASS AT TULSA INTERNATIONAL
AIRPORT
Ethylene
Propane
Acetylene
n-Butane
Propylene
Isopentane
Toluene
m-Xylene
Sum Alkenes
Sum Alkanes
Sum Aromatics
Sum NMHC
Percent Tailpipe
Emissions
Airport Wind
Direct ion (-3)
Wind Speed, mph(a)
8-26
Friday
0903 GST
6.4
16.8
3.2
15.6
3.9
13.5
4.2
0.1
11.6
99.1
32.1
146.0
34
190°
16.1
9-02
Friday
0912 GST
35.6
34.5
31.6
51«2
17.7
58.5
29.4
9.2
54.5
438.0
284.8
808.9
61
130°
8.1
9-03
Saturday
0901 GST
27.1
8.7
10.4
14.8
2.9
33.3
15.4
3.7
36.1
246.7
105.3
398.5
40
170°
6.9
9-16
Friday
0819 GST
40.0
40.5
40.8
68.8
20.7
75.0
28.7
10.1
62.4
420.8
112.4
636.4
99
160°
5.8
9-17
Saturday
0857 GST
7.8
16.5
3.8
15.2
6.0
9.5
3.3
1.0
13.8
81.5
41.9
141.0
42
180°
17.3
(a)
For the one hour preceding the sample.
66
-------
relatively higher values of acetylene and thus greater percentages attributed
to tailpipe emissions.
3.5.7 Distributions of Hydrocarbons From South to North at the Surface and
Aloft
Distribution of selected hydrocarbons as measured at the surface for 5
days at sites south, north, and in Tulsa are compiled in Table 3.39. Wind
direction on each of these days was from the south. Samples from the southern
site, Liberty Mounds, and the city CBD site, the Post Office, were taken
during the period 0600 to 0900 CDT. Data from the northern surface sites
were taken during the afternoon hours 1400 to 1700 CDT.
During the 0600 to 0900 CDT time period, the aircraft performed a
vertical spiral over the southern and city sites. Data for the corresponding
aircraft samples at 760 m (2,500 ft) MSL altitude are given in Table 3.40.
Comparison of the data in the two tables shows that at the upwind site,
concentrations near the surface always exceeded those of the concurrent
samples taken aloft. Samples taken at altitudes higher than 760 m showed
further decreases in concentrations of most species. Complete data from
these samples are listed in Volume II of this report.
A shallow inversion layer, which is almost always present near the
surface prior to the period 0600 to 0900 CDT, traps hydrocarbon from the
emissions surface during the night. Thus, in the morning greater concentra-
tions might to be expected at the surface than aloft. The small concentra-
tions measured above the inversion layer (e.g., at 760 m and higher) indicate
that there were no significant amounts of hydrocarbons coming from the south
into the Tulsa area on the upper winds.
Surface hydrocarbon concentrations at the city Post Office were much
higher than those of the background site. The increased concentration at
the surface in the city was not reflected in the sample taken at an altitude
of 760 km (2,500 ft) MSL immediately north of the central business district.
Only in one case, September 16, was the sum of NMHC over the city substan-
tially higher than the surface background. A corresponding increase in
acetylene concentration is noted in this sample, indicating urban vehicular
origin.
67
-------
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Integrated samples were collected at all northern ground sites during
the hours 1400 to 1700 CDT. By this time of day the atmosphere was well
mixed and emissions from Tulsa, which drift northward on the winds, would be
expected to be appreciably diluted. The data seem to indicate, for these
few cases, that the strength of urban hydrocarbon plumes varied considerably
with altitude and distance from the source. For example, on August 26, the
aircraft sampled an airspace above Sperry that was rich in hydrocarbons, yet
the corresponding surface sample concentration was over an order of magni-
tude lower. A recognized confounding feature in comparing these two samples
was the length of sampling time. The aircraft, with its short sampling
period, may have fortuitously sampled an air parcel having extremely high
hydrocarbons.
Surface and airborne samples taken farther north in the vicinity of the
maximum ozone plume (such as those of September 2 and 3) show NMHC concentra-
tions substantially lower than those present in morning samples in the city
(but still contain acetylene concentrations greater than those in samples
taken upwind in the morning). There are several reasons for this. First,
the increased mixing of the atmosphere in the afternoon allowed greater
dispersion and dilution; second, reactive hydrocarbons were removed by
photochemical processes; and third, local (mesoscale) trajectories indicate
that the air parcel sampled during the period 1400 to 1700 CDT downwind of
the city was usually not the same parcel that passed through the city at the
time of the morning sample. The air parcel passed through later in the
morning, after peak traffic had subsided.
3.5.8 Correlation between NMHC by Sum of Species and by Continual Chromatog-
raphy
At both city sites, the Post Office and the Health Department, concur-
rent samples for 0600 to 0900 CDT nonmethane hydrocarbons were taken in two
ways: by summing the concentrations of individual hydrocarbons in integrated
samples and by averaging three hourly values of NMHC obtained by the Beckman
6800 Environmental Chromatographs.
Regression analysis was performed to compare the results of the two
methods in determining NMHC in ppmC. At the Post Office site, for 37 cases,
the regression equation is:
70
-------
CNMHC, Beckman) = 0.8034 (NMHC, sum of species) + 0.1417.
The correlation coefficient, R, is 0.9415; R2 is 0.8867.
At the Health Department site, for 45 cases, the regression equation is:
(NMHC, Beckman) = 0.4590 (NMHC, sum of species) + 0.0903.
The correlation coefficient, R, is 0.453; R2 is 0.2050.
As the equations indicate, the correlation between NMHC (Beckman) and
NMHC (sum of species) is quite good for samples at the Post Office site and
is poor for samples at the Health Department site. Examination of individual
days of data from the Health Department site shows that the concentration of
NMHC, as determined by the Beckman 6800, is sometimes less, sometimes greater,
and sometimes nearly the same as the concentration determined by summing
species. During the field program, there were frequently problems with zero
and span drift with the analyzer at this site, as shown by frequent zero and
span gas checks.
Comparison of daily concentration values for NMHC from the Post Office
site shows generally good agreement between the two methods and few instances
of extreme disagreement. NMHC by sum of species averages about 6 percent
higher than NMHC as determined by the automated chromatograph. The agreement
(13)
is unexpectedly good, however, as earlier field and laboratory experiments
have shown that NMHC obtained by summing individual hydrocarbon concen-
trations might have been expected to be even higher than those found in this
study. One reason for this finding may be that a maximum of only 47 individual
hydrocarbons were quantified, and this number obviously does not account for
all hydrocarbons present in ambient air.
In summary, it appears that NMHC concentrations recorded by the Beckman
6800 at the Post Office site correlate well with NMHC by sum of species and
could be used as surrogate values for 0600 to 0900 CDT or other time periods.
On the other hand, values for Beckman NMHC concentrations at the Health
Department seem to be questionable and data should be selected for study
only for those days that had 0600 to 0900 CDT concentrations in reasonable
agreement with NMHC by sum of species.
71
-------
3.5.9 Comparison of Hydrocarbons from GC/FID and GC/Mass Spectrometry
Studies
Five Tenax samples were collected and qualitatively analyzed for volatile
organics by gas chromatography/mass spectrometry. Profiles of total ion
current versus order of elution from the column (e.g., mass spectrum number)
are given in Volume II of this report. Tables listing the compounds identi-
fied are also given in Volume II.
As many as 200 different compounds were identified in a 0600 to 0900
CDT Tenax sample taken at the downtown Post Office site on September 21,
1977. The composition of this sample (or the other four samples) consisted
of an assortment of alkanes, alkenes, alkyl aromatics, oxygenated compounds,
and halogenated compounds. About 83 percent of the compounds are hydrocarbons.
On September 21, samples were also collected at the background site,
Liberty Mounds, during the period 0600 to 0900 CDT and at the Vera site
(about 35 km north of the city) during the 1400 to 1700 CDT period. Table
3.41 presents a quantitative comparison (in arbitrary units) of volatile
organics at these three stations. A significant increase in the relative
quantity of alkanes, alkenes, alkyl aromatics, benzene, toluene, and ketones
occurred as the ambient air was transported from Liberty Mounds through
downtown Tulsa. Components of the sample taken at Vera were not as high in
concentration as in the sample taken in the city. This is a reflection of
the effects of compound removal by chemical reaction and by dilution due to
increased atmosphere mixing in the afternoon.
When the 47 compounds identified and quantified by gc/fid in the sum of
species task are compared to those identified by gc/ms, it is found that
gc/ms identifies 28 by name and 10 by molecular formula. Six of the low
molecular weight compounds "break through" the Tenax cartridge and are not
retained in quantities sufficient for identification. These compounds are
ethane, ethylene, acetylene, isobutane, propylene, and isoprene. Three
higher molecular weight compounds were not identified by name or formula by
gc/ms. These are 1-hexane, m-ethyltoluene, and o-ethyltoluene.
Hydrocarbons identified by name in the gc/ms study, which were not
searched for in the gc/fid sum of species study, include methylcyclopentane,
cyclohexane, 2,2-dimethylpentane, ethylcyclohexane, ethylbenzene, styrene,
72
-------
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isopropylbenzene, several naphthalenes, n-tridecane, n-pentadecane, and
n-hexadecane.
3.6 ANALYSIS AND INTERPRETATION OF AIRCRAFT DATA
3.6.1 Analysis Approach
An instrumented aircraft collected data on 2 days in August and on 7
days in September, to determine the horizontal distribution at 2,500 ft and
vertical distribution of meteorological and pollutant parameters in the
study area. In this section, the general features of the aircraft data are
examined. The aircraft flights were divided into morning flights upwind of
Tulsa, and afternoon flights downwind of Tulsa. Horizontal traverses were
flown on all of the flights, and vertical spirals to 10,000 ft MSL were
flown on most of the individual flights.
A general description of the background ozone concentrations on both
the horizontal and vertical portions of each flight is presented first. The
horizontal and vertical segments of the flights are considered separately in
more detail. Finally, comparisons are made between measurements made aboard
the aircraft and the surface measurements made at stations below the flight
paths and locations of the vertical spirals.
The aircraft data were plotted and appear in Volume II of this report.
Individual data points at 15-second intervals also appear in Volume II.
3.6.2 Background Ozone Concentrations on the Aircraft Flights
A summary of the mean background ozone concentrations and standard
deviations for each of the aircraft flights appears in Table 3.42. The term
background is not meant to imply that the ozone concentrations listed in the
table were solely the result of natural sources. These concentrations were
considered to represent the background burden, however, because they were
quite stable over the individual flights, as indicated by the small standard
deviations, and the source areas of these ozone concentrations could not be
identified. These background concentrations were determined by averaging
the individual 15-second data points over the sections of each aircraft
flight that were not obviously in the Tulsa urban plume. The background
ozone concentrations on the vertical spirals were obtained similarly and
74
-------
TABLE 3.42. BACKGROUND OZONE CONCENTRATIONS OF AIRCRAFT FLIGHTS
a.m. Flights
Flight
No.
T03
T05
T09
Til
T14
T16
T17
T19
Date
25 Aug
26 Aug
2 Sept
3 Sept
8 Sept
11 Sept
16 Sept
17 Sept
Mixing
Height,
ft. MSL
-
<1100
<1100
<1100
-
<1100
<1100
<1100
Avg.
Background
Horizontal
Mean
.071
.060
.064
.078
.076
.072
.068
.049
S.D.
.004
.002
.007
.005
.006
.005
.003
.002
03, ppm
Spiral
Mean
-
.064
.052
.071
-
.066
.061
.051
S.D.
-
.005
.005
.006
-
.003
.003
.004
p.m. Flights
T04
T06
T10
T12
T15
T18
T20
25 Aug
26 Aug
2 Sept
3 Sept
9 Sept
16 Sept
17 Sept
-
4000
5500
-
6500
5200
6300
.078
.073
.078
.091
.074
.076
.064
.004
.004
.006
.007
.004
.004
.003
-
.072
.061
.095
.062
.054
.051
-
.003
.007
,007
.003
.005
.005
data points included in layers with elevated ozone concentrations were not
included in the average. The consistency observed in the background ozone
concentrations within individual flights results from mixing of ozone and
ozone precursors before they arrive in the Tulsa area.
During most of the afternoon flights, an urban ozone plume with a width
only slightly greater than the width of the city of Tulsa, and centered
nearly in line with the mean surface winds, was observed downwind of Tulsa.
When the ozone concentration increased steadily to values more than 0.010 ppm
above the background, it was assumed that the aircraft was sampling within
the urban plume. The ozone concentrations beyond the point of the steady
rise within the plume were not included in the average for the background
concentrations. On most of the morning flights upwind of Tulsa a relatively
homogeneous horizontal distribution of ozone was observed, and each data
point on the horizontal traverses was included in the calculation of the
75
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average background ozone concentration. The consistency observed in the
background ozone concentration within individual flights results from mixing
of ozone and ozone precursors before they arrive in the Tulsa area.
On the vertical spirals of many of the morning flights a shallow layer
with increased ozone concentrations was observed. These layers were centered
typically between 2,000 ft and 4,000 ft MSL. The available data provide no
evidence as to the cause of this observation. During the afternoon flights,
much deeper layers of elevated ozone were often observed from the lowest
altitude of the spiral up to altitudes above 6,000 ft. These layers were
almost certainly produced by vertical mixing of the Tulsa plume. Unfortun-
ately, upwind spirals were not flown in the afternoon, and no spirals were
flown downwind of Tulsa during the morning flights. The ozone concentra-
tions within the layers of elevated ozone on the morning flights were not
included in the average background concentration. In all cases, only the
concentrations measured above the maximum vertical extent of the urban plume
were included in the calculation of the background ozone concentration on
the spirals during the afternoon flights.
The minimum horizontal flight background ozone concentration listed in
Table 3.42 is 0.049 ppm. The average background for eight morning flights is
0.067 ppm ozone. It is suspected that the background ozone concentrations
measured on the morning flights had an impact on the ozone concentrations
measured at the surface once the nocturnal inversion was destroyed and
mixing near the surface had been established. Without the availability of
an objective and reliable model of near-surface vertical mixing and photo-
chemistry, it is not possible to quantify that impact. These data do suggest,
however, that the atmosphere is capable of storing relatively high concentra-
tions of ozone, and that the background ozone burden above nocturnal inver-
sions may need to be considered in developing efficient control strategies.
In almost every case the background ozone concentrations observed on
the afternoon flights exceeded those of the morning flights. The average
increase in the background ozone concentration on the 6 days that had both
morning and afternoon flights was 0.012 ppm. Assuming that the immediate
impact of the Tulsa metropolitan area was confined to the region that could
be identified as the Tulsa plume, these data imply that the chemical compo-
76
-------
sition of the background air was photochemically active, even though very
little NO or NMHC was measured aboard the aircraft. Although the ozone
A
synthesis observed in the background air near Tulsa was minor, neglecting
the influence may lead to inaccurate predictions of maximum surface ozone
concentrations.
3.6.3 Analysis of the Horizontal Traverses
In addition to ozone, temperature, dew point, b , and in some cases
S Celt.
condensation nuclei were measured on the horizontal traverses. NO and NO
were also measured, but the concentrations were rarely more than the minimum
detectable limit of the instrument (0.005 ppm) and therefore have not been
included in the following analyses. The plots of these data appear in
Volume II. On each of the morning flights, except flight T19 on September
17, 1977, each of the parameters was nearly constant on each horizontal
traverse south of Tulsa.
On flight T19 the ozone concentrations changed rapidly, on each hori-
zontal traverse, in a way that suggests the presence of an ozone plume.
There were also some small variations in the ozone concentrations on the
horizontal traverses over and just north of Tulsa on most of the flights.
The variations in the ozone concentration near Tulsa in the horizontal legs
of morning flights are assumed to be caused by remnants of urban photo-
chemical activity of Tulsa of the preceding day. However, the rapidly
increasing ozone concentrations observed on flight T19 were seen as far
south as Liberty Mounds, and the cause of this phenomenon is unknown.
There was a maximum in wind speed of approximately 60 mph between 2,000
and 3,000 ft from 200° determined by a pibal release at 0530 on September 17,
1977, at the Tulsa International Airport. The vertical profile of tempera-
ture measured during the spiral at Liberty Mounds shows that the same layer
was stable, which would inhibit mixing. The cause of the elevated ozone and
its relationship to the other factors mentioned above is not clear. There
is a possibility, however, that the high wind speeds could have transported
that ozone from some other urban area and the stability within that same
layer, present throughout the night, may have inhibited mixing. The synoptic
trajectories for September 17, 1977, show that the air arriving in Tulsa at
0600 CST had passed near the Dallas-Ft. Worth area 12 hours earlier. A
77
-------
layer of high ozone concentration between 2,000 ft and 3,000 ft that had
rapidly changing ozone concentrations with altitude was measured on the
vertical spiral at Liberty Mounds. Another possible explanation of the
plume-like appearance of ozone on the horizontal traverses is that the
boundary of that layer may have changed altitude along the horizontal trav-
erse in such a way that the aircraft flew into the region of high ozone
concentration. On all of the morning flights the b and condensation
S Celt.
nuclei data were nearly constant across the horizontal traverses. There
were some small positive excursions in the condensation nuclei data that
probably were caused by local sources.
The ozone data from the afternoon horizontal traverses often showed an
urban ozone plume extending to the north of Tulsa. Regions of the downwind
horizontal traverses were considered to be within the Tulsa urban plume if
the ozone concentrations increased steadily and reached concentrations at
least 0.010 ppm higher than the average background. A list of the afternoon
flights with pertinent meteorological information, the background and peak
ozone concentrations, and the plume half-width is given in Table 3.43. The
ozone plumes measured on flights T10, T12, and T15 were very well defined
and have a shape and location that implicates Tulsa as the source. The
center lines of these plumes were approximately in line with the mean sur-
face winds leaving Tulsa, except for the apparent plume measured on
September 9 on flight T-15. In each case the width of the regions of ele-
vated ozone were on the order of the width of Tulsa. Unfortunately, no
upper air wind directions were available from Tulsa for flight T15 on
September 9. The surface winds were from the northwest, and the ground
stations north of Tulsa measured relatively low ozone concentrations all
day. The rawinsonde observations at 0600 and 1800 CST from September 9 at
Oklahoma City suggest that upper air winds were also from the northwest.
The source of that ozone plume, therefore, is unknown. The aircraft's ver-
tical temperature profile indicates that a layer of stable air near the
surface extended to a height of approximately 3,000 ft. The stability may
have decreased turbulent exchange of mass between 2,500 ft and the surface.
On 3 of the 4 days with distinct ozone plumes, the maximum ozone con-
centration was measured on leg 5, approximately 48 km (30 mi) downwind of
78
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79
-------
Tulsa. On the remaining day, September 3, the maximum ozone concentration
was measured on leg 3, approximately 32 km (20 mi) downwind of Tulsa. There
is no evidence to indicate that higher ozone concentrations were not present
farther downwind at later times. It is interesting that the urban ozone
plume did not experience a significant amount of spread in traveling the 64
km (40 mi) to the location of the final horizontal traverse. The plume
half-width was used as the measurement of the plume spread because in some
cases only half of the plume was observed within the limits of the flight
tracks. The plume half-width was determined by taking the distance from the
point of maximum ozone concentration to the point where the ozone concentra-
tion had fallen to a value 0.005 ppm above the background ozone concentra-
tion. The average plume spread on all horizontal traverses was approximately
34 km (21 mi). The city of Tulsa is approximately 26 km (16 mi) wide in the
east to west direction. Therefore, the ozone plume from Tulsa was only
slightly wider than Tulsa and did not widen appreciably in traveling the 64
km downwind.
For the most part, the b data were highly consistent across the
S C3 U
horizontal traverses of each flight. On each of the flights that had well-
defined ozone plumes (T10, T12, and T15), increased concentrations of con-
densation nuclei were measured in approximately the same locations as the
increased ozone concentrations. It would appear that the condensation nuclei
measured in these plumes represented small particle formation from photo-
chemical processes.
The condensation nuclei measured on flight T18 on September 16, 1977,
showed the most variation of any of the flights, despite the fact that there
was no evidence of an ozone plume. On the vertical spiral from that flight,
very low concentrations of CN were measured over the entire spiral and
therefore the origin of the condensation nuclei measured on the horizontal
traverses is unknown.
The net impact of Tulsa on ozone formation at 2,500 ft MSL can be
estimated. The difference between the maximum ozone concentration measured
in each plume, and the background ozone measured on the same horizontal leg
was assumed to represent the net impact of Tulsa on ozone formation. Concen-
trations obtained in this way for flights T04, T06, T10, T12, and T15 were
80
-------
0.023, 0.020, 0.076, 0.117, and 0.047 ppm, respectively. With the exception
of flight T12, the net ozone at 2,500 ft MSL was similar to that determined
at the surface for several of the case study days, to be discussed later.
3.6.4 Analysis of Vertical Spiral Profiles
The normal flight plan for morning flights called for two vertical
spirals. Each morning flight, with the exceptions of flights T03 on August
25 and 114 on September 8, 1977, began with a vertical spiral over Liberty
Mounds, from an altitude between 1,100 and 1,500 ft up to an altitude of
10,000 ft MSL. A second vertical spiral was flown over the central business
district of Tulsa, at the end of each of the flights, except flight T17 on
September 16, 1977. The second spiral was flown from an altitude between
2,500 ft and 3,000 ft MSL to an altitude of 10,000 ft MSL. At least one
layer with high ozone concentrations relative to the spiral background could
be identified on each spiral at Liberty Mounds. With the exception of a
high-altitude layer at 8,250 ft MSL on flight T05, those layers of high
ozone were similar in appearance and occurred at similar altitudes. In
addition, the same type of layers with high ozone concentrations were often
measured in the central business district spirals. A list of the morning
flights with the altitudes of the maximum ozone and the difference between
the maximum ozone concentration in the layers and the average background
ozone concentration on the spirals appears in Table 3.44. There is at least
one layer with ozone concentrations that are at least 0.010 ppm greater than
the average background on each spiral at Liberty Mounds and on all but one
of the spirals over the central business district.
Data from one vertical spiral are available from each afternoon flight,
except flight T04 of August 25, 1977. The ozone data from the spirals of
the afternoon flights are much different in appearance than those of the
morning flights. Deep layers with elevated ozone concentrations were observed
on the spirals of all the afternoon flights except flight T06 on August 26,
1977. In all cases the regions of elevated ozone on the afternoon spirals
began at the lowest point on the spiral and extended up to an altitude of at
least 4,000 ft MSL. Table 3.45 lists the afternoon flights that had layers
with increased ozone on the lower half of the spirals, the altitude to which
81
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TABLE 3.44. ALTITUDE AND CONCENTRATION OF MAXIMUM OZONE DURING
MORNING AIRCRAFT SPIRALS
Flight
number
T05
T09
Til
T16
T17
T19
Altitude of ozone
Location maxima, ft MSL
Mounds
CBD
Mounds
CBD
Mounds
CBD
CBD
CBD
Mounds
Mounds
CBD
CBD
Mounds
Mounds
8250
8250
2950
2800
2550
3150
4150
9550
3600
5150
3900
5350
3350
2400
Max. ozone
concentration, ppm
0.087
0.084
0.085
0.070
0.084
0.081
0.100
0.086
0.081
0.087
0.089
0.084
0.106
0.075
Max. ozone less
avg. background
0.022
0.019
0.035
0.020
0.014
0.011
0.030
0.016
0.016
0.022
0.024
0.019
0.046
0.025
the layers extended, the maximum ozone concentration measured, the altitude
of the maximum ozone concentration, and the difference between the maximum
and average background ozone concentrations. Because the afternoon spirals
took place downwind of Tulsa, it is assumed that these ozone layers repre-
sented ozone generated by surface emissions and mixed by thermal processes
to the altitudes given in Table 3.45. These ozone layers were often associ-
ated with horizontal ozone plumes, and therefore the altitude to which the
ozone was mixed is assumed to represent the vertical extent of the urban
ozone plume. The concentrations of the other parameters measured do not
coincide with the deep layer of elevated ozone observed on the afternoon
spirals.
3.6.5 Comparison of Aircraft and Ground-Based Ozone Measurements
The aircraft measurement program provided data for comparing ground-
level ozone measurements to much shorter time-averaged ozone measurements
made aboard the aircraft in three distinct altitude regimes. Ozone concen-
trations measured aboard the aircraft during low-approach flight segments at
82
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TABLE 3.45. ALTITUDE AND CONCENTRATION OF MAXIMUM OZONE DURING
AFTERNOON AIRCRAFT SPIRALS
Flight
number
T10
T12
T15
T18
T20
Location
Ramona
Ramona
Ramona
Talala
Nowata
Maximum alti-
tude, ft, MSL,
of ozone layer*
6000
6350
7050
6800
4350
Maximum
ozone, ppm
0.150
0.161
0.120
0.086
0.073
Altitude of
max. ozone
2050
2150
4250
3550
2500
Max. ozone
less avg.
background
0.090
0.066
0.055
0.031
0.023
^Altitude above which the ozone concentration is less than 10 ppb higher
than the average background ozone concentration on the spiral.
50 ft AGL, at the bottom of vertical spirals, and on segments of horizontal
traverses above surface stations were compared to hourly average surface
ozone concentrations. Each of the three comparisons was influenced by the
different time averages of the samples, and in some cases by considerable
horizontal distances between the locations of the two samples. The ozone
data collected on low-altitude approaches at approximately 50 ft AGL, over
runways at Okmulgee Airport, Tulsa Downtown Airport, and Tulsa International
Airport, were compared to hourly average surface data from the Liberty
Mounds station, located 22 km (13.9 mi) north of Okmulgee Airport; the Post
Office station, 7.7 km (4.8 mi) south of Tulsa Downtown Airport; and the
Health Department station, 7.4 km (4.6 mi) southwest of Tulsa International
Airport.
The comparisons between the two sets of data were made by calculating
linear regression parameters and correlation coefficients (r-values). The
correlation for comparison of afternoon low-approach flight data to the
surface ozone data, with an r-value of 0.885, was much better than the
correlation for low approaches from the morning flights of 0.621. All of
the afternoon low approaches were done at Okmulgee Airport and the higher
correlation for afternoon flights was observed in spite of the large hori-
zontal distance between the aircraft and surface measurements. The linear
regression equation obtained for the comparison of afternoon low-approach
data with the surface station data was:
83
-------
[03] 50 ft AGL = -0.029 + 1.777 [03] Liberty Mounds.
The regression equation for the comparison of morning low-approach data with
the surface station data, which included low approaches at all three of the
locations, was:
[03] 50 ft AGL = 0.021 + 0.722 [03] Surface.
When all of the data collected on low approaches at Okmulgee Airport,
on both morning and afternoon flights, were compared to the corresponding
Liberty Mounds surface data, a correlation of 0.941 was obtained. Although
the number of data pairs used to calculate these correlations is not suffi-
cient to establish any meaningful conclusions, it is apparent that the ozone
concentration in the upwind rural area around Okmulgee and Liberty Mounds
was, on the average, more homogeneous than that in the city of Tulsa. This
was true even though the horizontal distance between the locations of the
two measurements was much greater for the rural case. This result was
expected since local sources and morning traffic at the urban locations
influence both the production and destruction of ozone.
During the morning flights, vertical spirals were usually flown over
the Liberty Mounds station and over the central business district in close
proximity to the Post Office station. The temperature profiles from the
morning spirals indicate that the surface inversion probably kept the effec-
tive mixing height below 1,100 ft MSL in all cases. The presence of a
nocturnal inversion serves to isolate the near-surface atmosphere from the
atmosphere above the inversion. Therefore, a strong relationship is not
expected between the spiral base ozone concentration and the surface ozone
concentration on the morning flights. The correlation coefficient calcu-
lated for these data was -0.563, which indeed implies that no relationship
existed between the measurements.
There were two specific spirals for which the spiral base ozone concen-
trations exceeded the surface concentration by less than 0.010 ppm. On both
of these days the wind speeds during the time of the spiral measured on a
40-ft tower at the Health Department station were in excess of 13 mph. On
the remaining flights, which had differences in ozone concentrations between
the spiral base and surface station in excess of 0.030 ppm, the wind speeds
84
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measured at the Health Department were 6 mph or less. The Health Department
wind speeds were used because it was felt that the winds measured on the
tower were less influenced by surface effects than the winds measured on a
4-m tripod located at Liberty Mounds. Once again, the scarcity of data does
not allow significant conclusions to be drawn; however, the data do suggest
that high wind speeds may generate enough turbulence to keep the surface
layer mixed in rural areas in the morning.
Four morning spirals were flown near the downtown Post Office station
and even with wind speeds in excess of 12 mph the closest agreement observed
between the spiral base ozone concentration and the ground station ozone
concentration was 0.040 ppm. Therefore, the capacity for ozone scavenging
near the surface in urban areas is probably sufficient to destroy the ozone
near the surface even if the wind speeds are high enough to keep turbulent
mixing active.
During the afternoon flights, a spiral was flown at the estimated
location of maximum ozone. There were six afternoon spirals in all, with
one flown near the Sperry ground station, two near the Vera ground station,
and three near the Ochelata ground station.
A linear regression equation for all the afternoon spiral base ground
station comparisons was found to be:
Spiral base [03] = -0.020 + 1.398 [03] ground station, r-value = 0.952.
Two of these data pairs had observed differences of only 0.002 ppm in ozone
concentration between the spiral base and ground station. Wind speeds at
the Health Department for these two cases were greater than 14 mph. This
would imply that when sufficiently high wind speeds are present in the Tulsa
area the air is well mixed up to at least 2,000 ft MSL. Wind speeds associ-
ated with the remaining four spirals were all 10 mph or less. Once again
the limited amount of data is insufficient to make any definite conclusions.
These data may suggest that with wind speeds less than 10 mph, the vertical
mixing processes are not efficient enough to keep the lowest 2,000 ft MSL
mixed homogeneously even in the absence of a nocturnal inversion.
Comparison of the ozone concentrations as averaged from three 15-second
readings on the horizontal traverses of the morning flights at approximately
85
-------
2,500 ft MSL to the nearest surface station measurement led to a correlation
of -0.032. This result certainly implies that the influence of a nocturnal
inversion does not allow mixing to altitudes as great as 2,500 ft.
A regression equation calculated for the horizontal traverse aircraft
ozone concentration and the hourly average ground station ozone concentra-
tion for afternoon flights yielded the following relationship:
Aircraft [03] = 0.033 + 0.731 [03] ground station, r-value = 0.736.
It is difficult to interpret this result because the afternoon flights
were flown at times when surface ozone concentrations were still changing
due to photochemical synthesis. The differences in averaging times of the
two measurements, as well as possible differences in transport rates at the
surface and at 2,500 ft, may have influences that are impossible to describe
completely.
86
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4.0 ANALYSIS OF CASE STUDY DAYS
4.1 INTRODUCTION
Four groups of days were chosen for detailed analysis as case studies.
The days chosen for these case studies include the periods July 21-25,
July 28-30, August 2-5, and September 2 and 3. Within the first three of
these groups of days the maximum ozone concentrations of the summer study at
each station in the network were observed. The fourth case study period,
September 2 and 3, was chosen for analysis because aircraft measurements
were made on both days and a downwind ozone plume was observed at the surface
and at 2,500 ft MSL.
In performing the case study analyses, a series of steps was followed.
First, the meteorological conditions of each period were described in terms
of influences observed in Tulsa. Air parcel trajectories describing air
movement on both the synoptic scale and local scales were analyzed to help
identify transport processes active during each day.
Next, the distribution of selected hydrocarbons and NO at the upwind
A
(Liberty Mounds) and city sites (Post Office and Health Department) during
the 0600 to 0900 CDT sampling period is discussed. A list of the monthly
and overall average concentrations and standard deviations of selected
hydrocarbons and oxides of nitrogen is presented in Table 4.1 along with
selected ratios. The concentrations of the same parameters and values of
the same ratios for each case study day are included in the individual case
study analyses. The distribution of maximum ozone concentrations and the
length of time each station's ozone concentrations were in excess of 0.08
ppm are then presented.
Finally, a day-by-day discussion of each case study is given. Wherever
appropriate, explanations of the observed concentration distributions and
diurnal behavior of measured pollutants are discussed. Such explanations
include, in most cases, the relationship between the daily active meteoro-
logical influences and the resultant chemical behavior within the network.
Figures summarizing both the meteorological and chemical data utilized in
the case study analyses appear in each individual case study discussion.
87
-------
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89
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Additional figures describing the surface distribution of ozone are included
in the discussion of certain case study days. On these concentration-
distance plots the abscissa is linear distance to the north from Liberty
Mounds. The ordinate is ozone concentration in ppm, and each symbol is the
average ozone concentration for each station for the hour indicated. A
solid line extends from Liberty Mounds through the city to Sperry, Vera, and
finally Ochelata along a south-to-north path. The dashed line extends from
the city through Skiatook and on to Wynona, two sites northwest of the city.
When meteorological conditions were appropriate, an estimate was made
of the net impact of Tulsa on ozone formation downwind. The procedure
employed is .as follows. On days when southerly winds were present in the
study area, the surface ozone concentration measured at Liberty Mounds for
hours 1000 and 1100 CST was assumed to represent the background ozone influ-
encing the Tulsa area. The surface inversion was expected to be completely
destroyed between 0900 and 1000 CST by the morning's solar heating. There-
fore, ozone that had been trapped above the nocturnal inversion should have
begun to mix to the surface by 1000. The net impact of Tulsa emissions on
ozone formation is estimated by subtracting the background ozone concentra-
tion from the maximum ozone concentration measured at a site downwind of the
city.
It must be emphasized that this approach is one of several that might
be considered. It is similar to that outlined in the document EPA 450/2-77-
021 a, Uses, Limitations, and Technical Basis of Procedures for Quantifying
Relationships Between Photochemical Oxidants and Precursors. Also, several
assumptions are made: (1) the background ozone at other stations in the
network would have been similar to that observed at Liberty Mounds; (2) no
changes occur in the ozone concentration aloft during the period 1000 up
until the time of recorded ozone maxima; (3) the maximum ozone concentration
measured at the downwind station(s) is representative of the maximum ozone
concentration within the Tulsa plume.
4.2 JULY 21 THROUGH 25, 1977: CASE STUDY
4.2.1 Introduction
The period July 21-25 (Thursday through Monday) was chosen for case
study analysis primarily because the maximum ozone concentrations at both
90
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the Post Office and Health Department on July 22 were also the maxima of the
entire summer study at those sites. On July 23 the maximum ozone concentra-
tions at the city sites were also near the summer maxima. On July 24 and 25
the meteorological conditions were similar to those of July 22 and 23, but
on those days the maximum ozone concentrations measured at the city sites
were not abnormally high. Differences between these days will be identified.
July 21 was included in the case study because it was a day with condi-
tions that were representative of those most frequently observed in Tulsa
during the summer of 1977. July 21, therefore, provided a data base to
which the data of the days following it could be compared.
Figures that summarize the meteorological and chemical data for the
case study period are presented on the following pages. Figures 4.la through
4.1g are the National Weather Service 0700 EST surface weather maps for the
United States for July 20 through 26. Figures 4.2 and 4.3 show the synoptic
and local (mesoscale) backward air parcel trajectories for the case study
days. Figures 4.4a through 4.4e are the forward trajectories of the urban
air parcel for each day of the case study. The diurnal variations in temper-
ature and solar radiation during the case study are shown in Figures 4.5 and
4.6, respectively. Figure 4.7 illustrates the diurnal profiles for NO and
N02 at the two city sites. Figure 4.8 illustrates the diurnal profiles for
ozone at each site in the network.
Values for the individual hours of data for all the meteorological and
chemical data measured during the case study can be found in Volume II of
this report.
4.2.2 Overview of the Case Study Period
On the 0700 EST (0600 GST) surface weather map for July 21 (Figure 4.1),
a cold front was shown moving through the panhandle region of Oklahoma. An
area of high pressure which was centered over the southeastern States pro-
duced southerly winds in the Tulsa area until 1600 GST. Following 1600 the
front began to influence the Tulsa area and the winds began to shift to
westerly. The synoptic-scale trajectories (Figure 4.2) indicate steady flow
from the south for the 48 hours preceding the air parcel arrival times
(either 0600 or 1600 GST) in Tulsa. The local (mesoscale) back trajectories
91
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T&l -I^ra**
"S&^er*i,AP*?' 5
7 -T i *\i ;
/ »-UIM/ V\Ji---
/ *TV- ' ^SSr^fe "'
rA - -L .*.£& «r:.-^Ls
-J X-J*»i, ^^S"
-X S^xjSL
Figure 4.la and 4.1b.
United States surface weather maps for
July 20 and July 21, 1977.
92
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Figures 4.1c and 4.Id. United States surface weather maps for
July 22 and July 23, 1977.
93
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^y ,$*s
*&*£/* i
f\- \ *a*s=^
^/^^s^^
--r^-v1
Figures 4.1e and 4.If.
United States surface weather maps for
July 24 and July 25, 1977.
94
-------
" v*
Figure 4.1g. United States surface weather map for July 26, 1977.
95
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JULY 21
flRRIVING TRflJECTORIES
D 0600 CST
+ 1600 CST JULY 22
JULY 23
flRRIVING TRflJECTORIES
D 0600 CST .... v
+ 1600 CST JULY
Figure 4.2.
Synoptic scale trajectories for case study period July 21-25,
1977.
96
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JULY 25
flRRIVING TRflJECTORIES
D 0600 CST .... v oc
+ 1600 CST JUL> 26
T
Figure 4.2. Syaoptac scale trajectories for case study period July 21-25,
1977. (continued).
97
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WYN
QCH
K
101
ippb 03
JULY 21 !
1300
1 hr-
2hr-
3hr-
4hr-r
5hr-C
WYN
93
OCH
K
75
JULY 23
1200
LIB
71
Figure 4.3. Mesoscale trajectories for the case study period July 21-25, 1977,
98
-------
JULY 25
1800
Figure 4.3. Mesoscale (local) trajectories for case study period July 21-25,
1977. (continued).
99
-------
JULY
6
as
X
HYN
X
US
X
JULY 21
12
OCH
X
VER
K
JULY 21
IS
OB
X
Figure 4.4a. Forward air parcel trajectories for July 21, 1977.
100
-------
WYN
X
OCH
X
VER
X
JULY 22
a
VYN
OCH
X
VER
X
JULY 22
12
OB
X
LB
X
Figure 4.4b. Forward air parcel trajectories for July 22, 1977.
101
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JULY 23
6
LB
X
OCH
X
JULY 23
12
LIB
X
OCK
X
VER
K
JULY 23
IS
Figure 4.4c. Forward air parcel trajectories for July 23 1977,
102
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LIB
X
LIB
X
WN
A
OCH
X
JULY
12
LIB
X
LB
X
Figure 4.4d. Forward air parcel trajectories for July 24, 1977,
103
-------
OB
X
*$!
OCH
X
JULY 2S
a
us
x
QCK
X
VER
K
JULY 2S
IS
LB
Figure 4.4e. Forward air parcel trajectories for July 25, 1977,
104
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43,
1 I ' I ' I ' I ' I ' I ' | ' |
TULSfl INT. PURPORT TEMP. JULY 21 - 25
m
110.
105.
100.
95.
90.
85.
80.
75.
70
0000 1200 0000 1200 0000 1200 0000 1200 0000 1200 0000
TIME (CST)
Figure 4.5. Diurnal variation of temperature for the period July 21-25, 1977.
m
CO
1.60
1.40
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Figure 4.6. Diurnal variation of solar radiation for the period July 21-25, 1977
105
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(Figure 4.3), calculated for air parcel arrival at 1300, also show steady
southerly winds. In Figure 4.4a, forward trajectories of the Tulsa urban
air parcel are shown for air leaving Tulsa at four different times during
the day. The first three of these forward trajectories, for air leaving
Tulsa at 0600, 0900, and 1200, all show steady advection of the Tulsa urban
air to the north. The air leaving Tulsa at 1500, however, moved first to
the northeast and then drifted slowly back to the south. This was due to
the influence of the cold front, which disturbed the steady southerly winds.
The solar radiation measured at Skiatook reached a maximum near 1.3 lang-
leys per minute at 1100 but by 1500 it had decreased substantially due to
the arrival of a cloud cover associated with the approaching frontal system.
The maximum ozone concentration in the network of 0.135 ppm occurred at Vera
at 1300, and the influence of the frontal system probably did not offset the
maximum ozone significantly.
The concentrations of selected hydrocarbons, oxides of nitrogen, and
some important ratios, measured during the 6-9 a.m. CDT time period for the
days of the case study period, are listed in Table 4.2. The concentrations
of nonmethane hydrocarbons (NMHC) of 0.327 ppmC and NO of 0.073 ppm that
X
were measured at the Post Office were higher than the concentrations that
were measured at both the Health Department and Liberty Mounds. Under the
influence of the southerly winds, morning emissions from the refinery area
in Tulsa and morning traffic emissions produced concentrations at the Post
Office that were higher than at the Health Department. Actually, the con-
centration of NMHC at the Post Office was less than the July average of
0.430 ppmC. At the Health Department and Liberty Mounds the concentrations
of NMHC of 0.239 and 0.240 ppmC, respectively, were very close to the average
concentrations measured at those stations during July. Good ventilation,
resulting from the steady wind flow, probably caused dispersal of the refin-
ery emissions to some degree before the air reached the Post Office Station.
After the 6-9 CDT period, the total NO decreased at both the Post Office
and Health Department stations until the evening traffic period began around
1500 to 1600 CST.
By the morning of July 22 the front had moved directly into the Tulsa
area and had become stationary (Figure 4.1). The front had drifted slowly
109
-------
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to the south by July 23 but still influenced the winds in the Tulsa area.
The synoptic-scale trajectories for both July 22 and 23 (Figure 4.2) indicate
stagnation with very little large-scale air motion in and around Tulsa.
Both types of local-scale trajectories for July 22 (Figures 4.3 and 4.4)
indicate that light easterly winds were present in Tulsa early in the day,
but that during the latter part of the morning air stagnation occurred. The
lack of ventilation resulted in the accumulation of ozone precursors in
Tulsa. These meteorological conditions eventually resulted in the highest
hourly ozone concentrations of the entire summer at both city stations.
The early morning precursor concentrations were relatively low at both
city stations, but a concentration of NMHC of 0.536 ppmC was measured at
Liberty Mounds. That concentration was nearly double the July average at
that site. There was a very low contribution to the total NMHC from automo-
bile emissions, however, and the high morning concentrations of NMHC at
Liberty Mounds may have been largely due to sources associated with small
oil operations south of Tulsa.
The local trajectories for July 23 (Figure 4.4) indicate that southerly
winds were active in transporting Tulsa emissions to the north during the
late morning hours, but that stagnation developed during the afternoon.
Ozone concentrations in excess of 0.100 ppm were measured at the city sta-
tions on July 23; however, the network maximum of 0.118 ppm was measured at
Vera at 1200.
On July 23 the morning NMHC concentration at the Post Office station
was near the July average, while at both the Health Department and Liberty
Mounds, higher than average concentrations were measured. Local ground
level winds indicate that during the early morning hours air was moving to
Tulsa from the east, and such winds were often seen to contribute to higher
than average NMHC concentrations at the Health Department and Liberty Mounds.
Despite the continued influence of the frontal activity on local winds
in Tulsa on July 22 and 23, there was very little cloud cover associated
with the front on those days other than scattered thundershowers. The
diurnal plot of solar radiation is shown in Figure 4.6, and maxima of solar
radiation near 1.4 langleys per minute were reached on both days. However,
on July 22 there was 0.18 inches of precipitation measured at the Tulsa
111
-------
International Airport during hour 1600 and radar depiction maps show towering
cumulus clouds with tops at altitudes between 13,800 ra (45,000 ft) and
15,000 01 (50,000 ft) in the Tulsa area. The solar radiation did drop off
during 1600 and 1700 at Skiatook, but this was well after the ozone maximum
was measured.
On July 24 the front that had influenced Tulsa on July 22 and 23 moved
out of the area. Another cold front was approaching Oklahoma from the
northwest and by July 25 it had become stationary over the northwestern part
of Oklahoma (Figure 4.1). The synoptic trajectories for July 24 and 25
(Figure 4.2) show southwesterly winds typical of conditions preceding frontal
activity in the midwestern States.
The local trajectories also show southwesterly winds throughout July 24
in the Tulsa area (Figures 4.3 and 4.4). Late in the day on July 25, the
front began influencing the local weather in Tulsa and a wind shift was
apparent in the local-scale back trajectories (Figure 4.3). The forward
trajectories for July 25 (Figure 4.4) show northeasterly and easterly trans-
port. The solar radiation reached maxima in excess of 1.4 langleys per
minute on both days (Figure 4.6), and maximum temperatures were greater than
39° C (102° F) on both days.
Morning precursor concentrations were greater than the July average at
the Post Office on both July 24 and 25, although low molecular weight alkanes
were primarily responsible for the high concentrations of total NMHC. On
July 24, 0.128 ppm of NO was measured during the 6-9 a.m. CDT period at the
Post Office, which was nearly double the July average. The refinery complex
in the southwestern part of Tulsa was a strong influence on measurements
made at the Post Office station as southwesterly winds persisted during the
day. The maximum ozone concentrations were measured at Vera and Wyriona on
July 24 and 25, respectively. The local trajectories indicate that Tulsa
urban emissions did not influence Wynona directly on July 25; it is not
clear where that ozone had its source.
4.2.3 Analysis of July 21, 1977
The meteorological conditions in the Tulsa area on July 21 were repre-
sentative of the conditions that most frequently influenced Tulsa during the
summer of 1977. A weak high-pressure area that was centered over northern
112
-------
Florida on the 0700 EST weather map (Figure 4.1b) produced southerly winds
in Tulsa on July 21. A cold front was approaching Oklahoma and it extended
through the panhandle regions of Texas and Oklahoma at 0700 EST on July 21.
The onset of cloudiness, which reduced the solar radiation (Figure 4.6), and
a shift in winds from southerly to westerly beginning in midafternoon indicat-
ed the arrival of this front in the Tulsa area. Both the synoptic-scale
trajectories (Figure 4.2) and the local (mesoscale) trajectories (Figure
4.3) indicate southerly winds in the Tulsa area. The forward trajectories
of the urban air parcel (Figure 4.4a) show the northward transport of the
urban air until midafternoon when the effect of the front produced stagna-
tion in Tulsa.
The steady southerly winds in Tulsa, before the arrival of the front,
resulted in an identifiable ozone plume north of Tulsa. The evolution of
the urban ozone plume is most easily visualized by the concentration/dis-
tance plots shown in Figure 4.9. The elevated ozone concentrations north of
Tulsa were first apparent at Sperry at 0900. The ozone concentration in-
creased more rapidly at Vera, however, as shown in the hour 1100 plot, and
the daily maximum ozone concentration in the network of 0.135 ppm was meas-
ured at Vera at hour 1300.
Even though southerly winds were still measured during hour 1500 in the
network, significant reductions in the ozone concentrations were observed
north of Tulsa during hour 1500. Cloudiness produced by the approaching
front significantly reduced the solar radiation during hour 1400, and temper-
atures also decreased rapidly after 1400. Both of these factors may have
had an impact on the reduced ozone concentrations.
Using the procedure outlined in the introduction, the net impact of
Tulsa emissions on ozone formation can be estimated by subtracting the
background ozone concentration from the maximum ozone concentration measured
downwind of Tulsa. On July 21, the maximum ozone concentration in the
network of 0.135 ppm was measured at Vera at 1300. The average of the 1000
and 1100 ozone concentrations at Liberty Mounds was 0.045 ppm. The difference,
0.090 ppm, is an estimate of the net ozone production as a result of activi-
ties in and around Tulsa.
113
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.16
J4
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JO2
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.16
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02
00
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10 OO
- 1100
- 1200
I3OO
1500
X MOUNDS
O POST OFFICE
HEALTH DEPARTMENT
O SPERRY
SKIATOOK
& VERA
A OCHELATA
* WYNONA
Figure 4.9. Ozone concentration/distance plots for July 21, 1977,
114
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4.2.4 Analysis of July 22 and 23, 1977
The meteorological conditions in Tulsa on July 22 and 23 were quite
different than those on July 21. A stationary front was in the vicinity of
Tulsa by 0700 EST on July 22, and its position had not changed significantly
by 0700 EST on July 23 (Figure 4.Id). This front produced variable winds in
Tulsa on July 22 and 23. The synoptic scale trajectories for both July 22
and 23 indicate that there was only weak transport in the Tulsa area for at
least the last 12 hours prior to both air parcel arrival times (Figure 4.2).
The maximum temperatures were 35° C (95° F) and 37° C (99° F) on July 22 and
23, respectively (Figure 4.5). There was excellent solar radiation on both
days (Figure 4.6). The forward trajectories of the urban air parcel show
that there was almost no air parcel advection on July 22, and only slow
northward transport on July 23. In general, on July 22 and 23, Tulsa ex-
perienced similar meteorological influences. The lack of any significant
transport and plentiful sunshine resulted in the occurrence of the network
maximum ozone concentrations at both city sites on July 22. Although the
maximum ozone concentrations measured at both city stations on July 23 were
higher than average for July, slow northward transport was occurring and the
network maximum of 0.118 ppm occurred at Vera.
There were low concentrations of NMHC and oxides of nitrogen at the
Post Office site during hours 0600 to 0900 CDT on July 22 (Table 4.2). The
concentration of acetylene, however, was equal to the mean for July, and the
concentration of n-butane was less than half of the mean for July, perhaps
indicating that the refinery area, located southwest of the site did not
contribute to the NMHC concentration at the Post Office as much as it had on
July 21 when southerly winds were measured in Tulsa. On the morning of July
22, Liberty Mounds measured very high concentrations of NMHC and oxides of
nitrogen from hours 0600 to 0900 CDT, indicating, perhaps, that southerly
movement of Tulsa air had taken place.
The ozone profiles for July 22 from Sperry, Skiatook, Vera, and Oche-
lata (Figure 4.8) were all substantially different in appearance from those
of July 21. The maximum ozone concentrations measured at Sperry, Skiatook,
Vera, and Ochelata on July 22 were reduced from the maximum ozone concen-
trations measured on July 21 by 0.026, 0.022, 0.031, and 0.029 ppm, respec-
115
-------
tively. The maximum ozone concentrations measured at the Post Office and
Health Department of 0.127 and 0.124 ppm were elevated over the maximum
ozone concentrations measured on July 21 by 0.077 and 0.059 ppm, respectively.
Liberty Mounds measured a maximum ozone concentration of 0.081 ppm, an
increase of only 0.013 ppm over the maximum for the previous day.
The forward trajectory of the urban air parcel (Figure 4.4b) shows the
stagnation of air in the Tulsa area during the afternoon of July 22. During
the early morning hours there was transport to the south and the Liberty
Mounds site. The ozone distribution in the network on July 22 was nearly
constant until 1100 (Figure 4.10) when the urban stations first measured
ozone concentrations in excess of those measured at the other stations. The
ozone concentrations continued to rise at the urban stations until the
maxima were reached at hour 1300.
On July 23, the maximum ozone concentrations measured at both the Post
Office and Health Department sites (0.100 and 0.104 ppm) were considerably
higher than the mean maximum ozone concentrations during July of 0.067 ppm
for the Post Office and 0.074 ppm for the Health Department. Concentrations
of NMHC and oxides of nitrogen during the 0600 to 0900 CDT sampling period
at the Post Office were not unusually high. At the Health Department there
was a higher than average NMHC sum but the difference was mostly caused by
an increase in the high sum of alkanes. Vehicular emissions were probably
lower in the 0600 to 0900 CDT sampling period because July 23 was a iSaturday;
however, low-speed, variable winds produced conditions that inhibited the
dispersion of morning emissions in the urban area.
Between 0600 and 1000 CST the ozone concentrations increased rapidly at
each station in the network. These increases were probably a result of
ozone mixing to the surface from above the radiation inversion. The forward
trajectories of the urban air parcel show that there was northward transport
during the morning hours to Vera, and that stagnation began in the early
afternoon. This is important because the maximum ozone concentration of the
day of 0.118 ppm occurred at Vera at 1200. It is likely that the high ozone
concentrations measured at Vera were a result of ozone synthesis in an air
parcel that was transported from the urban area to Vera during the morning
hours and that then stagnated in the area of Vera. The high ozone concentra-
116
-------
.16
J4
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.10
.06
.06
.04
E .02
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.12
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.02
.00
0900
1000
1100
1300
X MOUNDS
O POST OFFICE
HEALTH DEPARTMENT
Q SPERRY
SKIATOOK
& VERA
A OCHELATA
* WYNONA
Figure 4.10. Ozone concentration/distance plots for July 22, 1977,
117
-------
tions measured at the city stations, then, were probably the result of ozone
synthesis due to precursor emissions from the late morning hours that had
stagnated in the urban area. The maximum ozone concentrations at the Post
Office and Health Department sites occurred at hours 1500 and 1200, respec-
tively. Both NO and N02 concentrations measured at the city stations were
relatively low during the early afternoon hours. The continued ozone synthe-
sis at the Post Office site during the early afternoon hours while ozone
concentrations were decreasing at the Health Department may have been due to
continued NMHC emissions from that area of the city. The data from the
Beckman-automated chromatograph do indicate continued elevated concentrations
(0.3 to 0.7 ppmC) of NMHC through the early afternoon at the Post Office
site.
4.2.5 Analysis of July 24 and 25. 1977
High pressure centered over the Gulf of Mexico on July 24 and 25 re-
sulted in southwesterly and westerly winds in Tulsa (Figures 4.7e and f).
The synoptic-scale trajectories for both days (Figure 4.2) indicate that air
was transported from central Texas and passed near Oklahoma City on its way
to Tulsa. Both the local (raesoscale) back trajectories (Figure 4.3) and the
forward trajectories (Figures 4.4d and e) of the urban air parcel indicate
northeast transport in the vicinity of Tulsa on July 24. On July 25 the
local trajectories show northerly winds at Wynona and Vera, westerly winds
at the Post Office, and southerly winds at Liberty Mounds. These inconsis-
tent winds at 1800 were the result of a wind shift that occurred late in the
day on July 25 due to the passage of a front as it moved across the Tulsa
area. The forward trajectories of the urban air parcel show easterly trans-
port on July 25. Skies were clear on both days and temperatures reached
40° C (104° F) and 41° C (106° F) on July 24 and 25, respectively (Figures
4.5 and 4.6).
At the Post Office, high concentrations of nonmethane hydrocarbons were
measured during the 0600 to 0900 CDT sampling period on both July 24 and 25
(Table 4.2). On July 24, a very low concentration of acetylene of 2.8 ppbC
and a high concentration of alkanes were measured. July 24 was a Sunday and
the low traffic volume accounted for the low acetylene concentration. The
NO concentration measured at the Post Office of 0.086 ppm from 0600 to 0900
118
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CDT was much higher than the average value for July. The low acetylene
concentration during the same time period indicated that the air parcel at
the Post Office from 6-9 a.m. CDT probably did not contain substantial
amounts of automobile emissions. It is assumed, therefore, that the re-
finery area was the major contributor to the 0600 to 0900 CDT precursor
concentrations measured at the Post Office. On July 25, the high concen-
tration of nonmethane hydrocarbons measured at the Post Office site was
again due to high concentrations of alkanes. The average NO concentration
during the 0600 to 0900 CDT period had decreased considerably on July 25
from that measured on July 24. At the Health Department, the concentrations
of nonmethane hydrocarbons and oxides of nitrogen on July 24 and 25 were not
unusually high compared to the average values for July.
All three trajectory analyses for both July 24 and 25 show that the
urban air was transported to the east of the network monitoring stations.
On July 24 at the Liberty Mounds, Post Office, Health Department, Sperry,
Skiatook, and Ochelata sites, the ozone concentrations were representative
of conditions expected in areas that were not strongly influenced by urban
sources.
At both Wynona and Vera, however, maximum ozone concentrations of 0.104
and 0.105 ppm were measured. These maximum concentrations, which occurred
at hour 1100 at Wynona and 1300 at Vera, were at least 20 ppb greater than
the concentrations measured at other stations in the network at the same
time. Also, the local trajectory for air arriving at Vera at 1300 passed
directly over Skiatook not more than 2 hours before 1300. In addition, the
ozone concentrations at both Wynona and Vera did not reach the daily maximum
concentration suddenly, but increased to their maximum concentrations slowly,
in a manner typical of ozone synthesis.
If the ozone measured at Wynona and Vera were produced by Tulsa emis-
sions alone, some recognizable influence should have been seen at Sperry,
and if emissions from Oklahoma City were responsible, it seems that Skiatook
would have measured elevated ozone concentrations also. Thus the cause of
the elevated ozone concentrations measured at Wynona and Vera on July 24 is
not clear from the data that are available.
119
-------
On July 25 the maximum ozone concentrations measured at many of the
network stations occurred at or after 1700. Even at Liberty Mounds and
Vera, where the daily maximum concentrations were measured earlier in the
day, increasing ozone concentrations were observed during the evening hours.
During the afternoon of July 25, the same situation just described for July
24 was observed again. Vera and Wynona measured ozone concentrations that
were considerably higher than at any other station. Westerly winds and
eastward transport were again indicated by the wind data throughout the
network. Again, the cause of the high ozone concentrations measured at
Wynona and Vera relative to the other network stations is not clear.
The maximum ozone concentration in the network was 0.123 ppm at 1800 at
Wynona. The local trajectories at 1800 showed the wind shift that was
presumably caused by a frontal passage at this site. The front moved through
Tulsa from north to south and the peak ozone concentrations occurred progres-
sively later from the northern to the southern sites. The ozone increases
late in the day on July 25 appear to be related to the frontal passage. The
ozone was either brought to the surface from aloft by a disturbance created
by the front, or there were high ozone concentrations in the air mass behind
the front. Since measurements of ozone were not made north of the front's
position or aloft, as part of this study, it was not possible to determine
the source of the ozone measured in Tulsa late in the day. It is unlikely,
however, that Tulsa emissions were the direct cause of that ozone.
4.3 JULY 28 THROUGH 30, 1977: CASE STUDY
4.3.1 Introduction
The days July 28 through 30 (Thursday through Saturday) were chosen for
case study analysis primarily because the maximum ozone concentration of the
summer study period at Liberty Mounds, 0.127 ppm, occurred at 1700 on July
29. This was unusual since this site most often reported rural, background
ozone concentrations.
A frontal system was the dominant meteorological influence on Tulsa on
both July 28 and 29. On July 30 there were clear skies and steady southerly
winds, the most common meteorological conditions observed in Tulsa, and this
day was included in the analysis to show the contrast between it and July 29.
120
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Figures summarizing the meteorological and chemical data for the case
study period are presented below. Figures 4.11a through 4.lie are the
National Weather Service 0700 EST surface weather maps for the United States
for July 27 through 31. Figures 4.12 and 4.13 show the synoptic scale and
local (mesoscale) backward air parcel trajectories for the case study days.
Figures 4.l4a through 4.l4c are the forward trajectories of the urban air
parcel at selected times of each case study day. Figures 4.15 and 4.16 show
the diurnal variation in temperature, and solar radiation. Figure 4.17
shows the diurnal profiles of hourly average values of NO and N(>2 at the two
city sites, and Figure 4.18 shows the diurnal profiles of ozone for each
site in the network.
Values for individual hours of data for the meteorological and chemical
parameters are not presented here, but can be found in Volume II of this
report.
4.3.2 Overview of the Case Study Period
The frontal system that had influenced Tulsa on July 25 was shown south
of Tulsa on the 0700 EST surface weather map for July 28 (Figure 4.lib). A
large high-pressure area was centered over the northeastern States, but the
presence of the front limited the influence of the high pressure area on
Tulsa. The synoptic-scale trajectory for air parcel arrival in Tulsa at
0600 CST (Figure 4.12) indicates that there was very little large-scale air
motion in the Tulsa area for the 48 hours preceding 0600 on July 28. The
synoptic-scale trajectory for air parcel arrival in Tulsa at 1600 CST,
however, indicates that there had been slow transport from the southwest
during the 24 hours prior to 1600 CST. The trajectory passed near the
Oklahoma City area during the 24 hours preceding its arrival in Tulsa. The
local back trajectories for July 28 (Figure 4.13) show that mostly southerly
winds were present in the immediate Tulsa area. The forward trajectories of
the Tulsa urban air parcel for July 28 (Figure 4.l4a) indicate that there
was slow transport of air from Tulsa to the northwest all through the day.
The solar radiation measured at Skiatook was relatively low, reaching a
maximum only slightly greater than 1.0 langleys per minute. Comparison of
the solar radiation profile for July 28 to that for July 30, a clear day,
shown in Figure 4.16, displays the relative depletion of solar radiation on
121
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SURFACE WE4THEB MAP
AND STATION WEATHER
AT 7 OO A M C S T
3te«&rv» $»3&tesr'tf.
Figures 4.1la and 4.lib.
United States surface weather maps for
July 27 and July 28, 1977.
122
-------
Figures 4.lie and A.lid.
United States surface weather maps for
July 29 and July 30, 1977.
123
-------
Figure A.lie. United States surface weather map for July 31, 1977.
124
-------
JULY 27
flRRIVING TRflJECTORIES
D 0600 CST ., v ._
+ 1600 CST JULY 28
JULY 29
ftRRIVING TRflJECTORIES
D 0600 CST .... v on
+ 1600 CST JULY 30
Figure 4.12.
Synoptic scale trajectories for case study period July 28-30,
1977.
125
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WYN
₯
71
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il
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SKI
X
65
VER
₯
128
SPE
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WYhT
X
86
WYN
X
OCH
X
67
i
JULY 30
ionn
Figure 4.13o Mesoscale trajectories for case study period July 28-30, 1977,
126
-------
JULY 28
6
LB
X
JULY 28
9
LIB
K
JULY 28
12
LIB
X
JULY 28
IS
Figure 4.14a. Forward air parcel trajectories for July 28, 1977.
127
-------
Ngl
JULY 29
6
NYN
X
OCH
X
JULY 23
a
LB
X
OCH
X
JULY 23
12
LB
X
WN
X
OCH
X
VER
X
JULY 23
IS
Figure 4.14b. Forward air parcel trajectories for July 29, 1977,
128
-------
LIB
X
LB
K
JULY
12
VYN
K
LB
Figure 4.14c. Forward air parcel trajectories for July 30, 1977.
129
-------
TULSfl INT. PURPORT TEMP. JULY 28 - 30
33
m
0000
1200 0000
1200 0000
1200 0000
TIME COST)
Figure 4.15. Diurnal variation of temperature for the period July 28-30, 1977
SKIfiTOOK SOLflR RflDIRTION JULY 28 -ft 30
0.00
1.60
1.40
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CO
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0.80
0.60
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m
CO
0000 1200 0000 1200 0000
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1200
0000
0. 00
Figure 4.16. Diurnal variation of solar radiation for the period July 28-30,
1977.
130
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July 28. Due to the low availability of sunshine, the maximum temperature
in Tulsa was also relatively low (Figure 4.15).
The 6-9 a.m. CDT average concentrations of selected hydrocarbon species,
oxides of nitrogen, and selected ratios are listed in Table 4.3. The monthly
means and standard deviations of the same parameters are listed in Table 4.1.
Low concentrations of NMHC relative to the July mean were measured between 6
and 9 a.m. CDT at both the Post Office and Health Department stations. The
low concentrations of NMHC and substantially higher percentage of NMHC due
to vehicular emissions implies that the urban stations were influenced to a
lesser extent by the refinery area than on days with more southerly or
southwesterly winds. The NMHC concentration was not available from the
Liberty Mounds station on July 28. The concentration of NO , averaged from
X
6-9 CDT at the Post Office station, of 0.104 ppm was considerably greater
than the July mean. Most of the NO was as NO, implying that a nearby
X
source, possibly city traffic, contributed to that high NO concentration.
By 0700 EST on July 29, the front had drifted north and was located
just to the north of Tulsa (Figure 4.11). The influence of the front again
produced scattered cloudiness in Tulsa on July 29 and the solar radiation
was considerably less than that of July 30, a clear day (Figure 4.16). The
synoptic-scale trajectories indicated that air had been slowly transported
from the southwestern part of Oklahoma, during the 48 hours preceding its
arrival in Tulsa at both 0600 and 1600 CST.
The local winds in and around Tulsa on July 29 were significantly
influenced by the presence of the front. The forward trajectories of the
urban air parcel (Figure 4.14) indicate that air leaving Tulsa at 0600 CST
travelled slowly to the north, while the trajectories for air leaving Tulsa
at 0900 indicate that very little motion occurred. Both the 1200 and 1500
trajectories indicate southerly transport followed by a shift in winds that
moved air to the west of Tulsa late in the day. The local back trajectories
(Figure 4.13) indicate air arriving in Vera from the northeast and curving
around to arive at the Post Office from the north. The last few hours of
the Liberty Mounds trajectory indicate that urban air may have been trans-
ported to Liberty Mounds late in the afternoon.
134
-------
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The 6-9 a.m. CDT NMHC concentrations measured at the Post Office and
Health Department stations were considerably greater than the July mean.
The percentage of NMHC due to vehicular emissions, however, was not signif-
icantly different than the July mean at either of the stations. In addi-
tion, the 6-9 CDT average NO concentration at the Post Office was lower
A
than average, while at the Health Department the concentration of NO on
July 29 was nearly double the July mean. Therefore, a complex interaction
between local source areas and local winds was active in Tulsa on July 29.
The highest hourly average ozone concentration of the summer at Liberty
Mounds of 0.127 ppm was measured at 1700 on July 29. The ozone measured at
Liberty Mounds probably resulted from the high ozone precursor concentra-
tions measured in the city, which were producing ozone while being slowly
transported to the south.
By July 30 the front was well out of the Tulsa area (Figure 4.11). An
area of high pressure was centered off the Florida coast. Steady southerly
winds and clear skies were observed in Tulsa all day. The synoptic trajec-
tories (Figure 4.12) for July 30 show air arriving at 0600 from the southwest
after it had passed north of Oklahoma City. The air arriving at 1600 came
from central Texas 48 hours earlier and passed near Oklahoma City. The
local back trajectories (Figure 4.13) show steady southerly winds, which
caused the trajectories to pass right over Tulsa and move on to the stations
north of Tulsa. The forward trajectories of the urban air parcel (Figure 4.14)
also indicate steady northward transport of air from Tulsa.
Both the NMHC and NO measured during the 6-9 CDT period on July 30 at
X
the Post Office of 771.1 ppbC and 0.150 ppm, respectively, were considerably
higher than the July means. At the Health Department, however, both the
NMHC and NO concentrations were lower than the July means. Liberty Mounds
A
also measured low concentrations of precursors during the 6-9 a.m. CDT
measurement period. Only 12 percent of the very high concentration of NMHC
measured at the Post Office station was contributed by vehicular emissions,
which was considerably less than the average for July of 40 percent. The
southerly winds seem to carry the industrial-type emissions from the refinery
area to the Post Office station without influencing the Health Department
sample.
136
-------
4.3.3 Analysis of July 28, 1977
The dominant meteorological influence on Tulsa on July 28 was a large
high-pressure area centered over the northeastern states. The influence of
the high pressure on Tulsa, however, was modified by the presence of a
stationary front located just south of the Oklahoma and Texas border (Figure
4.lib). There were overcast skies in Tulsa on July 28 until the 1000 hour,
and scattered cloud cover for the remainder of the day. One result of the
cloud cover was that temperatures were lower than average. The synoptic-scale
trajectories (Figure 4.12) indicate that the air parcel arriving in Tulsa at
0600 had moved very little during the preceding 48 hours. The air parcel
arriving at 1600 experienced slow transport from the southwest during the
preceding 12 hours. During the day on July 28 the stationary front moved
northward and passed through Tulsa by the next morning. There were mostly
southerly surface winds measured throughout the network during July 28.
Winds aloft were from the southwest. Both the local back trajectories and
the forward trajectories of the urban air parcel (Figures 4.13 and 4.l4a)
indicate that Vera was not directly influenced by the Tulsa urban air.
However, the maximum ozone concentration in the network, 0.116 ppm, was
measured at Vera at 1700. Since the maximum ozone concentration measured at
Vera was considerably higher than at other stations in the network, it is
assumed that Tulsa emissions were responsible for the ozone measured at
Vera. Unfortunately, the ozone data from Sperry were missing during the
photochemically active portion of the day and thus the advance of the Tulsa
urban plume cannot be completely described.
The slow northward transport and limited morning solar radiation on
July 28 delayed the first signs of ozone production until hour 1200, when
Skiatook measured an ozone concentration that was elevated with respect to
the other stations (Figure 4.19). At Vera, elevated ozone concentrations
were first measured during the 1400 hour. Both Vera and Ochelata then
measured relatively high ozone concentrations until 2000. During hour 2100,
Vera measured decreased ozone concentrations, while the ozone concentration
at Wynona increased. Southeasterly winds, which may have carried ozone from
Vera to Wynona, were measured during hour 2100 at many of the network stations.
137
-------
.16
J4
.12
JO
.08
.06
.04
.02
.00
.16
.14
.12
.10
.08
.06
.04
.02
.00
.16
.14
.12
.10
.08
.06
64
.02
.00
1200
1400
E
Q.
o.
UJ
z
o
rsi
o
1600
1800
2000
2100
X MOUNDS
O POST OFF ICE
HEALTH DEPARTMENT
a SPERRY
SKIATOOK
-------
Although July 28 was not an ideal day for ozone formation in Tulsa, the
net ozone production of Tulsa can be estimated. Since southerly winds were
measured in the monitoring network during most of the day, it can be assumed
that Liberty Mounds measured the background influence on Tulsa. The average
of the 1000 and 1100 ozone concentrations at Liberty Mounds was 0.043 ppm.
The difference between the network maximum ozone concentration of 0.116 ppm
measured at Vera and the background ozone concentration is 0.073 ppm which
is assumed to represent the net ozone formation of Tulsa for July 28.
4.3.4 Analysis of July 29, 1977
The 0700 EST surface weather map shows the position of the stationary
front to be immediately north of Tulsa (Figure 4.lie). This front was the
major influence on Tulsa on July 29, and it produced partly cloudy skies
during the day. There were variable winds measured in the network on this
day and the forward trajectories of the urban air parcel (Figure 4.l4b)
indicate stagnation of the urban air until the late afternoon hours when
transport to the south became apparent.
Surface weather maps for every 3 hours for the night of July 28 were
examined, and from these maps the time of the frontal passage was found to
have occurred between 0300 and 0600. An interesting nocturnal ozone increase
was measured at each station in the network at some time during the predawn
hours of July 29. Increasing ozone concentrations of this type have been
(1 2)
observed elsewhere. ' It is likely that the frontal passage caused a
disturbance that allowed ozone from above the radiation inversion to reach
the surface.
In addition to its effect on the cloud cover, the return of the front
to the immediate Tulsa area also produced variable winds in the monitoring
network. Prior to the time of maximum network ozone at Liberty Mounds of
0.127 ppm at 1700 there was a northeast wind measured at Ochelata. Although
the synoptic-scale trajectories indicate that air arrived in Tulsa from the
southwest, the local mesoscale trajectories were controlled by the tendency
toward northeasterly and northerly winds. Winds aloft were from the north
and northwest. During most of the afternoon the Liberty Mounds station was
measuring northerly winds, implying that Tulsa emissions were carried to
Liberty Mounds during the afternoon.
139
-------
Although there were overcast skies during the night and scattered or
broken cloud cover reported all day long, both solar radiation and tempera-
ture reached higher values on July 29 than on July 28 (Figures 4.15 and
4.16). The combination of improved solar radiation, increased temperature,
and the northerly winds carrying urban emissions to Liberty Mounds were
responsible for the maximum ozone concentration measured during the summer
at Liberty Mounds.
During the afternoon hours of July 29, NO concentrations at the Post
A
Office site (Figure 4.17) were lower than those usually observed when there
was a consistent southerly wind. There were peaks in both the NO and N02
concentration profiles at the Post Office site at hour 0600 that are indica-
tive of morning traffic emissions. During the remainder of the day and
until 2200, the NO concentrations at the Post Office were low. There were
' x
significant peaks of both NO and N02 measured at hour 2300. The winds had
shifted back to southerly prior to those peaks.
The most striking feature of the network ozone data for July 29 is the
diurnal ozone concentration profile for Liberty Mounds (Figure 4.18). The
ozone concentration at Liberty Mounds rose rapidly during the morning and
was stable through the afternoon until hour 1600. The onset of northeast-
erly and northerly winds in the afternoon of July 29 was followed by a rapid
increase in the ozone concentration at Liberty Mounds. At hour 1600 a very
sharp increase of 0.038 ppm occurred and a measured concentration of 0.124
ppm was attained. The 1700 concentration reached 0.127 ppm, which was the
maximum measured at Liberty Mounds during the entire summer study. Following
a shift to southerly winds, the ozone concentration then fell rapidly and
after hour 2000 the concentrations appeared to be approximately what would
have been expected had the ozone concentrations decayed from the concentra-
tion present prior to the peak.
The second highest ozone maximum of the study occurred for both the
Post Office and Health Department sites on July 29. The Post Office station
recorded a maximum of 0.112 ppm at 1800. The Health Department station
measured a maximum of 0.121 ppm at 1000, much earlier than the time of the
daily maximum for either Liberty Mounds or the Post Office. The occurrence
of the hour 1800 maximum at the Post Office site is associated with a reversal
140
-------
of the windflow from northeasterly to southerly. Soon after this change in
wind direction, the ozone distribution throughout the network became uniform,
with slightly higher ozone concentrations being measured at the Wynona site.
The reestablishment of southerly winds marks the time that the stationary
front no longer had any influence on the Tulsa area.
4.3.5 Analysis of July 30. 1977
High pressure centered off the Florida coast was the predominant influ-
ence on the weather in Tulsa for this day; clear skies and southerly winds
were predominant.
The ozone concentrations measured through the afternoon of Saturday,
July 30, at the Liberty Mounds, Post Office, and Health Department sites
were typical of background conditions. The afternoon maximum ozone concen-
tration at Liberty Mounds was 0.069 ppm at 1600; however, the maximum daily
ozone concentration of 0.070 ppm occurred at hour 2200. At the Post Office
site ozone concentrations were less than 0.050 ppm until 1800 when the day's
maximum of 0.067 ppm was measured. At the Health Department the maximum
ozone was also 0.067 ppm and was measured during hours 1300, 1400, and 1500.
Of the stations north of Tulsa, only Vera and Wynona measured maximum ozone
concentrations that were significantly above their average daily maximum for
the month.
Figure 4.20 illustrates the ozone concentration variability for the
network during various hours of the day. Beginning at hour 0600, all of the
stations in the network were measuring nearly the same ozone concentrations
of approximately 0.025 ppm except for the Post Office, which measured 0.005 ppm.
The ozone concentration at this site remained low for the next 2 hours while
the ozone measured at the other stations rose. By 0900 Sperry, Vera, and
Wynona appeared to be influenced by the urban plume. The Ochelata monitoring
station had no data for the 0900 hour. Vera was missing data for the 1000
and 1100 hours but measured the maximum ozone concentration of the day in
the network of 0.128 ppm at hour 1200. All of the other stations were
measuring concentrations considerably lower than Vera through the afternoon
until 1700. Throughout this period, Vera experienced the highest and Wynona
the second highest ozone concentrations; however, the data from Ochelata are
141
-------
.16
J4
.12
JO
08
.06
.04
6 «
Q.
o. .00
0600
0900
z
o
IM
O
J6
.14
.12
JO
08
.06
04
.02
00
1200
1700
X MOUNDS
a POST OFFICE
» HEALTH DEPARTMENT
O SPERRY
SKIATOOK
AOCHELATA
* WYNONA
Figure 4.20. Ozone concentration/distance plots for July 30, 1977,
142
-------
LU
z
o
N
O
.16
.14
.12
.10
.08
06
.04
.02
2000
2100
.14
J2
10
08
.06
.04
.02
.00
2200
2300
X MOUNDS
O POST OFFICE
HEALTH DEPARTMENT
D SPERRY
SKIATOOK
& VERA
A OCHELATA
* WYNONA
Figure 4.20.
Ozone concentration/distance plots for
July 30, 1977 (continued).
143
-------
missing after 1300. At 1700 the ozone concentrations measured at Wynona and
Vera were the same. Following hour 1700 until 2100 the Wynona station
measured ozone concentrations that were higher than at any other stations
reporting data in the network.
At 2000 the wind at Ochelata shifted to northerly and the ozone concen-
trations at all of the stations except Liberty Mounds began to decrease.
The ozone distribution during hours 2200 and 2300 returned to the typical
ozone distributions observed in and around an urban area with higher ozone
at the outlying stations and lower ozone at sites near or in the urban area.
Because steady southerly winds and uninterrupted solar radiation were
measured on July 30 in Tulsa, the net ozone produced by Tulsa can be esti-
mated. An average of the ozone concentrations measured at Liberty Mounds
during hours 1000 and 1100 of 0.056 ppm is assumed to represent the back-
ground ozone concentration that influenced Tulsa on July 30. The maximum
network ozone concentration observed downwind of Tulsa was 0.128 ppm, which
occurred at Vera at 1200. It is assumed that this maximum ozone concentra-
tion observed in the network was representative of the maximum ozone concen-
tration in the urban plume. Subtraction of the background ozone concentra-
tion, which is assumed to be similar at all of the network stations, from
the maximum in the network leaves a concentration of 0.072 ppm, which can be
considered representative of the net contribution of Tulsa emissions to
ozone formation.
4.4 AUGUST 2-5, 1977: CASE STUDY
4.4.1 Introduction
The days August 2-5 (a Tuesday through Friday) were chosen for case
study analysis primarily because the highest hourly average ozone concentra-
tions of the entire summer study at Sperry, Vera, and Ochelata of 0.135,
0.151, and 0.114 ppm, respectively, were measured on August 3. August 2 is
included because an unusual late afternoon increase in the ozone concentra-
tion was observed at each station. August 5 is of interest since the maxi-
mum ozone concentration of the entire study period for the Skiatook Lake
site (0.120 ppm) was measured on this date.
144
-------
Figures summarizing the meteorological and chemical data during the
case study period are presented below. Figures 4.21a through 4.21f are the
National Weather Service 0700 EST surface weather maps for the Unites States
for August 1-6, 1977. Figures 4.22 and 4.23 are the synoptic-scale traject-
ories and the local (mesoscale) trajectories for the case study days.
Figures 4.24a through 4.24d are the forward trajectories of the Tulsa urban
air parcel for each of the case study days. Figures 4.25 and 4.26 are plots
of the diurnal variation in solar radiation and temperature. Figure 4.27
depicts the diurnal variation in NO and N02 at the two city sites. Figure
4.28 illustrates the diurnal variation of ozone concentrations at each site
in the network.
4.4.2 General Description of the Case Study
On the 0700 EST surface weather map for August 2 (Figure 4.21) there is
a weak high-pressure area centered over the Ohio Valley. As a result of
this, easterly winds were observed in Oklahoma at 0700 EST. The synoptic
trojectories for both the morning and afternoon arrival times indicate that
the air arriving in Tulsa had come from the north, curved in a clockwise
motion south of Tulsa, and arrived in Tulsa from the west (Figure 4.22).
The local (mesoscale) trajectories indicate air motion from the east except
at Liberty Mounds where air arrived from the south (Figure 4.23). Actually,
the air arriving at Liberty Mounds also may have come from the east and
turned clockwise to arrive from the south. This would be consistent with
the other trajectories shown for the northern stations. The foreward trajec-
tories of the urban air parcel, shown in Figure 4.24, show how the winds
shifted around in a clockwise motion. The solar radiation (Figure 4.26)
reached a maximum mean of 1.5 langleys per minute and there were no extensive
interruptions in the solar radiation during the day.
The sum of NMHC concentrations measured during the 6-9 a.m. CDT period
on August 2 (listed in Table 4.4) were higher than the August means at all
three stations. The acetylene concentrations at each station were not
significantly greater than the August means, listed in Table 4.1, while the
concentrations of n-butane and other low molecular weight alkanes were
higher at each station than the mean concentrations for all August samples.
145
-------
^:r""""^i^4iii--'^^:
ST; .- ^> l--^x-~k yfL:
^-^^i^m
^4^-^^f;f ^
. rf-\ ^ ^.^^^"2^t^ v
i TO« ~~ <** ' * «* » __^ - tf\^ J fitT XY^* "^
/-^^^^^--r.. ^^/^^
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ifr-.rf _:fs*7 /^-'|%^
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1 \ a'uL. <»-«- i»*I»/ J"-f («./--' ^»^i \
s^llJ^i^rh.J
Figures 4.2la and 4.21b.
United States surface weather maps for
August 1 and August 2, 1977.
146
-------
Figures 4.21c and 4.2Id.
United States surface weather maps for
August 3 and August 4, 1977.
147
-------
, ",AV^- IOIf-^sr-
jfe-*~K^W^?%5
^i ^>. *\ \ "*-/
^r
SS; X -oj-^^^zg^
Figure 4.21e and 4.2If.
United States surface weather maps for
August 5 and August 6 1977.
148
-------
RUG 1
flRRIVING TRRJECTORIES
D 0600 CST nilr,
4- 1600 CST RUG
RUG-3
flRRIVING TRflJECTORIES
D 0600 CST
+ 1600 CST RUG
Figure 4.22.
Synoptic scale trajectories for case study period August 2-5,
1977.
149
-------
RUG 5
flRRIVING TRflJECTORIES
D 0600 CST nnn
+ 1600 CST RUG
v,. 1
Figure 4.22,
Synoptic scale trajectories for case study period August 2-5,
1977. (continued).
150
-------
GCH
RUG 3
IfOQ
flUG
1300
WYN
K
102
QCH
X
KM
SKI
1/02
flUG 5
IfOQ
Figure 4.23. Mesoscale trajectories for case study period August 2-5, 1977,
151
-------
NYN
X
OCH
X
RU6 2
6
LIB
X
OCH
WYN
X
fHJG 2
a
VER
X
LIB
NYN
X
OCH
X
ftUG
12
OCH
X
VER
X
1C
LIB
X
Figure 4.24a. Forward air parcel trajectories for August 2, 1977,
152
-------
OCH
X
flUB S
6
OB
flUO S
S
LIB
flUGS
12
LIB
X
Figure 4.24b. Forward air parcel trajectories for August 3, 1977,
153
-------
QCH
X
flUS
6
VER
X
OB
OCH
X
VER
flUS 4
3
LIB
X
tfYN
X
flUS
12
OCH
flUG
IS
OB
X
Figure 4.24c. Forward air parcel trajectories for August 4, 1977,
154
-------
flUG S
6
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Figure 4.24d. Forward air parcel trajectories for August 5, 1977,
155
-------
TULSfl INT. RIRPORT TEMP. RUGUST 2-5
- 80.
75,
70.
1200 0000 1200 0000 1200 0000 1200 0000
TIME (CST)
Figure 4t25. Diurnal variation of temperature for the period August 2-5, 1977,
110
105,
100.
95.
90. i
85.
1.60
SKIflTOGK SOLflR RflDIflTION RUGUST 2-5
0.00
1.60
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0.80
0.60
0.40
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0.00
ID
-z.
O
-<
CO
0000 1200 0000 1200 0000 1200 0000 1200 0000
TIME (CST)
Figure 4.26. Diurnal variation of solar radiation for the period August 2-5,
1977.
156
-------
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The 6-9 a.m. CDT average NO concentrations were also higher than the August
mean at the Health Department and Liberty Mounds but not at the Post Office.
The percentage of NMHC contributed by vehicular emissions was not higher
than the average at any of the stations.
On the 0700 EST surface weather map for August 3 (Figure 4.21), a small
high-pressure cell was indicated just north of the border between Oklahoma
and Kansas, and a small cell of low pressure was located over western Kansas.
The pocket of high pressure, although small and weak, had an influence on
the local winds. The synoptic-scale trajectories for August 3 (Figure 4.22)
again show a clockwise turning of the wind from east and south of Tulsa to
arrive from the southwest. The trajectory for air arriving at 0600 CSX
indicates that very slow transport had occurred over the 12 hours preceding
the arrival time. The trajectory for air parcel arrival at 1600, however,
shows that the wind speeds began to increase and the last 12 hours of the
trajectory indicate that there was some air parcel advection from the south-
west. The local-scale trajectories (Figure 4.23) for August 3 once again
show a definite clockwise shift in the winds. The air parcel that arrived
at Vera at 1400 had the highest ozone concentration measured in the entire
summer study. This air parcel had remained close to the metropolitan Tulsa
area throughout the morning. By 1200 CST the winds had become southerly and
the urban air was advected to the north. The forward air parcel trajectories
(Figure 4.24) also show the same features. The urban air remained in the
Tulsa area and, following 1200, began to experience steady transport to the
north.
The solar radiation may also have had an important influence on the
ozone concentrations observed at the downwind stations. The maximum solar
radiation for the day was approximately 1.4 langleys per minute; however,
during the morning hours, until 1000 CST, the solar radiation was limited by
cloud cover. Therefore, the morning precursor emissions may have accumulated
under stagnant conditions and as northward transport began, the appearance
of the sun caused rapid photochemical ozone synthesis.
The 6-9 a.m. CDT average precursor concentrations listed in Table 4.4
were not greater than the August means at any of the measurement sites,
except for the sum of NMHC measured at the Post Office, which had a concen-
161
-------
tration as high as that of August 2. The percentage of hydrocarbons due to
vehicular emissions was low in that sample, however, which suggests that the
refinery complex may have contributed to that high concentration of NMHC.
A squall line was shown in the immediate Tulsa area on the 0700 EST
surface weather map for August 4 (Figure 4.21). There was 0.01 inch of
precipitation reported during hour 0800 at the Tulsa International Airport.
The synoptic trajectories for August 4 (Figure 4.22) show that steady south-
erly winds had advected air to Tulsa for approximately 24 hours prior to
both of the air parcel arrival times. The local trajectories (Figure 4.23)
indicate that the winds in and around Tulsa were southerly to southeasterly,
although during the hours surrounding the precipitation there were mostly
easterly winds measured in the network. The forward trajectories of the
urban air parcel (Figure 4.24) show the influence of easterly winds during
the morning hours, and the southerly winds beginning in the afternoon. The
solar radiation was relatively low during August 4 with a maximum of approx-
imately 1.1 langleys per minute, which occurred at 1400 GST.
The 6-9 a.m. CDT NMHC concentrations on August 4 at the Post Office and
Liberty Mounds were below the mean for August samples, but at the Health
Department the morning sample was near the August mean. The percentage of
the total NMHC due to vehicular emissions at the Post Office and Liberty
Mounds was near the August means as were the 6-9 CDT average NO concentra-
X
tions at those sites. At the Health Department, however, the percentage of
NMHC due to vehicular emissions and the 3-hour average NO were considerably
X
greater than the August means, implying that a strong traffic source in-
fluenced the Health Department. At the Post Office and Liberty Mounds
sites, however, increased emissions from traffic sources and industrial
sources were likely. The maximum network ozone on August 4 of 0.111 ppm
occurred at Wynona. The local trajectory showed the air parcel moving
directly over the southwest area of the city and on to Wynona. Therefore,
the ozone measured at Wynona on August 4 was likely a direct result of Tulsa
emissions.
On the 0700 EST surface weather map for August 5, a stationary front
was shown just west of Oklahoma (Figure 4.21). This front did not move into
the Tulsa area on August 5, but a large area of cloudiness ahead of the
162
-------
front caused the solar radiation to be low (less than 0.8 langleys per
minute) most of the day.
The synoptic-scale trajectories (Figure 4.22) show winds from the
southwest for approximately 24 hours preceding air parcel arrival in Tulsa
at both arrival times. The local scale backward trajectories also show
steady southerly winds in Tulsa (Figure 4.23), as do the forward urban air
parcel trajectories (Figure 4.24).
The concentrations of selected hydrocarbons and oxides of nitrogen
(Table 4.4) were less than the August average at the Post Office and near
the August average at Liberty Mounds. All of the hydrocarbon species from
the Health Department sample were lower than the average August values. At
each of the three stations, the 3-hour average NO concentration was near
the August mean. The maximum ozone concentration of the entire summer study
at Skiatook of 0.120 ppm was measured at 1400 on August 5. Inspection of
both sets of local trajectories implies that the refinery area may have
directly influenced the Skiatook site on August 5.
4.4.3 Analysis of August 2, 1977
A disorganized area of high pressure was over the eastern States on
the morning of August 2 (Figure 4.21b). Throughout the day a frontal area
remained stationary along the Gulf Coast. This front also caused other
synoptic systems to stall, and the weather in Tulsa on August 2 was not
directly influenced by any major synoptic influences. There were sunny
skies most of the day and light variable winds as shown by both the synoptic-
scale trajectories (Figure 4.22) and the forward urban air parcel trajec-
tories (Figure 4.24a). The concentrations of ozone precursors measured at
the urban sites and at Liberty Mounds on August 2 were considerably higher
than the average concentrations during August. The ozone concentrations
increased to values above 0.08 ppm by midday at each station except Ochelata.
The ozone concentrations measured before the midafternoon hours are assumed
to have been generated as a result of plentiful sunlight (1.5 langleys per
minute at hour 1200), and the lack of large-scale air parcel advection. The
maximum daily ozone concentrations at each of the monitoring stations except
the Health Department, Sperry, and Ochelata sites occurred at or after hour
163
-------
1500. The ozone data after hour 1400 were missing at Ochelata, and at the
Health Department and Sperry the ozone concentrations rose to secondary
peaks after 1500. The maximum ozone in the network of 0.117 ppm occurred at
hour 1800 at Liberty Mounds. Throughout the network the winds were from the
south during the late afternoon hours. Tulsa International Airport reported
cumulonimbus clouds to the south late in the day. Since the late afternoon
increase in the ozone concentrations was network-wide, it is likely that the
ozone was brought to the surface by the downdrafts of large cumulonimbus
clouds from mid-tropospheric altitudes. Data from the 1800 CST Oklahoma
City rawinsonde indicate that there were variations in wind direction with
height: 190° at 392 m (1286 ft); 97° at 762 m (2500 ft); 349° at 2298 m
(7537 ft). Due to the possible influence of ozone downdrafting, the net
ozone production as a result of Tulsa emissions was not calculated for this
day. The cloud activity was south of Tulsa and the greatest increase in the
ozone concentration occurred at the southern site, Liberty Mounds. The
southerly winds could have pushed the ozone-rich air into and north, of the
urban area causing some dilution. Urban NO emissions could also have served
to deplete the ozone concentrations at the stations in and north of the
city.
4.4.4 Analysis of August 3, 1977
A stationary front remained near the Gulf Coast through August 3, and
a ridge of high pressure developed east of Oklahoma. High pressure and the
continued stagnation of synoptic systems due to the stalled front caused
stagnant conditions in Tulsa. The synoptic trajectories showed very little
motion of air in or around Tulsa. The sky was overcast during the morning
and did not clear until hour 1000. In addition, southerly winds were estab-
lished late in the morning as shown by both the local back trajectories
(Figure 4.23) and the forward urban air parcel trajectories (Figure 4.24b).
The urban air parcel in which the maximum ozone concentrations were
measured remained in the urban area until hour 1300 (Figure 4.23). There-
fore, urban emissions of precursor species throughout the morning may have
been available for ozone production on August 3. The solar radiation strength-
ened and northward transport began at approximately the same time. The
164
-------
conditions of accumulated ozone precursors and sudden availability of strong
sunshine produced a situation very favorable to ozone production.
The maximum ozone concentrations of the entire summer at Sperry, Vera,
and Ochelata were measured on August 3. At Sperry the maximum ozone concen-
tration of 0.135 ppm occurred during hour 1300, and at Vera and Ochelata
maximum ozone concentrations of 0.151 and 0.117 ppm, respectively, occurred
during hour 1400. The maximum ozone concentration of 0.151 ppm at Vera was
the highest hourly average ozone concentration measured in the network
during the entire summer.
The background ozone concentration determined by averaging the 1000 and
1100 ozone concentrations was 0.093 ppm at Liberty Mounds. It is likely
that this relatively high background ozone concentration resulted from
several days of ozone synthesis within the stagnated air mass. It is again
assumed that this background ozone concentration was similar at all of the
network stations, although the reliability of this estimated background
influence could not be determined because ozone measurements above the
height of the nocturnal inversion were not available. During the late
morning hours, the ozone concentrations at Liberty Mounds were changing
rapidly. The fact that the ozone concentrations increased throughout the
morning at Liberty Mounds until the daily maximum of 0.103 ppm, which was
measured at 1200 CST, also raises questions about the reliability of using
Liberty Mounds data as an estimate of the background ozone concentration.
The Wynona site appears to be more like a background site on this date and
an average of 0.076 ppm ozone occurs during hours 1000 and 1100. The maximum
network ozone concentration on August 3, which was also the maximum ozone
concentration of the entire summer study, was 0.151 ppm and was measured at
1400 at Vera. The difference between the maximum observed ozone concentra-
tion at Vera and the estimated Wynona background concentration is 0.075 ppm
and is assumed to represent the net ozone production caused by Tulsa emis-
sions on August 3. The data suggest that the maximum ozone concentration
measured downwind of Tulsa during the summer of 1977 was produced by the
combination of a large background contribution and conditions that were
favorable, both meteorologically and chemically, for ozone synthesis.
165
-------
4.4.5 Analysis of August 4, 1977
On August 4 the stationary front that had held up synoptic movement in
the mid-United States was no longer present. High pressure centered over
the Atlantic Ocean off the North Carolina coast controlled the weather in
Tulsa. There were, however, small local systems that influenced Tulsa,
notably a squall line that gave cloudy skies throughout the day and 0.01
inch of precipitation during hour 0800. The synoptic-scale trajectories
(Figure 4.22) indicate that southerly winds were present in Tulsa during
August 4, and the local trajectories (Figure 4.23) indicate a steady south-
east windfield in Tulsa. The forward urban air parcel trajectories (Figure
4.24c) show air movement to the west during the morning, followed by norther-
ly transport during the afternoon.
Increasing ozone concentrations were measured during the night of
August 3 at each station in the network. These nocturnal ozone increases
were more prevalent at the stations north of Tulsa than in the city or at
Liberty Mounds. The squall line in its development and movement could have
set up a disturbance that allowed ozone to be mixed down to surface from
above the nocturnal inversion, causing this network-wide ozone increase.
The maximum network ozone concentration on August 4 of 0.111 ppm was
measured at Wynona during hour 1300. The local back trajectories (Figure
4.23) indicate that the air in which this ozone was measured had originated
from the urban area approximately 2 hours earlier. While the maximum ozone
concentration north of Tulsa most often occurred at Vera, the steady south-
easterly winds on August 4 caused the Tulsa emissions to be transported to
Wynona, and Vera was influenced by rural air.
The net ozone production can be estimated for August 4 by assuming that
the network maximum ozone concentration of 0.111 ppm observed at Wynona
approximated the maximum ozone concentration in the Tulsa urban plume. As
before, the average of the 1000 and 1100 ozone concentrations at Liberty
Mounds, 0.076 ppm, was considered to represent the background influence on
Tulsa. The difference between the maximum ozone concentration and the
background ozone concentration of 0.035 ppm is assumed to be the net ozone
production of Tulsa on August 4. Because the morning precursor concentra-
166
-------
tions were not abnormally low, it is assumed that the low availability of
sunlight was primarily responsible for the low amount of ozone produced by
Tulsa on August 4.
4.4.6 Analysis of August 5, 1977
On August 5 the weather in Tulsa was dominated by the large high-pressure
area off the coast and by a cold front northwest of Tulsa. The front never
reached Tulsa, but a low-pressure trough west of Tulsa that took on frontal
characteristics did produce overcast and cloudy conditions in Tulsa. The
winds were southerly and, for the first time during this case study, steady
regional-scale transport was indicated by the synoptic-scale trajectories
(Figure 4.22). Strong southerly winds were also indicated by the local
trajectories. Lower than normal morning concentrations of both acetylene
and n-butane were measured at the Post Office and Health Department sites.
The total NMHC was considerably below the average value for August at the
Health Department; the sample was not complete at the Post Office.
Liberty Mounds once again measured a very high maximum ozone concen-
tration of 0.106 ppm, which could not be attributed to Tulsa emissions
because southerly winds were present all day. The maximum ozone in the
network of 0.120 ppm was measured at Skiatook at 1400. This was also the
maximum ozone concentration of the summer at Skiatook.
The cause of the high ozone at Skiatook on August 5 cannot be explained
from the available data because the local trajectories do not indicate a
direct influence of Tulsa on the Skiatook station. The ozone concentrations
at Skiatook and Wynona, however, were greater than at the other stations
north of Tulsa. It is possible, therefore, that there was a nearly constant
contribution of ozone at each station north of Tulsa that perhaps resulted
from transport from Oklahoma City. It is possible that NO emissions from
Tulsa depleted the ozone measured at Sperry, Vera, and Ochelata relative to
Skiatook and Wynona. The lack of strong sunshine may have caused a situation
that led to very little ozone synthesis north of Tulsa, and the net effect
of Tulsa on August 5 was to remove ozone via titration reactions.
167
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4.5 SEPTEMBER 2 AND 3, 1977: CASE STUDY
4.5.1 Introduction
The dates September 2 and 3 (a Friday and Saturday) were chosen for
study because (1) the flow of air was consistently from the south on both
days causing transport of urban air northward, (2) high concentrations of
ozone (>0.08 ppm) were measured at several of the sites in the monitoring
network, and (3) meteorological and pollutant measurements aloft were avail-
able.
Figures and tables summarizing the meteorological and chemical data for
this case study period are presented below. Figures 4.29a through 4.29d are
the National Weather Service 0700 EST surface weather maps for the United
States for September 1 through September 4. Figures 4.30 and 4.31 show the
synoptic and local (mesoscale) backward air parcel trajectories for the case
study days. Figures 4.32a and 4.32b show the forward trajectories of the
urban air parcel at selected times on September 2 and 3, respectively.
Figure 4.33 represents the diurnal variation of temperature for the two
days, and Figure 4.34 shows the daily variation in incident solar radiation.
Figure 4.35 illustrates the diurnal profiles for NO and N02 at the two city
sites and Figure 4.36 illustrates the diurnal profiles for ozone for each
site in the network.
Selected data from the aircraft flights are also presented. Figures
4.37 and 4.38 show the flight track for the morning and afternoon opera-
tions. Figure 4.39 shows the data from the morning spiral at Liberty Mounds
on September 2. Ozone data taken during the horizontal traverses of the
morning flight are plotted in Figure 4.40. The data collected during the
vertical spiral above the central business district are shown in Figure
4.41. Data from the horizontal traverses on the afternoon flight for ozone
are illustrated in Figure 4.42. Finally, the afternoon spiral data are
shown in Figure 4.43. Similar depictions for the morning and afternoon
flights of September 3 are presented in Figures 4.44 through 4.48.
Values for the individual hours of data for meteorological and chemical
parameters are not reported here but can be found in Volume II of this
report.
168
-------
Figures 4.29a and 4.29b.
United States surface weather maps for
September I and September 2, 1977.
169
-------
1
2L>Wg3»--33^
o&^'^i;
Figures 4.29c and 4.29d.
United States surface weather maps for
September 3 and September 4, 1977.
170
-------
SEPT 1
flRRIVING TRflJECTORIES
D 0600 CST
+ 1600 CST SEPT 2
SEPT 3
RRRIVTNG TRflJECTORIES
D 0600 CST __DT
+ 1600 CST SEPT
Figure 4.30. Synoptic scale trajectories for case study period September
2-3, 1977.
171
-------
WYN
K
50
SEPT 2
IfOO
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X
65
SEPT 3
1300
Figure 4.31. Mesoscale trajectories for case study period September 2-3, 1977,
172
-------
SEPT 2
6
LIB
X
SEPT 2
12
LIB
X
SEPT 2
1C
LB
X
Figure 4.32a. Forward air parcel trajectories for September 2, 1977.
173
-------
SEPT 3
6
IEPT3
LB
SEPT 3
12
SEPT 3
IS
LI?
X
Figure 4.32b. Forward air parcel trajectories for September 3, 1977.
174
-------
35.0
34.0
33.0
32.0
31.0
30.0
TULSfl INT. flIRPORT TEMP. SEPTEMBER 2&3
95.0
90.0
85.0
m
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75.0
70.0
0000
1200
0000
TIME (CST)
1200
0000
65.0
Figure 4033. Diurnal variation of temperature for the period September 2-3, 1977,
C/J
>-
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SKIflTOOK SOLflR RRDIflTION SEPTEMBER 2 & 3
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CO
m
0000
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0000
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1200
0000
0.00
Figure 4.34. Diurnal variation of solar radiation for the period September 2-3,
1977.
175
-------
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Horizontal Traverse, Ozone Concentration.
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4.5.2 General Description of the Case Study
The major synoptic influence on the Tulsa area on September 2 was a
high-pressure area that was centered over western Virginia (Figure 4.29).
The synoptic trajectories for both arrival times on September 2 (Figure 4.30)
show that there had been rapid transport from southern Alabama during the
48 hours preceding air parcel arrival in Tulsa. During the last 12 hours of
both the 0600 and 1600 trajectories, air flow from due south was indicated.
The local (mesoscale) back trajectories, shown in Figure 4.31, also show
steady southerly winds to have been affecting the Tulsa area. The forward
trajectories of the urban air parcel (Figure 4.32) also indicate transport
of the urban air to the north until 1500 GST. The trajectory calculated for
air leaving Tulsa at 1500 shows transport to the northwest. The solar
radiation reached a maximum of approximately 1.4 langleys per minute at 1100
and, although the profile was not completely symmetric, there were no exten-
sive periods of cloud cover indicated.
The 6-9 a.m. CDT average concentrations of selected hydrocarbons,
oxides of nitrogen, and selected ratios at the Post Office, Health Depart-
ment, and Liberty Mounds are listed in Table 4.5. The monthly means and
standard deviations of the same parameters are listed in Table 4.1. On
September 2 the sum of NMHC at all three stations was greater than the
monthly means. The total NO concentrations were also greater than the ,
monthly means. At the Post Office the percentage of the total NMHC due to
vehicular emissions was equal to the September mean, implying that contri-
butions from automobile emissions and from industrial emissions were elevated
during the morning. At the Health Department the percentage of NMHC due to
vehicular emissions was 99 percent indicating that there was a large contri-
bution to NMHC concentrations from vehicular emissions. The concentrations
of NO that were measured during the 3-hour 6-9 a.m. CDT averaging period
A
were also higher than the averages at each of the three stations. This may
also have resulted from increased NO emissions from vehicular sources.
x
On the 0700 EST surface weather map for September 3 (Figure 4.29), a
frontal system that had been approaching Oklahoma as a cold front stalled in
mid-Kansas. Although the high-pressure center weakened, it was still the
major synoptic influence on Tulsa on September 3. The synoptic-scale trajec-
191
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tories for September 3 (Figure 4.30) indicate very similar motion to that of
September 2, for both arrival times. The wind speeds, however, are consider-
ably less on the September 3 trajectories than on the September 2 trajectories,
The local trajectories (Figure 4.31) are also nearly the same as those of
September 2 and indicate steady northward transport until 1300. The forward
trajectories of the urban air parcel (Figure 4.32) show slow northward
transport of the urban air leaving Tulsa at 0600 and 0900 CST. The forward
trajectories for departure times of 1200 and 1500, however, show slow trans-
port of the urban air to the northwest. The solar radiation measured at
Skiatook on September 3 showed a sharp decrease in solar radiation after
1200 CST.
The concentrations of NMHC measured at the Post Office and Health
Department during the 6-9 a.m. CDT averaging period were considerably less
on September 3, a Saturday, than they were on September 2 (Table 4.5). In
addition, the percentage of the total NMHC due to vehicular emissions also
decreased considerably on September 3 as did the 3-hour NO average concen-
X
trations. At Liberty Mounds, however, there was 0.619 ppmC of NMHC measured
during the 6-9 a.m. CDT period, which was nearly three times the September
mean. The percentage of that NMHC concentration due to vehicular emissions
was 5 percent, the same as on September 2, and considerably lower than the
September mean of 20 percent. The NO concentrations measured during that
X
3-hour period were also increased over those measured on September 2 and
were nearly four times the September mean. The increases in NMHC and NO on
September 3 at Liberty Mounds are assumed to have been caused by some indus-
trial source.
On both September 2 and 3, aircraft measurements of 03, NO/NO , CN,
X
b , temperature, and dewpoint were made upwind of Tulsa in the morning
scat
and downwind of Tulsa during the afternoon. These data describe the hori-
zontal distribution at approximately 2,500 ft MSL and the vertical profiles
at selected locations of the parameters measured. A complete description of
the aircraft flight protocol and measurement system is given in Volume I of
this report.
The flight tracks followed on the morning and afternoon flights on both
September 2 and 3 are shown in Figures 4.37 and 4.38. On both days a stable
193
-------
layer was observed near the surface during the Liberty Mounds spiral that
extended up to an altitude of 2,000 ft MSL. A 1,000- or 2,000-ft thick
layer that had high ozone concentrations relative to the rest of the spiral
ozone data was observed on both days immediately above the stable surface
layer. On September 2 the maximum ozone concentration of approximately
0.080 ppm was measured in the high ozone layer at approximately 2,000 ft MSL
(Figure 4.39). The background ozone concentration, which was assumed to be
the average ozone concentration above the layer of high ozone, was approxi-
mately 0.05 ppm. A background ozone concentration of approximately 0.065
ppm was measured on each horizontal traverse of the morning flight (Figure
4.40) at 2,500 ft MSL. Another vertical spiral flown at the end of the
flight over the central business district of Tulsa measured a background
ozone concentration above 3,000 ft MSL that was very similar to that measured
at Liberty Mounds. Although 2,600 ft was the lowest altitude at which
measurements were made on the second spiral, the layer of ozone was also
apparent (Figure 4.41).
The ozone data from the horizontal traverses on the afternoon flight
clearly show an ozone plume extending to the north of Tulsa (Figure 4.42).
The maximum ozone concentration of 0.156 ppm was measured on the last hori-
zontal traverse approximately 40 miles downwind of Tulsa. The approximate
average ozone concentration outside of the plume area was 0.08 ppm. The
data from a vertical spiral flown near the center of the plume (Figure 4.43)
clearly show that ozone concentrations in the lowest 5,000 ft MSL were
greater than those measured on the remainder of the spiral.
On the vertical spiral over Liberty Mounds on September 3, the maximum
ozone concentration was approximately 0.08 ppm at approximately 2,800 ft MSL
(Figure 4.44). The average background ozone concentration above the high
ozone layer was 0.07 ppm, which made the ozone layer less evident than that
measured on September 2. The average background ozone concentration measured
on the horizontal traverses of the morning flight was 0.08 (Figure 4.45),
which was also increased over that measured on September 2. The vertical
profile of ozone measured over the central business district on September 3
(Figure 4.46) shows a background of approximately 0.075 ppm. The ozone data
from the horizontal traverses of the afternoon flight on September 3 (Figure
194
-------
4.47) clearly show an ozone plume similar to the ozone plume measured on
September 2. The maximum ozone concentration measured in the plume of
0.207 ppm occurred on the second horizontal traverse approximately 20 miles
downwind of Tulsa. A vertical spiral was flown near the center of the plume
on September 3 and, as on September 2, the ozone data indicate that the
surface was the source of the plume ozone (Figure 4.48).
4.5.3 Analysis of September 2, 1977
High pressure centered over the mountainous areas of North Carolina,
Virginia, and West Virginia controlled the weather in Oklahoma on September 2,
The 0700 EST surface weather map for September 2 (Figure 4.29b) shows that
there was a strong cold front approaching Oklahoma from the northwest.
However, this cold front was prevented from moving through Oklahoma by the
high-pressure system. The front stalled through the center of Kansas and
never affected the Tulsa area. The influence of the high-pressure area
resulted in steady winds through Oklahoma from the south and southeast. The
wind flow brought warm moist air into the Tulsa area, and the lack of any
other influences kept the skies mostly clear. Clouds that did develop over
Tulsa on September 2 were mostly high-altitude cirrus clouds.
The synoptic trajectories for September 2 (Figure 4.30) clearly show
the anticyclonic motion produced by the high pressure. The trajectories
imply that air arriving in Tulsa had originated in the southern areas of
Mississippi and Alabama approximately 36 hours earlier. The winds during
the last 12 hours of both the 0600 and 1600 CST trajectories were from the
south.
The local (mesoscale) trajectories show southerly winds throughout the
day in the Tulsa area. The early hours of the trajectory, 0800 and 0900 in
particular, indicate that near calm conditions were present, but after 1100
the wind speeds were above 10 mph. The Oklahoma City rawinsonde release for
0600 CST measured southerly winds from the surface to 1,500 m MSL. The 1800
CST rawinsonde release measured southerly to southeasterly winds from the
surface to 1,500 m MSL.
There were morning peaks in NO and N02 at both the Health Department
and Post Office monitoring stations; however, the peaks at the Health Depart-
195
-------
ment were more clearly associated with morning traffic (Figure 4.35). These
peaks were the result of the buildup of pollutant concentrations due to low
wind speeds that were present during the early morning hours. The fact that
the peaks were more variable and persistent at the Post Office site is
probably due to the influence of sources in addition to the morning traffic.
At 0900, when the windspeeds increased, both NO and N02 decreased at the
Health Department. At the Post Office site the NO and N02 concentrations
did not decrease until after 1200. Sites to the north of Tulsa also showed
the influence of urban oxides of nitrogen. Sperry recorded the highest
value of NO for the network (0.100 ppm) during hour 0600. The highest value
for N02 at Sperry (0.027 ppm) occurred during hour 0800. A small increase
in both NO and N02 was noted at the Vera site during hours 0900 and 1000.
There was no change in oxides of nitrogen concentration evident at the other
northern sites; values remained at or near background levels of 0.004 to
0.005 ppm.
On September 2, three sets of hydrocarbon grab samples were taken at
the surface sites. Selected values from the morning and afternoon samples
are given in Table 4.6. The 0500 to 0800 samples show a strong gradient of
increasing acetylene, n-butane, propylene, and sum of hydrocarbons from
upwind to downwind of the city. The Health Department had (based on an
acetylene factor of 15.5) the highest percentage of hydrocarbons attributed
to vehicular tailpipe emissions. The Sperry site, which is immediately
north of the city, had the highest overall hydrocarbon sum, yet only 38
percent is attributed to tailpipe emissions. The Sperry sample contained a
high percentage of low molecular weight alkanes (such as n-butane), which
had slowly drifted northward from the oil refining production and storage
facilities. The midmorning, 0800 to 1100 CST samples showed decreases in
acetylene concentrations at all sites except Liberty Mounds, which increased
slightly. At the Post Office, high concentrations of low molecular weight
hydrocarbons (e.g., n-butane) were measured. Wind directions during this
time were out of the south to southwest and high concentrations of low
molecular weight alkanes were probably a result of emissions from the petro-
chemical complex. By midafternoon, the total NMHC measured at all of the
northern sites was quite low. Acetylene (an indicator of tailpipe emissions)
196
-------
TABLE 4.6. SEPTEMBER 2 HYDROCARBON SAMPLES, ppbC
(05 to 08 CST)
Acetylene
n-Butane
Propylene
Sum
% Tailpipe emissions
(08 to 11 CST)
Acetylene
n-Butane
Propylene
Sum
% Tailpipe emissions
(13 to 16 CST)
Acetylene
n-Butane
Propylene
Sum
% Tailpipe emissions
Liberty
Mounds
1.0
36.0
2.0
303
5.1
2.4
22.4
0.0
350
11
Sperry
6.4
15.6
3.6
175
57
Health
Department
25.0
40.4
12.6
393
99
6.6
21.6
4.0
349 1,
29
Vera Ochelata
2.4 1.2
9.2 10.8
3.3 0.6
150 149
25 12
Post
Office
30.0
60.4
14.4
640 1
73
14.6
218.8
19.2
199
19
Skiatook
1.0
9.6
2.4
186
8
Sperry
34.4
196
18.9
,412
38
9.0
56.8
5.1
313
44
Wynona
0.4
6.0
0.0
40
15
was present at all sites, but decreased substantially at sites farther north
of the city. The concentration of compounds such as propylene, which are
very photochemically active, were also low compared to the concentrations
during the morning in the city. There are three factors that probably
contributed to the low concentrations in the afternoon samples: decreased
automobile traffic during the afternoon; larger mixing volume causing more
dilution than in the early morning; and removal by reaction.
With the steady southerly winds on September 2, Liberty Mounds repre-
sented the background, upwind station. At 0600 the Liberty Mounds ozone
concentration was only 0.008 ppm. There was a rapid rise following 0700
CST, however, and by 0900 the concentration was very near that day's maximum
value of 0.056 ppm (Figure 4.36). Once the ozone concentration reached
197
-------
approximately 0.050 ppm, it remained very stable until 1800 GST. The same
is true for the Health Department and Post Office ozone data. The fact that
relatively low daily maximum concentrations were attained early in the
morning and that concentrations near the maximum level were maintained
during the photochemically active portion of the day suggests that the
primary source of the ozone measured at Liberty Mounds, the Health Depart-
ment, and the Post Office sites on September 2 was downward mixing of air
that had been isolated above the radiation inversion. Investigation of the
aircraft data (Figures 4.39 and 4.40) reveals that during the September 2
morning spiral at Liberty Mounds, approximately 0.050 ppm of ozone was
measured at an altitude of 1,100 ft MSL. An overall ozone background con-
centration based on both the vertical spiral and the horizontal legs of the
morning flight was approximately 0.060 ppm.
During September 2, the northern sites were under the influence of
steady southerly winds from approximately 0900 through the remainder of the
day. At Sperry and Vera the concentration of ozone also rose sharply during
the early morning as it had at the southern site. However, the concentra-
tions continued to rise and reached a daily maximum at hour 1200. At both
Sperry and Vera the maximum hourly ozone concentration was 0.094 ppm. At
Ochelata the ozone diurnal pattern was very similar to that of the upwind
station until hour 1200. A rapid increase early in the morning was followed
by 4 hours of stable ozone concentrations of about 0.055 ppm. However, the
1300 ozone concentration increased substantially, and the daily maximum of
0.108 ppm was reached at 1400 CST. The local trajectories for September 2
indicate that an air mass left Tulsa at approximately 1100 hours, was in the
vicinity of Vera between 1200 and 1300, and arrived at Ochelata at hour
1400.
Concentration/distance plots are shown in Figure 4.49. During the
times illustrated, the wind direction across the network was from the south.
The 0900 plot shows a fairly uniform background ozone concentration over the
entire monitoring network. The plots for hours 1100, 1200, 1300, and 1400
show the plume movement north to Ochelata. These data all support the
concept of ozone formation and transport at the surface from Tulsa to the
north.
198
-------
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Figure 4.49.
Ozone concentration/distance plots for morning of
September 2, 1977.
199
-------
The afternoon aircraft data in Figure 4.42 also show an ozone plume
leaving Tulsa at 2,500 ft MSL. The data on the horizontal legs of the
afternoon flight were collected between 1230 and 1400 CST. The highest
concentrations were measured on legs 5 and 7 between approximately 1320 and
1400 CST. Leg 5 was flown slightly south of Ochelata and leg 7 was flown
approximately 8 miles north of Ochelata. These data indicate that the
downwind transport of urban ozone occurred both at the surface and at an
elevation of 2,500 ft. The afternoon vertical spiral indicates that ozone
was mixed on September 2 up to approximately 5,000 ft MSL. This suggests
that the ozone plume existed continuously in the vertical up to altitudes of
5,000 ft MSL.
At both Skiatook and Wynona, rapidly increasing ozone concentrations
were measured early in the day that were similar to the increase in ozone
concentration measured at Liberty Mounds. Both stations measured increasing
ozone concentrations that stabilized at approximately 0.055 at 1000 CST.
Later in the day, however, sharp increases in the ozone concentration were
measured at both Skiatook and Wynona. A maximum hourly average ozone con-
centration of 0.080 ppm was measured at Skiatook at 1500 CST. At Wynona, a
maximum ozone concentration of 0.082 ppm was measured at 1700 CST. The
concentration/distance plots for hours 1500, 1600, 1700, and 1800 are shown
in Figure 4.50. These plots show the substantial increase in ozone at
Skiatook and Wynona during hours when ozone was on the decline at other
sites. This behavior is likely a direct consequence of a wind shift from a
direction of 170° (during hours 1300 and 1400) to 130° and 150° (during
hours 1500 and 1600) that altered the path of the urban ozone plume.
In summary, a large urban ozone plume began to form by 1000 and was
transported north of Tulsa. The plume height extended from the surface up
to at least 2,500 ft MSL. The presence of the plume was noted at the Ochelata
site up until hour 1400. After this hour, the surface winds shifted from
southerly to southeasterly and carried the ozone plume to the northeast
sites of Skiatook and Wynona. In the absence of the wind shift, it is very
likely that ozone data from both Skiatook and Wynona would have shown a
diurnal ozone pattern very similar to that of Liberty Mounds.
200
-------
J6
.14
J2
.10
.08
.06
.04
.02
i"
Q.
Z -'6
O
M .14
O
.12
JO
.08
.06
.04
.02
.00
- 1500
-
-
-
.''>k-vvX>A
^ *-*
°
-
-
~ 1700
-
-
X
0
-
- 1600
-
-
-
-
^^0^^^**
0
-
-
" 1800
-
-
-"^^^-^tz^*"
*
-
X. MOUNDS SKIATOOK
0 POST OFFICE A VERA
HEALTH DEPARTMENT A OCHELATA
Q SPERRY * WYNONA
Figure 4.50. Ozone concentration/distance plots for the afternoon of
September 2, 1977.
201
-------
The presence of southerly winds and good solar radiation again offers
the possibility of estimating the net ozone formation of the Tulsa area.
The average ozone concentration during hours 1000 and 1100 CST at Liberty
Mounds of 0.055 ppm is assumed to be the background ozone concentration
affecting the Tulsa area. The maximum downwind ozone concentration of 0.105
measured at 1400 CST at Ochelata is assumed to represent the maximum ozone
concentration within the urban plume. The difference between these two
measurements of 0.050 ppm is then an estimate of the net ozone formation
resulting from Tulsa emissions on September 2 at the surface. Because there
was an aircraft flight on September 2 that showed an apparent ozone plume
leaving Tulsa, the net ozone formation as a result of Tulsa emissions at
2,500 ft can also be estimated. The maximum ozone concentration measured on
the aircraft during the afternoon was 0.156 ppm. It is assumed that, the
true impact of Tulsa emissions was confined to the area included in the
plume itself and, therefore, the average concentration outside the plume on
the afternoon flight was used to represent the background ozone concentration
at 2,500 ft MSL. On September 2 this downwind afternoon background ozone
concentration was 0.078 ppm. The difference between the maximum and the
average background ozone concentrations of 0.078 ppm is an estimate of the
net ozone formation of Tulsa at 2,500 ft MSL.
4.5.4 Analysis of September 3, 1977
By 0700 EST on September 3, the high-pressure center that was over
western North Carolina and Virginia on September 2 had weakened (Figure
4.29c). The Oklahoma area, however, was still influenced by anticyclonic
circulation and south and southeast winds were measured in the Tulsa area.
The synoptic trajectories shown in Figure 4.30 indicate directional motion
on September 3 similar to that of September 2 but with slower wind speeds.
The local-scale trajectories show southerly winds in Tulsa on September 3
(Figure 4.31). There were calm conditions indicated during hours 0700 and
0800. The skies remained mostly clear during the morning but solar radia-
tion was depleted during the afternoon (Figure 4.34).
Since September 3 was a Saturday there was not a clear traffic peak of
NO or N02 at either the Post Office or Health Department sites. There were
202
-------
relatively high concentrations of NO and N02 throughout the morning hours at
the Health Department and, as expected, very low ozone concentrations accom-
panied these high concentrations. At the Post Office site, NO and N02
concentrations were greater during the middle of the day than at any other
time.
On September 3, three sets of hydrocarbon grab samples were taken at
the surface sites. Selected values from the morning and afternoon samples
are given in Table 4.7. As was true on September 2, a gradient of increasing
acetylene, n-butane, propylene, and sum of hydrocarbons from upwind to down-
wind sites was present on September 3. Generally, however, the concentra-
tions of species were lower on Saturday, September 3, than they were on
Friday, September 2. Exceptions to this statement were the 0500 to 0800
samples at Liberty Mounds, which may have measured some industrial emissions
of Tulsa because of early morning northerly winds. At Sperry, large amounts
of low molecular weight alkanes were measured during the 6-9 CDT measurement
period. The percentage of sample attributable to vehicular tailpipe emis-
sions was also less in the early morning Saturday samples. The afternoon
samples taken at northern sites showed concentrations much lower than those
of morning samples. This was expected due to increased afternoon dilution.
At Liberty Mounds on the morning of September 3, the ozone concentra-
tion fell to zero at 0500 CST suggesting that a source of ozone-destructive
material was affecting the area. The third highest 0500 to 0800 CST average
NO (0.018 ppm) of all days at Liberty Mounds was measured on September 3.
A
In addition, the NO concentrations of hours 0300, 0400, and 0500 were
X
unusually high for Liberty Mounds. A northwesterly wind of 2 mph was meas-
ured at Liberty Mounds during the hours of 0400 and 0500 and perhaps air was
brought in from urban areas, causing the drop in ozone at Liberty Mounds.
By 0900 southerly winds were established, and the 0800 to 1100 CST
hydrocarbon and NO concentrations at Liberty Mounds were more in line with
X
average values. The persistence of southerly flow after 0900 caused Liberty
Mounds to experience background conditions. The ozone concentration rose
quickly to 0.063 ppm by hour 1000, then remained steady with average values
between 0.060 ppm and 0.065 ppm until late in the afternoon.
203
-------
TABLE 4.7. SEPTEMBER 3 HYDROCARBON SAMPLES, ppbC
(05 to 08 CST)
Acetylene
n-Butane
Propylene
Sum
% Tailpipe emissions
(08 to 11 CST)
Acetylene
n-Butane
Propylene
Sum
% Tailpipe emissions
Liberty
Mounds
2.0
63.6
2.6
620
5
3.6
24.4
4.8
173
32
Health
Department
11.0
26.4
4.8
285
60
6.6
25.2
1.8
216
47
Post
Office
12.0
40.0
6.3
367
51
8.2
146.4
10.8
687
18
Sperry
25.6
412.8
15.0
3,078
13
17.4
131.2
10.2
842
32
Sperry
Vera
Ochelata
Skiatook
Wynona
(13 to 16 CST)
Acetylene
n-Butane
Propylene
Sum
% Tailpipe emissions
5.2
21.2
0.0
150
54
1.0
8.4
3.6
107
14
1.0
7.6
16.2
12}
13
2.0
9.2
0.0
91
34
At the Post Office site the ozone concentrations averaged approximately
0.065 ppm throughout the day except for a decrease during hours 1300 and
1400. This decrease was accompanied by increases in both NO arid N0;>. At
the Health Department site the concentrations of ozone averaged approximately
0.075 ppin throughout the day. The slightly slower winds of September 3 may
have allowed sufficient time for production of ozone in excess of the de-
crease caused by NO titration of ozone. This would explain why the average
ozone concentration was slightly higher in the city than at Liberty Mounds
on September 3. The background ozone concentration at Liberty Mounds on
September 3 was only slightly greater than the background measured on Septem-
ber 2. The background ozone concentration at 2,500 ft MSL obtained during
the morning aircraft flight of September 3 was also higher than the background
measured aloft on September 2 by approximately 0.02 ppm.
204
-------
The diurnal ozone profiles for Liberty Mounds, the Post Office, and the
Health Department sites for September 3 are very similar to those of Septem-
ber 2. The rapidly increasing ozone concentrations between 0700 and 0900,
followed by steady concentrations, imply that these stations were measuring
predominantly background concentrations present in air that was mixed down
to the surface from above the radiation inversion.
The morning background ozone concentration measured by the aircraft
during the September 3 spiral at Liberty Mounds was approximately 0.070 ppm
(Figure 4.44). At an altitude of 3,700 ft there was a maximum ozone concen-
tration of about 0.08 ppm on the vertical spiral. A maximum ozone concen-
tration of approximately 0.080 ppm, at nearly the same altitude, had also
been measured during the Liberty Mounds spiral of September 2. However, the
background on September 2 was only about 0.050 ppm and the maximum at 2,800
ft appeared to be part of a layer. With the increased background on Septem-
ber 3, the ozone and maximum at 2,700 ft does not appear as a distinct layer
as it did on September 2. The background ozone concentration at 2,500 ft on
September 3, as measured on the horizontal legs of the morning flight (Fig-
ure 4.45), was approximately 0.080 ppm. It is evident that the background
ozone concentrations aloft were greater on September 3 than on September 2.
The afternoon flight of September 2 had shown concentrations of ozone of
approximately 0.080 ppm on those parts of the horizontal legs that were
clearly outside of the urban plume. These findings suggest that ozone at
concentrations as high as 0.08 ppm may have persisted at altitudes of 2,500 ft
throughout the night of September 2.
At each of the downwind stations, ozone concentrations increased rapidly
after hour 0700 until 1000. By 1000, the ozone concentration at Sperry and
Vera was approximately 0.030 ppm higher than the background concentration
measured at the upwind station. The concentrations stabilized somewhat soon
after hour 1000; the maxima for the day was not measured until 1300 at
either Sperry or Vera. At Ochelata the ozone concentration attained by 1000
was only slightly greater than the background site concentration at the same
hour; maximum for the day (0.093 ppm) occurred at 1500. As was the case on
September 2, the maximum concentration at Ochelata was measured 2 hours
later than at Sperry or Vera. The maximum hourly average ozone concentra-
205
-------
tion at Sperry was 0.116; at Vera, 0.126 ppm. These data imply that the full
impact of Tulsa emissions on ozone formation was not observed at Ochelata on
September 3. This is possibly due to the presence of slower wind speeds or
to the midafternoon wind shift, which may have kept the highest ozone concen-
trations of the Tulsa plume from reaching Ochelata.
The concentration/distance plots shown in Figure 4.51 best show the
behavior of the plume ozone after hour 1300. The ozone distribution, at hour
1400 indicates that Sperry and Vera were measuring the Tulsa plume and all
other stations were measuring concentrations near the background. A wind
shift from the south to the southeast occurred at hour 1400 and continued
for several hours. The ozone concentrations measured at Sperry and Vera
began to decrease, while at Skiatook and Wynona an increase in ozone con-
centration occurred during hour 1500. The winds continued to shift around
to the east and the ozone at Wynona increased to a maximum of 0.098 ppm by
1700. Both Skiatook and Wynona measured daily maximum ozone concentrations
late in the afternoon after the wind had shifted.
The aircraft data again showed a very well defined afternoon ozone
plume to the north of Tulsa (Figure 4.47). The maximum ozone concentration
measured during this flight was 0.207 ppm on leg 3 at a distance approxi-
mately 20 miles north of the center of Tulsa. That flight leg occurred
between approximately 1302 and 1318 CST. The maximum ozone concentration
measured at the surface was at Vera, a location almost directly under the
flight track mentioned above. Therefore, there was no apparent time lag
between the arrival of the plume at 2,500 ft and the surface. The path
followed by the plume on September 3 was quite different from the very
straight plume observed on September 2. The wind speeds were slower on
September 3, and the meandering path of the plume may be associated with the
slower winds.
Once again the net ozone production due to Tulsa can be estimated.
Southerly and southeasterly winds were present throughout the day in Tulsa
and therefore the average of the 1000 and 1100 CST ozone concentrations at
Liberty Mounds of 0.063 ppm was assumed to be representative of the back-
ground ozone concentration in the Tulsa area on September 3. The maximum
downwind ozone concentration measured on September 3 was 0.126 ppm, which
206
-------
E
Q.
Ok
Ul
o
rsl
O
.16
.14
.12
JO
.06
.06
.04
.02
00
.16
.14
.12
JO
.06
.06
.04
.02
.00
1300
1400
1500
1700
X MOUNDS
o POST OFF ICE
HEALTH DEPARTMENT
D SPERRY
SKIATOOK
& VERA
A OCHELATA
* WYNONA
Figure 4.51. Ozone concentration/distance plots for September 3, 1977
207
-------
occurred at 1300 at Vera. The difference between these two measurements of
0.063 ppm is assumed to represent the net ozone formation due to Tulsa emis-
sions on September 3. There were also aircraft measurements made on Septem-
ber 3 and the net ozone formation of Tulsa as measured at 2500 ft MSL was
determined in the same way as for September 2. The maximum ozone concentra-
tion measured on September 3 aboard the aircraft was 0.207 ppm. The mean
background ozone concentration on the afternoon flight of September 3 was
0.091 ppm. The difference of 0.116 ppm is then assumed to be an estimate of
the net ozone formation as measured at 2500 ft MSL on September 3.
208
-------
5.0 REFERENCES
Section 1.0
1. Uses, Limitations and Technical Basis of Procedures for Quantifying
Relationships Between Photochemical Oxidants and Precursors, Environ-
mental Protection Agency Report No. EPA-450/2-77-021a.
Section 2.0
1. S. L. Kopczynski, W. A. Lonneman, T. Winfield, and R. Seila, "Gaseous
Pollutants in St. Louis and Other Cities," J. Air Pollution Control
Assoc., 25, 251 (1975).
2. Uses, Limitations and Technical Basis of Procedures for Quantifying
Relationships Between Photochemical Oxidants and Precursors, Environ-
mental Protection Agency Report No. EPA-450/2-77-021a.
3. Research Triangle Institute, Investigation of Rural Oxidant Levels as
Related to Hydrocarbon Control Strategies, Environmental Protection
Agency Report No. EPA-450/3-76-035.
Section 3.0
1. E. J. Plate, Aerodynamic Characteristics of Atmospheric Boundary Layers,
AEC Critical Review Series, USAEC Division of Technical Information,
Oak Ridge, Tennessee, 1971.
2. S. L. Barnes, Mesoscale Objective Map Analysis Using Weighted Time-
Series Observations, NOAA TM ERL NSSL-62, National Severe Storms Labora-
tory, Norman, Oklahoma.
3. W. D. Bach, Jr., "Objective Analysis Technique," in Project Da Vinci II:
Data Analysis and Interpretation, Environmental Protection Agency
Report No. EPA-450/3-78-028, Appendix D.
4. W. D. Bach, Jr., Investigation of Ozone and Ozone Precursors at Nonurban
Locations in the Eastern United States, Phase II, Meteorological Analyses,
Environmental Protection Agency Report No. EPA-450/3-74-034a.
5. G. C. Holzworth, Mixing Heights, Wind Speeds, and Potential for Urban
Air Pollution Throughout the Contiguous United States, Office of Air
Programs Publication No. AP-101, U.S. Environmental Protection Agency,
January 1972.
6. Uses, Limitations and Technical Basis of Procedures for Quantifying
Relationships Between Photochemical Oxidants and Precursors, Environ-
mental Protection Agency Report No. EPA-450/2-77-021a, pp. 3-7.
209
-------
7. Research Triangle Institute, Study of the Formation and Transport of
Ambient Qxidants in the Western Gulf Coast and North-Central and North-
east Regions of the United States, Environmental Protection Agency
Report No. EPA-450/3-76-033.
8. Procedures for Quantifying Relationships Between Photochemical Oxidants
and Precursors: Supporting Documentation, Environmental Protection
Agency Report No. EPA-450/2-77-021b, pp. 3-12.
9. W. A. Lonneman, "Ozone and Hydrocarbon Measurements in Recent Oxidant
Transport Studies," in International Conference on Photochemical Oxidant
Pollution and Its Control Proceedings, Volume I, Environmental Protec-
tion Agency Report No. EPA-600/3-77-001a, p. 211.
10. S. L. Kopczynski, W. A. Lonneman, T. Winfield, and R. Seila, "Gaseous
Pollutants in St. Louis and Other Cities," J. Air Pollution Control
Assoc., 25, 251 (1975).
11. W. A. Lonneman, R. L. Seila, and J. J. Bufalini, "Ambient Air Hydro-
carbon Concentrations in Florida," Environmental Science and Technology,
12, 459 (1978).
12. Washington State University, Measurement of Light Hydrocarbons and
Oxidant Transport, Houston Study 1976, Environmental Protection Agency
Report No. EPA-600/3-78-062.
13. J. W. Harrison, M. L. Timmons, R. B. Denyszyn, and C. E. Decker, Eval-
uation of the EPA Reference Method for Measurement of Non-Methane Hydro-
carbons , Environmental Protection Agency Report No. EPA-600/4-77-033.
Section 4.0
1. C. E. Decker, J. E. Sickles, II, W. D. Bach, F. M. Vukovich, arid J. J. B.
Worth, Project Da Vinci II: Data Analysis and Interpretation, Environ-
mental Protection Agency Report No. EPA-450/3-78-028.
2. P. J. Sampson, "Nocturnal Ozone Maxima," Atmospheric Environment, 12,
951 (1978).
210
-------
APPENDIX A
MESOSCALE AIR PARCEL TRAJECTORIES
A-i
-------
63
OCH
SKI
VER
,1
SPE
S. MM
'"
JULY 2
1200
WYN
^
6f
QCH
«
MM
JULY 3
1700
WYN
K
MM
QCH
H
MM
JULY
A-2
-------
WYN
x-
MM
OCH
X
MM
JULY 5
1100
QCH
X
64
JULY 6
1500
X
55
JULY 7
1500
WYN
X
50
SKI
X
MM
-JiJ MM ,-
A-3
-------
WYN
X
JULY 11
1200
QCH
«
60
JULY 12
1600
A-4
-------
WYN
₯
39
OCH
X
56
JULY 13
IfOO
WYN
K
MM
OCH
VER
SKI
X
66
JULY L5
1200
WYN
SKI
K
63
JULY 16
1100
A-5
-------
WYN
OCH
K
67
JULY 17
1200
JULY 18
1300
WYN
K
75
OCH
K
MM
JULY 19
1000
QCH
K
7S
JULY 20
1200
A-6
-------
OCH
K
101
JULY 21
1300
81
WYN
OCH
K
75
LIB
71
JULY 23
1200
JULY 2f
1300
A-7
-------
JULY 25
1800
WYN
K
7§
SKI
X
67
OCH
K
MM
JULY 28
1700
A-8
-------
OCH
X
67
JULY 30
1200
SKI
K
65
WYN
A
54
OCH
H
I"1M
SKI
K
50
SPE
LIB
If
A-9
-------
OCH
K
m
VER
SKI
K
105
SPE
RUG 3
ItOO
flUG f
1300
A-10
-------
OCH
WYN
X
102
SKI
flUG 5
IfOO
QCH
X
70
flUG 6
1500
WYN
QCH
K
59
VER
flUG 7
IfOO
VER
HEfl
>&
flUG 8
IfOO
A-ll
-------
QCH
X
59
flUG 9
1700
H
29
SKI
K
A-12
-------
OCH
K
flUG 13
1000
WYN
X
80
SKI
K
68
flUG
1300
flUG 15
1200
WYN
flUG 16
IfOO
A-13
-------
WYN
RUG 17
1600
RUG 18
1100
PtiF
HEfl
WYN
26
OCH
X
2f
SKI
K
26
VER
K
23
SPE
K
25v
flUG 19
30°
75
NO TRAJECTORIES CALCULATED
LIB
K
30
WYN
68
OCH
flUG 20
150°
A-14
-------
flUG 21
1800
100
WYN
K
77
QCH
W
62
VER
flUG 22
1000
WYN
X
55
QCH
K
68
flUG 23
1700
A-15
-------
WYN
X
55
flUG 25
1200
flUG 26
IfOO
OCH
RUG 27
1200
K
51
OCH
SKI
K
38
flUG 28
800
A-16
-------
WYN
K
fl
OCH
K
flUG 29
1700
V£R *
L
59
WYN
OCH
X
50
flUG 30
1200
flUG 31
1500
A-17
-------
WYN
X
WYN
K
50
SEPT 2
1400
OCH
X
65
SEPT 3
1300
QCH
K
80
SEPT
1100
A-18
-------
WYN
X
53
SEPT 5
130?
/
WY/
X
59
QCH
SKI
K
65
81
WYN
K
66
WYN
X
58
SEPT
1500
A-19
-------
WYN
X
26
OCH
X
35
LIB
SEPT 9
1100
WYN
X
OCH
X
50
SKI
X-
SEPT 10
1600
SEPT 11
1500
Vfl
1
5
0
/
QCH
f 50 SEPT 12
a 1100
VER
X
SKI
63 SPE
X
v3 Cf *
^ »
i ...Pt3F up
** ^irf
/IB y
/ >y /
T1
f
; %;
t /£/
A-20
-------
SKI
X
43
SEPT 13
1700
WYN
X
42
SKI
X
42
SEPT If
1500
WYN
X
47
SKI
GCH
X
42
VER
LIB
SEPT 15
1600
WYN
X
70
QCH
VER
SEPT 16
1500
A-21
-------
OCH
WYN
X
61
SEPT 17
IfOO
SEPT 19
NO TRAJECTORIES CALCULATED
DATA SET INCOMPLETE
SEPT 20
1500
A-22
-------
SEPT 21
NO TRAJECTORIES CALCULATED
DATA SET INCOMPLETE
WYN
X
75
OCH
SKI
X
80
SEPT 22
1200
WYN
X
76
OCH
6* SEPT 23
0
VER
X
68
SKI
X
79 SPE
X
} '- _^
"*~~§° MM /-'
'^/v
LIB
X
73
A-23
-------
OCH
WYN
X
60
VER
SKI
X
67
SEPT 26
1200
WYN
X
67
WYN
X
30
OCH
X
35
SKI
X
30
SPE
X
LIB
A
SEPT 28
IfOO
A-24
-------
QC
WYN
X
62
EPT 29
1500
LIB
WYN
X
6f
OCH
X
62
SEPT 30
1800
VER
f
A-25
-------
APPENDIX B
SYNOPTIC SCALE AIR PARCEL TRAJECTORIES
B-l
-------
JULY 1
flRRIVING TRflJECTORIES
D 0600 CST ,. v.
+ 1600 CST !i JULY
4
- r-.L
IMI V 0
JULY 3
flRRIVING TRflJECTORIES
D 0&0° CST tin x/
leoo CST JULY
B-2
-------
JULY 5
flRRIVING TRflJECTORIES
D 0600 CST
+ 1600 CST JULY 6
flRRIVING TRflJECTORIES
...._ D 0600 CST ., v 0
JULY 7 + 1600 CST JULY 8
w..
B-3
-------
JULY 9
flRRIVING TRflJECTQRIES
D 0600 CST .... v
4- 1600 CST JULY
10
flRRIVING TRflJECTORIES
IMI v 1 1 n 060° CST mi x/ 10
JULY 11 + leoo CST JULY 12
\
B-4
-------
flRRIVING TRflJECTORIES
v «o D 0600 CST ....
JULY 13 + leoo CST JULY
:I
JULY 15
flRRIVING TRflJECTORIES
D 0600 CST .... v
+ 1600 CST JULY
16
V--4
B-5
-------
JULY 17
RRRIVING TRflJECTORIES
D 0600 CST tl
+ 1600 CST JULY 18
JULY 19
flRRIVING TRflJECTORIES
D 0600 CST .... on
+ 1600 CST JULY 20
B-6
-------
JULY 21
flRRIVING TRRJECTORIES
D 0600 CST
+ 1600 CST JULY 22
JULY 23
flRRIVING TRflJECTORIES
D 0600 CST .... v
+ 1600 CST JULY
V"\
"7
h-
i
I
.L..
v>\,
r-~
B-7
-------
JULY 25
flRRIVING TRflJECTORIES
D 0600 CST .... v oc
+ 1600 CST JUL> 26
JULY 27
flRRIVING TRflJECTORIES
D 0600 CST .... v 00
+ 1600 CST JULY 28
B-8
-------
JULY 29
flRRIVING TRAJECTORIES
D 0600 CST .... v
+ 1600 CST JULY
30
JULY 31
-------
RUG 1
RRRIVING TRflJECTORIES
D 0600 CST nil.
+ 1600 CST RUG
RUG-3
flRRIVING TRflJECTORIES
D 0600 CST Qlir,
H- 1600 CST RUG
B-10
-------
RUG 5
ARRIVING TRflJECTORIES
D 0600 CST
+ 1600 CST RUG
I '
RUG 7
flRRIVING TRflJECTORIES
D 0600 CST _lir% _
+ 1600 CST RUG 8
B-ll
-------
RUG 9
flRRIVING TRflJECTORIES
D 0600 CST _.._
+ 1600 CST flUG
10
~-..
RUG 11
flRRIVING TRflJECTORIES
D 0600 CST _.._
+ 1600 CST RUG
12
B-12
-------
RUG 13
flRRIVING TRflJECTORIES
D 0600 CST _,.
+ 1600 CST RUG
h--
RUG 15
flRRIVING TRflJECTORIES
D 0600 CST _,,_
-------
RUG 17
flRRIVING TRRJECTORIES
D 0600 CST
+ 1600 CST RUG
18
flRRIVING TRflJECTORIES
QtlP 1Q 9 060° CST aim
HUG 19 + 1600 CST RUG
20
B-14
-------
RUG 21
flRRIVING TRAJECTORIES
D 0600 CST 00
-I- 1600 CST RUG 22
flRRIVING TRflJECTORIES
Q|| D 0600 CST ,..._
nUG 23 + leoo CST RUG
v-\.
«
-------
RUG 25
flRRIVING TRflJECTORIES
D 0600 CST
-I- 1600 CST RUG 26
'
"r
RUG 27
flRRIVING TRflJECTORIES
D 0600 CST -..- 00
+ 1600 CST RUG 28
B-16
-------
RUG 29
flRRIVING TRflJECTORIES
D 0600 CST nilo on
+ 1600 CST RUG 30
'
flRRIVING TRflJECTORIES
D 0600 CST .
4- 1600 CST RUG 31
r
B-17
-------
SEPT 1
flRRIVING TRAJECTORIES
D 0600 CST 0_D_
+ 1600 CST SEPT 2
SEPT 3
flRRIVING TRflJECTORIES
S !iS§ £U SEPT
B-18
-------
SEPT 5
flRRIVING TRflJECTORIES
D 0600 CST 0_DT
-I- 1600 CST SEPT 6
-!
flRRIVING TRflJECTORIES
SEPT 7 ? ?|§g g|{ SEPT 8
'
B-19
-------
SEPT 9
flRRIVING TRflJECTORIES
D 0600 CST ____
+ 1600 CST SEPT
10
I
SEPT 11
flRRIVING TRflJECTORIES
D 0600 CST 0_DT
+ 1600 CST SEPT
12
B-20
-------
SEPT 13
RRRIVING TRFUECTORIES
D 0600 CST ot_DT
+ 1600 CST SEPT
RRRIVING TRflJECTORIES
SEPT 15 ? £88 §{ SEPT
16
B-21
-------
SEPT 17
flRRIVING TRflJECTORIES
D 0600 CST OCDT 10
+ 1600 CST SEPT 18
SEPT 19
flRRIVING TRflJECTORIES
D 06.00 CST or.n_ on
+ 1600 CST SEPT 20
B-22
-------
SEPT 21
flRRIVING TRflJECTORIES
D 0600 CST orDT 00
+ 1600 CST SEPT 22
SEPT 23
flRRIVING TRflJECTORIES
D 0600 CST or___
+ 1600 CST SEPT
B-23
-------
SEPT 25
flRRIVING TRRJECTORIES
D 0600 CST
+ 1600 CST SEPT 26
SEPT 27
flRRIVING TRflJECTORIES
D 0600 CST __
+ 1600 CST SEPT 28
B-24
-------
RRRIVING TRflJECTORIES
D 0600 CST _ OQ
-I- 1600 CST SEPT 29
B-25
-------
APPENDIX C
MIXING DEPTH AND ATMOSPHERIC STABILITY PARAMETERS
FOR CASE STUDY DAYS
Legend
0- solid line
R dashed line
4- 1800 CST sounding
0 0600 CST sounding
C-l
-------
Ld
t-
H
h-
MIXING RATIO Cg/kg)
10 20 30 40
50
JULY 21
i i i i
LjJ
Ci
Z)
h-
H
H
JULY 22
r i
280 290 300 310 320 330
POTENTIAL TEMPERATURE CK)
C-2
-------
MIXING RATIO Cg/kg)
10 20 30 10
50
3 -
LJ
Q
Z)
h-
H
h-
2 -
1 -
I I I I/'A I I I I I
r\
S
LU
K 2
H
> i
3
- 2
1
i i i
i r
I I I I
I . ,
I I
JULY 24
I II I I 111!
280 290 300 310 320 330
POTENTIAL TEMPERATURE CIO
C-3
-------
MIXING RATIO Cg/kg)
10 20 30 40
50
LU
H
I
_1
<
0
4
K \
. I . i
JULY 25
KVl I I I
i i i i i i i
I I
I l t t
I L
- 1
3 -
UJ
a
H
h-
_1
<
2
1
3
- 2
- 1
280 290 300 310 320 330
POTENTIAL TEMPERATURE CIO
04
-------
r\
£
LU
a
D
h-
H
h-
MIXING RATIO Cg/kg)
10 20 30 40
50
3 -
2 -
1
3
LJ
? 2
H
1 -
- 3
- 1
- 3
- 2
- 1
280 290 300 310 320
POTENTIAL TEMPERATURE CIO
330
C-5
-------
LJ
a
H
_1
<
MIXING RATIO Cg/kgD
10 20 30 40
50
r\
£
UJ
a
H 2
H
h-
_J
1
te
'
I
JULY 3t
. . . . I .
I .
I I I
. 1
3
2 -
1 -
3
2
1
280 290 300 310 320 330
POTENTIAL TEMPERATURE CIO
C-6
-------
MIXING RATIO Cg/kg)
10 20 30 40
SO
I i i i i I i i i
I 1 I 1 I I I I I I I I
- 3
2
- 1
- 3
- 2
- 1
280 290 300 310 320 330
POTENTIAL TEMPERATURE CIO
C-7
-------
MIXING RATIO Cg/kg}
10 20 30
-------
OKLAHOMA CITY RA^INSUNDh DATA
... P (MB) -
971,0
952,0
.950.0
931.0
900,0
__. 898,0--
850,0
800,0
750,0-
749,0
736,0
700 0
_j ^f,^-^ ^f
655.0
650.0
647,0-
627.0
605.0
600 0
if ^J. \J- jf-\f-
594.0
580,0
.
P (MB)
971,0
957,0
950.0
932 0
_ . _ -f -^ ^ 9 y _. -
900.0
850.0
- - - 800.0
750.0
709.0
.700.0
670.0
661.0
652,0
650,0
600,0
564.0
550.0
548.0
540.0
529.0
MONTH
.._ Z- (M)
392.
5b5.
- 584.-
762.
1061.
. 1065.- -
15bl.
2085.
-- 2634. -
2o45.
2792.
321i
*^ I*- A- -J- o
3757.
3825.
3657, -
4112.
4405.
u Ut>7
~ *T \tf--1 p - -
4547,
4738,
MOiMfH
1 (M)
- 392. ~~
523,
588.
757
4 J f-. _
1065,
I5o6.
-2091.
2b41.
3112,
3218.
- . ^j i^ ^ w'~4
3585.
3691.
- 3803.
3H28,
4^79.
- 49/4,-
5174.
5202.
5318.
5485.
7 DAY
T (C)--
23,3
25,3
25.3
25.8
24,9
24.8
21.8
17.6
13.1
13,0
11.3
8 5
\J 9 J - --
5.0
4.3
-3.8
1,9
0,8
0 4
V* ^ *T - --
-0,1
-1.0
7 DAY
T (C)
29.4
27,2
26,6
25 0
f~T * ^ V- - --
25,5
22.2
18,4
14,4
10.8
9.1
*(»*----
6,6
6.6
6,6
6.5
1.8
-1.7
-3.0
-3,1
-3,5
-4,8
21
MIX R
16,1
17.9
-17. 7
15,9
14,7
14,4
12.4
10,4
8,7
8.8
9,0
h 7
V' # *
6,3
7.2
7.8
7,0
3,8
U 0
*t # V
4.4
3,2
21
MIX R
16,2
15,4
15.2
15.1
A *J # 1
14,3
11,1
8,1
5,6
3,8
6,8
6.9
3.4
2.2
2,2
1,7
1 ,4
2.8
3.1
4,1
3.5
HOUR 600
PT (K)
299.0
302,7
302,9
305,1
307.2
307.3
309.0
309.9
310.8
310.8
310,5
3 1 1 9
- - J L-Ji 9 f
313.9
313,8
- - 313.6
314,3
316,3
316 5
- *J i v « J
316,9
318,0
HOUR 1600
PT (K)
305.1
304,2
304,2
304 2
-- * V " 9 C.
307. 8
309,4
310.8
312,2
313.3
312.5
**» *
313.7
314.9
316.1
316.3
318.2
319.7
320,5
320,7
321,6
321.9
csr
WIND (M/S)
160/ 3
202/ 6
202/ 8
215/10
229/ 8
CST
228/
23i/
79/
62/
60/
53/
36/
a/
360/
I/
S7/
1Q/V
107/
107/
2/
8
2
2
5
5
6
4
2
1
1
1
1
1
1
1
WIND (M/S)
-l/O/ 6 -
164/ 6
163/ 6
157/ 6 __.
146/ 4
93/ 3
/7/ 6
57/ 6
34/ 8
35/ 8
43/ 8
44/ 8
46/ 8
46/ 8
437 9
46/ 8
46/ 8
45/ 8
42/ 9
39/ 9
C-9
-------
UKLAHUMA CITY RAftlNSONDt DATA
p fMBl
. - - - - 972.0
954.0
._ ._. 950.0
900,0
889.0
nc. n ft
803,0
800.0
770 0
/ f v , vi
750,0
732,0
7ft ft n
- 673.0
654.0
6SO 0
616.0
600,0
t-pn n
573.0
550,0
. - - - P (MB)
970 .0
956,0
950,0
900*0
- - 850,0
800.0
. -75-9.0
750,0
712.0
700,0 -
~ - 665.0
650.0
-645,0
600.0
592.0
__S84-.0-
575,0
567,0
_._._557.0-
550,0
MONTH
-7 -(M) -
556.
- 595,
10/5.
1176,
1 Shii
2055,
2082,
240S
262b.
2835,
'I J (\ 4
3525.
3759.
3809
4244 ,
445t>.
H 5 9 1
' J ' i ,
4825,
5152,
MOW ? H
Z (H)
392
525,
582,
Itt65
- 1563.
2086.
2533.
2633,
3068,
--32 09.-
3633.
3821.
- -3884, _. -
4472.
4585.
...-4689.-
4813,
4925,
_ 5067,
5168,
7 DAY
T (C)
22,2
24,6
24,5
22.9
22,5
1 fi h
14,9
14,9
138
12,0
10,2
H T.
5,0
4,2
4.0
1,3
0.5
0 f)
- v v -
-0,7
-2,0
7 DAY
T (C)
3?. &
jt~ t*j
30,8
30,4
26,2
21,7
17,0
-12.8
12,1
8,9
8.. 9 --
7.5
6.4
-6.0
1.8
1.0
0,2
-0,5
-1.3
-1.4
-2,0
22 >
MIX H
14,8
16.3
16,0
11,0
9,6
11 7
11.3
10,9
6,0
7,7
9,0
- 5 8
6,4
5.6
5,5
5,3
3.1
1 h
* . **
3,9
2,5
22
MIX «
15,8
13,6
13,4
12.7
11.8
11,7
11.2
10,6
8,1
- 7.4
3,0
2,3
2,0
3,6
2,7
2.7
3,7
3.1
2,3
2.5
SOUR 600 CSF
PT (K)
297.7
301,8
302,1
305,1
305.8
305.6
306.7
307.0
309,2
309,6
309,8
311 .7
311,5
313.1
313,5
315,2
316.7
317.6
319.4
321,7
HOUR 1800 CST
FT (K)
308,6
307,9
308,0
308,5
308,9
309,3
309,4
309,7
310,8
- 312,3-
315,4
316,2
316,4- ..-
318,2
318,5
318-8 -
319.4
319,7 "-
- 321,2
321.7
rtlND (M7S)
207 2
257 3
257 4
3577 2
3367 2
3407 2
07 0
0/0
1087 1
947 2
847 2
837 1
1007 1
1007 1
1207 1
787 2
81/3
- 867 3 -
977 2
1157 1
rtIND (M/5)
3607 5 -
3607 4
17 4
3387 2 -
2297 2
2147 4
1997 3
2007 3
1377 1
1197 2
1327 2
1427 2
1457 2
1377 3
1277 3
1157 3
1047 3
1017 3
977 3
987 3
C-10
-------
OKLAHOMA CITY RAWINSUNDE DATA
p (Ma)
972.0
965.0
950.0
910,0
900.0 .
__ 850,0-
800.0
750.0
... 700.0-
650,0
648.0
.. 644,0 -
635.0
- - 621.0
605,0
600,0
593.0
561 . 0
' *r-\f -M, y- V
553,0
550,0
P (MB)
969,0
958.0
950,0
941 o
, . f *-^ j. ~^ ^j . . -
924.0
900.0
850,0
800,0
775.0
750.0-
740,0
700,0
-692.0
650.0
628.0
__. 600, 0
591.0
576.0
- - - 560.0
552,0
MONTH
- /: (M).-
392.
455,
- 594,
973.
1075.
* ' 1568.
2091.
2639.
3214.
3823,
3849.
.. - 3899,, .-_
4013.
4194,
44U5,
4472,
4566,
5009
5123.
5166.
MONTH
Z (M)
494,
575.
656 ,
819. -
1054,
.--155/,
2083,
2354.
--2632.
2/45.
3211,
'- 3307.-
3825,
4 1 Ob,
44 7b
4597!
4803.
- 5028.
5143.
7 DAY
r (o
21.7
25.9
25.6
24.7
24,1
20.6
16.9
12.9
- 8.6 ....
4.3
4.1
_ 3.9 .....
3.4
2.4
1.1
0,8
0.3
**? 6-
-3.6
-3,7
7 DAY
T (C)
36,8
35,0
33.4
31 .4
30.0
28,1
23,9
18,4
15.4
13.5 ...
12,7
10,6
9.8
5.8
3.6
1,3-
0,5
-1.0
-1,6 _
-1.6
23 1
MIX R
14.7
15.6
- 15.1
13.2
12,9
11.5
9,7
8.1
6.6
6,6
6.6
- 4,3
4.9
3.5
5,0
4.0
2.6
4,8
3,1
3,4
23
MIX K
- 13.2
12,4
11,8
1 1 .2
* * T fc-
11.1
11,0
10,6
10,0
9,5
.9,6
9,7
7,4
6.3
6.6
6.7
6,3
6.3
5.7
4.0
5.7
HOUR 600
PT (K)
297.3
302,1
303.2
306.0
306.3
307,7
309.2
310,6
312.0
313,8
313,9
---314.2
314,9
315,7
316.6
317.0
317,5
319. 1
- - - *J JL * i
319,3
319.7
HOUR 1800
PT (K)
- 312,8
312.0
311,1
309 9
310,1
310.5
311.2
310,8
310,4
311.2
311.5
314,2
314.3
315.5
316,1
317.6
318.0
318.6
320.5
321,8
CST
WIND
170/
ISO/
188/
220/
226/
274/
273/
287/
286/
291/
293/
29 9 /
308/
336/
360/
a/
165/
-188/
199/
203/
(M/S)
2
3
a - -
5
4
2
3
6
4 . _._.
3
3
3
2
2
1
1
1
2
1
1
CST
WIND
180/
203/
215/
227/
235/
238/
251/
260/
268/
291/
292/
275/
275/
300/
318/
319/
327/
332/
330/
323/
(M/S)
3
4
4
5 ....
6
6
4
a
a
a .
a
5
4 . . .
4
3
3
3
2
2
1
C-ll
-------
OKLAHOMA CITY RAftlNSONDC DATA
p._( MB >
969,0
950,0
919,0 -
900,0
850,0
800.0 -
750.0
712,0
7n o n
- - / V V .'V
680,0
666,0
, r n A
O J v , ~v ~~
, j, -r n
O*t J * v
629,0
... _ 617.0
600.0
576.0
C. C~ A A
542,0
- 513,0 -
HON
Z (M) -
392,
504.
858.
1044.
1546.
2073.
2624.
3062.
1i'J{\/l
J C, V *T 4|
3444.
3616,
7 o * /
_J w 4. ~O *
-7 Q t\ yt
J ' v "4 9
4083.
4239.
4464.
4791,
5158
- *X 1--J t^ -»
5275.
5709.
TH 7 DAY
T (C)
23.9
25,2
27.5
26,5
23,6
19,3
14,6
10,8
9 5
7 , -'
7.7
7,4
s s
- J , J
4 6
M , VI
4.1
2.2
0,6
-1,8
«? 5
~ ~ C- 1 -* ~
-2,8
-5,5
24 HOUR
MIX R P
14,9
14,3
12.4
12.2
11.5
10,9
10.0
9.2
7 0
f , V
7.4
4,0
5 1
j , *
5 6
^* 9 -*
3,8
6.1
5,9
5,4
4 2
" f *~
3.8
1.8
600
T (K)
299,8
302,8
308.0
308,8
310.9
311,7
312.4
312,9
3130
* 4 --^ 0 V
313.6
315,1
315 2
J * -^ * C-,
315. 1
-**-*$*
316,5
316,1
316.8
317.7
321 . 1
.J *- A V *
322.1
323,9
C5T
rtlND (M/S)
170/ 3
196/ 7
221/1 1
229/13
231/12
245/ 7
26 i/ 5
322/ 2
35 3 / 2
9/ 1
346/ 1
30 3/ 2
29 o/ 2
276/ 3
270/ 3
260/ 2
147/ 1
--- 140/ 2
143/ 2
192/ \,
P. (M8)
965.0
951.0
950.0
_g n n n
^-VA/ 9~^f
-850.0 ...
800.0
- 750.0 _
749.0
700,0
^76^0
650,0
603.0
.--.-600-.0
582,0
561.0
550* 0
- ' =* J +r *- V
549.0
524,0
500,0 -
473.0
MONTH
Z (M)
392,
527.
537.
1 028
- *-V lm\J +
1535.
2067.
2622.
2632.
3202.
3493
3818.
4435.
4475,
4716,
5015,
5168.
5102.
5553.
5924.
6365,
7 DAY
T (C)
39 . 4
35.9
35.9
31 4
~ j i . + -
26,7
21,4
15.7
15,5
10,8
___9.a. -
7,1
2.6
-2,3
0,4
-U7
-1,7
-1,7
- -2,0
-4,5
-5,6
24
MIX R
11,9
12,8
12,8
11,4
10,2
9,8
8.8
8,8
9,0
6.5
5,7
4,3
a, 2
4,2
4,4
3.0
2.8
1.4
1.2
1.0
HOUR 1800 CST
PT (K)
315,7
313,5
313.6
-313.9 --
314.1
314,0
313.6
313.5
314,4
-316,0
-317,0
318,6
318,7
319,3
320,2
- 322.0
322.2
326,1
327.5
331,4
WIND
210/
209/
209/
215A
211/
204/
211/
212/
235/
255/
267/
242/
240/
23U
O/
253/
253/
231/
237/
271/
(M/S)
5
5
5
7
5
5
6
6
6
5 -
6
3
3
2
0
1
1
4
3
3
C-12
-------
OKLAHOMA CITY RAWINSUNDK DATA
P .(MB-) -
967,0
950.0
946-.0
903.0
9oo;o
850.0 -'
800.0
750.0
. . _ . 700.0
b50.0
616,0
600. 0
581.0
569.0
561 . 0
550.0
537.0
500 0
456,0
450,0
P (MB)
967 0
959.0
950.0
900 x 0
850.0
800,0
750.0
718,0
700,0
650 0
600.0
550.0
540,0
528.0
500,0
-450,0
434,0
400.0
350.0
331,0
MUN
L (M)
392.
551.
568.
1002.
1032.
-- 1537.
2066.
2619.
- 3201.
3616.
4253.
^465
4723.
4889.
50U1 .
5158,
5348.
5912
6631.
6734,
MUN
1 (M)
392.
464,
551.
1044
- 1555.
2062,
2637.
3006.
3225.
3836
4495,
5158.
5336,
5514,
5946.
67b9.
7048.
7669,
8604,
90t>8.
FH 7 DAY
T (C)
25,0
27,2
27.8
29,1
28.9
24,4
20,3
15.9
11.2
6.3
2.6
0 8
-1.5
-3.3
-2.2
-2.2
-2,2
"5 1
-8.5
-9.2
[H 7 DAY
T (C)
40.0
37,5
36,7
31 .8
26.5
21.7
16.5
12.9
12,2
7 7
2.7
-2,5
-3.7
-1,8
-3.8
-9.0 -
-11.0
-16.0
-22.7
-25.5
25 1
MIX R
14.1
14,7
14.8
13.7
13.5
11,6
10,1
8,6
7.2
5,5
4,3
H 4
4.5
3.8
2.4
2.0
1,4
1 i
0.9
0,8
25
MIX R
12.3
13,5
13.0
11.7
10,3
10,2
9,7
9,1
7,2
6.4
5,6
4,6
4,3
1,3
1.1
0.7
0,6
0,5
0,3
0,2
HOUR 600 CST
PT (K)
301.0
304.8
305.8
311,2
311.3
311,7
312.8
313,8
314,9
316,1
316,7
31/0
317.3
31/.0
319.6
321,4
323.6
326 8
331,2
331.6
HOUR 1800 CST
PT CK)
316,2
314,4
314,4
314.3
313.9
314,3
- 314.5
314,5
316.0
317.6
319.2
321.1
321.3
325.7
328.4
331,9
332.8
334,1
338,1
339,7
WIND (M/S)
180/ 3
215/ 6
221/ 8
240/13
240/13
245/10
254/ 7
272/ 5
259/ 1 -
343/ I
345/ i
O/ 0
O/ 0
285/ 1
285/ 1
280/ 1
261/ 1
?t\h/ ^
281/ 4
278/ 3
WIND (M/S)
270/ 2
262/ 1
253/ 1
2-0 7 / 2
203/ 3
209/ 2
237/ 3
247/ 4
271/ 5
296/ 5
301/ 4
320/ 4
328/ 4 .
339/ 3
337/ 3
296/ 5 -
293/ 6
300/ 5
281/ 2
256/ 2
C-13
-------
7
P (MB)
-970.0
950.0
930.0
900.0
898.0
865.0
850.0
831.0
823.0
819,0
800,0
799.0
750,0
740.0
700.0
694.0
680,0
650,0
- 644.0
600,0
968.0
952,0
950,0
900.0
879.0
850.0
814.0
800.0
762.0
750.0
700.0
650.0
600.0
592.0
550.0
523,0
500,0
496,0
453.0
450.0
OKLAHOMA CITY RAViINSUfJDE UA
MU.JFH
I (MJ
392.
575,
76b.
1045.
1064.
1387.
1537,
1/35.
1812.
itibji.
2053,
20o4.
2605.-
2713.
31/7.
3248.
3417.
3/89.
38ob.
4442.
- MtJUTH
L (-0
392.
544.
563.
1045.
1253.
154/.
1922,
20/1.
24^6.
2621.
3201.
3Mlb.
4Uo9.
Mb/7.
bio/.
bboo .
i^c^b.
VttS.
no»7.
o/3b.
7 DAY
T (C)
r?2.2
21.1
20.7
dO.b
20. «
17.9
16.8
15.0
13. H
lo.2-
16,7
16.8
13.0
12.1
8.9
8.5-
*).!
7.1
6.6
3.2
7 DAY
T (C)
32.2
30.4
30.3
26.1
^4.d
21.5
18.7
17.9
15.6
lb.0
11.9
/.<4
2.5
l.b
-1 .a
-3.^
-b.l
-b.'-*
- 1 0 , b
-11.0
28 HOUR
MIX K P
16. c?
14.6
14. \
14. /
14.8
13.1
12. b
11.3
10,6
12. b
7.6
7.2
6.8
6,8
6,0
4.b
2,0
1.9
1.8
1.5
28 HOUR
MIX R P
17, b
17. b
l/.b
1 7.2
17.0
14.9
12.7
10.
-------
UKLAHOMA CITY
DATA
P (MB)
970.0
959.0
950.0
946.0
900.0
850.0
600.0
750.0
710.0
700.0
650.0
642,0
6l4;t)
600.0
599.0
588.0
574.0
550.0
539.(T
528.0
P (MB)
968.0
950.0
908.0
900,0
850.0
823.0
800.0
750.0
729,0
700.0
679,0
650.0
600.0
565.0
550.0
545.0
500,0
474,0
450.0
437.0
'kJlJT H
L CO
39f>.
49-4.
57 /.
blu.
1055.
1 5^o .
20od.
2615.
30/3.
3191.
3802,
3902.
4263.
4 q 4 H .
44o2.
46l 1 .
46U4.
5145.
5305.
J bfcS.
- rtUNTH
^ (MJ
392.
563.
966,
1044.
1545.
Ib24.
2067.
2616.
2655.
3194.
3446.
3d05.
4456.
4938.
5153.
5225.
59U6. -
6323.
6725.
6955.
7 DAY
T (C)
22.8
24. /
24.3
24,0
22.7
21.0
17.3
13,3
9.8
9.3
5.0
4,2
0.9
0.0
-0.1
1,2
0.0
-2.6
-4,0
-5.0
7 DAY
T (C)
33.9
30,8
27.0
26.3
21.3
18.6
17.1
13.7
12.1
9.9
8.7
6.4
2.2
-1,0
-1.0
-1.0
-5.7
-7,6
-10,6
-12.3
29
MIX H
14.3
15.0
13.2
12.0
10.4
8,4
? .2
6.2
5.4
5.3
4.1
3,9
5.0
4.7
4.6
2.1
2.2
4,3
5.0
4.6
29
MIX K
15.8
13.7
13,5
13,5
13.0
13.5
1 1.8
8.6
7,2
4,7
2.2
2.0
1 .5
1.2
1 .2
1.2
0.9
0.8
0,6
-- 0,6
HiiUk 600
P T ( K )
298.5
301,4
301.9
301.9
304,9
308.1
309.6
311,0
312.0
312.8
314.6
314.8
315 , 0
316, 1
316. 1
319,3
320,1
321,0
321", 1
321,8
HOUR 1800
PT (K)
309,9
308.4
308.6
308.6
308^5
308,5
309.4
311.4
312.2
313,4
3 1 ^, 8
316,2
318,6
320.4
322.9
323.7
326T0
328^7
339.8
330T5
CS1
csr
ulMD
340/
356/
a/
355/
271/
202/
167/
75/
26/
340/
333/
332/
333/
339/
342/
342/
273/
340/
331/
337/
341/
6/
34/
It/
340/
328/
308/
311/
322/
342/
356/
354/
352/
351/
356/
345/
340/
CM/3)
4
5
5
5
1
2
3
n
5
5
1
1
4
5
5
6
7
3
1
(M/S)
n
3
2
2
1
2
3
4
4
3
5
4
4
5
6
3
C-15
-------
OKLAHOMA CITY RAHINS'JNDE DATA
p (Mb)
968.0
950.0
940,0
900vO"
850,0
800.0
753.0
750.0
733,0
700; 0
676.0
650.0
f\ f\ r\
' 600, 0
550.0
531.0
-5W.-0
a50.0
aoo.o
-368.0-
350.0
MONTH
L CM)
392.
558.
652.
1036.
1534.
2055.
2566,
2599.
2/95.
3172.
34o5.
37b3,
'it1 f
- "443b.
5135.
5414.
5886.
ot>97.
7581.
-8193.-
6565.
7 DAY
T (C)
22.2
24,9
2t>,5
24.2
21,1
lb.0
10,8
10,7
9.7
8,2-
8.8
6.9
3n
* 0
-1.1
-3,0
-7,3
-13.3
-20.2
24.5
-26.2
30 HOUK
MIX R P
15.9
15. 1
14.3
12,3
9.6
9,4
8,6
8.1
4.8
2.1
2.0
1.8
It-'
.5
1.2
1,1
0,8
0,5
0.3
0.2
0.2
600 CST
T (K)
298. -1
302,5
305.0
306, -4
308.2
308.2
307.9
308,2
309,1
311.5
315,3
316,7
3« 0 /
19,6
322,7
323,7
324.1
326.5
328.7
330,9
333,3
foIND
170/
207/
223/
223/
217/
226/
211/
211/
217/
223/
226/
230/
"} "7 1 I
C. I 1 /
o/
332/
328/
309/
2727
-307/
318/
(M/S)
n
5
6
7
4
3
4
4
5
7
4
4
1,
"
0
1
1
4
6
6 -
12
P (MB)
964.0
951^0 -
950.0
900.0
- -85-OvO
800,0
794.0
7-86.0
753.0
750.0
- -700.0
672.0
650.0
646.0 <
600.0
590.0
550.0
543.0
500.0
450.0
MONTH
I CM)
392,
- 519.
529.
1015,
1 518v~-
2044,
2108.
2195.-
2561.
2595.
3175.
3514.
3769.
3815.
4447.
4584.
5149.
5251.
5902.
6/21.
7 DAY
T (C)
35.6
33.2
33.2
28,7
- 23,9
18.6
17.9
18.1
15.8
15.6
10.8
8.1
9.3
9.5
4.6
3.5
-1.1
-2.0
-5,4
-10,1
30 HOUR 1800 CST
MIX K
19.2
12.7
12.7
11.4
10,1
9.6
9.7
7,4
5.0
5.0
5 . 3-
4.0
2.4
?,2
2.5
2,5
1.5
1.3
1.2
0.8
PT (K)
312.0
310,8
310,9
311,1
311,2
311,0
310,9
312,0
313.4
313,5
314.4
315,1
319.5
320,0
321 .4
321.7
322.7
322.8
32o.4
330.5
WIND (M/S)
200/ 4
200/5 --
200/ 5
218/ 6
225/ 6
235/ 7
237 / 6
240/-6 --
270/ 3
275/ 3
310/ 4
330/ 7
344/10
346/10
348/1 1
344/10
330/ 8
32 7/ 8
50//11
303/13
C-16
-------
OKLAHOMA CITY RAWINSQNDE DATA
P (MB)
- 96P.O"'-
952.0
-950.0
900.0
889.0
864.0
-850.0-
800.0
750.0
749.0
700,0
662.0
-650.0^
619.0
605.0
600.0"
592.0
560.0
550.0
5 '18.0
MONTH
Z (MJ
39^-
553.
552.
102/.
1135.
138/4.
1526.
2052.
- 2602.
2612.
3179.
3641.
--3W7 -
4195.
43/5.
444-2.
4549.
4712.
5133.
51M.
7 DAY
T (C)
21.1
25.3
25,3
23.8
23.4
21.2
22.3
18.4
1«,1
14.0
9,5
6.6
5.5
2.5
0.7
0.3
-0.3
-2.2
-4.0
-4.2
31 HOUR
600
MIX R PT (K)
12.6
14.0
14,0
13.5
13.3
12.7
12.4
10.3
8.3
8,3
8.5
8,6
7,5
4,9
5.5
5,2
4,6
4.4
1.6
1,4
297.1
302.7
302.9
306. 0
306.7
306.9
309.5
310.8
311.9
311,9
313.0
314.8
315.2
316.1
316.1
316,4
316,9
316.6
319,3
319.4
CST
WIMD (M/S)
130/ 5
136/10
136/10
169/10
185/10
211/10
221/11
242/11
253/ 8
254/ 8
291/ 8
326/ 9
334/10
341/10
340/10
340/ia
340/10
340/10
337/11 -
336/11
._ ..
P (MB)
968.0
960.0
950,0
900.0
- 892.0
871 ,0
850.0
839.0
818,0
800.0
750.0
700,0
650.0
643.0
615.0
600. 0
--587,0
5«3.0
550.0
548.0
MONTH
L (M)
392.
464,
557.
1036.
1115.
1325.
1539.
1652,
18/2,
2065.
2oltJ.
3198.
3612.
3901.
4264.
4463,
4038.
469£.
515o,
5184.
7 - DAY
T (C)
30,6
29,0
28,6
26,0
25,5
25.1
23,2
21,6
21,4
20.0
15,6
10,9
6.2
5.5
2.8
-0.2
-1.8
-0,6
-3,4
-3.6
31 HOUR
1800 CSf
MIX R PT (K)
13.0
12,5
12.3
11.8
11,8
9.9
9.7
9.3
8.2
7.9
7.1
6.3
6.6
6.6
6.5
4.8
3.7
4.3
3.3
3.2
306,6
305.7
306.2
300.3
308.6
310,3
310.4
309.9
312.0
312,5
313.5
314,5
315.9
316.1
317.1
315,9
Sib.O
31 7.8
320.0
320.1
WIND (M/S)
80/ 7
76/ 9
74/11
79/ 9
81/ 9
88/ 6
109/ 4
131/ 3
182/ 5
189/ 6
188/ 8
222/ 7
294/ 7
29// 7
292/ 7
273/ 9
262/15
269/16
28//19
289/19
C-17
-------
OKLAHOMA CITY RAtolNSUNDE DATA
P (MB)
972.0
958.0
- 950.0
903.0
900.0
850,0
800.0
792,0
781,0
754.0
750.0
720-.0-
700,0
-AR9 0
AAX n
i ' i ^ U .«* 9 V
650,0
612.0
f>00 0
576.0
556.0
MUN
.._.Z-CM>--
392.
b!8.
592.
1034.
1063.
-1554,
2069,
2153,
2275,
25b4.
2608.
2947.
3179.
3509
3625_.
3787.
42/4.
- 4432
4756.
5034.
TH 8 DAY
T (C)
22.2
23.4
--- 23.0
20.3
20.1
^ 15, 1
13.0
12.4
11.8-
9.6
9.5
8,2
- 6,9
6.8
6*4
4,9
0.1
-1 1
-4.0
-5.6
2 HOUR
MIX R P
15.2
15.6
15,4
14.3
14.2
12.6
9.1
8.5
10,3
8.4
8,3
__.7,0
4.3
2.5
2 7
t- » '
2,8
2.8
3.0
3.1
- 3.7
600 CST
f (K)
297.8
300,2
300.5
302.1 ,.
302.2
303.0
305.0
305.2
305,8
306,5
306,9
-309.0
310.1
311.4
314.4
314.5
314.4
314.8
315.1
316.4
WIND (M/S)
360/ 5
336/ 5
328/ 5
228/ 4
228/ 4
193/ 4
224/ 3
223/ 3
223/ 3
224/ 3
224/ 3
228A 3
242/ 5
250/ 7
264/10
267/10
280/11
285/12 -
302/12
312/14
P (MB)
969,0
950.0
930,0
900- 0
- 850.0
800.0
7-7-9.0-
750,0
744.0
700.0
665.0
650.0
- -608,0
600.0
550.0
-506,0
500,0
496,0
463,0
455.0
MOW
Z CM)
_~- 392.-
572.
762,
i 053
1552.
2Q72,
2298. -
2617.
2684.
31 91-,
3ol2,
3798.
4338.
4444.
'3134.
5783.
5875.
5937.
6465.
6596.
TH .8 DAY
T (C)
33.3-
30,4
28.8
25.8
20.5
15,6
13,4
11.6
11.2
7.9
4.9
3,8
0.5 -
-0.1
-5.0
-9.8
-9.5
-9.3
-13,6
-13,6
2 HOUR 1800 CS
MIX R
12,5 _
15,8
11.3
1 1 .2
10,5
10.3
10,1
7.3
6,7
6.0
5.4
4.3
1,4
1.3
1.1
1.0
0,7
0,7
0,5
0.5
PT (K)
-309.2
308.0
308.3
308.1 - -
307,6
307.8
307,8
309,2
309.4
31 1,2 - -
312.4
313,2
315.5
316.0
318.1
-319,9
321,4
322.4
323.4
325,0
T
WIND (M/S)
-190/3 .
124/ 3
97/ 4
-- 94/-3 ..-.
59/ 1
73/1
349/ 1 - .. _. ..... ..
352/ 2
352/ 2
- 343/ 6 - - -. -
324/ 7
323/ 8
. 335/10 .- . .
338/10
349/11
338/11 -
337/12
336/13
33B/18
336/21
C-18
-------
OKLAHOMA CITY RArtlNSONDE DATA
p_(MB>
970.0
961.0
950.0
947,0
900.0
071 n.
- - O 'f "1 , v
850,0
800.0
785.0
752.0
750.0
7-1-7,0
700,0
684,0
650.0-
640.0
651.0
f, n 0 o
Ou v * V
585.0
568,0
P (MB)
968.0
950,0
900.0
as.o-.-o
. 800.0
784,0
._ 750.0-
737.0
700.0
650,0
600.0
585.0
568.0
550.0
500.0
.... (| 50-. 0 ..
400.0
350.0
^317.0
300,0
MONTH
-Z--CM-)
392.
469,
575.-
598.
1044.
1335," ~
1542,
2064.
- 2224,
2567.
2609.
296&T
3164.
3375.
--3793-.--
3919.
4034.
/I /I /I K
^f *-T '! J .
4642.
- 4875,
MONTH
L CM)
392.
w.
1045.
- 1539,
2061.
2233,
- 2608. -
2754.
3184.
_ 37-9-7.
4447. - -
4651.
4887. -
5143.
5692.
- 6703.
>b95.
«bb9.
92t>9.
9t>52,
8
-T (C)
21.7
24,4
24.7
24.9
23,7
22,8
21.0
17.1
- IS. 8
12,1
12,0
9.3
8.2
7.8
4,7
3.7
3,5
-0,1
-2.1
-4,0
8
T (C)
- 34,4
31.2
26,6
21,7
17,0
15.4
12.7
11.5
11.2
- - 6,3
1,0
-0,6
-1,0
-2.5
-7,6
-13.1
-19,3
-27,7
-34.0
-37.8
DAY 3
--MIX R
15.4
16.3
14,3
13.7
10,3
7.8
7,1
7,6
7,7
7,1
7.1
-4,4
3,0
2.3
2.0
1.9
1.9
t Q
- 1 * "
1.9
1,0
DAY 3
MIX R
16,3
12,2
10.8
- 9.4
9,0
8,8
5.6
4.3
4.5
. - 4,3
1 f ~r
3.6
3.7
- 2,0
1.9
1.5
0.9
0.4
0.2
0.2
0,2
HOUR 600
PT (K)
297,5
301,0
302,3
302,7.
305.9
307,9
308,1
309,4
309,7
309,5
309.6
310,6
311,5
313,2
314,3
314,5
315.6
316.0
315,9
316,4
HOUR 1800
PT (K)
-3-10.5
308,9
308,9
308.9
309.3
309,3
- -310,3
310,6
314,9
316,1
317,2
317,7
319,9
321,1
323,7
326.7
329,8
331,3
332,1
332.0
CST
--WIIN&-CM/S)-- - -
150X 3
173/ 4
191/ 6
194/ 7
207/ 6
216/ 3
234/ 2
204/ 3
192/ 3
179/ 3
179/ 3
-201/3
249/ 2
29a/ 2
322/ 6
331/ 7
336/ 8
Zkp / Q
-j7lC/7~ - - - - -
356/ 8
353/ 7
CST
WIND (M/S)
210/ 5 - --
197/ 6
190/ 6
185/ 6
183/ 6
184/ 6
192/ 5
197/ 3
335/ 2
317/ 9
325/ 9
333/ 9
342/10
341/11
333/15
335/11
312/12
301/14
- - 303/13
303/14
C-19
-------
OKLAHOMA CITY RAWINSONDE. DATA
Pt MR 1
l-l*i p }
968,0
959,0
.. - -950.0
942.0
932,0
- 900,0
850.0
800,0
^ 752,0
750.0
700.0
650-.0-
643,0
- 636,0
628,0
623.0
V CM. -* * *
600.0
552.0
550.0
519.0
p. (MB)
- ._ 966.0-
950.0
* J v v
908.0
. .... - 90'».0 -
. 900.0
- 850.0
815.0
800.0
765.0
_. 7-50.0
746.0
700.0
- 679.0-
650.0
6«2.0
--60Q.O
550.0
548.0
500.0
453,0
MONTH
7 (M) T
*» \ ' 1 / '
392.
472.
554,
628.
722,
1029,
1527.
2052.
2581,
2604,
3187,
3802.
389 U
3985,
. 4084, - -
4149,
4456.
-5126. -
5155,
5614.
MONTH
i (M)
-392,
538,
941.
--985,
1019.
1519.
1681.
2045.
2421.
_ 2589. ._...
2634.
3175,
3424, --
3787,
3889.
-4445.
5145.
5173.
589a,
0653.
8 DAY
- (C>
22,8
23,3
23.3
23,3
25.1
23.7
21,4
19.0
16,5
16,4
11.7
-5 .-9.
5,0
4,8
5,5
5.5
3.4
»1,2 -
-1.4
-5,2
8 DAY
T (0
34.4
30.7
27.3
-26.6
26.3
21,1
17-. 6 _.. .
17,1
15.7
._45,6-~-
15.5
11,6
-9.9
9.0
8,7
- -4, a
-1.6
-2,0
-8.3
-13.3
4 HOUR
600 CST
MIX -R PT (K)
12.7
12.6
12,6
12.3
11.0
10,7
10,2
9.5
_. 8,9- . -
8,9
8,1
7.9
7.9
7.6
. - 4.0- -
3.5
3.1
2.3
2,2
2.2
298.7
300,0
300,8
301.6
304,3
305.9
308,6
311,4
314,2
314,4
315,4
315,6
315,6
316,3
318,3
319,0
320.0
322,3
322,4
323,2
4 HOUR 1800 CST
MIX R PT CK)
14.9 310.7
11,5 308.3
10,9
10.5
10,3
10.4
- 9.9
8,5
4.9
5.4
5.6
5.1
5.6
3.9
3,4
3.3 -
2,9
2.8
2,0
1.1
308,9
308.5
308.6
308,2
308.3
309,4
311,8
313,5
313.9
315.3
.. 316,2
319,1
319,9
320.9
322.1
322.0
322.9
325,8
WIND (M/S)
170/ 5
178/ 8
183/12
186/16
188/20
197/21
208/14
219/11
251/ 9
251/ 9
285/ 5
309/ 4
310/ 5
307/ 5
303/ 4
299/ 4
309/ 2
322/ 4 -
321/ 4
328/ 6
WIND (M/S)
160/ 9 -
164/10
171/11
172/11
172/11
178/11
186/ 8 .
194/ 8
219/ 7
231/ 7
^ T n / ~7
23'4/ 7
284/ 7
294/ 6 -
30 I/ 6
305/ 6
330/8
333/ 8
332/ 8
339/ 5
32 O/ 7
C-20
-------
p (MB)- -
969,0
966.0
950,0
933.0
900,0
869,0 -
850,0
814.0
800,0
750.0
700.0
-- 656-,-0
650.0
644,0
- 6ao,o
563,0
550.0
--522-.0-
507,0
500.0
MONTH
I (M)
392.
421.
567.-
737.
1044.
1355,
1543.
1925,"-
2071, -
2626.
3207.
-37-46.
3822,
3698,
.4475,
4986.
5172.
5564.
5812,
5925,
8 DA
T (C)
23.3
23.5
24.6
25.8
24,3
22,8
23,3
22.4
21.2-
16,4
11.2
7.2
6.5
5.6
-- 2,0
-1.3
-2,7
- -6,1
-8,0
-8,5
Y 5
- MIX R
14.4
14,4
14,0
13.3
11.5
9.9
8.7
6.9
- 7.1
7,3
7,1
6.9
7.4
7.8
6,1
4.7
4,6
4,4
3.8
2,9
HOUR 60(fC3T
PT (K)
299,1
299.6
302,2
304.9
306.6
308.1
310,5
313.5
313,7
314,4
314,9
316,2
316,3
316,1
318,"
320,4
320,8
321,6-
322,0
322.6
WIND (M/S)
170/ 4
177/ 6
183/11
191/15
205/16
223/12
239/10
264/ 7
269/ 7
273/ 6
271/ 5
229/3
224/ 3
213/ 3
195/ 4
200/ 6
198/ 7
212/ 4
214/4
210/ 4
P (F4B)
969,0
954,0
950,0
900,0
850.0
800,0
-7-72,0
762,0
752,0
-750.0
700,0
650,0
600.0
593.0
550.0
500.0
450.0
430,0
400.0
374.0
MONTH
I IM)
392,
526,
566,
1047.
1547.
2068,
23/1.
2481,
2593.
2616.-
3199,
3817,
4471,
4566.
5169.
5925.
6735.
7081.
7626.
8126,
8 DAY
T (C)
33,9-
31.7
31,3
-25.8-
21.4
16,5
13,6
13.4
16,4
-16.3 -
12.8
7,8
2.4
1,6
-2.1
-7,1
-12,0
-14.1
-18,0
-20,8
5 HOUR
MIX R P
14,0
12,5
12.3
10,5
10,0
9,4
9,0
5,5
6.3
6,3
5,6
5.8
5.4
5,4
4.1
2,7
1.9
1.6
1,4
0.7
1800 CST
T (K)
309,9
309,0
309.0
308,1
308,6
308,7
308,8
309,7
314,1
314.3
316,6
317,8
318,9
319.0
321,5
324,3
328.1
329,7
331.5
334,2
WIND
190/
178/
176/
166/1
174/
186/
185/
1«0/
1/4/
174/
198/
338/
318/
312/
307/
313/
328/
301/
238/
253/
(M/S)
6
7
7
0
7
8
7
6
5
5
3
1
4
4
9
7
3
1
2
3
C-21
-------
OKLAHOMA CITY RAWlNSONDt DATA
P ( MR ^
974.0
959,0
950.0-
915,0
900.0
850.0
800,0
786.0
7SO 0
735.0
700.0
- AhS 0
_. - - A S 0 .. 0
- . - -600,0
569 0
550.0
545,0
5190
.... 500.0 --
450.0 -
MOM
/ ( 1A 1
c V '*' i
592.
b35.
613.
943.
1087,
1585.
2097.
2246,
2815.
3216,
- "4 h ? 9
3826
4477.
4904
5175.
5247.
5633
5925,
6743,
FH 9 DAY
T ( r i
i - *, \j i
18.9
25.4
- 24,9
22.8
21.6
17.4
15.4
14,8
IP n
11.3
8.4
h h
5.7
2,3
0.0
-2.4
-3.1
- -4 8
-6,3
-10,0
2
MTV D
12,7
15.9
15,4
13.2
12.7
10.9
6,4
5.2
5 0
5,0
6,1
3 7
3 6
-* » ''
3,0
2.6
2.2
2,1
i 2
1 .1
0,7
HOUR 600 CSF
PT (K )
294.2
302,2
302,5
303,6
303.8
304,4
307,6
308.5
310.0
310,6
311,8
314.3
315.4
318,7
320 .9
321,2
321,2
323 7
325.3
330,6
W I N 0
ISO/
190/
191X-
191/1
188/
199/
217/
225/
25 5 /
309/
357/
109/
I in/
154/
13 I/
165/
183/
1 7 9 /-
185/
184/
2
6
9
0
9
7
5
5
1
1
1
2
3
2
?
1
1
3
6
3
. ... P. (MB)
973 0
956.0
950.0
9^00
r ~t V* V
900.0
- - - - 850.0
829.0
800.0
750.0
711 0
700.0
. 672.0
65 0 . 0
646,0
620.0
60£. 0
595.0
550.0
54.4,0
500.0
MONTH
L (M)
552.
608.
797
108t>.
- 1563.
1798.
2102.
2646.
3089
3218.
- 3554, ...
. .3827..
3878,
4213,
4479
4547.
5185.
-5267, -
5932.
9 DAY
T (C)
32 2
26,8
28.4
26 9
24.3
19.7
18.2
15.8
11,4
7.7
_ 7,5
. 6.8
- 6.3
6.1
3.8
3.5
3.3
1.0
- 1.6
-6,8
2
MIX R
139
i J , 7
11,8
11,6
11.6
11.3
10,7
-7.7
6,9
5,5
4.5
3.7
2,2
2,2
2,2
3,1
2 4
2.1
2.1
1,8
1.2
HOUR 1800 CST
PT (K)
307 7
305,9
306,0
306 3
306.6
306.8
307,4 '
308,0
308.9
309,6
310.8
313.6
316,1
316.4
317.5
320. 1
320,7
325., 2
323.2
324,7
WIND
1 5()/
151/
151 /
151 /
152/
160/
146/
130/
158/
14 7/
133/
96/
47/
40/
37X
1 46/
146/
41/
41/
312X
(M/S)
5
5
6
5
4
4
4
4
2
1 _
1
1
1
2
2
i
1
3
3
1
C-22
-------
OKLAHOMA CITY RAWINSUNDC DATA
P (.MB-)
974,0
961.0
- 950,0
900.0
850.-0-
300.0
791,0
775.0
. _ 750.0
717.0
700,0
689 0
680.0
650.0
: _ 64-7-. 0-
600.0
589,0
cc n r\
500.0
484.0
P (MB)
970.0
951,0
950,0
900,0
-850,0
800,0
771,0
750.0
729.0
-7 flit (X
665.0
650.0
_ - 600,0
582.0
550.0
. _. .. . -500,0
472,0
463.0
- - - 450.0
400.0
MUN'IH
Z--(M)
392.
509.
-- fall.
1066.
1579,
''2095.
2191,
2363.
2638.
3012.
3215,
3 $45
3448,
3817,
3854. - --
4466.
4615,
Si b-4
5916,
6175.
MONTH
L (M)
392 ,
5o8,
577,
1055.
1552,
20/1.
- 2383.-
2ol5,
2051,
3186
3o07.
3794.
- 4447.-
4o93.
5146.
--.5902.
0352.
6501,
t>725.
/617.
9 DAY
T (C)
20,6
26.6
25,9
22.1
18,1
14,2
13.4
13.4
11,1
7.9
6.1
4.6
6,1
4,8
4,6
2,3
1.7
*! .5
-6.1
-7.6
9 DAY
T (C)
--32,8
26,9
28. 9
24.4
19,6
15.7
- 13,3 _ .
11.1
8,8
7.0
7.0
6,3
3,5
2,4
-0,4
-5,5 .-
-8.5
-9,8
-11.4 _
-15.4
3 i
MIX R
13.8
14,3
13,8
11.7
10,0
9,1
9,0
5,3
5,4
5,3
6,8
6 7
3,2
2.1
1,9
1.7
1,8
1 7
1,5
1.6
3
MIX R
- 11.4
10,6
10.6
9.6
8.6
6,8
5,8
6.1
6.5
3.1
2.3
2,2
2.2
2.3
2,1
1.8
2.2
2.7
2.7
1 .^
HOUR 600 CST
PT (K)
296,0
303.2
303,5
304,3
305,1
306.3
306,4
308.2
30H,6
309,1
309,2
309. 0
311,8
314.4
314,6 -
318.7
319.7
322.3
325.5
326.7
HOUR 1800 CST
PT (K)
308,6
306,4
306,5
306,7
306.7
307.9
308,6
308,6
308,6
310,2
314,8
316.1
- 320.1
321.6
323.6
326,3
328,0
328,2
328,8
334,9
WIND
160/
161/
162/
167/
188/
O/
O/
45/
43/
44/
53/
60/
67/
92/
96/
163/
184/
>"i p /
266/
276/
WIND
-1-50A
154/
154/
164/
172/
176/
-176/
188/
201/
20 7 /
219/
H28/
252/
272/
262/
272/
291/
298/
301/
2857
(M/S)
3
5
6
6
4
0
0
I
2
3
4
cr
5
6
6
4
4
i
6
4. . .
(M/S)
.7
7
7
7
4
2
2 -
3
4
i
6
4 ...
5
3
2
5 .... -
6
7
/ -
8
C-23
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
PEPORT NO.
! EPA-450/4-79-008C
2.
J4 TITLE AND SUBTITLE
Study of the Nature of Ozone, Oxides of Nitrogen and
Hydrocarbons in Tulsa, Oklahoma
Volume III Data Analysis and Interpretation
|7, AUThORjS)
IS. PERFORMING ORGANIZATION NAME AND ADDRESS
! 12. SPONSORING AGENCY NAME AND ADDRESS
15 SUPPLEMENTARY NOTES
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
September 1979
|6. PERFORMING ORGANIZATION CODE
18. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/OR ANT NO.
13. TYPE OF REF'ORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
J_
| 16. ABSTRACT " ~ '" " "~ " "" ' " ' ~ "~ ~ '"" """
I The 1977 Tulsa Study was conducted to provide the EPA with a high quality data
1 base for use it) testing various photochemical simulation models, The city of Tulsa
represents an isolated urban area, and thus provides an excellent location to observe
ozone formation from an individual urban area. The monitoring program was designed to
facilitate the observation of incoming pollutant transport and the formation of ozone
downwind. Pollutant and meteorological measurements were made frorr ground level moni-
toring sites and aboard an instrumented aircraft,
This volume reports on the analysis and interpretation of measured parameters.
Included are analyses of (1) the meteorological representativeness of the study area,
(2) the statistical relationship of ozone to other parameters, (3) the hydrocarbon
I and aircraft ozone measurements, and (4) case studies of periods of high ozone
i concentrations.
KEY WORDS AND DOCUMENT ANAL YSIS
DESCRIPTORS
18. DISTRIBUTION STATEMENT
b. IDENTIFIERS/OPEN ENDED TF.RMS C. COSATI Field/Group
19. SECURITY CLASS (This Reportj
20 SECURITY CLASS (This paife)
21. NO. OF PAGES
293
22. PRICE
EPA Form 2220! (Rev. 477) PREVIOUS EDITION is OBSOLETE
-------
CO CD -«-
83 ^
CO O
2
S<2w
w
------- |