report: 1981-06-00 (volume 4) summer field study; the ...15, 1978-december 10, 1978 intensive field...
TRANSCRIPT
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THE ORIGIN AND FATE OF AIRBORNE POLLUTANTS
WITHIN THE SAN JOAQUIN VALLEY
VOLUME 4 - SUMMER FIELD STUDY
by
Meteorology Research, Inc. California Institute of Technology Division of Chemistry and Chemical
T. B. Smith Engineering D. E. Lehrman
D. D. Reible F. H. Shair
Prepared for California Air Resources Board
June 1981
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The statements and conclusions in this report are those of the Contractors and not necessarily those of the State Air Resources Board. The mention of commercial products, their source or their use in connection with material reported herein is not to be construed as either an actual or implied endorsement of such products.
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ABSTRACT
An extensive observational proqram, lasting from November 1978 until
October 1979, was carried out to investigate the origin and transport of
pollutants in the San Joaquin Valley. Field studies were conducted during
the winter, summer and fall. Volume 3 describes the results of the November
15, 1978-December 10, 1978 intensive field study, along with two additional
tracer experiments conducted during relatively stagnant conditions in February
1979 and March 1979. The present volume (Volume 4) describes the summer
(July 1979) program. Volume 5 describes the fall (September 1979) program.
Participants in this study were Meteorology Research, Inc., California
Institute of Technology, Rockwell International (EMSC) and Environmental
Research and Technology (ERT). Six tracer releases provided the core of the July 1979 field program.
These releases were supported by supplementary meteorological observations
and airborne air quality sampling. Three Rockwell International vans,
located at Modesto, Merced and Madera, operated continuously to provide
additional air quality data. Filter samples obtained at each of the vans
were analyzed by ERT to investigate the particulate chemistry in the area.
The July 1979 field program was characterized by relatively warm
temperatures at the 850 mb level compared to the previous five-year average
suggesting conditions more conducive than average for pollutant buildup.
Maximum ozone concentrations observed during the July 1979 tracer
studies ranged from 0.11 to 0.17 ppm and were relatively uniform throughout
the valley. During the tracer studies, maximum carbon monoxide concen
trations ranged from 2 to 5 ppm, and maximum NOx concentrations ranged from
0.18 to 0.32 ppm; both the CO and NOx concentrations reflected strong urban
sources and were closely related to peak traffic periods.
During July, the average wind flow into the valley at Stockton and
Los Banos was a11 hours of the day.
At Fresno and Visalia the low level winds were usually from the southeast
during the early morning but from the northwest during the rest of the day;
the duration of the southeasterly winds was longer at Visalia, associated
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with the northward spreading of the "Fresno eddy" which develops during the
night as a result of stable conditions in the southern end of the valley.
Tracer released from Manteca during the morning of 7/13/1979 was
transported by northwesterly winds along Highway 99 for about 40 miles and
then along the San Joaquin River the lowest portion of the valley). The
tracer released from Manteca during the afternoon of 7/16/1979 was also
transported along the San Joaquin River. Horizontal and vertical rates of dispersion of the tracer were consistent with neutral or slightly unstable
atmospheric conditions, during both tests.
Tracer released from Livermore during the afternoon of 7/18/1979 was
transported by westerly winds over Altamont Pass and into the San Joaquin
Valley. On the day following the release, the tracer "cloud" was transported
down the western side of the valley in a manner similar to that found during
the releases from Manteca.
Tracer released from Reedley during the afternoon of 7/25/1979 was
initially transported by the upslope winds into the national forest and park
areas of the Sierra Nevada Mountains. Some of the tracer was then trans
ported by the nighttime downslope winds and finally impacted regions on the
western side of the valley. Tracer released aloft into the nighttime jet was transported to the
extreme southern end of the San Joaquin Valley by late morning of the day
following the release. The nocturnal jet appears to be an efficient mech
anism of transport to the southern end of the valley, but minimal ground level
impacts occur until the surface mixing layer deepens during the following
day.
Tracer released from Pacheco Pass during the afternoon of 7/30/1979
was carried aloft and essentially none was detected at ground level within
the valley.
In summary, pollutants transported into the San Joaquin Valley from
the California Delta, San Francisco Bay and Livermore regions were found to
primarily impact the western side of the northern half of the San Joaquin Valley.
The meteorological conditions during the summer are much less con
ducive to pollutant build-up than the relatively stagnant conditions which
often occur during the winter.
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The principal exit region for pollutants from the valley is the
Tehachapi mountain ridge which forms the southeast border of the valley.
The upslope flow along the north-south edges of the valley is relatively
inefficient in removing pollutants because of its diurnal nature and the
broad width of the valley. Consistent with the influx of air at the mouth
of the valley, the transport within the valley was generally southward.
The nocturnal jet enhances this southward movement and provides a mechanism
for distributing pollutants throughout the valley.
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1.
2. 2.1 2.2 2.3 2.4
3. 3.1
3.2
3.3
3.4
3.5
3.6
4.
Table of Contents
Introduction
Overview of the Meteorology and Air Quality Introduction Meteorology Air Quality Particulates
Tracer Surrmaries Test 1 13-14 July 1979,
(0700-1300 PDT) Test 2 16-17 July 1979,
(1300-1900 PDT) Test 3 18-19 July 1979,
(1510-2030 PDT)
Manteca Release
Manteca Release
Livermore Release
Test 4 25 July 1979, Reedley Release (1200-1700 PDT)
Test 5 27-28 July 1979, Airborne Herndon-Chowchilla Release (2300-0215 PDT)
Test 6 30 July 1979, Pacheco Pass Release (1200-1725 PDT)
Conclusions
Page
1-1
2-1 2-1 2-1 2-18 2-25
3-1
3-1
3-33
3-66
3-89
3-112
3-130
4-1
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LIST OF TABLES
Table No, Page
2.2.1 2.2.2 2,2.3
2.3.1 2.3.2 2.3.4 2.3.5
2.4.1
2.4.2
3.1.1 3. 1.2 3. 1.3 3, 1.4
3.1.5
3.2.1 3.2.2 3.2.3 3.2.4
3,2,5
3.3.1 3.3.2 3.3.3 3,3.4
3,4.1 3.4.2 3.4.3 3.4.4
3,5.1
3.6.1
Average Surface Pressure Gradients (July 1979) 2-3 1000-foot Resultant Winds (m/s) - July 1979 Average Wind Components* Along Valley Axis (July 2-7
Maximum Hourly Concentrations (ppm) July 2-19 Maximum Hourly Concentrations (ppm) July 2-20 Average NMHC Concentrations (ppb) July 06-09 PST 2-23 Time of Maximum Concentrations PST July 1979 2-24
Average Total Particle diameter<~ 20 µm) Concentrations Measured During July 1979 2-25 Estimated Contributions of Source Types to Average Fine Particle Mass During July 1979 2-27
Surface Winds at Manteca 13 July 1979 3-3 Aircraft Mixing Heights July 13, 1979 3-11 Maximum Hourly Concentrations July 13, 1979 3-14 Air Quality Measurements CARB San Joaquin Valley Project July 13, 1979 Sampling 3-16 Air Quality Measurements CARB San Joaquin Valley Project July 13, 1979 Sampling 3.... 17
Surface Winds at Manteca 16 July 1979 3-35 Aircraft Mixing Heights July 16-17, 1979 3-40 Maximum Hourly Concentrations July 16, 1979 3-42 Air Quality Measurements CARB San Joaquin Valley Project July 16, 1979 Sampling 3-44 Air Quality MMesurements CARB San Joaquin Valley Project July 17, 1979 Sampling 3-45
Surface Winds at Livermore 18-19 July 1979 3-68 Aircraft Mixing Height July 18, 1979 3-70 Maximum Hourly Concentrations July 18, 1979 3-74 Air Quality Measurements CARB San Joaquin Valley Project July 18, 1979 Sampling 3-78
Low-Level Winds 25-26 July 1979 3-91 Aircraft Mixing Heights July 25, 1979 3-96 Maximum Hourly Concentrations July 25, 1979 3-98 Air Quality Measurements CARR San Joaquin Valley Project July 25, 1979 Sampling 3-99
Maximum Hourly Concentrations July 27, 1979 3-118
Maximum Hourly Concentrations July 30, 1979 3-134
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LIST OF FIGURES
Figure No. Page
2.2.1 850 mb Temperatures - July 1979 2-2 2.2.2 Comparison of Wind Component (600 m) and Pressure Gradient 2-4 2.2.3 Comparison of Wind Component (600 m) and Pressure Gradient 2-6 2.2.4 Average Wind Components Along Valley Axis July 1979 (05 PDT) 2-9 2.2.5 Average Wind Components Along Valley Axis July 1979 (09 PDT) 2-10 2.2.6 Average Wind Components Along Valley Axis July 1979 (13 PDT) 2-11 2.2.7 Average Wind Components Along Valley Axis July 1979 (17 PDT) 2-12 2.2.8 Average Wind Components Along Valley Axis July 1979 (21 PDT) 2-13 2.2.9 1000 Ft-agl Streamlines - 18 July 1979 (21 PDT) 2-15 2.2.10 1000 Ft-agl Streamlines - 18 July 1979 (05 PDT) 2-16 2.2.11 Component Winds Along Valley Axis (Fresno) July 27-28, 1979 2-17
3.1.1 Surface Weather Charts - 13 July 1979 (05 PDT) 3-2 3.1.2 1000 Ft-agl Streamlines - 13 July 1979 (07 PDT) 3-4 3.1.3 1000 Ft-agl Streamlines - 13 July 1979 (09 PDT) 3-5 3.1.4 1000 Ft-agl Streamlines - 13 July 1979 (13 PDT) 3-6 3.1.5 1000 Ft-agl Streamlines - 13 July 1979 (19 PDT) 3-7 3.1.6 1000 Ft-agl Streamlines - 14 July 1979 (03 PDT) 3-8 3 .1.7 Vertical West-East Cross Section of Wind Component (m/s)
to Valley Axis - 13 July 1979, 07 PDT 3-10 3.1.8 Maximum Hourly Ozone Concentrations (pphm) - 13 July 1979 3-12 3.1. 7 Vertical West-East Cross Section of Ozone Concentrations (ppb)
Measured Between 0646-0916 PDT - 13 July 1979 3-13 3 .1.10 Sampling Routes 13 July 1979 3-15 3.1.11 Aircraft Sounding - 13 July 1979 3-19 3.1. 12 Aircraft Sounding - 13 July 1979 3-20 3.1.13 Aircraft Sounding - 13 July 1979 3-21 3.1.14 Aircraft Sounding - 13 July 1979 3-22 3.1.15 SF5 Release - Manteca 13 July 1979 3-24 3.1. 16 Sampler Locations 3-25 3.1.17 Highway Traverses 3-28 3.1.18 Gaussian Comparison 3-29 3.1.19 Tracer Trajectory 3-31 3.2.1 Surface Weather Charts - 17 July 1979 (05 PDT) 3-34 3.2.2 1000 Ft-agl Streamlines - 16 July 1979 (13 PDT) 3-36 3.2.3 1000 Ft-agl Streamlines - 16 July 1979 (19 PDT) 3-37 3.2.4 1000 Ft-agl Streamlines - 17 July 1979 (09 PDT) 3-38 3.2.5 Component Wind (m/s) From Turlock - 16 July 1979 3-39 3.2.6 Maximum Hourly Ozone Concentrations (pphm) - 16 July 1979 3-41 3.2.7 Sampling Routes - 16 July 1979 3-43 3.2.8 Aircraft Sounding - 16 July 1979 3-46 3.2.9 Aircraft Sounding - 16 July 1979 3-47 3.2.10 Aircraft Sounding - 16 July 1979 3-48 3.2.11 Aircraft Sounding - 16 July 1979 3-49 3.2.12 Aircraft Sounding - 16 July 1979 3-50 3.2.13 Aircraft Sounding - 17 July 1979 3-52 ..,, t"\ 1 A
J.l.l'+ Aircraft Sounding - 17 July 1979 3... 53 3.2.15 Aircraft Sounding - 17 July 1979 3-54 3.2.16 Aircraft Sounding - 17 July 1979 3-55 3.2.17 SF5 Release - Manteca 17 July 1979 3-58
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LIST OF FIGURES (Continued)
Figure No. Page
3.2.18 3.2.19 3.2.20 3.2.21 3.3.1 3.3.2
3.3.3 3.3.4 3.3.5 3.3.6 3.3.7 3.3.8 3.3.9 3.3.10 3.3.11 3.3.12 3 .3.13 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5
3.4.6 3.4.7 3.4.8 3.4.9 3.4.10 3 .4.11 3.4.12 3.4.13 3.4.14 3.5.1 3.5.2
3.5.3 3.5.4 3.5.5 3.5.6 3.5.7 3.5.8 3.5.9 3 .5.10 3.5.11 3.5.12 3.6.1 3.6.2
3.6.3 3.6.4 3.6.5 3.6.5
Sampler Locations - Test 2 3-59 Highway Traverses 3-61 Gaussian Comparison 3-62 Tracer Trajectory 3-65 Surface Weather Charts - 18 July 1979 (05 PDT) 3-67 Time-Height Cross Section Component Winds (m/s) From Altamont Pass 18-19 July 1979 3-69 1000 Ft-agl Streamlines - 18 July 1979 (15 PDT) 3-71 1000 Ft-agl Streamlines - 18 July 1979 (19 PDT) 3-72 1000 Ft-agl Streamlines - 19 July 1979 (05 PDT) 3-73 Maximum Hourly Ozone Concentrations (pphm) - 18 July 1979 3-75 Sampling Routes 18 July 1979 3-77 Aircraft Sounding - 18 July 1979 3-79 Aircraft Sounding - 18 July 1979 3-80 Aircraft Sounding - 18 July 1979 3-81 SF5 Release - Livermore 3-84 Sampler Locations - Test 3 3-85 Tracer Trajectories 3-87 Surface Weather Charts - 25 July 1979 (05 PDT) 3-90 1000 Ft-agl Streamlines - 25 July 1979 (15 PDT) 3-92 1000 Ft-agl Streamlines - 25 July 1979 (23 PDT) 3-93 1000 Ft-agl Streamlines - 26 July 1979 (05 PDT) 3-94 Time-Height Cross Section Component Winds (m/s) from Cherry Gap 25 July 1979 3-95 Maximum Hourly Ozone Concentrations (pphm) - 25 July 1979 3-97 Sampling Routes 25 July 1979 3-100 Aircraft Sounding - 25 July 1979 3-102 Aircraft Sounding - 25 July 1979 3-103 Aircraft Sounding - 25 July 1979 3-104 SF5 Release - Reedley 3-106 Sampler Locations - Test 4 3-107 Air and Auto Traverse Comparison 3-108 Sampler Trajectories 3-111 Surface Weather Charts - 28 July 1979 (05 PDT) 3-113 Time-Height Cross Section Component Winds (m/s) from Madera 27-28 July 1979 3-114 1000 Ft-agl Streamlines - 27 July 1979 (23 PDT) 3-115 1000 Ft-agl Streamlines - 28 July 1979 (09 PDT) 3-116 1000 Ft-agl Streamlines - 28 July 1979 (11 PDT) 3-117 Maximum Hourly Ozone Concentrations (pphm) 27 July 1979 3-119 Wind Profiles Test 5, 27-28 July 1979 3-121 Nocturnal Jet Velocity Profiles 3-122 SF5 Release - Airborne 3-124 Sampler Locations - Test 5 3-125 Air Trav Data Comparison 3-126 Sampler Trajectories 3-128 Surface Weather Chart - 30 July 1979 (05 PDT) 3-131 Time-Height Cross Section of Through Pass Component of Wind (m/s) at Pacheco Pass - 30 July 1979 3-132 1000 Ft-agl Streamlines - 30 July 1979 (15 PDT) 3-133 Maximum Hourly Ozone Concentrations (pphm) - 30 July 1979 3-135 SF5 Release - Los Banos 3-138 Sampler Locations - Test 6 3-139
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1. Introduction
SurT111er months in the San Joaquin Valley are characterized meteor
ologically by intense solar heating and generally clear skies. Strong frontal passages do not occur but weak cold air troughs move through the area resulting in changes in stability and fluctuating mixing heights.
These changes are reflected in significant day-to-day variations in pollutant levels in spite of the apparently small changes occurring in the synoptic weather charts. Fresno-Olive Street, for example, showed
maximum daily ozone concentrations ranging from .03 to .17 ppm during the month of July 1979.
The principal driving force for the low-level winds in the valley is the pressure gradient between the coast and the interior (east of the Sierra Nevadas, for example). The cold air trough passages serve to increase these surface pressure gradients and increase the flow into the valley from the northwest.
The strong solar insolation and the possibility of stagnation
episodes within the vaiiey raise serious questions concerning ozone formation during the summer months. Additional problems which were addressed during the summer field study were the transport of pollutants from the Bay area into the San Joaquin Valley, the role of the nocturnal wind jet in redistributing material throughout the valley and the effectiveness of upslope transport in removing pollution from the valley.
The summer field program consisted of six tracer releases as listed below. Each release was supported by pibal wind soundings and aircraft measurements. A network of five additional pibal stations was maintained independently during the field study by the California Air Resources Board (CARB). These stations were located at Stockton, Los Banos, Fresno, Visalia and Bakersfield, regardless of test location. Two pibal sounding stations supported by the field program itself were moved from test to test to obtain the best wind coverage possible.
Three Rockwell International vans were positioned to the east of Modesto, Merced and Madera to obtain surface air quality data. Environmental Research and Technology (ERT provided filter samplers which were operated at each van. Analyses and interpretation of the filter samples were carried out
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by ERT. The Atmospheric Testing Branch of the CARB at El Monte obtained hydrocarbon samples several times daily at Stockton, Tracy, and at two locations in Fresno. A number of aircraft samples were a·lso obtained. The
samples were subsequently analyzed by CARB for C2 through C10• The following tracer releases were carried out during July 1979:
Release Location Date Release Time Jul_y 1979 PDT
Manteca 13 0700-1300
Manteca 16 1300-1900 Livermore 18 1510-2030 Reedley 25 1200-1700 Herndon to
Chowchilla (airborne) 27-28 2330-0215 Pacheco Pass 30 1200-1725
The present volume (Volume 4) discusses the details of the July field program including a11 pertinent tracer and aircraft sampling data (Appendix to Volume 4). Surface and pibal wind data have been furnished to CARB on magnetic tape. Separate reports (Volumes 6 and 7) give the details
of the Rockwell International and ERT work, respectively. Portions of these reports have been used in the present volume where appropriate.
Volumes 3, 4 and 5 of the report series cover the details of the three field programs. Volume 2 contains an extended summary of the entire program and a discussion of a number of special analysis topics which resulted from the field measurement program. Volume 1 is an Executive Summary of the program.
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2. Overview of the Meteorology and Air Quality
2.1 Introduction
The following sections describe the general conditions which occurred during the July 1979 intensive field period. The overall meteorological conditions are summarized and compared to climatological records to determine the representativeness of the test period. Descriptions of
air quality and particulate concentrations for the intensive period are sunmarized from the more extensive reports by Rockwell International and ERT which appear as Volumes 6 and 7 of this report series.
2.2 Meteorology
850 mb Temperatures
Temperatures at the 850 mb level provide a simple indicator of the regional air pollution potential. Warm temperatures aloft create the
stability required to trap the pollutants in the lower layers. Figure 2.2.1 shows the daily variation in 05 PDT temperatures at
850 mb for Vandenberg AFB and Oakland during the month of July 1979. The five-year average temperatures for Vandenberg and Oakland are also shown in the figure.
After the first seven days of the month, the temperatures at 850 mb were generally above normal. Test dates are indicated in the figure. All tracer tests were carried out under conditions of above normal temperatures aloft. As indicated, Test 3 was conducted with the 850 mb temperature eight degrees above normal and represents the most stable episode period encountered during July.
Surface Pressure Gradients
In the absence of major changes in synoptic weather patterns during July, the principal driving force for winds in the San Joaquin Valley results from lower surface pressures east of the Sierras relative to the coastal areas.
Strong surface heating in eastern California and Nevada causes a low pressure, thermal trough to persist throughout most of the summer.
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.,,..,.,,.,,·'
'·\i -Five Year
I Average ------- -...-20
u I \,~
"' ,_ w
=> er 10 l l l l l l
N w Tests I 2 3 4 5 I, "' I Q.N :,,:
,_w
Vandenberg
:;."' Oakland
Tracer Relei1ses0
1
5 10 15 20 25 30 Date
Figure 2.2.1 850 mb Temperatures - July 1979
ll/DZZ
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Table 2.2.1 gives the average surface pressure gradients during
July 1979 between San Francisco Airport and Las Vegas. This parameter is
one indicator of the strength of the surface pressure gradient affecting
the valley. Other pressure differences could also be used. The table shows typical diurnal changes in pressure gradient with peak values in the late
afternoon when the results of the afternoon heating have taken effect.
Day-to-day relationships between surface pressure g~adients and
wind speeds are apparent but are occasionally masked by local effects not adequately measured by the simple, single pressure gradient parameter being
suggested above. Figure 2.2.2 shows the daily variations in pressure gradient
for July 1979 at 1600 PDT related to the 600-m winds at Los Banos and Stockton
at 1700 PDT. Wind speeds in the figure refer to the component directed along the valley axis with positive numbers referring to wind flow from Stockton
toward Bakersfield.
Table 2.2.1
Average Surface Pressure Gradients (July 1979) San Francisco-Las Vegas
Time Pressure Difference (PST) (mbs) 00 6.0
03 5.6
06 4.6
09 4.4 12 5.2
15 6.3
18 6.7
21 6.2
The pressure gradients in Figure 2.2.2 indicate lower than average
values throughout much of the month with the exception of two periods around
the 10th and 27th. Reference to Figure 2.2.1 indicates that the warm temper
ature period during mid-month was associated with below average pressure
gradients.
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1 0
"' ...... E:
C 5 w w CL. I V) ' ' / \. ...,_... STOCKTON ( 17 PDT)C
WIND COMPONENT ALONG VALLEY AXIS
z
3:
0
1 0 1 5 20 25 30 DA TE
.0
\J
E
.... z L.J... C C( IX (.!'
L.J IX :, V)
10 I 6 Year Average
VJ 5 L.J IX CL.
1 0 1 5 20
PDT PRESSURE GRADIENT (SFO- LAS VEGAS)
25 3 0 DA TE
81/054Figure 2.2.2 Comparison of Wind Component 600 m) and Pressure Gradient
July 1979
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There is considerable similarity between the pressure gradient vari
ations and the wind speed characteristics for Stockton and Los Banos. In
particular, the large pressure gradient values near the 10th resulted in
unusually strong wind flow. The pressure gradient peak on the 27th is also
somewhat reflected in the Stockton wind speeds. The primary difference
between the two plots occurs near the 20th when the major drop in pressure
gradient is only partly reflected in the Stockton-Los Banos winds.
A similar comparison of the San Francisco-Las Vegas pressure gradient
and the Bakersfield wind at 600 mis shown in Figure 2.2.3. In this case,
the minimum pressure gradient on the 20th shows up clearly as a negative
wind component at Bakersfield. The similarities in the two plots, in fact,
are quite pronounced with the exception of the peak pressure gradient on the
27th.
These figures indicate the association between surface pressure gradi
ents and the flow along the valley axis but suggest that the details of the
wind response to gradient fluctuation may not be entirely consistent through
out the valley. In particular, the northern and southern parts of the valley
may respond in somewhat different ways.
Valley Wind Characteristics
Pibal wind coverage during July 1979 was carried out for 22 days at
the five locations shown in Table 2.2.2. Observations were taken on virtually
every day at the times shown in the table. Additional observations were made
on test days but are not available for the entire 22 day period.
Resultant winds at 1000 feet (agl) for the 22-day period have been calculated by averaging wind components over the 22 days by time of day.
Principal features shown in the table are:
Northwest winds at Stockton and Los Banos at all hours. Southeast winds at Fresno (09 PDT) and Visalia (05 and
09 PDT) in association with the Fresno Eddy.
Peak winds at 21 PDT for most locations.
Light west to northwest winds at Bakersfield except for
late afternoon and evening.
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l 0
"' ....... E
0 5 LW LW Q..
V')
C z: ...... ::i:
0
l 0 l 5 20
..c::,
~ LW .... 0 cc 0:: t!:)
LW
0:: ::, V')
V')
LW 0:: Q..
l 0
6 Year Average
5
PDT PRESSURE GRADIENT (SFO-
l 0 1 5 25 3 0
Figure 2.2.3 Comparison of Wind Component (600 m) and Pressure Gradient July 1979
2-6
BAKERS FI ELD ( 1 7 PDT)
WIND COMPONENT ALONG VALLEY AXIS
25 30 DATE
LAS VEGAS)
DA TE
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Table 2.2.2
1000-foot Resultant Winds (m/s) July 1979
PDT 05 09 u i7 2i
Stockton 310°/4.4 319°/3.3 316°/3.5 321°/4.8 291°/7.4
Los Banos 304 /5.5 320 /4.1 341 /4.3 335 /5.1 328 /7.4
Fresno 338 /3.9 134 /2. 9 282 /2.5 303 /4.5 313 /7.7 Visalia 167 /2.4 169 /3.5 285 /2.1 316 /3.9 320 /4.6
Bakersfield 316 /1.0 276 /0.4 309 /1.9 317 /3.9 330 /2.7
Table 2.2.3 shows the average wind components directed along the axis
of the valley for July 1979. Surface wind components at Stockton are shown
together with 1000-foot components at all pibal locations. Positive values
indicate flow directed from Stockton to Bakersfield.
Table 2.2.3
Average Wind Components* Along Valley Axis (July)
a. Surface Winds (m/s) Location Time (PDT)
03 09 15 21
Stockton 2.0 2.7 3.9 3.5
b. 1000-foot Winds (m/s)
Location 05 09
Time (PDT) 13 17 21
Stockton 4.3 3.3 3.5 4.8 5.7
Los Banos 4.9 4.2 4.3 5.1 7.4
Fresno 3.8 -3.8 1.7 4.0 7.7
Visalia -2.1 -3.3 0.9 3.8 4.7 Bakersfield 1.3 0.2 1.8 3.8 2.7
* Negative components refer to southeasterly winds
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As indicated in the table, flow is directed into the valley in the
lowest 1000 feet at all times of day. The negative values at Fresno and
Visalia result from the influence of the Fresno Eddy, Peak flow into the
valley occurs at 21 PDT. It is to be noted that the flow along the valley
is relatively constant at all locations at 17 PDT, suggesting a constant flux
into and out of the valley. For the other hours, however, continuity is not
maintained and it is clear that major areas of convergence and divergence
must exist.
The component values along the axis of the valley are shown in more
detail in Figures 2.2.4 through 2.2.8. Average profiles of the axis wind
component are shown for each location at 05, 09, 13, 17 and 21 PDT.
The principal features of interest in the figures are the following:
The average profiles at 17 PDT (Figure 2.2.7) are
similar at all locations.
The average profiles at Stockton and Los Banos
are similar at all times.
At 21 PDT the Visalia profile is similar to Fresno
but with slightly reduced speeds. The Bakersfield
profile at 21 PDT, however, shows a marked decrease
in velocity to 1000 m (agl) and an increase in speed
above that height. This is interpreted as the first
evidence of low-level blocking of the flow in the
southern end of the valley by stability and terrain.
It is apparent that a part of the flow is diverted
aloft to a level where escape over the terrain is
possible. This is considered to be the initiation of the Fresno Eddy.
At 05 PDT the effect of the blocking has extended upstream to Visalia. Velocities are reduced in the
lowest 1000 mat both Bakersfield and Visalia but
increased aloft. This development is associated with
the spreading of the Fresno Eddy to the north.
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'o I
I
f ),
y
\I
2500
~ \
t 2000 ~
e ~ ~
0 ,•I
z =:, 0 er '-'>
w 1500 ~ > 0 cc c::c ~ :i:::
.... ~ w :i:::
1000
500 -- STOCKTON I•---- LOS BANOS ------- FRESNO
I
f
I
•I•I I
•I
I I
,1 --VISALIA r _---BAKERSFIELD
•I
-5 0 5 r./s -5 0
Figure 2.2.4 Average Wind Components Along Valley Axis July 1979 (05 PDT)
8 ~
'-' ..,
I
I•
,' I f '
I
5 m/ s
II /049
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2500
i 2000 ~
E-0 z :=, 0 ex: Cl
1500
1-:r:: Cl
LIJ :r::
l 000
-- STOCKTON ---- LOS BANOS ------- FRESNO
.•
I ,•
I
•I
I
•
I,•
--VISALIA ----BAKERSFIELD
0
500, .•· .... ' I
<( 1' , .. r ••·I•
-5 0 5 w,/ s -5 5 m/ s
11 /050
Figure 2.2.5 Average Wind Components Along Valley Axis July 1979 (09 PDT)
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2500
2000 E ~
0 z :=, 0 c::: t!l
L..i 1500> 0 a:l < I-X t!l
L..i X
1000 -- STOCKTON
'~, - --- L,.U,;, BANOS ·····-· FRESNO
500
-5
Figure 2.2.6
. ;
•I
•' •
' •
J ; __ VISALIA I ~---BAKERSF!cL:)
I
I•I '•' •I
•I
I
•
0 5 11/ s -5 0
Average Wind Components Along Valley Axis July 1979 (13 PDT)
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~ . ' . ~
I
• I. '
'
2500
2 000 ....... E ~
C z ::, 0 c:: c.:,
w 1500> 0 cc c:c I-:c: c.:,
w :c:
1000
500
F
SCK >Lose
. ~ ' '
__ SiOCKiOI\ BANOS---- LOS
•..•.•. FRESNO
f
• f :
\
~ \
' I I ~ ' ~. ·~ :
;
' -5
Figure 2.2.7
0 5 ., s -5 0
Average Wind Components Along Valley Axis July 1979 (17 PDT)
2-12
,, \ .I \
~
\ ~\
~ I
1,/J
5 II/ S
ll /052
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• •
,~'-. \
•, \ '. ' ---. '-._
'_
"'
2500
2000 E
C z: :::, 0 c:: t.:,
1soo-
cC
1-::t: t.:, .... ..... ::t:
1000
Isoo+-
-- STOCKTON ---- LOS BANOS ------- FRESNO
-5
Figure 2.2.8
Loss
SC(!K~,F .
•.. .. I\ : .' .•
.• .\\··.·,. .
....
I
'· \
\'. ' ~ \ -I
··-.r h
I ;
,._) ,,~,.,.
.:.. -
0 5 .. , 5 -5
Averaae Wind Comoonents Along Valley Axis July 1979 (21 PDT)
2-13
V B
1 f\\ t '•
•
I ' • •
'• I
I• I\
•
1
•I I
•I
•
--VISALIA -- --BAKERSF!EU
' j• \
♦
~ '
' I ' I
/ •
0
81/053
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By 09 PDT the blocking in the lowest 1000 m affects
the wind flow at Fresno. Both Visalia and Bakersfield
continue to show increased velocities above 1000 m.
Remnants of the low level blocking and increased
flow aloft continue as late as 13 PDT but to a
reduced degree. By 17 PDT the flow becomes rela
tively uniform at all locations.
The foregoing leads to a physical picture in which the northwesterly
flow is blocked in the southern part of the valley by terrain as low-level
stability develops in the early evening. The low-level flow is diverted into a cyclonic eddy about 1000 m deep which gradually extends to the north as far
as Fresno. Some of the northwesterly flow approaching this eddy is deflected
aloft and is able to escape from the southern part of the valley at altitudes
above 1000 m.
Two phases in this development are shown in Figures 2,2.9 and 2,2,10,
At 21 PDT on July 18 (Figure 2.2.9) the flow in the valley was uniformly from
the northwest at 1000 ft agl. The wind speed at Bakersfield (3.7 m/s), how
ever, was considerably less than at locations to the north, indicating the onset of the blocking effect. By 05 PDT of the following morning (Figure
2.2.10) the eddy at 1000 ft had extended as far north as Fresno.
Of the 22 days in July 1979 for which detailed pibal data were avail
able, the Fresno Eddy formed on 18 days. There was no significant eddy on July 10, 11, 26 and 28. Reference to Figure 2.2.1 indicates that these days
were characterized by cold trough passages aloft, resulting in disruption of
the stabilizing conditions required for the eddy formation. Under these
slightly less stable conditions, wind flow can continue from the northwest
all night, transporting air out of the southern part of the valley.
Nocturnal Wind Jet
On numerous nights a nocturnal wind jet is observed to form in the
San Joaquin Valley, particularly in the Fresno area. Northwest winds in
crease in the low levels, peaking at 21 to 23 PDT. An example is shown in
Figure 2.2.11 for the night of July 27-28 when a tracer release was made
into the center of the jet. The time section of valley axis wind components
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...,
4 N i
. . . " . - --Figure 2.2.9 1000 Ft-agl Streamlines - 18 July 1979 (21 PDT)
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•ta.I ~ft ! If If '.
. . . " . - . -,. ...... ,·.-·· ...... -
•.•
.... ,. Figure 2.2.10 1000 Ft-agl Streamlines - 19 Juiy 1979 (05 PDT)
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0 0 0
\..., _.-o1711D ~ \ '-./\)
0
-- I \ E 1447 ~
~' C z :::::, 0 0:: <.!) 1170 ('Lu > 0 ... 3 a:l c(
846 I-:c <.!)
N ..... I,__. Lu
-..J :c 612 r-
313 I-
, I \ --... 3 __________,
' ~ \..@_ rT~ ~,,,3 m/s
0 0 81 /043
11 15 19 23 3 7 11 TIME ( PDT)
Figure 2.2.ll Component Winds Along Valley Axis July 27-28, 1979
(Fresno)
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indicates increasing low level velocities beginning about 19 PDT with a peak near 300 m elevation at 23 PDT. The influence of the Fresno Eddy is shown by the negative wind values at 09 PDT.
The jet is caused by decreasing friction in the low layers accompanying the evening stabilization of the low levels. Under the influence of a strong driving force due to the existing pressure gradient, the air aloft accelerates resulting in relatively high velocities at low levels. During the 22 days of pibal data in July 1979, a strong jet occurred on nine nights while a moderate jet formed on four others. Further discussion of the
nocturnal jet is given in Volume 2.
2.3 Air Quality
Tables 2.3.1 and 2.3.2 give the maximum hourly concentrations of various parameters as observed during the July 1979 intensive field program. Concentrations were observed at Modesto (RI), Merced (RI) and Madera (RI) by Rockwell International vans. The remainder of the concentration data were obtained from CARB Air Quality Data. Similar data for the months of July 1977 and 1978 are also included for comparison.
Comparison of July 1977, 1978 and 1979 indicates that peak hourly concentrations were very similar in all three years. It is therefore concluded that the pollutant conditions during the field period were as representative
of Juiy poiiutant episode conditions as could reasonably be expected.
Ozone
Maximum hourly ·concentrations of ozone in Table 2.3.1 indicate rather uniform values throughout the valley but with slightly higher concentrations near the major urban areas. A number of locations on the eastern side of the valley show maximum values above the federal standard of 0.12 ppm. There were eight days of exceedances at the Modesto (RI) site during July 1979 and five and eight exceedances at the Merced and Madera sites, respectively. Lowest hourly maxima occur on the western side of the valley. There appears to be little change over the three-year period 1977-79. Maximum concentrations recorded at the regularly reporting stations were .16, .16 and .17 ppm in the three years. Shaver Lake shows a peak hourly value of .13 ppm for each year, indicating the importance of upslope fiow from the valley.
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--------------------------------------------------------------------------------
Table 2.3.1
Maximum Hourly Concentrations (ppm) July
03 co Field Field
Location 1977 1978 1979 1977 1978 1979
Bakersfield .12 .13 .16 8 6 4
Coalinga .10 .10 1 2
Five Points .12 .08 .08 2 2
Fountain Springs .13 .13 Squaw Valley .13 .16
FNO-But 1er
FNO-CSU .17 2
FNO-Downtown
FNO-Olive .16 .15 .17 8 4 5 Hanford .12 .05 .11
Lindsay .11 .14
Los Banos .12 .13 .10
McKittrick Merced .14 .10 3 2
Modesto .12 .17 3 3 Oil dale .16 .14
Shaver Lake .13 .13 .18 2 2 1 Stockton .16 .14 4 3 Taft .09 .10
Turlock .15 .15 .16
Visalia .09 .13 .12 5 4
Modesto (RI ) .19 0.6
Merced (RI) .13 Madera RI .15 1.2
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--------------------------------------------------------------------------------
Table 2.3.2
Maximum Hourly Concentrations (ppm)July
X 2 Field Field
Location 1977 1978 1979 1977 1978 1979
Bakersfield .38 .35 .27 .04 .08 . 06
Coalinga .04 .09
Five Points .02 .01
FN0-CSU
FN0-0live .43 .15 .18 .02 .02 McKittrick
Merced .24 .13
Modesto .22 .39 .02
0ildale .15 .15 •07
Stockton .23
Visalia .20 .17 .13
Modesto (RI ) .04
Merced (RI ) .03
Madera (RI) .02
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co The maximum CO concentrations during July 1979 show the strong
influence of urban centers. Bakersfield and Fresno consistently record the
highest values in the valley, ranging from a peak value of 5 to 8 ppm in the three-year period. Peak hourly values of 1-2 pm'are typical for the rural areas and the west side of the valley.
Nitrogen Oxides
Nitrogen oxides (NOx) concentrations also reflect the influence of
urban areas. Generally, Fresno and Bakersfield report the highest hourly concentrations. In July 1979, however, there were four days at Modesto during the month which exceeded peak concentrations at any other location.
With the exception of Modesto, the peak hourly NOx concentrations during July 1979 appeared to be slightly lower than observed in 1977 and 1978. In the rural areas and the western side of the valley, NOx concentrations tend to be very low, frequently not exceeding .10 ppm.
Sulfur Dioxide
Sulfur dioxide concentrations in the valley were generally low during July 1979. Highest values were recorded at Bakersfield and Oildale where .06
and .07 ppm, respectively, were observed. The remaining maximum values measured in the valley were .01 to .02 ppm. These background values were the same as observed in July 1977 and 1978 but the concentrations for Oildale and Bakersfield were slightly lower than observed in the previous two years.
Hydrocarbons
Non-methane hydrocarbons (NMHC were measured at Stockton, Tracy and two locations in Fresno during July 1979. Samples were obtained and analyzed
by the Atmospheric Testing Branch, California Air Resources Board (El Monte). Samples were usually taken three times per day and subsequently analyzed for
C2 through C10-
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Table 2.3.4 gives the average concentrations of various hydrocarbons
measured during July. Total NMHC averaged less than 200 ppb with the ex
ception of Riverside which was influenced by one large sample of propane.
The automobile contribution to NMHC was low at all stations as suggested
by the low values of acetylene. Propane was the largest contributor to the
total NMHC concentration.
NOx concentrations were not obtained at Stockton during July 1979.
Concentrations of NOx at Union Island between 06 ad 09 PST ranged from .01
to .04 ppm. Values at Stockton may have been somewhat higher. Use of the
Union Island NOx values yields an average NMHC/NOx ratio of about 5 with
a range from 2 to 14 on individual days. The small concentrations of NMHC,
however, preclude the formation of much ozone, particularly in view of the
low concentrations of the more reactive forms of NMHC.
Time of Peak Hourly Concentrations
Table 2.3.5 gives the principal periods of the day when peak ozone
and NOx concentrations were observed at several stations during July 1979.
On some days, the peak concentrations occurred outside of the principal
period indicated. If such occurrences were sufficiently frequent the time
of day was included in the table in parentheses.
It is apparent from the table that there are two peak ozone periods
in the northern part of the valley. One of these occurs near or slightly '
after noon and can be attributed to local sources. The second occurs be-
tween 15 and 20 PST and must be associated with transport of ozone or precursors into the area. It is to be noted that the late afternoon peak at
the three Rockwell sites appears to be at about the same time of day. As a consequence, the evidence of a pulse of ozone moving from north to south
along the valley axis is not particularly good. Anthropogenic activities along Highway 99 with associated urban influences may be a better source
for the late afternoon peak. The stong urban, local influence at Fresno is apparent from the
timing of the peak at 11-13 PST.
NOx peaks occur most frequently during the morning hours from mid
night to 08 PST, reflecting the accumulation of combustion products during
the most stagnant period of the day.
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Table 2.3.4
Average NMHC Concentrations July 1979 (06-09 PST)
(ppb)
Name Number of Samples Ethane
Stockton 9 11
Tracy 9 11
CSU 3 22
Fresno Riverside
2 20
Ethylene
Acetylene Propane Propylene Pro pad i ene
Isobutane
8
7 45
8 0
12
7
6 18 6 0 9
11
10
49 10 0 7
9
9 209
21 0
13
N-Butane 20 13 14 23
1-Butene 2-Butene y _____ .,L ----
1~openLctne
N-Pentane
1 4
.., ~ t::::J
13
1
3
17 8
1
3
24
16
0 5
61
39
Total 134 99 167 418
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Table 2.3.5
Time of Maximum Concentration (PST) July 1979
0 NO Modesto (RI) 17-20 (13-16) 06-08 (20-23) Merced (RI) 16-20 (13-14) 00-07 Madera (RI) 11-14 (16-20) 00-06 (11-12) Turlock 12-14 ( 15-17) Modesto 14-17 05-07 Madera 14-17 FNO-CSU 11-13
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2.4 Particulates
2.4.1 Total Particle Composition
Average total particle concentrations from the July 1979 intensive
are listed in Table 2.4.1. The major components on the average at aii three
sites were silicon, sulfate, and carbon with silicon tending to be the
largest, and sulfate and carbon concentrations being nearly equal. Average
concentrations of the crustal-like elements were highest at Merced and about
equal at Modesto and Madera. Average concentrations of the other elements
were not significantly different from one site to another. The average mass
concentration at Merced was about 20 percent higher than at the other sites.
Table 2.4.1
Average Total Particle (diameter <~ 20 µm) Concentrations Measured During July 1979
Component Modesto (14 Sameles) Merced Location (14 Sameles) Madera (7 Samples)
(,, n /m3)\t"' ;:, I '" I (% Mass) (µ g/m3) (% Mass) (µg/m3) (% Mass)
Mass 68.6 82.3 64.0 so=4-
9.5 13.8 8.9 10.8 7.0 10. 9
N03 3.1 4.5 2.7 3.3 2.4 - 3.8 +
NH,1·+
2.9 4.2 2.4 2.9 1.8 2.8
C 7.8 11.4 8.3 10.1 7.3 11.4
Al 3.5 5.1 4.8 5.8 3.9 6.1
Si 10 14.6 14 17.0 11 17.2
Cl 0.10 0.1 0.13 0.2 0.078 0.1
K 0.99 1.4 1.3 1.6 0.99 1.6
Ca 0.97 1.4 1.3 1.6 0.82 1. 3
Ti 0.19 0.03 0.26 0.3 0.21 0.3
V 0.019 2.6 0.020 0.02 0.018 0.03
Fe 1.8 0.02 2.6 3.2 2.1 3.3
Ni 0.011 0.04 0.0086 0.01 0.0078 0.01
Zn 0.030 0.03 0.035 0.04 0.020 0.03
Br 0.020 0.2 0.021 0.03 0.019 0.03 nL t'U " 1 ')u • .1..>
/'I , /'IVe .J.V
/'I ,v,i /'l /'lO'l
V• VJV /'l 1V••
Sum of Measured Comeonents 41.1 59.9 46.9 57.0 37.8 59.0
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2.4.2 Source Contributions to Total Particle Concentration
Averages of the estimated contributions of the source types to total
particle samples for the July 1979 period are in Table 2.4.2. Emissions of
crustal-like materials accounted for the largest fraction of the mass.
Emissions from uncultivated land contributed substantially less material than
did emissions from cultivated land.
Emissions of crustal-like materials accounted for the largest fraction
of the mass. Emissions from uncultivated land contributed substantially less
material than did emissions from cultivated land.
Contributions of particles emitted directly by motor vehicles and oil
combustion were small, accounting for less than 1 percent of the mass at all
sites.
Ammonium sulfate contributed 9 to 15 percent of the average mass, while ammonium nitrate contributed 3 to 6 percent. Carbon from unidentified
sources accounted for about 10 percent of the average mass. The source types in the calculations, including excess carbon, accounted
for 96 to 102 percent of the average measured mass.
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Table 2.4.2
Estimated Contributions of Source Types To Average Total Particle Mass During July 1979
Source Type Modesto 14 Samples)
Location Merced
14 Samples) Madera
(6 Samples) (µg/m3) (%) (µg/m3) (%) (µg/m3) (%)
Cultivated land 37.0 54.0 57.0 70.0 49.0 74.0
Uncultivated land 6.0 9.0 3.0 4.0
Motor vehicles (primary)* 0.4 0.6 0.4 0.5 0.3 0.5 Oil combustion (primary)** 0.2 0.3 0.2 0.2 0.2 0.3
(NH42 S04 10.0 15.0 8.0 10.0 6.0 9.0
(NH4) N03 4.0 6.0 3.0 4.0 3.0 5.0
Unidentified C 8.0 12.0 8.0 10.0 8.0 12.0
Sum 66.0 96.0 80.0 98.0 67.0 102.0 Measured Mass 69,0 82.0 66,0
* Includes only motor vehicle exhaust. Resuspended road dust is not
distinguishable from cultivated and uncultivated land. Conversion
of NOx emissions to nitrate is included with NH4 N03. ** Sulfate formed from S02 emissions and nitrate formed from NOx emissions
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3. Tracer Summaries
3.1 Test 1 13-14 July 1979, Manteca Release 0700-1300 PDT)
3.1.1 Meteorology
General
The synoptic meteorology of the 13-14 July period was characterized by an extensive, flat high pressure region aloft over the southwestern states (Figure 3.1.1). Maximum heights at 500 mb were located just offshore of California inducing subsidence and warming of the air aloft over the region of interest. The warming and stabilization of the atmosphere is reflected in the 850 mb temperatures from Oakland and Vandenberg shown in
Figure 2.2.1. At the surface, a thermal trough was established over the Central Valley and southern desert resulting in an on-shore pressure gradient. Clear skies prevailed throughout the San Joaquin Valley. Visibilities were greater than 20 miles in the northern region of the valley, but decreased to about 10 miles in the southern portions. Surface temperatures were near normal for the time of year; maximum temperatures near 100°F were measured at all locations in the valley with Bakersfield reporting a high of 104°F on the afternoon of the 14th.
Transport Winds
Surface winds at the tracer release site are tabulated in Table 3.1.1 from the start of the release until midnight when the northwesterly flow ceased and winds became light and variable. The winds at the release site were persistent from the northwest at speeds ranging from 2-4 m/sec throughout the morning and afternoon. Streamlines of the airflow at 1000 ft-agl, constructed from observed pibal winds, are depicted on Figures 3,1.2 through 3.1.6. At 0700 PDT on the 13th, a strong northwesterly flow was present on the west side, extending the entire length of the valley. At the southern end, a Fresno eddy had formed. Air was diverted and returned northward along the east flank of the valley. The formation of the eddy is a common occurrence in the summer months and is described in more detail in Volume 2 of this study.
3-1
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lo 0..
U")
Cl
,-...
°'...... °'
>, r:::,
-:,
M ......
V)
+-' ~
..c ~
u s.. Cl)
..c +-' ~ Cl) 3:
Cl) u .... ~ ~~-
......
....... M
Cl) ~ ::,
-~ C'l
LL.
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I
Table 3.1.1
SURFACE WINDS AT MANTECA 13 JULY 1979
T;m,l"I, Wind (PDT) (m/s)
0700 290/2.4
0800 285/3.1
0900 295/4.2
1000 300/4.2
1100 300/3.8
1200 295/3.8
1300 300/3.6
1400 300/3.5
1500 300/3.3
1600 315/3.2
1700 305/2.9
1111"'-
., nnn. "'Inn'"' r:'!OUU ;)UU/ C.o :;J
1900 305/1.8
2000 270/1. 2
2100 290/1. 3
2200 ?QI; /1 . i:;---, .... -2300 005/0.6
3-3
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-("
st.._,••c'!!f!f'•
. . . - - - --Figure 3.1.2 1000 Ft-agl Streamlines - 13 July 1979 (07 PDT)
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...
U&.LI
0 C'...
-~., ! 1f' Ip,. . . . - - - --·- :; . . ' ... .-..
-, 4;·
. ;'
Figure 3.1.3 1000 Ft-agl Streamlines - 13 July 1979 (09 PDT)
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~ N I
.,_, .. -_!_••=~!•~c::::~!-~tf_:__:___~_ c-,... - July 1979 (13 PDT)
- Figure 3.1. 4 1000 Ft-ag1 Streaml ,n. es - 13
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...
HM.I
-~ • '! ! 'If If ,. . . . - - - --
I
Figure 3.1.5 1000 Ft-agl Streamlines - 13 July 1979 (19 PDT)
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..,
sc ... ,~ft.........¥.....JJf..-.Jf ••
. . . . . - --Figure 3.1.6 1000 Ft-agl Streamlines - 14 July 1979 03 PDT)
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By 0900 PDT (Figure 3.1.3) the southerly flow had extended as far
north as Modesto Reservoir so that the eddy dominated the entire valley.
This northward extension was unusual within the July observational period.
Generally, the eddy does not extend very much beyond Fresno. The eddy per
sisted through most of the day (Figure 3.1.4) but was replaced by northwest
winds throughout the valley by 1900 PDT (Figure 3.1.5). By 0300 PDT (Figure
3.1.6) on July 14, however, another eddy had developed in the southern end
of the valley. This eddy continued to grow northward to encompass Fresno by
0900 but did not extend as far north as Modesto Reservoir.
The importance of the northward extension of the eddy on the morning
of July 13 was that the normal northwesterly flux of air entering the valley
was forced to the western side and was constricted in horizontal width.
Velocities were consequently increased considerably compared to the flow field
usually observed. This is shown dramatically in Figure 3.1.7 where a vertical
cross section of the flow field from Modesto Reservoir to Los Banos has been
constructed. Pibal winds were resolved into up and down-valley components at
construct the figure. Winds of Los
Banos at 500 mas a result of the constricted flow.
Under these flow conditions the tracer released from Manteca was di
verted to the west side of the valley and was carried rapidly southward. The
eddy mechanism provides a means for redistributing the tracer throughout the
valley by the following day.
Mixing Heights
Mixing heights were determined from aircraft soundings by noting the
top of the pollutant or low-level turbulence layer. Table 3.1.2 gives the
mixing heights for all soundings made on July 13.
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..-V)
E I E ~
~ :I: C!l ...... LU
w ~ I ..... 0
8 4
0
1500
/ ,/,;l m/1
1000
Southerlly Wind
INortherl:~ Wind 16
500 I- ,I ___,--4
;_//12
----·----....... ---~
_,____________ o
---------· I~
' 4 81/037
0
LOS BANOS TURLOCK I
MODESTO RES.
Figure 3.1.7 Vertical West-East Cross Section of Wind Component (m/s) (Positive Component into Valley) - 13 July 1979, 07 PDT
to Valley Axis
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Table 3.1.2
AIRCRAFT MIXING HEIGHTS JULY 13, 1979
Time Location* Mixing Height (PDT) (m [above ground level]) 0603 Modesto Airport 210
0842 7 W Livingston 480
0916 15 E Modesto Airport 270
1648 Modesto Airport 570
1919 7 W Livingston 720
1951 15 E Modesto Airport 480
(* Distances in miles)
3.1.2 Air Quality
Regional Pollutant Levels
Maximum measured hourly average ozone concentrations for July 13 are shown in Figure 3.1.8. Within the valley, on the 13th, exceedances of the California ambient air quality standard were experienced only at Fresno and Bakersfield. However, in the Sierra Nevada, downwind from both urban sources, violations of the standard also occurred. On the 14th, widespread exceedances of the ozone standard were experienced in the northern and eastern
sections of the vaiiey. Oniy on the extreme west side did concentrations remain less than .10 ppm.
Maximum hourly concentrations for CO, S02 and NOx anywhere in the valley on July 13 are shown in Table 3.1.3. Maximum values for the Rockwell International sites are also included.
The effect of the southerly flow on the east side of the valley (Figure 3.1.3) on ozone concentrations is shown in Figure 3.1.9. This cross section across the valley between Los Banos and Modesto Reservoir was constructed from aircraft soundings and horizontal traverses. Low levels of ozone aloft between Los Banos and Turlock) correspond to the northerly flow of air shown in Figure 3.1.7. On the eastern side of the valley, ozone concentrations were much higher in the southerly flow. The Fresno eddy therefore provides a mechanism for redistributing pollutant concentrations within the valley.
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~.- I ---- --½- ,.:,:-,r_ -- ~--: -- ---- ------- --,., ~- • - -C. - .A.' 1 ,r - --' .
f \ -~r- . - . . I
!1 ~ "\. ! - l
--~\\ ~·. ~··, r\ \ \. 'hl\: "'--~=S --~ Cl
~ ~ ·i "1;,? '1,-tg J,. !, -;.<~ . , '. (-"--~_·_t ~\·'""·'"'" ~ J.~-~_;.~ - , -~ -,~
- ) '--1:! .· / ,~~.,, \) =;t' ., ~ \. c-1:-·,
L Ct:, ~:&. I"'~\:~ -D- J=-<- 6 .<\ .. ~ ~ ;, ~)-,
\. :[)::~:~"§'~ J_ ,-o:,c;:,, \ . '. ~~ 17:t \]'" ~ -\?>.,- f-,_, . ,,,.~~U'-" c. - • -. 0"1 :~-. '\....._, '-~__, .....~ '~ ~~ ..:.,~:o~~ir~J~< ~~\~ ~= ~~~-. ~~8 ~ -~;~~-J;] "\\ ·-,.. ,
l~, .~;.- ~ < - J --:::- ~· ,~ I
\1.:..""'--.~- ·.. r., ~- 11 ·. >--~ ~ \°'~ ' -,-.\ - , ' . - - --=- ~.\.. "" '
(~~~. L\\~ ~- "t/~ u·. - ~~\' 1
~~~~\t~t 5 ~ 7 J,~ ¼~ ~~\) ~ 1~~ 1 () ~ _ 12 \ L -"'° ;"'0./'-~ ~'\Q -,..__,.,.- , "~ ') ' . . ~J - ...:, .
.... --..
.
.
y -~, 2'_.Ji~--
- --,,_ ,-
,~- -'-~
~.. -........:
'
5
1
0- ~-~ '-<;-.._ - .... -
..1 J t._,-1,j - ~' '-
,,, -' .:,
'.
-·
;'...
\ ... ._ ~
\
.
N I
CJ ,o -..
Figure 3.1.8 Maximum Hourly Ozone Concentrations
3-12
(pphm) - 13 July 1979
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1500
1000 ~
-1/1 E I
E ~
I-::c c.!)-w
I w I-' ::c w
500
90~
70/,/
-·---
' '~
-10/ .., _,o/ ,____ 80~
~ 81 / 038
O~ I I
LOS BANOS TURLOCK MODESTO RES.
Figure 3.1.9 Vertical West-East Cross Section of Ozone Concentrations (ppbMeasured Between 0646-0916 PDT - 13 July 1979
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Table3.l.3
MAXIMUM HOURLY CONCENTRATIONS JULY 13, 1979
Parameter Location Maximum Value m
S02
S02
Fresno-01 i ve
Modesto
.02
•02
co Bakersfield 4.
NOx
S02
S02
NOx
NOX
NOx
Bakersfield
Modesto (RI) Merced (RI)
Modesto (RI)
Merced (RI)
Madera (RI)
.20
< • 01
< • 01
.02
•01
.01
Aircraft Sampling
Two sampling flights were made, one in the early morning (0603-0929
PDT), and again in the late afternoon (1648-2014 PDT). The sampling routes
were designed to define the distribution of air quality meteorological condi
tions in a vertical cross section across the San Joaquin Valley. Traverses
at foui constant altitudes weie flown along a valley transect passing near
Turlock and Modesto Reservoir. Spirals were flown at locations roughly one
third and two-thirds distance along the traverse route and over the Modesto
Airport. Figure 3.1.10 shows the sampling routes for both flights. Tables 3.1.4 and 3.1.5 give the general pollutant characteristics found on each part
of the sampling route.
In the morning the horizontal distribution at 1500, 3000 and 5000 ft
msl displayed the same general trends; ozone and bscat were greatest on the
east side of the valley, decreased to the center of the valley, then remained
relatively constant on the west side.
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\
I 1 761: .,._~ ,., -·.. ~ .::~ ~66 l:
\\' 1.\.
-',~;t:•·te· ·,-~-
10 nm
SAMPLING ROUTES· 13 JULY 1979 P. M.
Figure 3.1.10 3-15
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Table 3.1.4
AIR QUALITY MEASUREMENTS CARB SAN JOAQUIN JULY 13, 1979 SAMPLING
VALLEY PROJECT
Start Time (PDT) 0603
0646
0721
Location (Point)
1
2-3
3-2
03 Mean Max eeb eeb 79 103
74 101
85 111
bscat Mean Max x10-6m-l)
55 164
68 290
54 114
S02 Mean Max peb peb
1 2
0 1
0 1
NOx Mean Max peb peb
5 17
6 22
4 13
NO
Mean eeb
3
2
2
Max eeb
10
10 10
0803
0842 2-3 4
92
95
101
114
41
49
84
124 0
1 1
2
4
4
12
12
2
2
10
9
w I ..... °'
0901
0916 4-5 5
73
104
83
186 77
86
154
190
0
1
1
3
14
6
24
22
5
3
13
13
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Table 3.1.5
AIR QUALITY MEASUREMENTS CARB SAN JOAQUIN JULY 13, 1979 SAMPLING
VALLEY PROJECT
Start Time PDT 1648
Loc,at ion (Point
1
03 Mean Max (eeb l (epb 106 139
bscat Mean Max (x10-6m-l
44 154
S02 Mean Max (eeb (eeb
1 2
NOx Mean Max (eeb (eeb 10 40
NO
Mean 1:eeb
5
Max (eeb -
17
1n4 2-3 138 157 75 150 1 1 10 29 3 14
1801 3-2 123 176 53 140 0 1 7 23 4 15
1839 2-3 145 192 62 146 1 2 7 22 3 14
1919 4 llO 141 57 150 0 1 9 44 5 34
1938 4-5 134 154 67 126 -1 0 9 22 3 10
1%1 5 154 188 73 138 1 3 10 23 53 17
w I ..... .....
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The contrast between the eastern and western sides of the valley is
shown in Figures 3.1.11 and 3.1.12 which were taken to the west and east of
Highway 99, respectively (see Figure 3.1.10). Figure 3.1.12 shows a marked
ozone layer centered at 600 m (agl) with a peak concentration of .18 ppm. This
layer also exhibits high bscat values, indicating the aged nature of the pollutants. No such layer is shown in Figure 3.1.11 on the west side of the
valley.
High concentrations of ozone continued to be present aloft over the
eastern part of the valley during the afternoon. Figures 3.1.13 and 3.1.14
show soundings made at Points 1 and 4 (Figure 3.1.10) during the late afternoon.
The observed mixing height was about 500-600 m for both soundings with ozone
levels of .14 to .15 ppm within the mixing layer. On the east side of the
valley, however, (Figure 3.1.14) the ozone concentrations aloft reached a
maximum value of .18 ppm in contrast to .11 ppm over Point 1 (Figure 3.1.13).
Southeast winds within the upper ozone layer continued through 1300 PDT but
had shifted to north to northeast by the time of the sounding (Figure 3.1.14).
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(flF,Pl T '- .:1~ lJ l ~•L;'J f)J Zl-lP~-R0 ~2:1~:Cl p t.,f;t 1.,
Ll ~I! 7 / I, I / ·l ~ CIJ TI ·v1_t< ,-)CJ ;,;f 4 LAHT~ILl(Ll~A~\: ot.~/ o
Tl~f: ~!4t: 1~ TtJ j!"ld:,::'6 ~lh. L~C~~C il~~.: le 1'1~,ll
-1r---------J--------10--------,o--------Ja--------41--------~0--------cc--------10--------do--------qo-------1ccl~Jdl ,,,,., l I 1
I ~~U I "'"" ll L T I 14701 .,x~ l r 1 l44LI I .,., B l T I
l-. l u I "NE* l T I.<~ LI I 8 D L T~~ .¢:
1 'j 'i r:i I l r ""' ,,u I.> lO I .:::,'4 ~ I) l T LEGEND 12-iu 1 11.=:: ll !l l T 12~( I ;;: J 0 l T FULL IL l( I ::: H L < r PARAMETER SCALE llMJ~ll:JC I <· X 'I C L T -I l 7 /J I .,;.; D L I (Turb) 10 cm •ta sec - 1 E* I 14u I N<X R L l T
O. S ppm z1 11 u I ,;i.;,:: 0 L L T (Oa)
lu80 I ~S* d L l T (NO, NOx) O. 2 ppm N,X l~~O 1 ;;._x h C l T
A I iJ ltl I [, l 1 (SOa) O. l ppm 5** ~ L 9'-lt; I S1H--A 1'! 0 L I 1
., 1) (b,.,.,) 10 x l~-~ m - Br ~60 I l T
I QJu I " d J l T o•- 100' C** (Temp) T T 'll)O I *X ~u l r
w u 117u I I\ ,J l T (Dew Pt) 0 • - 100' C D I "' *
f-J n ~4U I ¢:) ~ :) l T t •110 I *~ ~d .J l T'° ,~o I 5 ::ii:~ 1~ G l T,~., I ¢¢: t tl l T Figure 3.1.11 Aircraft Sounding - 13 July 1979 M Jl(J I N* * ,J l T
o9U I V d I) t l T M <,t,0 I ¢X h iJ L * s <,jU I *X d U l T E L oOO I h D l T E~"
.._j 10 I >* 0 !.) l I t ~4u I S* ll U l T t ~lu I S* 8 D l f r 4 ij(J I '-'N ll (J l t T 4 'i'l I "X 'l 0 l ff
:_i,:)4bJ I ti 11 T () ;;. tl I)19(1 I 'l T t
3oli I \'I\ ~ C l I f J3u I Ill 5 X l C l T f JOt; ,, :( ~I ~ C L r llu 1 ~ • M C l T l 4 G I S,,-.1)( ,1 C I L 10 I '.i I\ X a I) 1 T l lHu I .:.;, X o C l 'l I l I ~ ~ J( 0 l II\, "
~
llu I k C l T q., ' I X I\ G l r
• " <
t-hu I 'j•'lj r, 1/J
l 0- - - - - - - - -r:--- -- -- -- lo- -- - --- - L )- -- - - -- - 1 1l- -- - --- - ., -1-- - --- - - --11~ - - - - - -- - ti,~-- - - ---- 7ii- - - - - - - -11•1- - - --- -- - qi)------- I ,l)tl
Pt--1'\Ct "...:T -.~~ fl,ll :.CAL.:
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(~fPLJ V~M ~l ~uf) :lJ 11-AP~-~~ 52:t4:L1 PAGc 2fJ
UI\ ff 7/11/ll .:icurf r1vt" fJ Cf• r c.., I t,, ... r INL,t LAH lg 11,ft:1•1 •\J\: 1H, 1\/ h ll•c: ~:1,,:11 T;: 'l:l4UI ~IN. G1~C1;f..,L lltV.: "' .,,,.~u
-10---------n--------10--------lo--------Jo--------4n--------~0--------oc--------1c--------aa--------Qo-------1cc l5h0 I f)j;¢ ·If. l 1 I l'>JLJ I 1,:..:~ \t Z T t l:OGLl I J1.¢: :¢1, l T I
I• 7u I C *<" l 1 I 1-.4•) I ... o,:* ~ l I I
1-.Jul "''* l 1;q.; I ,,x h l l
LEGENDl 3 '>L I s;.¢-" n C l T I J 1 t,, ~f ~ ur tt L 1 12. -JO M*t.; i F l r FULL I lt>C *~ F l T PARAMETER ~ lli!!!.Qb
, 1t.:3L: .k Ed 0~I (Turb) 10 cm 3/s sec-, E:1, •)LJI NS*~ D i T ,. .;.I J7u, G l 1 (Oa) 0, 5 ppm :z; I l '- e C T* l
(NO, NO•I 0. Z ppm IN,Xl ll~ ~1* EI:) L l T I OAu J;r ~ ri l T (SOa) 0. I ppm s 10~0 so BU l 1
l IUlO ~o 8 ~ l T 10 x 10-• m -, •
lb,.., I IS T -,qi) SNE~ H U L 1 I 'H'll.: • 0 l T (Temp) O"-IOO'C T T '<Ju ~ ~• 8 Ut l T
., X (Dew Pt) o•- IOO'C ID w u ~OU· ijUF l 1 I 0 ~70, ::: ¢ !J T~ l
0 t li,.O ;l1f .¢, ~ u L T N
Figure 3.1.12 Aircraft Sounding - 13 July 1979
.. bl'l S,N* ~ [) l T ]ijQ t-,p=: .. ;:: l T 75U ,.5, t • lT* 7l0• NS* du T l ,. t,-11) N:::Jl 0 R T l
5 obU NOf ll 1 T l l h JU ., st l, d T l
bO•J ~IS X E D b T l ~n ~"- Jl 0 >I Tt l ')'t(]1 ,;1 K [ltl T l f 5 111, I,; 5A D d T ,l E 4~UI N S X uu T / E • 5:J, IJ J" 5 X IT 4-'ll X d u fl ,qu .:;: X dD lT t 3~U 0 iiO l T F•
¢J 1~ X o/) l T t J0U \," X bO l T F ,.ll( X fl r c' 4,J' ~· .... • I) I ti L s Jf p I) l T ' l ,J ~ X tl fl f I.,.; ~ t. f) ' T I l ,', \, ,... .., JI; I) 1
1 'j I ,.. ,. •jf'
r11., " f( p;
- l d---------•,-· - --- --- 1•,--- - --- -2:~---- -- -- j 1;-- -- -- -- <.t'J---- - - -- .. ,1- - - - - - --n-J-- - - - --- Jr!-- -- --- - 1 >- --·-- -- -Q1J------- JLC 1>1 f<LI f'. f l r:: ~ l..1.l ',t,~t,
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(t)r:µt T .ih~ Cl il-'1_,,) 1;3 !l-APH-1)0 )~:22:J4 P AG t
UVfS P(lt,,Il'A T 7/13/IY ~ ( lj f I
LA~TKIGCt/~A~~; hr)q/ Tl~r: lb:47:4U re 11: ,:Ll ~I•~• GMCL~I; tlfV.: z9 ~,~,u
-1a---------.1--------1~--------20--------io--------4.i--------~o--------•o--------1a--------~o--------qo-------1cc 1 ') 1. (J I f;<•NHC L T Cl l :-,r:1, I <•hi l T Cl 1., 7,J I <•N*• l T Cl
l '• 40 "'''ti JC t l T CI 14 Ill * Cr. * l T Cl 11~0 * 0 e f l T CJ l j "l(J I~ X :.i, * l l CJ l J. ?t; t l T CI l /Q~l f]~ I: l CI I LoC ~ ;~:f l I LEGEND CI l .! HJ ~~•Cijt T Cl l l '1 e, S 00i L T FULL CI I l 7 u ~ c~ l T PARAMETER ~!!.,. CI~ I 14 J ~. ~ r. l I CI
(Turb) 10 cm •1., sec-, EI l l J 'l -~iC Ml( l I CI' Iv P .J ~ ~. :.;. X f l I (0:,,) 0. 5 ppm z CI lO~U *X l T CI
A 10/U :. 1,J;. t l T (NO, N01) a. 2 ppm N,X CI L '1\.ilij ~N C.* i. l T CI
(502 ) 0.1 ppm s T Yn1J s * a l T CI I ~~.I \C¥k l T IOxlO-•m- 1 B CJCbscat)I -I 1)1..1 ~,.:: t,.: Li l T CIw
I u 1170 ~tt\; !,:: t· l T (Temp) o·-1oo•c T CIN ..... r, ~4C: ~u :::x f l T CI
(Dew Pt) 0 • - 100 • C Dt dlO t l T CiS O "" 7PO ,I*• F T CI(CN) 100 x IOa cm ·a
-, , (.1 Cs tl T CI.. *" ,. 1ld '., N bJCl) F i. T CI c:,QJ N -~ Dl< LET CI f)b(I DX Figure 3.1.13 Aircraft Sounding - 13 July 1979 CI* *
5- o1U :, N H D X l H CJ t,r,,::L "b DX l tl CI i.; 7t) '> " 'I * f I T CI - ~-)
,,.. r, 8 O,X I' L T CJ ., l il 1;"" ti ex f l T CJ 4 ~ ~J •; " 11 ex l T (J
4':)lJ Nt11)X C l T~ Cl ... ~d s t l T CI* 3YC I: T\ "" l CJ'" •i * 36d " ,, n f l T CJ j :hJ ,) ~ ti ( 0 t l T CI 30l) s ~ ~ti LJ l T CI '1,; \ ~X d 0 I' l T CI l¼L \ ~A M I) f l T CI ,10 f\ J. I, 0 L Tt <I l2L r, ~-,~ l T CJ l~J '> ~ ~11 Q I r I CI 11~ ~ ~ X ij 11 l T CI ~J l\j i~ "C l f t CI l1L I ~ l l f CJ l<i a < l I f Cl
- i o - - - - - - - - - 1i •- - - - - - - - 1 8 - - - - - - - - .: o - - - - - - - - :.. n - - - - - - - - 4. l - - - - - - - - '=' t, - - - - - - - - o ·1 - - - - - - - - 7 o - - - - - - - - - - - - - - - ~ o - - - - - - - Ju Cll-J -
Pt~Ct~J ~r ~~LL 'l(~l~
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C"i-:._)t 1 vFr l)l "'1;_,) ·)J I l-1\1.lfJ-dO ~:d: -?/: j4 ,,. AG c 2()
c 4 1 • r, 1,1n I'<- CUT t 1;y,_u P~tr.f '1 LA,clklU(~/~A)\; Oo4/ 8 1 I.• I , I Q : 'i I : 1 4 T,J , 0 : •, : 1 I ~I~. ~~(L~C ~Ltv.: ,.7 ~,~s1.1
-1a---------o--------1,>--------JJ--------iil--------4:1--------so--------6a--------10--------eo--------~o-------1co 1 ~-"i,'J I •'•D~ fT l Cl L ':> '0 SX N Dti I ! CI I -:.no ,.x i;g t Cl l ~ 7'> N~ XOti ~ ! CI 14·• 0 l Cl l4lu "' *. ' ~ " * l l Cl 13,u X 'i I\ < f T l CILEGENDl .i ""J <_;r.., :;,u T)I L C l _;,(.J 'ii\ I q r l C l29u ~~ ') .A t'-' T l FULL
C l t ,, •J ,, ;( PARAMETER ~MBOLV•' l ~ C 1<1~ ls "" (Turb) 10 cm "la sec-, E C 1/l)C "'s • l C I I 7 0 1\5 X fl-' l (Oa) 0. 5 ppm z C l l•+o l* X C(NO, NOx) 0. 2 ppm N,XI I I u s~ JI. * ~ T l C l C l~l.) T* X l o (SO3 ) 0. I ppm s C l L •:;u S~ X F till T C'l !OxlO-•m-1
L l<l./0 )~ I( .:. ~ 0 T l (b,...) B C T '':J s. ~ X t I~~ l I C/tl') ;11. • * u l (Temp) 0° - I00"C T
C C
w I 1 4·\u X ¢ LI l C N ,,oo * (Dew Pt) o·-1oo·c D
u s I: 'I (; T lN " X C 1) 8 7U SN , I: !l C T l 100 x 10• cm-• C C
• (CN)t htfU 51, I: ~ C T l C n Lu I~ 5 X E H IJ T L C 7110 I( '\ :;:. Tl hU " s ... u,c
C
"' no :,N ,. C LT
¢ Figure 3.1.14 Aircraft Sounding - 13 July 1979 C
C ,.~ tJ9l) i-s • ,. 0 C ,.s bt,1) s 11. r ,. D C l t,'IJ 'I r.~ x ll D LT Cl
tiOo * E *• 0 l T CI ~l() St, ~ Xll C l T CI ')(t') '\ " • Xd 0 l T CI -' l. (j ~ * ll I D l T CI <+itu S "E 8X C L T CI .. 'i,J ~ Xr e L T CI 4lU S~ ~~ Ll ' l T CI jtl.J ~ 11. Ob C l T CI :1ufJ ')f',jJ( il Tl CI i 1
: l 5"' ;'. ~ I) l T Cl j/lu I T CI ,' 70 ~ '). ·l IJ l Cl
') I r :1 )( U T
,- ''°' L
, CI 1111 ) I\ t iJ X U L T CI I ·I 'J N ,:, "I( r~
/ "' J
l CI l •, u " t [) I CI l ;, l " ' I 1 (I
_, II,!\ \ u T (I', I T (I",
-l')---------J--------10--------L 1)--------,0--------4;)--------~il--------b'l--------1·1--------hf)--------y 1)-------1cc ~cf'(li~T U~ ~Ull \CAL~
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3.1.3 Tracer Test 1
Release Location: Manteca, San Joaquin County
Time and Date: 0700-1300 POT, 7/13/79
Amount: 104 pounds of SF6 per hour
Release conducted during northwesterly winds of between 2 and 4 mps.
Throughout the release day, winds on the western side of the valley were
northerly while an opposing southerly flow was noted on the eastern side of the
valley.
Initial transport southward
During Automobile Traverse 1-1, beginning about 0900 PDT, a maximum SF6
concentration of about 320 PPT (450 PPT/lb-mole of SF6 released/hr) was
detected near Modesto along Hwy 132. 179 PPT of SF6 was detected during the
0900-1000 PDT automatic hourly-averaged sample at Modesto (see Figure 3.1.15).
Modesto I ies about 16 miles south of the release site thus the average tracer
transport speed was at least 8 miles/hr (3.5 mpsl. This compares favorably
with the 2-4 mps surface winds measured at the release site between 0700 and
0900 PDT. Automobile Traverses 1-2, 1-4, 1-5 and 1-8 al I passed through
Modesto on Hwy 132. The tracer plume retained the structure found during
Traverse 1-1 until about 1400-1500 PDT, about 1-2 hours after the end of the
release. At the Modesto hourly-averaged sampler, 250 +/- 30 PPT ( 350
PPT/lb-mole SF6 released/hr) was detected between 1000 and 1400 PDT. Only 117
PPT, however, was detected during the 1400-1500 PDT sample.
Continued southward transport during afternoon
The tracer was also detected further downwind during a number of
automobi ie traverses. During Automobiie Traverse 1-6, a maximum concentration
of 240 PPT (340 PPT/lb-mole SF6 released/hr) was detected along Rd J17. During
Traverse 1-9, 124 PPT of SF6 (174 PPT/lb-mole SF6 released/hr) was detected
along Hwy 140, west of Merced. During Traverse 1-12, 161 PPT (226 PPT/lb-mole
SF6 released/hr) was detected along Hwy 140 and concentrations as high as 116
3-23
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SJV-1 7/13/79 - 7/15/79
300 1 Jfhn, MODESTO 0 I+ I I I I I I I I I I I I I I I I I I I I I I I I I I I+ I 1 , I I , I l I I I
300 rI LIVINGSTON 0 I I I1fil+u I I I I I I I I I I I I 1 , I I LJ I I I ~ I ' I , I+ I I I , I I I I I
100 Ii DOS PALOS 0 1 I 1 1 I~ L__J I I 1 1 I • hi I H 1 1 I 1 1 I 1 • I 1 • I H I t I I 1 • I
100 r TRANQUILITY 0 I I I 11 1 I L I I 1 +J1::6 1 I L L b-t-t I f r:::6--i L-I L I L I lx:x1xlx1r1xlx1X1xlzi'+ I
100 I. MADERA 0 1 I 1 1 11 t .p ,.LrwJ--u I 1 1 I I K---Lt J 1 1 I 1 1 I : , I 1 1 l 1 1 I H +1 • I
100 r-' . O'NEALS
0 I , 1 11 1 I 1 : ,r1xixlwx1rlx1X1rlx1X1xl I t I 1 1 l 1 ' L L l I t+A L I 1 1 I =4 I I I 100 r
MARIPOSA 0 I t L I 1 +I H I tM:I I l L l L 1ylxw•xlx1,1xlxwxb:x1 Li I I c I l t t I 1 +I L L I L l Il
o... 0..
r, (D LL lJ) LJ
100 r (It 1.1. d , w , , , J .J , , 1I , L, bhr.l , , 1 , , 1 , , 1w .., T
100 r-1
0 I 1 •+LJ 1,, 1,, L, 1,, L, b-w ix-I, 1, 1 I 1 1 I u 100 r
_i,,l,c_JL_,. ,,l,..J,,1,,1,,1,,1,,1,,1
PATTERSON4 L 1 I I I I • 1 , • 1
GUSTINE Li ,4 1 , I,, I,, 1
MERCED . 1
IQ
100 r , CHOWCHILLA
0 I I I 1, I I+ I I I t::H::t L I 1 , ' I I I I , Lj H I Htttt! I I I ' ' I ' ' I+ I I ' I I 100 r FRESNO
0 j 1 1 I 1 1 I 1 1 I • 4I • '= k..J I L I I H 1 1 6 1 wI I 1 1ttlw.ttttttlx-tutl,,.11:ttlw+t+ I 100 r OAKDALE
0 I+1 J • 1 l , 1 I I H 1 • I 1 1 I 1 1 I 1 1 I Ht'ttl,,.HtHtl,,.Ht:tltk:HtHti.+ 1 I 1 1 I 1 1 I 1 • I 100 r-
:I I I
0 Lft I I I I f
6 9 12
RELEASE RELEASE
MODESTO RESERVI I I I I I I • I I I- I I I
I I I I hi I I I I I I Ld I I I I I J 1 I I I I I I I+ I I I I I I I I I I I 15 18 21 24 3 6 9 12 15 18 21 24 3 6
PACIFIC DAYLIGHT TIME
LOCATION: 623 LBS SF6 AT MANTECA TIME, 0700-1300 PDT, 7/13/79
Figure 3.1.15
• INDICATES MISSING DATA ARROliS INDICATE BOUNDS OF StMPLING PERIOD
3-24
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----
SJV
1
.. '
'
:~ ).' I .~Art,~
j,TA,"•,HS.',,;,.,,,:«:.,,,.
',
"-4,0'f'AMl!r. \ il,.J,,111/1.
\ ~> - ' A '-,
Figure 3,1.16
* INDICATES SAMPLER LOCATIONS ((@), IS THE RELEASE SI TE 3-25 ~/
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PPT (163 PPT/lb-mole SF6 released/hr) were detected along Hwy 152, west of
Chowchilla. During Traverse 1-13, SF6 concentrations of about 90 PPT (125
PPT/lb-mole released/hr) were detected over a wide zone along Hwy 180, west of
Fresno. The locations of the maximum concentrations detected during these
traverses indicated that the tracer was initially transported southeasterly
along Hwy 99. Along Hwy's 140, 152 and 180, however, the plume appeared to
have shifted towards the west. This may have been due to the action of the
southerly flow in evidence on the eastern half of the San Joaquin Valley.
Because of the strength of the southerly flow on the eastern side of the
valley, the northerly flow on the western side may have been diverted more
towards the west.
Further evidence of the shift westward of the SF6 can be found in the
hourly averaged data. Al I hourly-averaged data collected is included in Figure
3.1.15. SF6 was detected at Livingston, along Hwy 99, between 1000 and 1100
PDT. Livingston lies about 40 miles south of Manteca, suggesting a mean
transport speed of about 10-13 miles/hr (4.4-6 mps). SF6 concentrations above
15 PPT were first detected at Dos Palos, about 70 miles south of the release
site and 25 miles west of Chowchi I la, during the 1500-1600 PDT sample,
corresponding to a mean transport speed of about 8.8 miles/hr (3.9 mps).
Finally, SF6 was detected at Tranqui I ity, about 100 miles south of Manteca and
25 miles west of Fresno, during the 1700-1800 sample which corresponds to a
mean transport speed of 10 miles/hr (4.4 mps). Maximum hourly-averaged tracer
concentrations of 162 PPT (228 PPT/lb-mole of SF6 released per hour), 92 PPT
(129 PPT/lb-mole released/hr) and 54 PPT (76 PPT/lb-mole released/hr) were
detected at Livingston, Dos Palos and Tranquility, respectively. The maximum
concentrations detected at these fixed sampling sites agreed favorably with the
maximum concentrations detected during corresponding automobile traverses.
Note that essentially no SF6 was detected at sites along Hwy 99, south of
Livingston, or In the foothi I Is on the western slope of the Sierra Nevada
Mountains. Again, this is consistent with the apparent decoupling between air
flow on the west and east sides of the San Joaquin Valley:
3-26
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Comparison of plume dispersion to Gaussian plume model
The tracer was apparently transported by strong, unidirectional winds
suggesting that the tracer transport and dispersion might be accurately modeled
via the Gaussian plume model. As shown in Figure 3.1.17, the concentration
profiles encountered during most traverses were essentially Gaussian in shape.
The standard deviation in concentration was estimated to be about 1.81 +/- 0.26
miles for traverses along Hwy 132 through Modesto. The average trajectory from
Manteca to the plume centerline at Modesto meets Hwy 132 at an angle of about
45 deg. Thus the crosswind standard deviation in concentration was about
1.81*sin(45 degl=l .3 miles=2.1 km. Thus the horizontal dispersion of the
tracer at this distance downwind corresponded to Pasquil I-Gifford stabi I ity
class C. The estimated crosswind standard deviations in concentration along
other automobile traverse routes are included in Figure 3.1 .18. The
Pasqui I I-Gifford Stabi I ity Class curves presented are extrapolations of the
curves presented in Turner (1970r". The horizontal dispersion is consistent
with Pasqui I I-Gifford Stabi I ity Class C or D for distances less than 100 km
downwind of the source. The deviation at greater distances may be due to
variations in wind speed or atmospheric stab ii ity that occurred near nightfal I.
Also included in Figure 3.1.18 is the vertical standard deviations in
concentrations estimated from the crosswind integrated surface concentrations
(see Turner, 1970). The data shows no significant tendency to increase with
distance downwind of the source, suggesting that the tracer was wel I-mixed over
an essentially constant height. The vertical standard deviation is 80% of the
mixing height. Based on the traverses along Hwy's 140 and 152, the maximum
mixing height was about 400/.8=500m or about 1640 ft.
Carryover into subsequent day
Low levels of SF6 ((5-10 PPTl were detected throughout the San Joaquin
Vai iey north and east of Fresno on the day fol lowing the release. Due to the
I imitations of the SF6 measurement technique, it is not possible to
quantitatively estimate the amount of carryover into this day.
* Turner, B. 1970: Workbook of Atmospheric Dispersion Estimates, PHS Publ. No. 999-AD-26, 84 pp.
3-27
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TRAVERSES SJV-1 '"'
HWY 132 TRAVERSE 1-5 1235-1316 PDT:1ill~k. ,,,,,,, """;;; -----DESTO
~ \
~RAV 1-9 1428-1518 PDT
I ii ii II II II lV:::> MERCED
~'
'"',
\ -,, TRAY 1-12 1688-1814 PDT
',,
HWY !~ ,,0!11Uli1111il!Ui1,
\ \
\
AVE 7
FRESNO
T 3SS PPT 1
Figure 3.1.17
3-28 NORTHERN SJV SCALE - le 208000
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SJV-1 GAUSSIAN COMPARISON 100
X ~
... IJ. LL UI 0 u z 0 1-4 CJ') 10 a:: w ll. (/) 1-4
C
. N 1-4
0:: 0 :I:
1
D
10000 r
A 8 C
X
... IJ. IJ. UI 0 1000LI
z Q0 C 1-4 (/) E0a:: w ll. (/) F 1-4 100C
t-• 0:: UI >
10 I I I I I I I I I I I
10 100 1000
DOWNWIND DISTANCE. KM Figure 3.1.18
o DATA TAKEN AFTER END OF RELEASE 3-29
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Summary
During this experiment, the tracer was released at the northern mouth of
the San Joaquin Valley. In this vicinity, a northerly flow (blowing into the
val leyl persists essentially 24 hours per day during the surTY11er. Pollutants
generated in the San Francisco Bay Area and the California Delta can be
transported into the San Joaquin Valley through this region.
During this test, the tracer was released during the morning. Typically,
the atmosphere is more stable during the morning than during the afternoon. On
the day of the test, however, the wind flow patterns detected in the valley
suggested more unstable conditions than might normally be expected. High wind
speeds were detected, for example, at Los Banos (16 mps at 0700, 1000 ft
elevation). In addition, southerly winds were found on the entire eastern haif
of the valley while strong westerly winds were detected on the western side.
At one time during the day, the velocity shear between the western and eastern
sides reached as high as 24 mps. These conditions led to dispersal of the
tracer at a somewhat higher rate than might be expected from meteorological
data collected only at the release site.
The tracer was initially transported along Hwy 99. The tracer was then
transported down the lowest part of the valley, along the San Joaquin River on
the western side. There was no evidence of the tracer being influenced by the
upslope winds along the Sierra Nevada on the east side of the valley. An
overview of the tracer transport path is shown in Figure 3.1.19. Since the
tracer tagging pollutants from the San Francisco Bay Area and the California
Delta was preferentially transported down the western half of the valley, and
since higher concentrations of ozone and other pollutants were found on the
eastern side of the valley, the Bay Area apparently had little impact on
pollutants in the San Joaquin Valley on this day.
The concentration profiles downwind of the release site were essentially
Gaussian in shape. The horizontal dispersion of the tracer corresponded to the
disperion expected for Pasquil I-Gifford Stab ii Ity Class C or D. This
comparison to the Gaussian plume model was based on 12 different traverses
along 5 different routes at various distances downwind. From automobile
traverse data it was possible to estimate that the tracer was essentially
wel I-mixed vertically to a height of about 1650 ft.
3-30
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w I w....
@ ,.-,,;'
'\ (v
! JEl.mI Sil£ - rwm:CA I
IC/IllIO 0 10 10
'1111.U
~
~
&J~'
IO<>c,
\_~"--( ~
ARROW POINT INDICATES OBSERVED TRACER LOCATIONS NUMBERS REFER TO HOURS AFTER RELEASE START (0700 PDT., 7/16/79)
Figure 3.1.19
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Low concentrations of the tracer were detected over a wide area in the
central and northern valley on the day after the release. At least some of the
tracer released on the previous day was redistributed throughout the northern
valley by the night and early morning wind flow patterns.
3-32
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3.2 Test 2 16-17 July 1979, Manteca Release (1300-1900 PDT)
3.2.1 Meteorology
General
and was
states.
The syn
characterized
As can
optic meteorology of 16-17 July is depicted
by a regional high pressure aloft over
be seen from Figure 2.2.1, this period was
in Figure 3.2.1
the western
th~ beginning of
a significant warming trend aloft which was to continue for several days.
At the surface a thermal trough was established over the California interior
which created onshore pressure gradients. Skies were clear within the
valley with only a few scattered cumulus reported over the higher mountains.
Visibilities were reported down to 7-10 miles in the central and southern
portions of the valley in the afternoon. Stockton reported restricted
visibilities due to smoke on the morning of the 16th, but conditions im
proved later in the day. Surface temperatures were above normal in the
valley for the time of the year. On the 17th, Fresno reported a high
reading of 107°F and Bakersfield 109°F.
Transport Winds
Surface winds from the tracer release site at Manteca during the
release period are summarized in Table 3,2,1. Winds were from the north
west at 2-3 misec. The regional flows in the San Joaquin Valley during
the experimental period have been determined from the 1000 ft streamlines
and are depicted on Figures 3.2.2 through 3.2.4. At the start of the
tracer release (1300 PDT), the flow was generally from the northwest at
speeds of 2-3 m/sec. In the central portion of the valley, the eddy which had been present during the early morning had drifted eastward, but the
flow on the west side was still being diverted westward by the eddy in
fluence. On the west side, northwest streamlines continued the length of
the valley. This basic flow pattern continued until the 1900 PDT obser
vations, when the flow became northwest throughout the valley at speeds
ranging from 3-6 m/sec (Figure 3.2.3). The same general flow pattern
continued for the following several hours, although wind speeds increased
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,-:
:,...., ;:, ....
fCl 0..
LO 0
.....°'
....°'
V, .µ I,..
..r:"' u I,... CIJ
..r:
.µ
:;: "'CIJ
CIJ u
'+-"' 1,... ::,
V')
..... N . M
CIJ I,.. ::, C'\
LI..
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Table 3.2.1
SURFACE WINDS AT MANTECA 16 JULY 1979
Time Wind (PDT) (m/s) 1300 305/2.2 1400 300/2.7
1500 305/3.0
1600 325/2.7 1700 310/2.7 1800 305/2.8
1900 325/2.3 •
to a maximum (6-11 m/sec) at 2300 PDT. At 0300 PDT on the following morning, an eddy again formed in the southern portion of the valley and continued to
develop, reaching a maximum between 0900 and 1200 PDT (Figure 3.2.4). By 1700 PDT the flow was generally from the northwest again. The vertical and temporal characteristics of the winds aloft can be characterized by the time-height cross section of the winds above Turlock given on Figure 3.2.5. The pibal winds have been resolved into components parallel to the valley axis which are shown in the cross section. The northwest flow was relatively shallow during the tracer release extending only through a 2000 ft layer above the ground. Flow with a southerly component prevailed above. A moderate to strong flow transporting air south into the valley persisted at low levels throughout the experimental period. Maximum speeds within the northwest flow of over 10 m/s were observed late in the evening of the 16th.
Mixing Heights
Mixing heights were determined from aircraft soundings by noting the top of the pollutant and/or turbulence layer. Table 3.2.2 gives the mixing layer depths for July 16-17. As indicated, there is a marked tendency for higher mixing depths at the edge of the valley compared to the center.
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....
C'
... .-;· ' .. • . ....
.......
Figure 3.2.2 1000 Ft-agl Streamlines - 16 July 1979 (13 PDT)
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(·
.... .,, C",-,
C"
•,14, • C '! ! 1f f la ... -· - - --
- . r ,...
1a. ..... -·-....... . .. ... ., . , ..
--.... ~-
f
Figure 3.2.3 1000 Ft-agl Streamlines - 16 July 1979 (19 PDT)
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....
.. ·- .... . . ..... au,1..1
••&'!!!IP'• ... . --·
. . . - - - -- .." ,. Figure 3.2.4 1000 Ft-agl Streamlines - 17 July 1979 09 PDT)
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2817
2547
2277
2007 ~
V'I E I
E 1737
I-:c <.!J ...... 1467 w :c
w 1197 I w I.D
923 ......," I
639 '~~
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l ~
2
----o -2-.. ."-... J I ~
2 _____. 340
2-4 -2
,,,,,,,----------------......__...,... _2
f 8 ---.........._fr-~\_---·.:__) __,_ J .__, 4 b 6---:---__...,- 4 ~6"""~8
13 15 l 7 19 21 23 l 3 5 7 9 11 13 15 l 7 19 15
HOUR (PDT) 11/059
Figure 3.2.5 Component Wind (m/s) From Turlock -(Positive Represents Upvalley Flow)
16 July 1979
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Table 3.2.2
AIRCRAFT MIXING JULY 16-17,
HEIGHTS 1979
Time (PDT)
July 16
1653 1730
Location*
Modesto Airport Modesto Reservoir
Mixing Height (m [above ground level])
600 770
1755 1851
Foothills Patterson
(30 ENE Modesto) 990 970
1958 July 17
0541 0618
Modesto Airport
Modesto Airport Modesto Reservoir
150
120 80
0642 0732
Foothills Patterson
(30 ENE Modesto) 300 120
(* Distances in mil es)
3.2.2 Air Quality
Regional Pollutant Levels
Maximum hourly ozone concentrations throughout the valley on July 16 are shown in Figure 3.2.6. A number of exceedances were observed in the valley. The highest hourly average recorded was at Bakersfield (.14 ppm). On the following day, a maximum of .17 ppm was observed at Fresno and exceedances occurred at Whitaker's Forest and at Miracle Hot Springs, indicating the upslope transport of ozone and precursors from the valley floor.
Maximum hourly concentrations for CO, SOz and NOx anywhere in the valley on July 16 are given in Table 3.2.3. Also shown are the maximum values recorded at the Rockwell International vans for the day.
Aircraft Sampling
Sampling was conducted late on the afternoon of the 16th (1650-2013 PDT) and again on the morning of the 17th (0540-0850 PDT) to determine the flux of pollutants into the San Joaquin Valley. The sampling pattern was
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(
(- Figure 3.2.6 Maximum Hourly Ozone Concentrations (pphm) - 16 July 1979
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Table 3.2.3
MAXIMUM HOURLY CONCENTRATIONS JULY 16, 1979
Parameter Location Maximum Value m
S02 Bakersfield .02 co Fresno-Olive 3.
co Bakersfield 3.
NOx Bakersfield .19
S02 Modesto (RI) < • 01
S02 Merced (RI) < .01
NOx Modesto (RI) .01
NOx Merced (RI) .01
NOx Madera (RI) .02
similar on both days. The flight pattern consisted of a vertical cross section of the valley with two constant altitude traverses and a series of spirals on
a line roughly perpendiclar to the valley axis between Modesto and Turlock.
Spirals were flown over the Modesto Airport at the beginning and ending of
sampling to document any temporal changes. Figure 3.2.7 shows the sampling
routes carried out on July 16 and 17. Tables 3.2.4 and 3,2,5 give the general
pollutant characteristics observed on the flights.
The horizontal distribution of ozone and bscat was reversed from the
sampling on the 13th. The greater pollution burden was found on the west side
of the valley. At 4000 ft-msl (1919 PDT) ozone concentrations averaging over
.10 ppm on the west side decreased to under .05 ppm on the east end of the traverse, Gradients were not as great on the 1500 ft-msl traverse, averaging
.13 ppm on the west side as opposed to .11-.12 ppm on the east side. Maximum concentrations of ozone in excess of .18 ppm were measured over Patterson on
the west side as opposed to less than .14 ppm on the east side. Figures 3.2.8 to 3.2.12 show the aircraft soundings taken during the
late afternoon of July 16. Figure 3.2.8 is a sounding over Modesto Airport.
The mixed layer extends to about 610 m-msl but extensive ozone and bscat exist
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• •;
"""' - ,.... •. - _....___ .
1----S_c_a_l_e__--1( ., :~/: 1 0 nm_ . _ ·-· . ..n, . - · _
SAMPLING ROUTES 16 JULY 1979
Figure 3.2.7 3-43
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Table 3.2.4
AIR QUALITY MEASUREMENTS CARB SAN JOAQUIN VALLEY JULY 16, 1979 SAMPLING
PROJECT
Start Time PDT)
Loc:ation (Point)
03 Mean Max (ppb) (ppb)
hscat Mean Max (x10-6m-l)
S02 Mean Max (ppb) (ppb_) -
NOx Mean Max (ppbL (ppb_)_
NO
Mean Max' . __J£P.b) __ Jppb)
0653 l 79 130 80 210 1 2
1730 '),_ 84 138 64 156 1 1
1755 3 99 143 76 158 0 1
1817 4-5 124 155 112 190 1 2 1851 6 124 185 93 184 1 3
w 1919 6-4 80 111 81 152 1 1 I .p. .p. 1959 l 103 168 109 192 1 1
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Table 3.2.5
AIR QUALITY MEASUREMENTS CA.RB SAN JOAQUIN JULY 17, 1979 SAMPLING
VALLEY PROJECT
Start Time (PDT
Location (Poii nt)
03
Mean Max (ppb) (ppb)
bscat
Mean Max (x10-6m-l)
SD2
Mean Max (ppb) (ppb)
NDx
Mean Max (ppb) (ppb)
NO
Mean (ppb)
Max (ppb)
0541 1 63 120 76 186 1 2
0618 2 67 105 68 138 1 2
0642'. 3 63 105 64 136 1 3
0706 4-6 73 92 79 144 0 1
0733 6 52 119 56 188 1 11
07511 6- 1i 34 47 30 64 0 1 w I
.p. 082? 4-6 79 108 75 138 1 1
(J1
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F
E
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Figure 3.2.8 Aircraft Sounding - 16 July 1979
.. ~ I) s I) R l E T 4s,o s ('I
" l t T 470 ; 0~ t l T JO>I) s LFI lf_ T ·ir,,u s L; " l E T
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\Jt.t<Cl "'l ,,r f.Ull :-,Lllilt
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PAGI 121-APK- 0 54:22:llC UH• l T Ii t 1, 0 l M ,; 0 0 .\
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*4l0 ; < l T ;G10 s t l T*
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r1:r:PLT \tf,' 01 uL'•1 ,13 .'1-APR-••,l ,;4:22:ll ,_i,,\r,[ 9
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LFigurel
3.2.11 Aircraft Sounding - 16 July 1979 ••RU s 1: o e 1 l ,:. ".,t) 5 t * T l ·~ l u s F 1'.ll T Z J~u s T l :H1LI s rlU E .. l lU '
,,o l1 301) s i·i* lT < lu s d* /T l4~ '., * ll l T dO ':, t lU l T I ij iJ s [ l)c, l 1 J. 'jlJ ':, L l T u~ s I T
QO '> '
l T bO \ '\
- l 0- --------,1- --- - - --10- -- - - -- -LO- - -- -----Ju- -- - -- - -~11--- - -- - - ,,,- - - - --- -t,•J- - - - - -- - /G-- - - - -- - ou- - - -- -- - ; 0- -- - --- - ICC Pt-'(t •·~T ,.,t-:. 1--=-1.,Ll \f l\li
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-; '1
(,1)t=VL T \.t-=K -Jl ,,1L )j Jl-APR-c 1' Slt:22,:ll PAGI 17
cAT 7/l~/7"'1 .<Cult: '1V•k ~CINI I (.AU';1<fll([/Ot1:-:,I._;: t1"1J A
T J r,t,i ; 1 q: '5 d: _-, 7 rq IO: 1 !.- : La ~,~. G~CO~C flr~.: ?Y ~(~-ill
-l~---------u--------lJ--------zo--------,o--------41)--------~G--------6C--------7C--------e~--------qa-------lOC l',h) I s E C e (. ' l r I ':,ill) I ); l U d C i 1 I l ~ 7 •J I ~ l 11 ll C l r I 1•40 I S f O ~ l i T I I • lo I 'i lJf e l l T I 1 ~P,J 1 -> .=u .,, T I H,~,l I > t G c ( l T I I ·1,20 I -; II '1 II IC T It ·>o 'i f i.) " L I libC s ,, C e L I T 12 Iv Sf- [ 1 ( l T I i"l 0 '.iF L e \. I T 1110 \f l) ~( l I l 40 ',[ I) " C l T I 1 I •J sc L tll L T LEGEND l 011 t, '>f (; e l l T
~
l
I O'>ll l : 7 U
qq()
s s s
t t
fj( 1i
C C.ti Gil (.
l l
l
T T I
PARAMETER FULL SCALE ~YMBOL
T "lllli <; IJ ~ C l r (Turb) 10 cm 2/3 sec-, E
w I tn 0
I T IJ I)
ll"'.\1_;
l,D V ~I 1,J ~14 (J
dlU
s C ,. ,.
<; • s t
~1 e ,, ~ D e
D~ CH
C l Cl C Z
C ;_ C i.
T T
T T T
(Oa)
(NO, N01)
(502)
O. 5 ppm
0. 2 ppm
O. l ppm
z N,X
s
"'
7>i0 J~n ir~o 69~
<; )
s s
f C8 t.;( ll
* ~ ,J P.
C C
r C
l l l
E l
T
T T
T
!b,... l
(Temp)
10 X 10-• m -i
O• - 100 ° C
B
T
"' 6~0 s fl ~ C f. l T (Dew Pt) 0 ° - 100° C D ~
l
t,' u ()0(,
'>70 ~) 4 U
5 5 s E S F
11 0 C 0
~ l
* e 13
l ~ I
C (
T
* .. .. (CN) 100 x 109 cm -a C
-; l tl ~t 140
s s
f f
D I)
ti 'l
C C
T l T L Figure 3.2.12 Aircraft Sounding - 16 July 1979
4<;0 s E D ~ .oz ~ • ., t) 5 E o e .. l'l(; ~ E D tt l*
1'>0 s D P. <>C
no 5 0 e l* ,100 s t 0 ~ lCT
.? 70 ~ r, ~ Zll
;?40 s r, ~ l CT
.no :, t Oh I * l ~ 11 5 ~ ;J l E T C
l 'iU s ,, 1: 1 .. T C
1/G q,)
<; <;
~ ,, IC ,, l
T T
t L
t)IJ - e I I C
1 •.; I I I I,, '-- 1 :1- - --- --- -t)- - -- -- - - l 1\--- - ---- l'>-- - - -~·- - ; ,1- -- ---- -,, :J- -- -- -- - 'JO---- - -- -(. ·J-- - -- - --10- --- --- - tjlJ- ---- -- -Q J- ___ ..,, __ 1l:O
µ-~c~~T G~ ~\Jll \(Alf
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above this level. Figure 3.2.9 is a sounding made over Modesto Reservoir
about one-half hour later. The mixed layer extends to 840 m-msl. Above this level is a very dry layer from 1050 to 1320 m. Another ozone-rich
layer then extends from 1350 m to 1680 m.
Over the foothills to the east of Modesto Reservoir (Figure 3.2.10)
the mixed layer was considerably deeper (1260 m-msl). Above that level,
however, the ozone-rich layer was also found. The total ozone burden in the
mixed layer was slightly larger than observed at Modesto Reservoir. Figure 3.2.11 is a sounding made at Patterson on the far west side
of the valley. The mixing layer is considered to extend to 1020 m-msl with
high ozone levels (.18 ppm). Above the mixed layer was a deep and wellmixed layer characterized by ozone levels above .10 ppm. This layer extended
to 1980 m-msl. Winds within the upper zone layer were from the south to
southeast for all of the above soundings.
The aircraft completed its afternoon flight with another spiral
sounding at Modesto Airport. Low level stability had developed by this time (1958 PDT) and surface layer mixing was confined to the lowest 180 m (msl ).
Considerable ozone remained aloft, however, isolated from the surface sources
of NO. The total ozone burden above Modesto Airport was not substantially
different from that observed at 1658 PDT.
The aircraft took off the following morning to repeat the flight
pattern of the previous evening. Figure 3.2.13 was the first sounding made
(0541 PDT). Surface depletion of ozone is readily apparent to a level of
330 m (msl), corresponding to the top of the temperature inversion. At hiqher
levels substantial concentrations (.12 ppm) of ozone existed to 1320 m where
a dry layer commenced.
Figure 3.2.14 shows the sounding made over Modesto Reservoir at 0618
PDT. The mixing layer and ozone depletion extends to a somewhat higher level
but concentrations of .10 ppm exist aloft. Over the foothills at 0642 PDT
(Figuie 3.2.15) a similai pattei~ existed but with slightly lower ozone con-
centrations above the mixed layer.
At Patterson, on the west side of the valley (Figure 3.2.16) the sur
face mixed layer (and ozone depletion) extends to 330 m-msl. Aloft ozone
concentrations of over .10 ppm exist but only to a level of 870 m-msl. Above
this level the dry layer appears as indicated in the Modesto Airport sounding.
3-51
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(ti=Pl T vc..: Jl M,;P r,j 11-AP.<-n<J ?~:14:',? I-• Alit
Jt,1• 111//7'1 t<(uH: r:v~R P(INT LA~T~·(GCt/V,~~: blb/
ll""f": c:41:...:1 fLr '1:'it:3:ji 1-'I~. i;l-!(UI\L. £.Ltv.: 29 M(~'iLI
-1n---------o--------1O--------zo--------10--------41--------~n--------hC--------1O--------dU--------4O-------ICC l'"l\r.J I (; S *l 1 1-1n ~ S '>l T I 4 7L, (; s Hf l l ~,4U C s Pl T H•lll s l T') "C
I,, •o 0 5 •1l• T
I ·,~.J s 1.i. t l') T
I J lo -; ,, l T
l c' '-lO 'i J l T l li-JO s e TCl)
C1 i ~:) s U"I l T pn(; 'i 'Je l T I l 7 O s C·l l T l I 4 (J ; t ll e l T 11 Io s F l)t l ,,t ,J'J(i ; t l T• I •-J~ll 'i C e l T
• 1020 s t u e l T
L 9qc 'i E 1 ~\ l T T 41,0 s F C B I T I q30 'i t * L T
w T qoo ', t,; L T LEGEND I
(J'l u i;7U s l)d l T N •J 04U ~ DR l T FULL
~IQ s f C P. L PARAMETER SCALE llMBOL 7~P 'i Do l T 7~u s r-e T (1"urb) 10 cm 3/,- 1ec - E ,. s '-
1
1 ?O Ile T (Oa) 0. 5 ppm z
bQI) 'i Dill' l T M 0011 'i ~Dtl z 1 (NO, NOa) 0.2 ppm N,X 'i t.3U 'i E DU l T
t,QLl 'i l T (SOal 0.1 ppm sL 0" ', 7 ·J s E Dd l T 10 X 10-6 m -l B(b...,)•, 4 J s l T* ll ? 1 ') s 03 T T* (Temp) 0 ° - 100 ° C 'tl-10 'i IJ b lf T
4'Jo 'i 0 ftj ! T (Dew Pt) o•- 100°c D-T
·, lO 'i :Jr Fl T
1 ~o s * 1:l T Figure 3.2.13 Aircraft Sounding - 17 July 1979 j 1(J BU l T
't/L, s C ~ E l
301) ) l r"''' e ,! 1 ~; \ ~ i t,. ') ", I ti ,:: r ,10 ', t d·'.· T .. ,l~U '> T ,, T~l .-:; I) s I
l 1 ,, 'i t-:, 11 T
q,) I S ' <I, T ~
t,r, l ~ i \!1 I <; I l
-11)---------u--------L0--------21--------iJ--------4:)--------~f)--------h)--------10--------~~--------~11-------tcC t>f~(ll"iT ,:F Full ,C~Li,
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F
l
. .__,_.,
r> t ;; t 72 I -A~ a - ,rn ~ 5: L4: 'l .'(i_rµLJ \t~ ul ~c~ nj
1,Y rl tl(ll'\( IK(l,llGAP: 111111-1 Ll\r'TKJl;Cl:/PA:.,S: f-;7t,/ Tl~f: ~:lo:£2 TL 6:l~:1~ ~,~. G~(L~i; LltW.: 7 "' P,' I") L ,
-11---------,1--------1a--------20--------10--------4~--------~c--------6C--------7n--------Bn--------QO-------ICC IC S df l T I
IC 'i bt: l T 1 JhO
I " ~ 1 1~, C,, I I) s ,. l 14-, -J JC S ~ 1-l T
l44U I QI Ml T I~ I 81 1 l F T
l :Hh.:i lF- ~ 'I [) T ,; L 1l ~ Sl 1J f l
l 3 2. 1) ~ ~) f l T l ,· -1,;i 51; d I: l T
l Lb li S,I le l T
UHi s u le b l T ) 7 Tinc "
!_) t TI 110 ll l .. ...l 1 .. u C l I I Lo ti l T- LEGEND IL PiJ' s l) l T"
A IO~CI s tLJ 8 l T FULL
L Io?:, f u b l T PARAMETER SCALET 'I'll! ' ~ u ri l T ~2h
I 'lotl s' E u e l T (Turb) 10 cm 2/1 sec-, E r 'IHI s f [, t l T
w I u 401'1 C L; ,i l T (Oa) 0. 5 ppm z
(J'I I) e 70 E D ~ l T w (NO, NOx) 0, 2 ppm N.Xb40 'i C D ii l T
ulu s E Ll l T" (SOa) 0. l ppm s 1PO ~ [) r l T
;~ 7 "lll ,; I., E l T (b,..,) 10 x 10-• m -, B 1?(1 s F u ti l T eQU s .',l, Ii l T (Temp) o·- 1oo•c T"
'., bO(J s blt l T (Dew Pt) o•- 1oo•c D
l h l(. E l T* b :),.1 f C::t> l T ... 1t, s C B F. l T S411 s D Ii 7t T Figure 3.2.14 Aircraft Sounding - 17 July 1979r., 1(1 ., t' Tu ti l ~~d s I) T 4';(1 5 (, " b l f T 4/;) 0 t l c T ,HU s 0 e el l~O , 1; t l T ~
·, L; t I I. T j i '·' .3) (1 0 H l t T 2 71) C e l C 1 l~G C ~ I I I' tlll ·) IJb T l H;; \ LJ~ I I l "i ,i 'i " 1; ,:, T I 1 )I) , r ~ [ I I"
Q, I qf !J I bu I I
-1r1--------- >--------1n--------2~--------11>--------40--------•,11--------~1--------/1J--------dr,-------- 0-------1on P"M(L~I nF fLLL SCALI
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COFPLT v~~ \l ~0n 03 /1-APR-dO ~~:to:~L PAf.t 'l
CA Tc: 7/17/7<1 ~CUT I ·,1 a PCl'-cT I
LAPTRIUCt/PAS~: ~/6/ 4 11Mt: b:4L: 'I TL t:~q:44 ~IN, r.~CU~C 1:lrv.: Z74 ~l~Sll
-1n---------o--------tn--------,o--------J0--------41--------5o--------bO--------71--------ao--------9o-------100
o•-1oo•c T
171'11 I C C SFS l T I 17,,ul u CfSJ l T 1710 I '.J *5 ~ l T lo'IDI tJ L~EB l T l t-;i;d [) c.s * l T l 6 ;•q 11 s~ ~ l. T I 5 ,10 ,) *C p l T l'ih0 n SfC 'l l T l i)-;10 I) 5 b* l T l "l Gu I) SfL 4 l T , .. JI) I) ,. d l T 14ll\)
[', 'LJ O*~
:-;:::: ti
rt l
L T
T LEGEND
11,l 0 F* B z T 1 J'lO S*D •\ l T FULL I J.'U *CD H l T PARAMETER SCALE .[:!.M!!.QJ.,
A
1zqo 1 /. 1'>0
¢((;
*C.G h
,l l l
T T
(Turb) 10 cm 2/3 sec-, E
l lllO S* C B l T (Oa) 0. 5 ppm z
w I ...(J1
T I T
u ,J
llOO 11"70 1 t•• u 11 l 0 l O 1~0
S* C H
*S C d C B*s
us ~* ,. tC ~
l l l I l
T T
T T T
(NO, NOx)
cso.1 (b,.., I
O.Z ppm
0. 1 ppm
10 X 10-6 m "l
N,X
s B
~ I O'>tJ * tC ti l T (Temp)lldO IJ S* ~ l T
'I >u I) SCt ll l T (Dew Pt) 0°- 1oo•c D ~ 91t,•., ~ 5Ct B l T
<; 3J *( I. d l T 100 x 10• cm·• C
, (CN)
1-1 q~o SOL I: tl l T ~7J , * l T I*
l eoo :, eC 11 ~ [. T I
C !J B l T Figure 3.2.15 Aircraft Sounding - 17 July 1979 I81U * I7PJ * (, lJ B l T I ., 'lU s t C I) 8 l T I72U s C CE l T I
bqC s * d It T I
t,t,U >* B f..i T IH , l To~O ' (, u I
<JU:J s ( o, e l T I ~7v '.il:.C ~ fl T I .,'l1'tt) 'iltJ l T I ", 1 0 '> L n ~ f L T I
.., ~i IJ ,c I T I I ..,,o :, L d t., l C T I
.t., l l, , l d GI f r I
l'-Jd ·, L - I T
)hll ,c l T c I
"·' L r" l"" -; T T:,,r)·) L I!'
>-••••• .. -f,)••••••••••·•••'"•••••""••••••• llf <' 1 <, I-1 ·)----- --- - ' -- -- -- --1••--- - -- - - t'.0-- -- --- - \1)------- -4,1---- --- -~(J - .. - - ...........
t'ttt(f 1111 ..,,- ,t..ll •'-•l•
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PAlJt I JU-APk-tlil ~5: l't:02CtH:i:,l T v f:N tJ l t-'t.hl OJ
1-· CL, T t- Cvt~ PCll-,l !>C~T· 1t11l1~ L~kr~ll1CE/~•A~S: ~,o, 6 TIM : 7;,2:~7 TJ 7:4d: ~ ~IN. GR(U~C flcv.: lU t'C~SLI
-10---------0--------10--------2u--------su--------4,>--------~o--------6C--------1c--------80--------9o-------lOC Is 1t1 IO S H t l T I I, Od
(41.> IO
IC S
S l>t *
l
l
I
r I
14 4-., I~ I 0
IC I u
·, S
-> *
l l
T T
I I ~O I D :, "- l T I J 'io I u :; :.,; l T LEGEND 132u IJ S H l T
l /4l: s cl * l FULL l lbG UH, lLOU
n [)
r,
S e tl S ,, El
c; K ,: Z
T T T
PARAMETER
(Turb)
~ 10 cm •1., sec-,
SYMBf&
E
I J 7L, 1140
D fl
'> c;
u:' M
l l
l T (Oa) o. 5 ppm z
11 I Cl l OfiO
lO"'u
11 J C
:)
s
~
tl
"
l l l
T T
T
(NO, NOx)
(SOa)
0.2 ppm
O. I ppm
N,X
s A L
11,n, -,i(t,
ll 0
s s * l
l T T (b"""')
10xl0-4 m- 1 B
w I Ul Ul
T l T
Ll
960 411] ,rnn tt/0
D I)
r, ,)
:,
,,
* * * l
r T T l
(Temp)
(Dew Pt)
o·-1oo·c
0 • - 100 • C
T
D
I) ,140 \, .;: h l T ,, hill /Ru
s s
(: llH
f ~
l
l T T
Figure 3.2.16 Aircraft Sounding - 17 July 1979 7"lfJ s t c~ l T
"' 72J s ,. 8 l T t,40 ' i:u ~ l T ,. bf>(J 5 c lJl1 l T
~ tdU :, f f) e l T L t011 s E ll 8 L r
..,_ 7LJ s t- ,u B l r ~4U s 0 B E l r ~10 s u 8 * T 4HU ) ,; H t l T 4S1 s CH .. l T 4li, 5 D l r l l j~J ', .. l T >bl) s t* l T ~1 3 tl I s l T :,ou s n E ~ l T nc s ll H l l T ~ 4 0 s 1 H T LI I) s (; ~ l ., I et. ~ l ttl; l '1 lJ
1 l1J
l l , t.•)n
u b :.;, 40 l s :1,
t,I,) l 5 .~ I l
1U l :, 11;
- 11--- -- -- --•)- - -- - --- 10- -- - - - - - c. C- -- - - -- - ·I :1- --- --- -,, ·J- --- -- - - - 'lll- - - - - - - -~ ·)-- -- - --- f •; - -- --- -- df)-- - -·----91)- ------ .l 00
P<k(l·Nl Jf H_;Ll 'i(Mr
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Winds in the ozone iayers aioft were from the south for a11 soundings made during the morning. Transport of ozone aloft from the southern part of the valley to the north is indicated in this series of soundings.
3-56
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3.2.3 Tracer Test 2
Release Location: Manteca, San Joaquin County
Time and Date: 1300-1900 PDT, 7/16/79
Amount: 104 pounds of SF6 per hour
Release conducted during northwesterly winds of between 2 and 3 mps. A
southerly flow on the eastern side of the valley (the Fresno Eddy) was replaced
during the course of the release by northwesterly winds.
Initial transport southward
During Automobile Traverse 1-1, beginning about 1500 PDT, a peak SF6
concentration of about 630 PPT (880 PPT/lb-mole of SF6 released/hr) was
detected near Modesto along Hwy 132. The peak concentration was detected
slightly to the west of Modesto. 94 PPT of SF6 (132 PPT/lb-mole SF6
released/hr) was detected during the 1500-1600 PDT automatic hourly-averaged
sample at Modesto (see Figure 3.2.17). At the Modesto hourly-averaged sampler,
70 +/- 15 PPT ( about 100 PPT/lb-mole SF6 released/hr) was detected between
1500 and 1900 PDT. The timing between the start of the release and the
detection of SF6 at Modesto was the same as during the first Manteca release.
The concentration profile was centered farther to the west than during the
first test and center! ine concentrations detected along Hwy 132 during this
experiment were about double the corresponding center I ine concentrations
detected during the previous test. The detection of higher concentrations
during this experiment is surprising in that the release began during the early
afternoon rather than during the typically more stable conditions persisting
during early morning. The unusual meteorological conditions alluded to in the
previous test were evidently the source of the enhanced instability detected
during the first test. SF6 concentration profiles detected during Automobile
Traverses 1-2, 1-4, 1-6 and 1-7 showed an SF6 peak near the same location as
found during Traverse 1-1. The maximum concentration detected during the
traverses, however, tended to increase throughout the afternoon. Maximum SF6
concentrations of 632 PPT, 643 PPT, 860 PPT and 1248 PPT (1753 PPT/lb-mole SF6
re! eased/hr),
3-57
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SJV-2 7/16/79 - 7.'18/79 150 ,- n-rn MODESiD
0 I f" ' LH I / I I hi I / / 6 , I ,:111:!l:111:111:!!l:1tt:11t..Ji1:1:111..J4,, / I I I I I I I , I I 150 -
PATTERSON 0 I + , I , • I , , I • L L I I O I , , L • t l l:lf:tl:tff:tH..J:tH:11:til:tH:tH.,J' , l , , I , 1 I , , I
150 .= GUSTINE
0 I , , I , +L-1 , LIJ]-1 , Lj / I / L I / I I / ,.,J.,,., I / / I / / I / / I I I I / I I / / I 100 .-
DOS PALOS 0 L, , I , , I + : I t:::d-t--t l I L ) , , I 1 1 L , '4t4 ,.,.l*/:!11..l:!'1*'..j:!1:!!1:iil:!1:1!t:ttl:!t\ , I , , I
100 r TRANQUIL lT¥
0 L / ) / I I I / I I t1=il=6 Ll4U I 1:11;1.,J:!l:::I I / / I / LJ / / kt / I L / I / / I / I I 100 -
OAKDALE 0 I ,,+1 , , I , • 1H I , , I I k-4 1 J INI , I /:IH..,J:!H:IH..,J:!H:IH.,J:!H:IH.J:Jll1' , I • , I 1 1 I , 1 I
100 ,- · MODESTO RES
l 0 I + , I 1 1 b,,,J..,...,*L , I ' 1 I , 1 l .1 t I : , I , /1M:!1:1H:td:11;1:111:tl-w,. 1 I • , I 1 , I , , J a.. a.. 100 - LIVINGSTON r,
CD 0 I , , I • , l 1 , I , J , 1 L 1 6 ..1 l • l!,JH*i...J:1114 1..j*i:ll1:IH*i*1.li11:111'4 1 1 I 1 1 I 1 1 I LI. U) 100 -L...J MERCED
0 I • , I , ,rL--ttJ , U::t , 6 cJ u I H I H I , • I µ I , d , , lJ +I , , I , , l 100 ,-
CHOWCHILLA DI LI I I I I I ,L. I I bl L I I I I I I I I / / I I I I t:'H:lfl:JII
f I I I I I I / I I I I I I I I I I
- I
10i -MADERA
0 l,1, I, 1 I , 1 I 1 ,-Ill , 1 I 1 1 I u I H b--, I 1 • I , kb • I , , I , , I , , +, , I 100 -
FRESNO 0 L., • ) , , I , , I , +l+ , I w I t d , , I : , 6 1 I , , '*' I 1 1 I , , I 1 1 I • • I
100 ,-O'NEALS
0 L, 1 I , 1 I 1 1 +1 1 I 1 , l,, 1 I 1 1 L, : I • 1 L, 1 l H Li:!1*l*1:111..J:111:111:4tt:tH:it\ 1 1 I 100 - n MARlPOSf.
0 I j : I ! .,..J I I ...... L u ~ : I LL~ L I- L1 L1 1 lNL-lli~*I..J'!t1:111iJ'!tl" I I I I I I II
12 15 18 21 24 3 6 9 12 15 18 21 24 3 6 9 12
PACIFIC DAYLIGHT TIME
RELEASE LOCATION: 621 LBS SF6 AT MANTECA RELEASE TIME: 1300 PDT, 7/16/79
Figure 3.2.17 • INDICATES MISSING DATA
ARROWS INDICATE <:Ut,DS OF SAMPLING PERIOD
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SJV
2
I 1
.... , l
~,rt,na ·
~Qr ~Cl~w:~7-~fcfi r,dro -...-fywar
ij4 .,
~uno~F"·!.
.-
_,
--~-- ~
t;\,. I. -'lfArl,,t..
:.TA,·.,.13- \ I
f,ittn,"• rAr!~
',
,... I 1,,o•fA...,._ • ~ k..JlllfT.' ..,_ '·
' .- A ......_ J'G ' f ~
l. Vall
. A
t::_~ .,
Figure 3.2.18
* INDICATES SAMPLER LOCATIONS ((~·: IS THE RELEASE SI TE 3-59 ~
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respectively. As mentioned previously, Traverse 1-1 began about 1500 PDT,
while Traverse 1-6 began at the end of the release (1900 PDT). The increase in
concentration detected during these traverses was probably due to a
increasingly stable atmosphere as evening approached.
Continued southward transport during evening
As in the previous test, the tracer was detected west of Hwy 99 during
traverses along Rd J17 (west of Turlock), Hwy 140 (west of Merced), Hwy 152
(west of Chowchila), Ave 7 and Hwy 180 (north and west of Fresno). Typical
concentration profiles along these traverse routes are shown in Figure 3.2.19.
The maximum concentrations detected along these traverse routes were 424 PPT
(about 600 PPT/lb-mole of SF6 released/hr) along J17, 347 PPT (490 PPT/lb-mole
SF6 released/hr) along Hwy 140, 112 PPT (158 PPT/lb-mole SF6 released/hr) along
Hwy 152, 55 PPT (78 PPT/lb-mole SF6 released/hr) along Ave 7, and 56 PPT (79
PPT/lb-mole SF6 released/hr) along Hwy 180.
The hourly-averaged samplers also showed behavior similar to that of the
first test. During this test, however, Gustine received high concentrations of
SF6 (maximum of 116 PPT, 164 PPT/lb-mole SF6 released/hr) while Livingston did
not. The tracer plume was thus detected farther west during this test than
during the previous release. Dos Palos and Tranqui I lity were also impacted by
the tracer plume. The arrival of SF6 at Dos Palos (2200 PDT) corresponded to a
mean transport speed of just over 3 mps. Tranqui I lity was close to the
centerline of the plume in that a maximum concentration of 41 PPT (58
PPT/lb-mole SF6 released/hr) was detected between 0200 and 0300 PDT, 7/17/79.
The arrival of SF6 at Tranquility (0000 PDT, 7/17/79) corresponded to a mean
transport speed of about 4 mps.
Gaussian plume model comparison
As in the previous test, the traverse data can be used to evaluate the
dispersion parameters for the Gaussian plume model. As shown In Figure 3.2.19,
the concentration profiles along the traverse routes were essentially Gaussian
in shape. Figure 3.2.20 contains a summary of the horizontal and vertical
dispersion parameters estimated from each of the traverses. The solid lines in
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TRAVERSES SJV-2
TRAVERSE 1-2 1600-1639 PDTHWY 132
TRAV 1-5 1858-211144 PDT
J17
HWY 14111
HWY 152
'-,,
____,\._\..t.tADERA
AVE 7
HWY 18111
FRESNO
3'!1111 PPT I Figure 3.2.19
3-61 NORTHERN SJV SCALE - 1r 208000
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SJV-2 100-
2:: X
LL
••
LL w 0 u z 0.... (/) 10 D:: I.LI Q. en .... C
•N.... D:: C::c
• ~ LL I.LIB 1000 z 0
(/) -D:: UJ Q. en
100 -C
...= D:: I.LI >
GAUSSIAN COMPARISON
,.A a C
0
() ----------~D
I I10~·--------.-.__.,......,_._,.,~•~•....________________.......,,~,-1• 10
0 DATA
100 1000
DOWNWIND DISTANCE. KM Fi gu re 3. 2. 20
TAKEN AFTER END OF RELEASE 3-62
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the figure correspond to the predicted coefficients for each Pasqui I I-Gifford
Stability Class based on extrapolations of the curves presented by Turner
(1970). The vertical dispersion parameter was again back-calculated from the
horizontal dispersion coefficient by mass balance considerations. As noted in
the figure, the horizontal dispersion coefficients slowly increased with
distance downwind but were generally consistent with Pasqui I I-Gifford Stab ii ity
Class C or D. The apparently decreasing stab ii ity with increasing distance
downwind is surprising in that the shorter distances correspond to
mid-afternoon while the larger distances correspond to the presumably more
stable evening conditions. The calculated vertical dispersion coefficients for
each traverse corresponded to Pasqui I I-Gifford Stab ii ity Class D. The
calculated vertical dispersion coefficients are also consistent with a more
unstable atmosphere (than stab ii ity class Dl with a constant or slowly varying
mixing height. An average transport speed of 3 mps was assumed in the
calculation of the vertical dispersion coefficient. Due to the uncertainties
associated with the vertical dispersion coefficient calculation it is not
possible to determine whether the tracer slowly mixed upward continuously or
quickly mixed within a wel I-defined mixing layer. The estimated mixing height
in the valley, based on pibal data, was 2-3000 ft. If the tracer was
wel I-mixed vertically, the vertical dispersion coefficient calculation suggests
a mixing height of about 400 m or about 1300 ft.
Carryover of tracer
As in the previous test, low concentrations of the tracer (5-10 PPTl were
detected over a wide area north and west of Fresno on the day after the
release. Again, the night and early morning winds apparently redistributed the
tracer throughout the northern valley any tracer not transported out of the
valley.
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Summary
Many characteristics of the first release from Manteca were repeated
during this experiment. An overview of the transport path of the tracer Is
shown in Figure 3.2.21. The tracer was again preferentially transported down
the central and western sides of the valley.
concentrations were detected on the east side of the valley, San Francisco Bay
Area or California Delta pollutants transported into the valley apparently had
little effect on valley air qua I ity.
It was possible to interpret the dispersion of the tracer in terms of the
Gaussian plume model. The horizontal dispersion corresponded to that expected
under mildly unstable atmospheric conditions, Pasqui I I-Gifford Stab ii lty Class
C or D. The vertical dispersion corresponded to that expected in neutral
stab ii ity, Pasqui I I-Gifford Stab ii ity Class D. The vertical dispersion was
also consistent with a wel I-mixed layer with a height of 1300 ft.
As in the previous experiment, low but non-zero concentrations of the
tracer, were detected on the day after the release. It was not possible to
quantify the amount of carryover from the release day.
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lb. e.-ci
<,.I I
O'I u,
'o.......__, 1.,,..._ ..._,......... -\
'\ Cv
~ ~,. ~~
~
! IEl.00: S11£ - fVMEr.A I
11CAU IO 0 IO 10
HllU
0~
~~ _j
100o
ARROW POINT INDICATES OBSERVED TRACER LOCATIONS NUMBERS REFER TO HOURS AFTER RELEASE START (1300 PDT., 7/16/79)
Figure 3.2.21
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3.3 Test 3 18-19 July 1979, Livermore Release (1510-2030 PDT)
3.3.1 Meteorology
Genera1
The synoptic meteorology of 18 July, depicted in Figure 3.3.1 was characterized by intense ridging aloft on the west coast, extending well up into northern Canada. Warming of the temperatures aloft due to subsidence is reflected in the plots of 850 mb temperatures at Oakland and Vandenberg in Figure 2.2.1. At the surface, thermal troughing due to heating of the interior resulted in onshore pressure gradients. A high pressure area located near Four Corners reinforced the surrvner monsoon flow over the southwest desert, allowing moisture to penetrate into central California at middle levels and causing widespread shower activity in the central and southern Sierras. Skies in the valley remained clear and visibilities were generally good except in the northern portion. Stockton reported visibility restricted
to 4 miles by smoke. Temperatures were several degrees above normal with Fresno reporting a high of 108°F.
Transport Winds
As shown in Table 3.3.1, the surface flow at the release site was directed towards Altamont Pass during the afternoon of the 18th and until
......... , I.I,...,_..., .,..,..,..,..,4,. .,.,, ... _.._,..,..,.t -.h..-.,,+ t:.. m/~ ; n~arl_y 111ur11;,1~ on the following UOJ • n111u :::,t,Jct:u:::, OVCIO~'CU OUVUL. V Ill/~ Ill
the afternoon and increased to a maximum of over 8 m/s in the late evening. By 0300 PDT on the 19th, the winds were no longer directed through the pass and speeds decreased. From the pibal data taken at a location 4 miles east of Altamont Pass sulTITlit, a time-height cross section of the wind component representing flow into the San Joaquin Valley axis was developed and is shown on Figure 3.3.2. A main point to be noted from the cross section is the persistence of a significant component of the wind directed ino the valley at low levels (18 hours duration or more). The flow maxima occurred between 2100 and 2300 PDT on the evening of the 18th. Depth of the flow was about 500 m.
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fC) 0..
U"l 0
,._ °' °'..... >, ~
::, ""'.:)
CX) .....
V, ...., '-ttl'
.c:: u '-a.,
.c::...., ttl a.,
3 a., u ttl
'+-5
Vl
..... M. M
a., '-::, O>·-LJ..
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Table 3,3.1
SURFACE WINDS AT LIVERMORE 18-19 JULY 1979
Time Wind PDT) (m/s)
July 18
1600 255/5.4
1700 245/6.0
1800 250/6.6
1900 250/6.8
2000 250/6. 0 2100 245/6. 5
2200 245/7.9
2300 240/8. 4
July 19
0000 240/7.4
0100 240/6.3
0200 250/4.7
0300 190/1. 3
0400 120/1. 2 l'\L n. IL A0500 C.-:JU/-:J,'t
0600 095/2. 7
0700 150/1.6
0800 155/1. 7
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2 2790
2520 ~ 2250
E ~
Cl 1980z ::, 0 0: (.!' 1710 LU > 0 co 1440 ~
I-:c t!l 1170..... LU :c
:)'896
612
313
C'\ '-'
0 m/s
0
2 2
;---0 0
13 15
Figure 3.3.2
17 19 21 23 l 3 5 7 9 11 13
TIME (PDT) 81 /030
Time-Height Cross Section Component Winds (m/s) From Altamont Pass 18-19 July 1979 (Positive Component Represents Flow Into Valley)
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Flows within the valley during the test can be described by the streamlines constructed from the 1000 foot measured winds from the pibal
network. The 1500 PDT flow is shown in Figure 3.3.3. From the stream-
lines it can be seen that northwest winds were predominant in the northern and central portions of the valley. By 1900 PDT (Figure 3.3.4) the north-west flow extended throughout the valley and persisted until the following morning. Maximum speeds ranging from 8-9 m/s were observed between 2100 PDT on the evening of the 18th and 0100 PDT the following morning. By 0500 PDT the Fresno eddy was established (Figure 3.3.5) in the central and southern
portions of the valley. Subsequently, winds dominated the flow in the southern half of the valley through 1100 PDT.
Mixing Heights
Mixing heights were measured by the aircraft during the afternoon flight on July 16. Heights were determined primarily from the characteristics of the
observed ozone and bscat vertical profiles. Measured mixing layer heights are given in Table 3.3.2. In two of the soundings, there were two principal layers. Heights of both layer tops are given in the table.
Table 3.3.2
AIRCRAFT MIXING HEIGHT JULY i8, i979
Time Location* Mixing Height (PDT) (m [above ground level])
July 18 1645 Modesto Airport 210 (690) 1747 Brentwood 620 (1250)
1830 Livermore 560 (* Distances in miles)
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.... .,, <", ..,..
,:_, ••c.11:!!lf'•
. . . - . - --.._ .-,·- '
L, • ~ •.•
Figure 3.3.3 1000 Ft-agl Streamlines - 18 July 1979 (15 PDT)
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-C'
N I
9tM.I ...
-~ C "! ! tf' r l•
. . . - - - --Figure 3.3.4 1000 Ft-agl Streamlines - 18 July 1979 (19 PDT)
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------
- --
/~ ~ ~---------- . \
l - r 1· - ~ --~~~---------' \\ :\~-l-- . / L
ll '"'°""•,;\\ '--~w ~~ j'> '\.- ,. ('._ ()
~~ ~ _ii t1p '1;-t,( kt-;~~--: ~ "\/..... . i \ -\... ...._ \\.j :•~~ ..'T0 . - .. w-...I?_
c; "-' / . .,,... • '·"-..-,, v-... - - - ·,1r0·~ ~. . --:', C''\<·1"' 4,-,
\.:~ b_ , . -~ _,.;;, >~-,-~?~\:: ,- - -,.....-.--%-~ . -. -~~fo~·-?-:2~_
5u11 ·~~-> "\.. ~--" - .:-,~.. '-
"'"'~"of~t~~\~~ > . ~ ~ -~;-:t.:sl~ '\\ ·-,..,. lt;:.-,·".C:?::..~ < t~ C\.._ ~ <-'~ I \1.~'-7'"',: ,<; . . - ~ "\,.),. ~" ~~- \I '•l <,.) .. - C. ~ _, ~ - •.- ~ ---~,, I \ ~ ~ ~ - .....,. ~'-~~-::) (
~~\:~~ . . ____........_ ' ~~~~~\ \
(· ~~ ~-- ~,:\·. ... y -~-- :s.:_ ·-<';-..... ~
-4.~, , ..... - . "'_: , al "'· ' . ~ .... -.. ~
~
-" ..
\
; ' ..;;, ~. .,,, ....~
f
N I
. ,.. .... ~- ... ·- ;,·
. . . - . .,
.:!-,.
..... .--·
-~ --;·
Figure 3.3.5 1000 Ft-agl Streamlines - 19 July 1979 (05 PDT)
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3. 3. 2 Air Quality
Regional Pollutant Levels
Maximum hourly average ozone concentrations throughout the valley on July 18 are shown in Figure 3.3.6. Exceedances of the .10 ppm standard
were frequent within the valley. Highest observed hourly concentration was .17 ppm at Fresno. Locations within the Sierra National Forest recorded values of .11 ppm.
Maximum hourly concentrations of S02, CO and NOx throughout the
valley on July 25 are given in Table 3.3.3 together with the maximum values recorded at the Rockwell International vans on the same day.
Table 3.3.3
MAXIMUM HOURLY CONCENTRATIONS JULY 18, 1979
Parameter Location Maximum Value fnnm\..,..,,.,
S02 Bakersfield .02 co Bakersfield 2. co Fresno-Olive 2.
co Stockton 2. co Modesto 2.
NOx Bakersfield .19
NOx Modesto (RI) .01
NOx Merced (RI) .05
NOx Madera (RI) < .01
S02 Modesto (RI) < • 01
S02 Merced (RI ) < • 01
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V
~-- c; ~ ',. -A."'1.7-z~
~~
...... .....l. ~~~-- •' ..
C' <"
-~ .. ,.,1•, ~
·. '
"--' . ~ ~- -..
:x::::::::::=, - --••etolO-OICI•
' ---
t. I --- -~ ---~~-::.-- · 2-- -- - - -- - - --- -l. L_:.~~s ~~-e-~~ \_ ,/1_\, ~ ~---::
'.\:w r,.,f: ~ ~- . J~ ',, .f'~~ '- r
Ve~~ ~y "l"'?JZ /,. :.~~~~ ~-,_ t \ I( ~ • iJ -\S<:,_,~,,TO ft y~-:_~~ •,,~ '5\ ~- ~t4 =-: ~~"'~~~~~::_
L t_f, ~- / I ""-~ ~ J'§> ,_\~~ts__~~~ 11 l\ _ / , ; _-~ ~~)-,__ r "'~ ~~\\.-- . - ~) ~- 0?19 ---------~-I ,,_'.',".,cof.:-':,,....,:., ~ ;;:,~~~~~- \~ \ --, __
L --~--;,-...:.-,:;;,_"" 1-N ~ ~ -- --~~ ] '1\ " , '·-" ..s ) -;,,;= "i""'..,,, -.:k: -- , . ~ Lb \ ·.~I t~<-.. \ ?\~ c.-"$_ 12 ~;:, . ~----~ _?~>----·-;: ~ "·C. I \.-. '----2,. t ~ '? ts · ~ ..... C\... ','\ l ! \ ")_~~---:- ~ - . iS--S' : 12 10 \f(_- ·- ~ "'·\ -~ ~ ~ '
(~"~ ~~~~ \,t ~~ -~~~• i·•••m li-. c--._ - ~ . 10 / ( . -- '"' ~ 'JC ~14_/') ·-1-..S,--\ /_-, _ , ~ \ t'·-:s~ _ 1 .;;__~ ~ -~ ,
-~/q
11 ') ' r - ~\ ,( -"-\, I •--:- 1 . - " ~\ ~ 5 -;,--...-_ -\: \.
- ~ \:~ ~ '\ I --.._ • 0~.~y ':~~- ~ ~•~--;;-, ', - ;
'\ 7-,_ , ••, - - --. vi,, . \, --1-'"' 8 ' :
•• ~'< ~' ~~'-.,, 12 '---'u - •,, "- • ', _ \ C' :-...\s. ', \.f, ' ~ - '-' . \
~
0
N I
,:.u.1 •-•-_!=_':'! X == ~
(- Figure 3.3.6 Maximum Hourly Ozone Concentrations (p-phm) - 18 July 1979
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Aircraft Sampling
In conjunction with the tracer release from Altamont Pass, the airplane sampled in the late afternoon (1645-2000 PDT); concentrating on a
triangular route between Tracy, Brentwood, and Livermore. Two altitudes were traversed between Brentwood and Tracy, east of Altamont Pass, and at an altitude within the surface mixing layer on the other two legs. Sampling was also conducted within the mixing layer in the valley to and from Modesto. Spirals were flown at Livermore, Brentwood, Tracy and Modesto.
Figure 3.3.7 shows the flight pattern followed on July 18. Table 3.3.4 gives the overall air quality characteristics observed during the flight.
Sounding profiles for Modesto, Brentwood and Livermore appear in Figures 3.3.8 to 3.3.10.
The sounding at Modesto (Figure 3.3.8) shows several layers of pollutants. A lower layer (to 240 m-msl) was capped by a high bscat layer between 270 and 510 m-msl. A very dry layer is indicated between 750 and 1080 m-msl
containing relatively high bscat values. The wind flow in the upper layer was from the northwest.
At Brentwood (Figure 3.3.9) there were two main layers, both characterized by high ozone values (maximum .22 ppm). Above 1260 ma very dry and
clear layer is shown. The sounding at Livermore (Figure 3.3.10) shows a well-mixed layer to
750 m-msl with values of ozone to .10 ppm. Above this layer the dry, clear air was again found but a second ozone layer was centered at 1050 m. The wind direction at the height of the second layer was from the west.
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w I -., -.,
\ it.,d ~.\:.,, l~' 0 ~ • '-.._ I)22 1RM
11 / /ON!'1"~_ 6 \s•:(~l'cf'••· i' '1(', k,\~~:C, •, · -_\.'>_ •_I 1-f'\\\ / -i-'<-i~•~2~-
J-,, o:',-,f'!r-C__ - )~,I•. , 6lL'-< \ , \ :\:,J ,- ,-.,~ "'"'"""': .. --~ , \\\, o II ~ 1
.:_:,,, "')-' " /, ~ -\~.~ :,..· )1'~-'-"'-!-:..::rf~ ,;1~.J "'"'···· Lii-'.1/v ·-~~os~- _,~er..,.'½\ OJ \, _ . / \ ..[,~ '\ ~~-.. ;,: '. ,\) °\:~·~0
• i \At ;, c-:;:; ;,.._ \/7 ,. <;;:; ;~!~ ~~~ - - ~ A,~ ..:,uh1not ·•./.:.._~ ./ • ,· • ...._.µ.i..;..'--'-.,.+.,,._~~..,__._~......I.) . \ . ~- .. '"'-I·:\'-./ ~ < '
!lo., -...,, '
~~"?7"~v:r-,......~,
\ L.L
:,.;:
,/1~.f
.,... j
~
8
:13 "
~ANf◊•A~I~.\--~::::--.. .. ---:---'"/1 --:,-· '~.._:_·:,x:,:G,',;b ·.;J.,c-"k;:::: 'I ""'I''~ J .,..[ ••••• ....:.t·~-.:..-.....->::-,~~~-::y/,-;:';.,, :M• ~,~·-~4~0,·~: ,,.•/ ?25s·~::1r-(>,. ';K~~l "•'·::..• ·t;!\_-----,,1)~, '-;;;;-;-;;-' ,, :=_ i', ... ,? ~< (-.i.j·'. \~·/LI_':::·"··-·_'."·~\~,·-r,,:,..,·7 . _.'.r:,~ -.-, .'.:. .. ;----::.... v~. · .. ~.:::,·"1'1v'--,,0.:J•l4_/'\..:..11\'1< '',--+,.Ii.,-·.1 ,, V 11... •
,., ) "7"0 6. 1 ,, ",.;> '< I 1 .. 1 1_'\. .. - _....__.-. -,,, -1· /.,, .,,-, ·~ v.-, ,,,,- 1/ (i'• 1 1 ,•,~~1\'f , ,,, I f, 1:•11 !l.l' , '
<J"\ • •~- _ - - '.;-, •,,,. -:i, _.. ,':' '" / ...... , ',,. ,',,"\ .:., , ·•.:: I\ ' J \ I• J.-. •ce:.·..: I ,'+I<)];~~·,,,>, \ ,. 0 -------, , . [ ,~--·-- r . ; ·· ......~"' ~ :_.___..,, tA-1 fAPf", ."' _, - ....... I~\p--r l~ 41~:1:.'l(~ /I\, ~ ,,. ,..... •,r • 1 1 ..~ r-~ ?, _ ~~·-----,·) /', , 1:.;,n • f'i'j ,, • 1 - ._ -~ .,.,._ .,,,_,.__~ 7 /1 .
-:''Y/.•t \ 1 • < '"' "·'' ::)(:_. ·t•µ~:~.:• ,\J_1 •• \'/ ., '""-. .._,(J ;,~•~";;,,,.•~; .,N"'t:<"• .._~ ~~ ~...._ •~'1\~'~ L'~,', ~i~i ~--: ',, ',Scale /'.' . \ /' l \·i.,,"r•:•·;,// " ·~ 1· I' ,'\ ,;;,••. , ,,.\,.lc'~·~I,_ - i I,
0 ' ' I (.\•IJ.47 / . :-. 't ,\v·, ,t..l ".., I ~'l nr1~ I' --------• ,I ( •'.J~j I ~• I j _J._ j I I I lr.1 .. t (',I;,_~ r-•l -::,<"J ,::-,\.:' \ I l\' 'f ..,,.::-:-.::~ ::1..: • •• ~- c__j
10 nm -I .. .
JH 4 I I ' I ···,: \,:I .... ) ( \··',! .J.,·,-~. 1-- ,, , :fJ'(l 1I ~:.~)•~ (.'r ,.,1
~aMl"'l\ i:iH,-.,, ~11-,. ,.c. ,\, __',_./':' - 4089_••• -~--...¥,...,..,_ __ _.._' _ _; ,_!:,PATTJR',t,. •Jt,~(1, ,~°7',';\,._,• I •_I 1./\ ~--~~ ,,r,, ... ,
<;:AMPLING ROUTES 18Julyl979
Figure 3.3.7
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Table 3.3.4
AIR QUALITY MEASUREMENTS CARB SAN JOAQUIN JULY 18, 1979 SAMPLING
VALLEY PROJECT
Start Time (PDT)
Location (Point)
03 Mean Max (ppb) (ppb)
bscat Mean Max (xlo-fim-1)
S02 Mean Max (ppb) (ppb)
NLix Mean Max (ppb) (ppb)
NiJ Mean (ppb)
Max (ppb)
0646 1 37 152 145 ll08 0 33 6 44 4 34
1719 1-2 147 241 163 ll96 1 4 14 32 4 13
17•H 2 132 223 82 196 0 21 17 36 6 18
1812 3-4 117 179 86 144 0 0 20 36 5 13
1830 4 71 145 51 130 0 0 17 44 7 15 w I 1844 4-5 94 165 82 200 -1 0 23 41 10 28
-..J co 1855 5 66 76 37 68 0 0 8 15 8 15
1916 5-3 71 82 35 70 0 0 19 27 12 20
1929 3-5 161 176 109 156 0 0 24 36 7 15
1943 fi-1 158 192 131 266 1 4 23 40 7 15
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Pb.Cr lf IJFPLT VfR Ill MtJ'l J.l 00--00 1J:1~,1~
4..Cl.l• ,.,-'It-~ f-'(l~l~.llt·: 7/lt/74 L4RTe I LCI /P4a'i: b1 I'/
~I~. !-rl[L~C ~L•:~.: ,. I 1" :) l)llMi: lo:4',:e, Tu 1,,"i:1~ 4
-10---------o--------1~--------2c--------jn--------40--------'>D--------bC--------10--------oo--------~o-------1co h 3U IC S ~ * 1 l T l',OU IC $ 1\0 f l T l470IC S/1,~*l T 1,4v IC ~ *o"< T l'tlO,llJ S*Otl T Jj~O • _ 'i t\·99fL l 13~0 l 0 s lI\,. T
l 320 II Ll s I<.• L T _; <; ,. ,";,:_, TI 1 'llJ
ILoC cl X Ts ,, "'l I Z :1,J u s Ir I l"4 X T
1200 C s ti r. l X T
1170 11 u s j~OA l T LEGEND ., Tl 140 II JS i! l
I) ,,,i T1 11 v I SN l FULLJudd IC s * iH::l T
J05v IC s "llf l T ~ §YMBOLPARAMETER 4 1020 IC SN ~ TJ( * (Turb) JO cm •13 sec-, El '190 ID s.. Xt l T ~
T Cjt,Q IC 5"')( d T (Oa) O. 5 ppm z" I '13 J IC SNX l t ~ r
T (NO, N01) 0. 2 ppm N,XT 900 ID SX"-l t e w u >i70 IO s 0" T I
., cso.1 0.1 ppm sD ~'tO ID SNX ce T......
1.0 l d I u ID s * tl ~ T Cb_l 10 X 10-•m-1 B 780 IC S* l E e T 7~0 IC ; l ~ F T (Temp) O • - 100 • C T* 720 I D s * l fl T"' b90 D s ,c, l ' tl I: T (Dew Pt) O • - 100 • C D
,I ooU S* x: l B f T s o3u S* X L b E Figure 3.3.8 Aircraft Sounding - 18 July 1979 l oOO SU/I, X t* ,1u s i;C t,. l BE
~ 4(J ,·" • C l C:
'> lO S I\X. C l l_ * 4~U ~ I\ X D l t T H 4'lu S I\ X C l f T 'l 42J SIii • C C T C
l'hl 'it, ~ l E T 3~0 <;" • C l F T ... ., lt; ·)S~ X l f T ~
jlJU 'I t: T t l711 l ~ f'"'S* T 24C \ ,\ X C F ~ T ,,ll C S r1 T I a J s ~. Ll 4 "' T 1-'H, (; l .. I"' . "
l d17) ', " . L ,. T
" ) • Ll 1 f T (J J l l ",;.
J() ,;: A L / I•, ,- T
- i ()- -- ------~)- - -- -- -- in--- - - --- '')- ------ - ) i) •• -- -- -- -- - ·-- - - ·1C)- - - -- - - - t,/)- ---- -- - 70---- ----~ ,)----- ··-- .. o- ---- -- )CC-(o ')-
~csct r,J LI fLLl '..l~L.
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~
C0FPLT \fS ul ~~~ OJ oo--ou 13:Jo:19 ~A<.f
fATF: 1/ISl14 ~CLTr: l, Vf ·( p L. I I\ l LA"T"l~(t/PA~S: 617/ 4 TIM•': o:zc:ie To o.,i .. :., ~Ir.. GR(L~C tl~v.: 11~1~\ll
-10---------o--------10--------?C--------]0--------40--------~u--------b0--------7C--------80--------qo-------lCC l~OC IC S e ,,x l 1 I l 4 70 l C S o t l T I l44Ll 10 'i ~~, * l T 1410 I') S ,,,o, l I llijU IC S Ne,•E l T 13~0 ID ~ ci*f l 1 13~0 IC 5 ~P: ti< l 12'10 IC S tld l T,,. ,.
LEGEND1 l 01, l) s r l T u ,c 0 S "ij J( E l l llOO C S XH t l FULL" PARAMETER SCALE ]5YMBOLI I 7o S ",._ ~ » l T I l 41J ':i* E T z* (Turb) 10 ~m •ta sec-, E1110 s £ T l* * 10~0 s ~c *t T l (Oa) O. 5 ppm z I O'iO SN C t T l* (NO, NOx) 0. 2 ppm N,XIOlO S N 0 t ti X T l
~ 991) s ~. C *6 T l 1s0.1 0. 1 ppm s L 'lbl) ~ ~; u * f T l
10 X 10-6 m -iT •nu SN C i<* T l Cb-> B I ',IQU u H8 T l"s.. (Temp> o·-1oo•c TT 870 ~ E•3 T l
w u H'tO S N D T l I " (Dew Pt) 0" - 100 • C 0
0 810 S II i; X6t T l00
·~ ,.
t
0 t 7HO (J T ls " 751) s .. ~ T l* Figure 3.3.9 Aircraft Sounding - 18 July 1979 720 S C II liiX T l
M t,90 s (JI\ Tl bbO S IJ N b X t Tl o3D ~o tt l( E lT"' 5 1>00 SMl nx f ZT
L 5711 S I\C 8 X i * ~40 S ,, 0 •e t T l ,.'>11.J ~ C E T i. 480 s ,, r. X 6 F T l
.. ,a ~N C t\F T l
.. ,a ,, D •
~ T l
]Qt; S~ C X E ,I T l
UJiJ s ~ u IX n T L
HO s ~ IJ X E 'I T ·1cu 5 N C EX tl T l
uo \ ~ G ~ Xrl T l
/ 41) ~ ~ C Xii T l
?IC • rl·.1 1~. L Tl
l·l!.., ii -:; ·~ ,, • l f ,;; ,.ll 'JG '., ~ C *
ll•J J; ~ T ~ "' j•: '> C"' " .' ., ' ¢
I6.i l, l 1 .,;,JI.. lF T '
,J I-10---------J--------to--------,~--------~t;--------4J--------~•)--------L~--------,~--------d'l--------qo-------1cc
I
~[•Ct~T Lf F~ll ~C~lf
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PA Lt IIU0--00 IJ:3o:l.,CUFPLl Vfk Ul M~O 03
L:A T··; 7/lt/P k ( Li Tr "1 ,, 1-' l I I, 1 .,.
lAKTeJt,;Gt/PA~<;: ~ 171 1 ~1~. Gk(~~L tL•-v.: llc et ~,l Ifl~c: 0:~-,:~4 TU I: t: Jb
-10---------0--------10--------2a--------Jl---------.0--------~o--------oc--------10--------tu--------~o-------1cc 17101 I 1<>811 I I Io'><., I I cl ll I ,qu l -,o O LEGE:ts.'D l ~ 30 •~ou l47Ll 14 4t) PARAMETER
FULL SCALE SYMBOL
l4lJ !Hu 135U 1320 12Q(; I
(Turb)
(Oa)
(NO, NOx)
10 cm •ta sec-,
O. 5 ppm
O. 2 ppm
E
z N,X
w I co....
A L T I T u D
llnC 1230 12CG 11 7.J I I 40 I llO 1080 IO~J lOlO
I I IC IC
D
J I JC
'l I)
iJ
s s s s s
s s
f'·" "' * X Id')
X* NX f:I.\ ~. 1*
L Zt *
l
l l
l
T r T T
1 T r
(SOal
(bK.. )
(T~mp)
(Dew Pt)
0. I ppm 110 X 10•• m-
o•- 100' C
0'-I00'C
s B
T
D
~ ~~o
bLl
JC ID
s s
e*" t. *X
L
l r T
!Figure 3.3.10 Aircraft Sounding - 18 ,July 1979 -,30 111 s d* X l T
" 9(JU
rl7U JC ID
s s
Cl :;;.
X* t X
l l
1 T .., 84L IC s B r, * L r
~ 610 JC ~ li'- X l C T L 1~~ I D 5 * X l[ r
7 'iU 11 s r,P. <:X l T l l.•.J lJ s * f X l T bqV * ,._b X f l T tib(J S:J I\ b E X l T 030 <;J l,tt f X l T (, .J 1) ; N (; q f X l T ~J 7 V t, C ~ ~ l ~ r ...,41, ,.. tJ ~ l X T ., 1 tJ ~ " u e l T ¼ iju s I\ 0d l T 't ~.) '> " no X l I 4 l.i.J O~t X I j ~•J S I\ J'.l A . T j";d r,1 ,J tj t L r _l I!)
lU .; t7C
..) ~ C
~"' I
• •••
I
T
* L4C ,.. i.,:r') A
ill - I .')- -- - - - - - - ,,) - - - - - - - - 1 •J - - - - - - - - '- ) - - - - - - - - > :J - - - - - - - - •• \I - - - - - - - - "': i- - - - - - - - r,,; - - - - - - - - 1 1 - - - - - - - - ri, 1- - - - ·- - - - ·1 ·)- - - - - - - I ( +l
1> ~ r ( / 1\ f l. t f l, l l '.: ( tr, ( I
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3,3,3 Tracer Test 3
Release Location: Livermore, Alameda County
Time and Date: 1510-2030 PDT, 7/18/79
Amount: 101 pounds of SF6 per hour
Release conducted during west-southwesterly winds (directed toward Altamont
Pass) of between 5 and 7 mps. Winds within the San Joaquin Valley were similar
to previous test
Initial transport into the San Joaquin Valley
The tracer was transported by the generally westerly winds at the release
site through Altamont Pass and into the San Joaquin Valley. The tracer was
first detected in concentrations as high as 103 PPT along Coral Hollow Rd in
the San Joaquin Valley during Traverse 1-1, conducted between 1658 and 1725
PDT. During Traverse 1-6, an essentially Gaussian plume with a peak of about
900 PPT 11300 PPT/lb-mole SF6 released/hr) was detected at about 1930 PDT along
Corrai Hoi iow Rd. Corral ~I low Rd. I ies directly east of Altamont Pass~
During Traverse 1-4 conducted between 1919 and 2045 PDT, SF6 was detected along
Interstate 5 between Gustine and Altamont Pass. The tracer was spread quite
uniformly (peak concentration of 83 PPT) over the entire distance of about 45
mi !es. The route probably traversed the western edge of the tracer plume. The
first evidence of a clear plume within the San Joaquin Valley was found during
Traverse 1-5 in which concentrations as high as about 440 PPT 1640 PPT/lb-mole
of SF6 released/hr) were found along Hwy 132 between 1-5 and Hwy 99. The
tracer concentration profile along Hwy 132 was broader than that detected
during the previous tests from Manteca due not only to the greater distance
traveled but also to the turning and divergence of the Altamont Pass flow as it
entered the San Joaquin Valley. Also during Traverse 1-5, which ended shortly
after midnight 7/19/79, SF6 was detected at about 20 PPT as far south as Hwy
140, west of Merced.
SF6 was detected at the Modesto hourly-averaged sampl Ing site beginning at
2100 PDT, 7/18/79. A maximum concentration of 215 PPT 1310 PPT/lb-mole SF6
released/hr) was detected in Modesto between 2200 and 2300 PDT. As shown in
3-82
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Figure 3.3.11, SF6 was also detected at the west San Joaquin Valley sites of
Patterson and Gustine. A maximum of 198 PPT (290 PPT/lb-mole SF6 released/hr)
was detected at Patterson between 0100 and 0200 POT, 7/19/79. Low but non-zero
SF6 concentrations (about 20 PPTl were first detected at Patterson between 1800
and 1900 POT. Between 2000 and 2300 POT, low but non-zero levels of SF6 (10-15
PPTl were detected at Gustine.
Tracer detection during the night fol lowing the release
During the night of 7/18/79, SF6 was detected at 10-40 PPT over a wide
area on the northwest side of the San Joaquin Valley. There was a
concentration gradient between that portion of the San Joaquin Valley closest
to the Altamont Pass (as high as 458 PPTl to that region of the San Joaquin
Valley west of Merced and Chowchilla (10-80 PPTl. Due to the complexities of
the wind flow patterns between Livermore and that region of the San Joaquin
Valley west of Merced and Chowchilla, the tracer concentration profile was
highly irregular. Due to the timing of the release, the tracer was probably
I imited to a shallow layer of air close to the surface. During the night, the surface winds in the northern end of the San Joaquin Valley were quite low. At
Stockton, the winds in the lower 1000 ft were less than 2 mps during the 0100
PDT pibal and essentially calm during the 0300 PDT pibal. As would be expected
from the low wind speeds at Stockton, the hourly averaged sampling sites in the
northern end of the San Joaquin Valley detected SF6 throughout the night of
7/19/79. SF6 was detected continuously at Livingston between 0300 PDT and and
the conclusion of sampling at 1400 PDT on 7/19/79. 98 PPT was detected between
0500 and 0600 POT. SF6 was also detected throughout the night at Gustine and
Patterson, Some SF6 (as high as 59 PPTl was detected as far north as Modesto
between 0300 and 0700 PDT. During the evening of the release, SF6 was detected
at low levels c<10 PPTl as tar south as Fresno. A number of hourly-averaged
samplers and automobile traverses showed these levels. This may have been due
to carryover from the tests conducted 7/13/79 and 7/16/79. It was not possible
to estimate the amount of the carryover.
3-83
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In. n. r, !D LL Ul L.J
SJV-3 7/18/79 - 7/20/79 ...._,.,.nr - _..
C:IUl<:J • ~ PAT1ERSONA4, I u 1,, I 1:--+! 1, ! 11 b ...1,.w.1....~, 1, 1 ! 11 I 11 I0 10'0 -: GUSTINE
0 I 1 • + · 1 I • • L • • I cCTr+:cH • l-, 1 I 1 1 L, 1 l 1 1 L 6+ 1 1 I 1 1 I 1 1 l ]00,
DOS PALOS
0 I • • I • • I + • 6 • 6 t::d H I • J , 1 w L, , I , : I : I , i I w +1 I • • I 100 - FIREBAUGH
0 1 , , 1 , , , , , 1 , t..Lw H L. , , , , 1 , 1 Li 1 , 1 , , H , , L1 , , , , , 1 6+ 1
100 - TRANCIUlLITY 0 / 1 f j I f / 1 1 I 1 f I I I I ! I I I f l l I N I I b / I f l MH bD l f I I '", I
250 - rfl MODESTO 0 I +1 l • • I • • I • .. b--c:t-l , • l : , I + , I 1 • I 1 1 I I t I I t I I t I : t I 1 1 I
100- ~ LIVINGSTON
0 Lr :+ • · I : 1 Lt-d ~ 1 : ''1 1 : I , • I • , I 1 • I 1 • I 1 , I , • I 100 ,--
MERCED Ii'! I , , I : ,1. l , : l : , I • LI • t I , , I , t I , t:L d L , I .,.,i,.,..1,.'+ I , , I : 1 I - I •
100 -CHOWCHILLA
01:·i·,'+:i•· 1 :·1,1lt1i·1 1 1 ! 1 1l,,l,,l,,!11!41l,•I 100,
MADERA ,.. I , , I • • I 1 1 L .., • 1 ! 1 1 I w- l I tA H 6 , I I hl 1 1 I 1 , I , , I , i I , 1 ! i.:; T I
100 ...-FRESNO
~ j f f I I I I I I I I I I I f I I f I f t j 1 +L~ I,, l I I J t I I I ,..1.i....1.,.,J,..41,.J.,...t I 100,
MODESTO RES 0 ',r-1 Li, I, LI u I 1, L, I, 1 L cJ +,I,, I,, I,, I,, I,, I,, I·· I
100 -MARIPOSA
0 L.1 , I , _.J 1 1 I • LI 1 1 I • 1 I : • I • .J • • I I t I • , I • • I • , I 1 • I , 1 I 1 1 I 100 ,--
O'NEALS 0 I j I I j j I I i ,to ! .. I LJ L,;.....,'7 u . I ; ; L 64 I I I I I I I I I I I II I I I
12 15 18 21 24 3 6 9 12 15 18 21 24 3 6 9 12
PACIFIC DAYLIGHT TIME
RELEASE LOCATION, 541 LBS AT LIVERMORE RELEASE TIME, 1510 PDT, 7/18/79
Figure 3.3.11
• INDICATES MISSING DATA ARROWS INDICATE BOUNDS OF SAMPLING PERIOD
3-84
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SJV
3
I
...
1
Figure 3.3.12
INDICATES SAMPLER LOCATIONS
\.LAYfA&U'lt I k.~FT.
\ _;.'- l"'
*
/]); IS THE RELEASE SITE 3-85
--~
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Tracer carryover into day following the release
Automobile traverses on the day fol lowing the release showed that the SF6
was spread over most of the San Joaquin Valley north of Fresno. During the
morning of 7/19/79, concentrations ·of 10-20 PPT were detected while during the
afternoon SF6 concentrations were genera! !y be!ow 10 PPT. The concentrations
detected during the day after the release were higher than those found after
the previous releases from Manteca. This was probably due to the late hour of
the release which reduced the loss and dispersion of the tracer during unstable
afternoon conditions and to carryover from the previous releases. Nighttime
wind speeds, at least in the extreme northern end of the valley, were also
lower than during the previous two tests. A mass balance estimate indicated
that about 600 lbs of SF6 could be accounted for in a rectangular area bounded
on the east by Hwy 99, on the west by 1-5, on the north by Manteca and in the South by Hwy 180. This estimate was made using an average concentration of 17
PPT (+/-10 PPTJ detected during Traverses 2-2, 2-3, 2-4 and 2-5 and by assuming
a 2000 ft mixing height. Due to the uncertainties inherent in this
calculation, the mass balance merely indicates that a majority of the SF6
released was detected within the San Joaquin Vai iey during the day after the
release.
Summary
During this experiment, the tracer was released from the Livermore Valley
during mid and late afternoon. High levels of ozone and other pollutants are
typically found in the Livermore Valley, possibly due to transport from the San
Francisco Bay Area. This experiment was designed to determine if these
pollutants represent a significant flux into the San Joaquin Valley. The
tracer was transported into the valley and, as might be expected from the
previous tests, was preferentially transported along the western side of the
valley. An overview of the tracer transport path ls shown in Figure 3.3.13.
Due to the late release time (1510 PDT-2030 PDT), the tracer was detected only
as far south as the region west of Chowchll la and Merced on the night after the
release. The late release time also increased the amount of carryover into the
subsequent day, as compared to the two previous tests. An amount equal to
3-86
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·-
w I co ......
Cv,_,,-,,
hlCv6-/0
~ ~~ .._, ) --o---- ~C
! 1£LEA<f SllE - Ll'.!IDE I ,0
ICllll 0
MlllU
10 10
:~
(SJ~'
1000
'i~
~
ARROW POINT INDICATES OBSERVED TRACER LOCATIONS NUMBERS REFER TO HOURS AFTER RELEASE START (1510 PDT., 7/18/79)
Figure 3.3.13
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essentially al I of the SF6 released could be accounted for within the northern
San Joaquin Valley on the day after this release. The majority of the tracer
detected on this day must have been due to the release made during this
experiment but it is also possible that a smal I amount of tracer remained from
either or both of the first two tests.
3-88
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3.4 Test 4 25 July 1979, Reedley Release (1200-1700 PDT)
3.4.1 Meteorology
General
The synoptic meteorology of 25 July was again characterized by
ridging aloft over the southwestern states (Figure 3.4.1). Maximum heights at 500 mb were located over southern California with consequent warming aloft and atmospheric stabilization as reflected by the 850 mb temperature trends shown on Figure 2.2.1. At the surface a thermal trough
was established over the Central Valley resulting in an onshore pressure gradient. The skies were generally clear throughout the San Joaquin Valley. Visibilities during the test ranged from 15 miles in the northern portions of the valley to 10 miles in the south. In the Fresno vicinity, visibilities ranged from 10-15 miles. Surface temperatures were above normal for the time of the year. Maximum temperature reported was 107°F at Bakersfield.
Transport Winds
Low-level winds during and after the release are given in Table 3.4.1. Early in the release period the low-level winds were southwest, shifting to west or west-northwest by the middle of the release. Wind speeds remained relatively high during the night until the early morning hours.
The 1000-foot streamlines (Figures 3.4.2 to 3.4.4) reflect the moderately strong northwest flow throughout the valley during the night. The wind speed at 1000 ft at Fresno was 11.7 m/s at 23 PDT from the northwest. By 05 PDT, an eddy had formed in the southern part of the valley as shown in Figure 3.4.4.
Pibal winds from Cherry Gap (in the mountains east of Reedley) were resolved into components parallel and perpendicular to the valley axis. The time
variations in the perpendicular component (Figure 3.4.5) can be used to delineate the diurnal variations in the upslope-downslope flow. As shown in the figure,
a strong upslope flow developed after 11 PDT and lasted through 19 PDT. Maximum depth of the flow was about 800 m. During the balance of the observational period the flow had a component toward the valley at all levels which masked any drainage flow that might have been present.
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WF:DNESDAY, JULY 26, 1979
r-·-~------,, -- T T-- ,,-----, 1- ---~----'t\-,:~p
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:::::::::.. ""'" "' ;,.,"'":.:.: \ ~~. • _' ".. __'"-~\--=-~-~ 100' ),;
SU'RfA([ WEATHER MAP. [-\Y· '\-: -" -'s...-~ ·- -- . ANn STATION W[ATHER :-\_: ~~- -~~- ~-'-- -- --- ---- ---AT 7 00 AM l Sf - - -- -
> .,,., ) ,<' J
Figure 3.4.1 Surface Weather Charts - 25 July 1979 (05 PDT)
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Table 3.4.1
LOW-LEVEL WINDS 25-26 JULY 1979
Time Reedley Fresno (PDT) (Surface-100 m) (Surface)
25 July
09 144°/3.7 m/s Calm
11 191 /4.3
13 217 /2.2 240°/2.1 m/s
15 260 /4.5 240 /3.6
17 275 /2. 0 290 /3.1
19 254 /1. 4 300 /3.1
21 27 0 /3. 9 280 /4.1
23 330 /4.2 290 /4.6
26 July
01 320 /3.7 290 /4.1
03 300 /1. 0 290 /3.6
05 305 /0.9 Calm
07 087 /1.4 160 /1. 5
09 152 /1.8 220/2.1
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... ·- .
,,-....._." -, ; ;.•a..:.. ~ l -< - ...,'
'- I \
Figure 3.4. l Streamlines - 25 July 1979 (15 PDT)2 1000 Ft-ag 3-92
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---------
....
HM.I
0 C" <"
-~-~Jf-..-Jf , • . . . - - - --
------,
Figure 3.4.3 1000 Ft-agl Streamlines - 25 July 1979 (23 PDT) 3-93
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.,..... ···"!!!!''·
111 --~ , .••111<. - ·• ......, .-..
. . . - - - -- ....... ,.
·-7
r
Figure 3.4.4 1000 Ft-agl Streamlines - 26 July 1979 (05 PDT) 3-94
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11 13 15 17 19 21 23 i 3 5 7 9 81 /040
TIME (PDT)
Figure 3.4.5 Time-Height Cross Section Component Winds (m/s) From Cherry Gap25 July 1979 (Positive Component Represents Upslope Flow)
-4
-6"
2 790
2 520 ... _4
2250 ........ -6
E ~ 1980 Cl z :=i 0 1710c::
~ c:.!:l
w > 1440 0 c::, .... -4c:,:
::t: f- 1170 c:.!:l ...... u..J ::t: 896
612
313
-===~
-4
m/s
'- -4
Ur··\ '-J ~
-4
-2
3-95
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Mixing Heights
Aircraft mixing heights were measured on July 25 and are shown in Table 3.4.2. As noted in earlier tests, the mixing height over the slopes
tends to be somewhat greater (relative to the terrain) than over the valley itself.
Table 3.4.2
AIRCRAFT MIXING HEIGHTS JULY 25, 1979
Time (PDT)
Location* Mixing Height (m [above ground level])
1529 5 N Reedley 785 1603 23 E Reedley 645 (1370) 1735 6 NNE Grant Grove 1060
(* Distances in miles)
3.4.2 Air Quality
Regional Pollutant Levels
Maximum hourly concentrations of ozone are given in Figure 3.4.6. Numerous exceedances of the .10 ppm standard were observed in the north and east portions of the San Joaquin Valley. Concentrations of .15 ppm were measured at Modesto, Fresno and Bakersfield. All three monitoring sites along the Sierra Nevada slopes reported concentrations in excess of .10 ppm.
Maximum hourly concentrations for CO, S02 and NOx anywhere in the valley are listed in Table 3.4.3 together with the maximum hourly values recorded at the Rockwell International vans.
All hourly concentrations were relatively low with the exception of NOx at Modesto. Another unusually high value (.39 ppm) was recorded on July 24 at Modesto. Otherwise, no comparable values were observed during the month. The unusually high values suggest that the measurements may not be representative of a wide area around Modesto.
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l
(
(
N I
s: "-1. t
0 C"
<"
"'d----=.!_~~ ..... .===o 7• ,o ~~ •
figure 3.4.6 Maximum Hourly Ozone Concentrations (~phm) - 25 July 1979
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Table 3.4.3
MAXIMUM HOURLY CONCENTRATIONS JULY 25, 1979
Parameter Location Maximum Value
SD2 Bakersfield .02
CO Fresno-Olive 3.
NDx Modesto .32
SD2 Modesto (RI) < .01
SD2 Merced (RI) < .01
NDx Modesto (RI) .01
NDx Merced (RI) .02 _N_O..A--________M_ad ra RI) .01
Aircraft Sampling
In conjunction with the tracer release near Reedley, the airplane
sampled in the afternoon (1529-1920 PDT) downwind in the Sierra Nevadas. The
sampling route consisted of the following key elements: Three spirals; one in the valley near the tracer release
location, one in the Sierra Nevada foothills, and another
in the High Sierra region at the convergence of the South
and Middle Forks of the Kings River.
Three constant altitude downwind traverses parallel to the
Sierra crest at as low an altitude as safety would permit
and,
A traverse from the Sierra crest down the South and
Main Forks of the Kings River to the valley, descending
with the terrain at as low an altitude as safety would
permit.
Table 3.4.4 gives the overall pollutant characteristics measured on the
flight. Figure 3.4.7 shows the map of the flight patterns employed on July 25.
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Table 3.4.11
AIR QUALITY MEASUREMENTS CARB SAN JOAQUIN JULY 25, 1979 SAMPLING
VALLEY PROJECT
Start Time PDT)
Location Point)
03 Mean Max (ppb) (ppb)
bscat Mean Max x10-6m-l)
S02 Mean Max (ppb) (ppb)
NOx Mean Max (ppb) (ppb)
NO
Mean (ppb)
Max (ppb)
1!,29 1 71 124 97 204 5 7 11503 2 85 112 140 218 4 6 1629 3-4 110 154 155 236 0 2 1711 5-6 102 127 137 234 0 2
w I
<D <D
1:735
lBlO
1B51
7
8-9
10-11
123
144
130
141
183
171
154
159
143
236
230
216
4
0
3
6
3
5
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w I ..... 0 0
'=! ' 11 \J ~-~~ SAMPLING ROUT F'S
Fiigure 3.4.7
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Aircraft soundings made during the afternoon of July 25 are shown in Figures 3.4.8 to 3.4.10, The sounding over the valley north of Reedley (Figure 3.4.7) shows a relatively well-mixed layer to 870 m-msl. Ozone concentrations
reached a maximum of .11 ppm in this layer. Another pollutant layer with much lower concentrations existed above 1230 m.
The sounding over the foothills east of Reedley (Figure 3.4.8) showed a well-mixed layer to 1620 m-msl but with a higher, mixed layer extending to 2300 m.
The break between these two layers corresponded to a shift in wind direction from the upslope flow to an easterly direction.
In the Kings Canyon (Figure 3.4.9) uniform mixing was evident from the bottom of the canyon at 975 m-msl to 2800 m-msl or roughly to the mean terrain height at that point. Within the mixing layer, ozone averaged about .13 ppm. Thus, the deep river canyons seem to be able to provide a major ventilating mechanism for valley air. The traverses parallel to the crest would seem to support this conclusion as ozone bulges are evident over the canyons of the various forks
of the Kings River. The maximum mean ozone concentrations encountered during sampling were found on the 1680 m-msl traverse some 30 miles downwind from Reedley. Peak ozone levels were in excess of .18 ppm on that traverse. Over the High Sierra traverse between points 5 and 6, some 42 miles east of Reedley, mean ozone concentrations were still in excess of .10 ppb. The extent of the intrusion of polluted valley air into the mountains is well-defined by the east-west traverse down the Kings Canyon. Ozone concentrations rose to over .10 ppm within a couple of miles from the Sierra crest and increased to a maximum about 5 miles east of
the convergence of the South and Middle Forks of the Kings River (point 7), where levels as high as .17 ppm were measured. Thus, the maximum impacted area from the valley sources can be at substantial downwind distances.
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c 1JcvL r " ..·'-' ut ,ii,..:.;n CJ 0O--no li:~1:0~ PAI,!-
c•lc: 7/l?/7q K(l.;lt: ,:v~u P(l/d LAHTHIG(t/PA~,: o~O/ ll~E: 1~:lE:,1 TU 1~:49: J ~,~. C~CU~C Elt~.: Ile ~l~,ll
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I'.• ~u I C* U l I l "i ti .~ r, '; [ 'I / T 1 'l"ic cs ~ rl T l',Uu " C B l T I., 7u *t \J l T I., 40 * d l T 14 I ,J s~ ,1 l T u •o ,* ~ l r l .3'i~: * b l T 1370 * ., l T )lqo * ~ l T 12<> C: C~~ tl L T ll.10 t: St ~ l T llCtl C s~ !j z T 11 71,1 t.: .. b l T
• 114\.I c~ d l T 111 o SCt ~ l T
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w T <;q(j *'-: e l T I l, 'ibll o l T"'~ ..... u 9311 U* K l T0
N C 90;, cSt ti l r LEGEND ~70 SL I'. t l T ~40 s C E u T FULL .. h l ll <; U ~ E L T PARAMETER SYMBOL~ 730 s ,) tl t l T ,, ,~o (Turb) 10 cm •t,. sec -i E~ C B1- l 1
> 72-> ~ C ~ lE T (0,.) 0. 5 ppm z l bQC, s C B .. 1
bbl, s u ~ l t T (NO, NO1) 0.2 ppm N,X ~3(1 s D e L E 1 cso.1 0. I ppm s ,iQ1) s 0 B l t T ;7() s u li a (b,..,) BT lOxl0-4 m- 1
j'tlJ s C B fl T (Temp) 0"-I00"C T,10 s C B cl T
4 (1 s .. l t (Dew Pt) o·-1oo·c D 4",IJ s u,i l " T .. l(J s 0 , * 3go 0 l~ T Figure 3.4.8 Aircraft Sounding - 25 July 1979" 3b0 s u d l I· 1
B,.J liO l ~ T
_lQ(J " s ;j('. l ET £ 7 U \ \) ~ t T l4G I $ IJ d l ' t T 2'U.1l S Od Zt T l~U 1 S li e l t l ~ ,.J I S D•i I I: f 1iu I ~ 1) H l T >
-10---------J--------10--------20--------1~--------40--------~r--------~o--------10--------eo--------90-------100 Pt~(f"jT C,F FlJll 5CAU
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PAl.:d ~JL--~u 12:47:04CLFPL l V':>< Ul MLJ·l 1.)j
fc CL, T ! V t,, 11 CI, I(:~, ; 1/?~/1J LlRr~tl:(L/~A~~: bd)/ TIM£: ib: 3:Lb TL lt:J~: 7 ~I~ CK[UhO lltV.: ~•• "l~SLI
-L0---------0--------10--------L0--------50--------4U--------~o--------bO--------l0--------80--------~u-------1co
!41 J I C ~ t * T I /40J I C S tilt I I I .J 10 I O 5 e , t T I l 1" d 1 C S 11 L E 2310 I C'i .lZ t
ll~O I 0 ~ I I
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llqu , '- nt T ·)l lbO s *•\ T ,7l 30 I ,J I. * T
?10() I ~ t: l tl T
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; 2c l" I ls HO I C l. ze T
1950 I s D E" T A 11.J l1J s C I' 8 ll ,L I H'IO C ti l T
T 166() s C 8 El T I I b rn ~ C ll tl T r lhOU s C b l T E
w I u l 77:J s ") b z T E
,..... J 114.J 5 i.; l T E LEGEND0 " I: 171U s C " L T Ew lb~O s L fl l T t
FULL lb5tJ s i; b H T PARAMETER SYMBOL
M lblO s C '\ L Tt ~E. 1l~~o s C E tl l T (Turb) 10 cm%, 11ec - E
1560 ; C ti -" (Oa) 0. 5 p,pm zs 1~3U s C D 'l T 1,
L !~OU s C fl l r f (NO, NOx) 0. 2 p,pm N,X1410 s D a l T E 1441) s D ll L T t 1s0.1 0. I ppm s J <, lu 5 C t1 l T E JO X 10-• :rn- 1(b,..,) BljijQ s i; ti l I f 1350 s D d l r E (Temp) o•-1oo•c T 1320 s (; ti l I E 12qc. s D 6 l T I: (Dew Pt) o·-1oo·c D
l2t>C s 0 l T t l230 s D 1 l I: T Figure 3.4.9 Aircraft Sounding - 25 July 1979 uo~ 'i D ~ z T E I 17u 'i C u l TE I l4u s r ~ l T 111 u s C d l T c ,10~1.l IJ fl l T r ,IL 5u C <l l T ,,1u>u s C l T , ,.s q(J n ti I T
':46,J ) u r, l ~30
-1n---------,1--------1n--------,u--------jo--------•,,--------~o-------~bo--------1n--------dO--------qo-------1uc Ptk(cNl ~f ~~lL >(Alt
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CllF PL T yr> Lil MC'..l 03 nc--no 12:41:04 PAt,f l I
' IV ~ ,, p L I "·- T ' LlAT•! 1Jl~/1q kr:ult: LAMTNIG(t/PA:,S: 6HO/ 'i TIME! l7!34!4i TU 17:~u: 0 ~I~. GR(w~C EltV.: Y7> Ml~SLI
-10---------o--------10--------20--------10--------•o--------~u--------b0--------10--------ao--------qo-------1cc 24QI) I S C Te f, l I 24b0 I S C JT l /4i0 I S iJ •l T tl lo1tCv I Su fl L 2HU I SlJ I Ill l
lj40 I SO o El 7 2 31 u > l, 11 l * ll~C ; e [T l ll'iC II l H) ,,
:; •l ~ T l F 2l<JO $ L I' U'O LEGEND
" ?l~U s I) .:. T!= l FULL n JU s C * T l PARAMETER §.!JMBOL~ HCu s l, ti ET ,' !U7U s 0 tl E T l (Turb) 10 cm "/3 sec-, E lll40 ) C ,l.f T l
(Ca) 0. 5 ppm Z2010 s L -~ LT l
A 1q~o s L ll H l (NO, N0x) 0.Z ppm N,X l l <i'iU s C A '' l T 1 no s L * l (502) 0.1 ppm S I I ti9v s C t1 Tl t 10 x 10-, m -i B(b_lw T ldbU s C e Tl tc
I,__. u 1830 s C ~ Tl E (Temp) o·-1oo•c T 0 C 1800 s C B T l E .i:,.
E 1710 s G ~ T * (Dew Pt) 0 • - 100 'C D l74U s 0 Ii T j~ ':
1710 s 0 e " T l Figure 3.4.10 Aircraft Sounding - 25 July 1979 lbqU 5 0 ~ T l" ti q. ~~lt.5ll s u lt;20 s 0 ,1 Tl E" Es 15qo s ~ ~ Ti~
F.l l~bU s C ti ,)
:;rj1~30 s 0 f ,,ij1-,00 s C E ,,1410 I s G I\ 't
t J)l 44ll I s C Ii
1411) I s C I\ lT
I 3 ~U s C ti llt
DoO s ~ •I F l T
C 11 1l 1 flHll s uqo s L h ~- .~ T
,1 TEllhC ~ C Ii :, C h ,1 TI ZIC ) C d ,I TI lll C
I I I rJ s ~ i. T <; ' t, ,1 f Tl l.1t 1l
L ~ f l 1I 11 O 11,, r. ,., ' s L .I. T,-lO~J 1 \J l 1) l
•J~0 l-1•1--------->--------10--------i0--------10--------~o--------~o--------b•J--------10--------~ 1>--------~o-------1c~
~c~C~~T c, FULL srALf
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3.4.3 Tracer Test 4
Release Location: Reedley, Fresno County
Time and Date: 1200-1700 POT, 7/25/79
Release Amount: 97 lbs SF6/hr
Release conducted during afternoon westerly upslope winds. Surface winds at
the release site varied between about 2 and 5 mps during the release.
Initial upslope transport
During Traverse 1-1, conducted between 1430 and 1558 POT, SF6 was detected
in two locations along Hwy 63. About 8 miles east of Reedley, concentrations
as high as about 1100 PPT (1660 PPT/lb-mole SF6 released/hr) were detected. A
separate SF6 plume with concentrations as high as about 260 PPT were detected
northeast of Reedley. The release began at the onset of the afternoon upslope
flow, and the existence of two separate SF6 plumes was the result of the wind
direction variation as the flow developed. The plume detected directly east of
the release point was transported by the fully developed upslope fiow that
persisted until between 2100 and 2300 POT. SF6 was detected in the National
Forest and Park areas (Whittaker Forest and Grant Grovel beginning about 1730
POT-1800 POT. This corresponded to a mean transport wind speed of about 5
miles per hour. A maximum hourly-averaged sample concentration of 65 PPT (98
PPT/lb-mole SF6 released/hr) was detected at Whittaker Forest between 1900 and
2000 POT. No other fixed sampling site showed a significant SF6 concentration
during the evening of the release (see Figure 3.4.11). By 1830 POT, during
Traverse 1-5, a distinct tracer plume was detected along Generals Hwy between
Grant Grove and Lodgepole. The concentration profile detected during this
traverse is displayed in Figure 3.4.13. Also included in the figure is the
concentration profile detected by an airplane traverse through the same area.
Excei ient agreement can be seen between the tracer concentrations detected by
the airplane and automobile traverses. It is difficult to assess the crosswind
width of the tracer plume due to the tortuous nature of the traverse routes.
Based upon the airplane traverse data, the crosswind standard deviation in
concentration was between 3 and 4 miles (5-6 km). Grant Grove I ies about 30
miles (48 km) downwind of Reedley suggesting that the horizontal dispersion of
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SJV-4 7/25/79 - 7/27/79
100 l ~ . WH l I 11\11.Cl'I:
0 1 I 1 1 +• • I H::OUb:Cb--b-fb , I t • H:::t I t t I w I 6-1 +t t I t I I FOREST
100 E LODGEPOLE 0 , I,,~ IL I I I J..,_ J L, [ ud I, w HI, It HH':I ,+,II,, I
100 E FRESNO
0 _, I f" 6 t..1 , , I , d /11:Hl:iw:tll-ll!'~.J!tl:lti.+ , I , , I , , I , , I , , I , , I .L..-d
100 li O'NEALS 0 L.Llu_lw.J. 1 I I f.J j / I I / / 6 L L ! I l J t!i / j I I 4 / I / / I / / I
100~ MADERA 0 .I.. I I L I I / / L l:fl:tll-~Ml!tt!'-1 ..J / / LJ / I / / I + / I I I I l / J
100 E CHOWCHILLA 0 1 I+, I 1 1 ) 1 1 L-Mi-, ) 1 t L..J i. L I 1 ..J 1 1 I , 1 µ , I 1 1 L+_Ll_.L.L LJ..JJ
t 100 l FIREBAUGHa.. a.. 0 ,l 1 1lHl1~,,l,,l,,4,l,,Lu.J ,.., (0 100 r Li.. ~ TRANQUILLITYUl
0 L I I~ 1 I 1 1 L I J 1 1 l c:L-.J..H l H I tf!'ftlf-.if-Bffu..4-LLLL.lLL1L-1
100 li HURON 0 .1.-LLLL l + , L I I 1 1 I u 1~J : 1 1+1 l 1 Ll.u..1.u.l.u.J
i00 E CORCORAN 0 LU ill L l t"' : L~ I 6--d--, l l H I h L b / ~~... 1:. l I / I \ ' I +d
100 [ ALPAUGH 0 Ll.ul.Li. I 1+I wd u I 1 1 J 1 1 L I I I u H I I t I 1 1 I I d 1 1 Lt+ I
100 Lu WASCO 0 tl..u.l..i.,ptliu-ii-.111-litt1t.t1t.l,.,HI-J,.tlt..J I hj I H µ I I t1t6tt11-~~j
100 rI BAKERSFIELD
0 i...ul L ilLL.p- · 1 t V:L\-J , , L ~ , , J , , L~ : I H ) u I t , I 1 1 l u.J 6 9 12 15 18 21 24 3 6 9 12 15 18 21 24 3 6
PAC!F!C DAY~lGHT ~:~E
RELEASE LiJCf~ !m,: 484 LBS 5c:-5 ,._, Rr~wL~V RELEASE TIME: 1200-1700 PDT, 7/25/79
Figure 3. 4 .11 * INDICATES MISSING DATA
ARROWS INDICATE BOUNDS OF SAH"''..ING PERI!J!l
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SJV
4
Figure 3.4.12
• INDICATES SAMPLER LOCATIONS ~ IS THE RELEASE SI TE
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SJV-4 AIR AND AUTO TRAVERSE COMPARISON 100
01::==--,4....-----L------1~--.......----L---~----' 0 2 4 6 8 10 12 14
STRAIGHT LINE DISTANCE ALONG TRAVERSE <MILES)
Figure 3.4.13
3-108
50
AUTO TRAV 1-5 7/25/79 1B23-191!12
AIR TRAV 1-3 FIRST HALF OF TRAV RT 7/25/79 1B11!1-1B21!1
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the tracer corresponded to highly unstable conditions (Pasquil I-Gifford
Stabi I ity Class A or Bl. The rapid horizontal dispersion of the tracer was
probably due in large part to mechanical turbulence generated by the rough
terrain. In order to account for al I of the tracer released, the SF6 must have
been wel I-mixed over a height of about 600 m (about 2000 ft).
Transport during nightime drainage flow
After nightfal I, preferential cooling of the mountain slopes led to
drainage flows oriented towards the valley. The upslope motion of the tracer
was halted. At Whittaker Forest, the tracer was detected throughout the night.
Due to the flow reversal, a 5 hour tracer release led to an 18 hr impact at
Whittaker Forest. The concentration data collected at the hourly-averaged
sampler at Whittaker Forest is shown in Figure 3.4.11. Note that the tracer
concentrations detected at Whittaker Forest dropped to zero during the
subsequent afternoon upslope flow, presumably transporting the tracer out of
the San Joaquin Valley. Also included in the figure is the hourly-averaged
data collected at the other fixed scrnpl ing sites employed during the test. At
most sites within the valley, I ittle or no SF6 was detected. Note however,
that tracer concentrations as high as 31 PPT were detected between 0500 and
0900 PDT at Huron on the western side of the valley. The tracer detected at
this location was apparently transported across the entire width of the valley
by the combination of nighttime drainage winds on the mountain slopes and the
valley floor eddy structure referred to in the meteorological discussion.
Clearly, the nighttime drainage winds reduce the effectiveness of the daytime
upslope flow as a mechanism for ventilation of the valley. Since the afternoon
upslope flow is typically stronger and deeper than the nighttime drainage flow,
at least during the summer, the diurnal mountain-valley wind cycle does account
for a net flow out of the valley. As shown during this experiment, however,
I ittle, if any, of the tracer released into the upslope flow during the
afternoon was transported out of the valley by nlghtfa! !. After midday on the
day after the release, only low levels of tracer were detected in the San
Joaquin Valley. Either the second day of upslope flows were sufficient to
transport the bulk of the tracer out of the San Joaquin Valley or the tracer
was effectively dispersed throughout the valley.
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Summary
During this experiment, the tracer was released from Reedley, a location
southeast of Fresno, during the afternoon. This test was designed to evaluate
the importance of the afternoon upslope flow on the overal I ventilation budget
of the San joaquin Valley and to quantify the impact cf val !ey po! !utant
sources on air quality on the western slope of the Sierra Nevada Mountains.
The tracer was initially transported upslope at an average speed of about 5
miles/hr. Good agreement between automobile and airplane traverse samples was
noted along and above Generals Hwy along the western slope of the Sierra Nevada
Mountains. The tracer concentrations detected during these traverses suggested
that the tracer was wel I-mixed to a height of about 600 m or 2000 ft. The
width of the tracer plume during these traverses was consistent with
Pasquil I-Gifford Stab ii ity Class A or B (highly unstable conditions) over flat
terrain. The enhanced horizontal dispersion of the tracer was probably due to
mechanically induced turbulence over the rough terrain.
As the afternoon upslope flow weakened and reversed during the evening and
nighttime hours, the upslope movement of the tracer was arrested. The 5 hour
release led to a measurable impact 18 hours in length at Whittaker Forest. The
tracer was also detected in fhe San Joaquin Valley during the night after the
release, indicating that at least some of the tracer was returned to the valley
by nighttime drainage flows. The tracer was detected as tar west as Huron,
about 45 miies southwest of the release site. An overview of the tracer
transport path ls shown in Figure 3.4.14.
It was not possible to estimate the amount of tracer remaining in the
valley on the day after the end of the release. Low concentrations of tracer
were detected over a wide area. As wi I I be made clear in the discussion of
Test 5, however, there is reason to believe that at least 25% of the tracer
released during this test remained within the valley during the night of
7/27/79, 2 days after this release. By considering the San Joaquin Valley as a
wel I-mixed tank, this loss rate corresponds to a mean residence time of the
tracer within the valley of just over 2 days.
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WASCO
~ j 1£1..M SITE - lmlEY
C 10
ARROW POINT INDICATES OBSERVED TRACER LOCATIONS NUMBERS REFER TO HOURS AFTER RELEASE START 1200 PDT., 7/25/79)
Figure 3.4.14
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3.5 Test 5 27-28 July 1979, Airborne Herndon-Chowchilla Release (2300-0215 PDT)
3.5.1 Meteorology
General
The major synoptic features of the meteorology on the morning of the
28th are shown on Figure 3.5.1. At 500 mb a weak short wave trough was moving
across the northern half of California, but not significantly influencing the meteorology in the San Joaquin Valley. Temperatures aloft over central
California remained warm as shown by the isotherms at 500 mb and also by the 850 mb temperatures at Vandenberg and Oakland plotted in Figure 2.2.1. At the
surface a thermal trough again developed in the interior of California. Sky
conditions on the 28th were clear and visibilities were generally good. Maxi
mum surface temperatures were near normal with both Fresno and Bakersfield reporting a maximum of 100°F.
Transport Winds
The tracer release on 27-28 July was made by aircraft at a level of 400 m
above ground. The aircraft track was parallel to the wind, flying back and forth
between Herndon and Chowchilla.
The pibal winds from Madera were resolved into components parallel and
perpendicular to the valley axis. The parallel component was used to examine
the transport up-valley and is shown on the time-height cross section in Figure
3.5.2. From the cross section it can be seen that the night jet was established
at the time of the start of the elevated tracer release and that the jet continued for the release duration. Wind speeds averaged over 12 m/s during this period.
As shown by the 1000 ft streamlines at 2300 POT (Figure 3.5.3), flows
were northwesterly and roughly parallel to the valley axis through the length of
the San Joaquin Valley. The flow remained similar throughout the night. The
streamlines developed from the 0700 PDT data on the following morning show
cyclonic curvature developing at the southern extreme of the valley, signaling
the formation of the eddy which was fully developed by the next observation
time at 0900 PDT (Figure 3.5.4). By the 1100 PDT observation time (Figure
3.5.5), the "Fresno" eddy had moved north allowing the northwest flow on the
west side of the valley, which had persisted throughout the test, to diverge in
the southern end.
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~ Cl 0...
Li> 0
>, ..... :, 'J
00 N
Ill...., s... re, .c u s... QJ .c...., re, QJ
:::;i:
QJ u re,.... s... :,
V'l
-:: Li>
·("')
QJ s... :, a,
LL.
3-113
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2 790
2520
2250
E ~ 1980 0 z
0 :=,
1710 0:: C!l
u.J > 1440 0 co c:c
I- 1170::c C!l ...... u.J ::c 896
612
313
0
0
4 ~
8 -..,,
~~' 4
=-----2
2
6
10 12
23 1 3 5 7 9 23
TIME (PDT) 81/041
Figure 3.5.2 Time-Height Cross Section Component Winds (m/s) From Madera 2i-28 July 1979 (Positive Component Refers to Northwesterly Winds)
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t
c--
, ~ N I
SUll,I
-~-'! If 'f ' •• . . . - . . --.. ,. ,.. ....... -·· ' ,, - .-..
....... ~..
Figure 3.5.3 1000 Ft-agl Streamlines - 27 July 1979 (23 PDT) 3-115
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C'
.._.... ' s,a&.t
•-• C , !'f tf f la
I.JI .......
. . . - . - -- ..,,
r
Figure 3.5.4 1000 Ft-agl Streamlines - 28 July 1979 (09 PDT)
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( ....
-0
•Ut.l
-~., ! 1f ' ••
. . . - - - -. Figure 3.5.5 1000 Ft-agl Streamlines - 28 July 1979 (11 PDT)
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Mixing Heights
No sounding data were obtained from the aircraft flights. Maximum
m,x,ng heights derived from the pibal wind data ranged between 1200 m and
1500 mat Fresno on July 27 and 28.
3.5.2 Air Quality
Regional Pollutant Levels
Maximum ozone concentrations throughout the valley on July 27 are given
in Figure 3.5.6. Highest observed concentration was .11 ppm, measured at the
Rockwell International van near Modesto •• 10 ppm was the highest value recorded
at any of the CARB sites.
Maximum hourly concentrations of other pollutants in the valley on July
27 are given in Table 3.5.1. All values were rather low, indicating a relatively
clear day in the valley.
Table 3.5.1
MAXIMUM HOURLY CONCENTRATIONS JULY 27, 1979
Parameter Location Maximum Value
S02 co NOx
S02
NOx
NOx
Bakersfield Bakers field
Bakersfield
Merced (RI)
Modesto (RI)
Merced (RI)
.04 2. .27
< • 01 .03
•02
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(
N I
C"
0 C"
<".., -z.
1~-UI
ID~ -~-~~--~--:::3' l• ~ -:x:=:::::,:-·-=
• O ID to JO Cl wo• - --' .....
( Figure 3.5.6 Maximum Hourly Ozone Concentrations (pphm) - 27 July 1979 - 3-119
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3.5.3 Tracer Test 5
Release Location: Airborne - from Herndon to Chowchi I la, Madera County
Time and Date: 2300, 7/27/79- 0215, 7/28/79
Release Amount: 67 lbs SF6/hr . +Release made into low=leve! Je,. Winds were northwesterly at about
12 mps in the jet.
Nocturnal Jet chracteristics
The nocturnal jet,which occurs frequently during the summer in the San
Joaquin Valley, is formed due to the decoupling of the stable surface layer
from the air aloft. The lack of surface shear stress al lows the air above a
few hundred meters in altitude to accelerate to velocities in excess of 10 mps.
The velocity profile typically goes through a maximum about a thousand feet
above the ground. The velocity profiles measured at Fresno by pilot balloons
are shown in Figure 3.5.7. Note that the 2300 PDT, 7/27/79, and 0100 and 0300
PDT, 7/28/79, velocity profiles are very similar. Note also that the veiocity
decays exponentially with altitude throughout the night (Figure 3.5.8). Only
the slope (or exponential decay rate) varies between the velocity profiles.
The later velocity profiles fal I off more rapidly than the first three. If the
atmosphere could be characterized by a constant eddy dlftusivity, the velocity
profiles might be expected to fal I as the square of the altitude. This
prediction is based on the analogy of flow in the nocturnal jet to the
steady-state problem of shear flow in a channel with paral lei boundaries with a
no shear stress condition at the lower boundary and a constant velocity layer
at the upper boundary. The deviation from the height squared law for the
velocity decay with altitude may be a reflection of the variation of eddy
diffusivity with height.
The presence of a high velocity jet just above the surface layer can lead
to a significant redistribution of pollutants within the valley during the
night. Pollutants that mixed upward during the afternoon could be efficiently
transported towards the southern end of the valley and detected at ground level
as the mixing height increased on the fol lowing day. This tracer release was
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SJV-5 7/27/79 - 7/28/79 5000 -
_J t.:)
<. I-LL
I w :::) I--I-_J
<
'lo ..4000 - .. .. .. .......... l""Sl""II -~IDIOIO - 'I,
\ 2000 - ~
'\. '-1000 - \, ...... .....
0L I
5000 -
4000 -
3000 -
2000 -
1000 -
0 L1
5000 -
" '-\, \, \.
~ ~ ~ ~ I~
.. 'I,
\. \. I,
J. l
~ ' ~ 0 I
\. \. \
~ ~
~ ~ ~ ~I
.. .. .. \ \
~ \
i ~
1 l
~ \ ~
~ ~ ~ ~ I~
••• I,
I, \,
J. l, \,
l,
I. \. \,
I'"
I
I
'-\, \. \. \
f ~ » ~ 01
.. .. ... .. \,
I,
\,
\,
\
~ ~
1~1
.. .. " \. l ~ ~ \.
~ r
• •• l
'I, '\,
',,
\. \. \. \. r
•
\,
\ \ 'I,
\, I,
. ~ \ \\
i '
• •.. .. 'I,
\,
\, \. \ '-. \, \, ... 'I, I
'\,
'I,
'\,
I.
' • ,. ,. ~
,. ,. ~ ,.
FRESNO
VISALIA
4000 -
3000 -
2000 -
1000 -
0 L1 18
...
... " 'I,
l,
\.
~ \. \. \. \. \. f'
l. I, 'I,
\,
\,
\.
~ ~ ~ \ t
24
',,
'-'-.. 'I,
' l. L
l... I
l, I, .. .. .. .. I,
'l. 1 l \. \,
;-. I
... .. .. .. .. .. .. •.. ... .. .. 'I,
• I 6
l, 'I, .. .. .. .. .. ..... .... ...... • .
'\, .. .. \. \. \. I. l l, ... ... .. •
\, ... ... .. .. l. l BAKERSFIELD l 1 1,
•• • T
12
PACIFIC DAYLIGHT TIME
Figure 3,5.7
WIND VECTOR WIND VECTOR
3-121
LENGTH SCALE ALIGNED WITH
- 1 CM• 15 MIS WIND DIRECTION
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7
*
1
Hllll
"u w en en ' a: w I-w ~ ....,, 1121 w *C'iJJ ;;Ja.. ren
z ..... 3=
7
1· L
0 1000 2000 3000 4000
ALTITUDE (FT AGL)
Figure 3.5.8
3-122
NOCTURNAL JET VELOCITY PROFILES
FRESNO 7/27/79
• 230111 PDT 1 0100 7/28 3 030111 7/28 5 050111 7/28 7 071110 7/28
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designed to evaluate the effectiveness of this transport mechanism. The tracer
was released from an airplane flying in the high velocity portion of the
nocturnal jet. The airplane flew between Chowchi I la and Herndon throughout the
release. The tracer source could thus be approximately characterized as an
elevated, I lne source.
Transport towards southern end of valley
Automobile traverses detected 10-15 PPT of the tracer over a zone about 20
miles wide in the center of the valley. SF6 was detected at ground level along
both Hwy 180, west of Fresno and Hwy 198, west of Visa! ia. SF6 was also
detected at these same low levels at Tranquility as shown in Figure 3.5.9. It
appears unlikely, however, that most of the SF6 detected in these samples was
fran the tracer released into the nocturnal jet. The tracer was spread over a
length of at least 40 miles. 10 PPT SF6 in a volume measuring 20 miles in
width, 40 miles in length and 1500 ft deep accounts for a majority of the
released tracer (about 120 lbs). Yet during airplane traverses conducted on
the day after the release, concentrations as high as 75 PPT were detected aloft
at the extreme southern end of the San Joaquin Valley (see Figure 3.5.11).
Presumably, a majority of the tracer was transported into this zone. It is
also unlikely that such a large fraction of the tracer was transported rapidly
through the stable surface layer of air. A much more I ikely source of the
tracer detected in the center of the San Joaquin Valley is the release begun at
Reedley less than 60 hours previously. The tracer was apparently transported
back and forth across the center of the valley by the diurnally varying wind
flows. Due to the nighttime drainage condition, the carryover was detected in
the center of the valley. The estimate of the total mass of tracer detected
during the mid-valley traverses is about 25% of the tracer released during the
previous test. If al I of this tracer was from the previous test, which appears
I ikely, this loss rate corresponds to an characteristic time for exponential
decay (a mean residence time assuming good mixing within the valley) of just
over 2 days for the meteorological conditions that prevailed prior to this
experiment.
As mentioned in the previous paragraph, the highest concentrations of
tracer (except for a few Isolated samples) were detected on the day after the
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la. a.. ,.., to LL. U) L.J
SJV-5 7/28/79 - 7/29/79 50 r-
~ CHOWCHILLA
0 p-d t::t::b-d ' d I I I 1 I I 1 I I , 1 I bl I , I I , I L "+ I , I I I I , , I , , I
50 r FRESNO
I
0 crl-cd-cd , t J..11:11:hu11:/ltht11:ttht11:~ 1 , I 1 , I , 1 I , , I , , I , , I 1 , I , , I 50 r
~ VISALIA
0 I, I l.;-ci I Lt:1 I 6-, I'd I+ I t:d ~ 1 j HI H 1,.' I'' I, I I 50 ..-,
~ FIREBAUGH
0 llt:±-0 Ln-J.11:1 Ltt1thtl!tt Li ,d r::td t:d od I "+ I I I ' ' I ' , I ' ' I 50 r-
~ TRANQUILLITYJ-:i,, ru, t:bd,,, rn,,,,,, LI .l..,.J m 1,, Li+,, 1,, 11 , 1,, 1 0
50 r ~ HURON
0 l,, lt4 6 r6, 1,, L, 6, 6, L, 1,, I,, I,, I,, I,, I,, I,, I 50 r
~ CORCORAN Lt, 1.p,-ru b-d,, 1, LI H 11 d H 1,,,,,,,, r,, 1,, r,, 1,, 1 0
50 r ~ ALPAUGH
0 l t , I.f=1 ' 1 1 l H I I t I 1 1 ) H 6.., b+-; I H I w I H I ••iit+ t i , 1 i t t i 50 ..-
~ DELANO
0 L, f I H Lo+, • ' • I LH--1 t-b J.-o Li I L-,1 Otttt11tlit,. I , , I , t I t , I
50 r ~ WASCO
0 L t If c:i-tt-J-.n J--rrL 1 I t::H I I L U 0tl.t11tt1tltt11:11 !.11ttt'-t I I I I I t t I
50 ~ BAKERSFIELD
••••• ' I I I I ·~ I I I I I
1 1 1 1 1 1 1 10 ;,t '~~~I 'i'2H 1~1~ ~1 ~~ I 3 , ~~.J '11dI tJ 1
1~ ~1 , 0
PACIFIC DAYLIGHT TIME
RELEASE LOCATION, 219 LBS SF6 AIRBORNE RELEASE TIME, 2300-0215 PDT, 7/27/79
Figure 3.5.9 • INDICATES MISSING OAT~
ARROWS INDICATE BOUNDS OF SAMPLING PERIOD
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SJV
5
Figure 3.5.10 • nintrATC'<'.' <'.'AMl'll C'O I nrATTnllC'
1 IUJ 1 l.,M I L.J .JMnr LLI\ LUl.,M I 1 Ull.,)
~)'IS THE RELEASE SITE 3-125
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SJV-5 AIR TRAY DATA COMPARISON
ta.. a..
50r-, (0 ~ (f)....
AIR TRAV 1-7 1124-1137 7/28/79
0 --~~----~-----~---~-~----100
t- I a.. a..
r-, (0 50 ~ ~ (f) '--' '
I
~ )-J0 l I
0 3 6 9 12
TIME <MIN)
Fi gu re 3. 5. 11
AIR TRAV 1-8 1137-115e 7/28/79
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release at the southern end of the valley. An average concentration of 29 PPT
was detected over the entire southern boundary of the San joaquin Vai iey at an
altitude of 1000 ft during Airplane Traverses 1-7 and 1-8 (Figure 3.5.11). The
tracer was apparently transported to the southern end of the val lay by the
nocturnal jet, but there appears to be no evidence of mixing downward by midday
of the day after the release. As the mixing height grows during the afternoon,
however, the tracer transported from the northern end of the va I I ey wi I I have a
chance to mix downward. No automobile or airplane traverses were conducted
during the afternoon to verify this.
Summary
During this experiment, the tracer was released into the nocturnal jet
which frequently develops above the San Joaquin Valley in the summertime. The nocturnal jet refers to a region of air with maximum velocities in excess of 10
mps. The velocity maximum typically occurs about 1000 ft above the surface of
the San Joaquin Valley. The jet apparently forms due to the decoupling of the
air aloft from the surface layer. The lack of shear stress at the surface can
lead to acceleration of the air aloft. This test was designed to evaluate the
nocturnal jet as a mechanism for transport of airborne pollutants from the
northern half of the valley to its southern end.
SF6 was detected at ground level west and southwest of Fresno. The amount ,....&. ~._.. .... ...,..,.,...,,,...4,, ro I o::::i.e.o..-1of SF6 detected within this zone was a majoiity UI Ille; OIIIVUIII I VIV\,.,I..>"""'-'• Yet
the concentrations detected in this zone (about 10 PPTl were an order of
magnitude less than the concentrations detected at the southern end of the
valley on the day after the release. Also, the winds in the nocturnal jet were
directed along the eastern side of the valley. The tracer detected southwest
of Fresno on the night of the release was apparently not from this release but
carryover from the previous experiment. The tracer released during this
experiment was apparently not detected at ground level on the night of the
release. As mentioned previously, tracer from this experiment was detected
aloft at the southern end of the valley on the morning after the release. A
crude picture of the apparent tracer transport path is shown in Figure 3.5.12.
The tracer was apparently stil I confined to a shallow layer about 1000 ft off
the ground. The tracer was probably detected at ground level only after the
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'•I l'ALI• • ID ••.....
~ SITE - ~nm TO OOOHUA •• IO TAFT
ARROW POINT INDICATES OBSERVED TRACER LOCATIONS NUMBERS REFER TO HOURS AFTER RELEASE START (2300 PDT., 7/27/79)
Figure 3.5.12
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mixing height increased to above the level of the tracer al lowing fumigation of
the tracer to ground level.
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3.6 Test 6 30 July 1979, Pacheco Pass Reiease (1200-1725 PDT)
3.6.1 Meteorology
General
The synoptic meteorology (Figure 3.6.1) during Test 6 was character-ized by a region of high pressure aloft at 500 mb centered offshore of the
central-southern California coast. As reflected in the 850 mb temperature trend shown on Figure 2.2.1, the air mass residing over California remained warm and stable. At the surface, a thermal trough was established over the interior of California. A weak weather front off the Washington-Oregon coast was not affecting conditions in the San Joaquin Valley. Skies remained clear throughout the test. Afternoon visibilities in the valley ranged from 10-12
miles, although smoke was observed in the distance at both Stockton and Bakersfield. Surface temperatures were above normal for the date. Both
Fresno and Bakersfield reported maximum temperatures of 104°F.
Transport Winds
During the tracer release, pibal winds were taken on both the west and east sides of Pacheco Pass on alternating hours. The measured winds were resolved into wind components roughly parallel and perpendicular to the orientation of the pass. The parallel component was used to define the flux through the pass and is shown on the time-height cross sections in Figures 3.6.2 (a and b). The major feature of the cross sections is the low level convergence of the flow at the pass, i.e., the flow was directed toward the summit on both sides. This would imply that the tracer material would be carried aloft in the convergence zone. Within the valley, the afternoon flow at 1000 ft-agl is described by the streamlines on Figure 3.6.3. Northwest flow predominated throughout the valley with winds generally on the order of
3-5 m/s.
Mixing Heights
No aircraft sounding data were available during the release period. Maximum mixing depths in the San Joaquin Valley as determined from the pibal data ranged from 1000-1300 mat Los Banos and Fresno.
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lo 0..
en 0
O'>,-... O'> .....
..., 5,..
..i="' u 5,..
~ ..., QJ"'
3
QJ u
'+-"' 5,.. ::i
C.,")
...... I.O. M
QJ 5,.. ::i Ol·-LL
"' ;,-..J ;:, ....
3-131
0
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(a) West Side of Pass (b) East Side of Pass
19 80 ,-1980 ~
u -4 - -)1710f- 1710
-2
1440 1440 - -~V, V,E
I E -~~ IE 11 70 E 1170~
~
I-I-:x:
<.!) :x: 896<.!)...... 896 ......w w:cw
I,_. :x: I -2 w N 612 612
-2
-4-3131 313 r
-2
13
HOUR
15 17
(PDT)
14 16 18
HOUR (PDT) 81 /060
Figure 3.6.2 Time-Height Cross Section of Through Pass Component of Wind at Pacheco Pass - 30 July 1979
(m/s)
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....
, C'
..._ .•.·-. ' u.._r
e e C !! 'f tf' -Ip \• L_. .., •
. . . - - - -..
(
Figure 3.6.3 1000 Ft-agl Streamlines - 30 July 1979 (15 PDT)
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3.6.2 Air Quality
Regional Pollutant Levels
Maximum hourly average ozone concentrations for 30 July 1979 are
shown on Figure 3.6.4. Numerous exceedances of California's ambient air
quality standard for oxidant were experienced throughout the valley.
Maximum concentrations (.14 ppm) were measured in the Fresno urban area.
Levels as great as .12 ppm were experienced at Whitaker's Forest in the
Sierra Nevadas.
Maximum hourly values of other pollutants in the valley on July 30
are shown in Table 3.6.1 together with maximum hourly concentrations ob
served at the Rockwell International vans. Relatively low levels of all
pollutants were observed during the day.
Table 3.6.1
MAXIMUM HOURLY CONCENTRATIONS JULY 30, 1979
Parameter Location Maximum Value
S02 co NOx
S02
S02
NOx
NOx
NOx
Oil dale
F resno-01 i ve r_ .... ..,_,.. f'\14 .,,,, r r.t:::>11u-v 1 1 v-c;
Modesto (RI)
Merced (RI)
Modesto (RI)
Merced (RI )
Madera (RI)
•07
5.
.18
.01
< • 01 .02
.02
< • 01
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l
(
(. Figure 3.6.4 Maximum Hourly Ozone Concentrations (pphm) - 30 July 1979
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Aircraft Sampiing
The aircraft sampled in the late afternoon (1551-1911 PDT on
July 30 to provide (l aerial coverage of the tracer plume and (2 to
measure the flux of pollutants from the Santa Clara/San Benito Valleys into
the San Joaquin Valley. To this end, traverses were flown within the mixing
layer in the San Joaquin Valley, over Pacheco Pass, in the Santa Clara and
San Benito Valley and across the Diablo Range from Hollister to Mendota.
Spirals were flown on the east side and west side of the pass and over Fresno.
Although the data system failed to. record the meteorological and air
quality data, from observations and the strip chart recorder the following
comments are offered:
The top of mixing at Santa Nella Airport was 2700 ft-msl.
Some mixing was observed to 6000 ft-msl in the Santa
Clara Valley.
On the east-west traverse across the pass, ozone sharply
increased just east of Bell Station (near the summit
suggesting vertical transport and little exchange through
the pass.
Ozone levels in excess of .30 ppm were observed at 2500 ft
msl over the South County Airport in the Santa Clara Valley.
Ozone levels dropped off sharply after leaving Hollister
Airport heading east over the Diablo Range suggesting no transport into the San Joaquin Valley at that time.
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3.6.3 Tracer Test 6
Release Location: Pacheco Pass above Los Banos, Merced County
Time and Date: 1200-1725 PDT, 7/30/79
Release Amount: 99 lbs SF6/hr
Release was made into a convergence zone between a easterly fiow fru11 the San
Joaquin Valley and a westerly flow from the coastal side of the pass.
The majority of the tracer was not detected at ground level during the day
of the release. High concentrations of the tracer were detected only during
Traverse 1-1 which passed through Pacheco Pass and the release area. Low
levels of tracer were detected during other automobile traverses, notably
Traverse 1-2 and 1-3, but the levels detected during these traverses could not
account for more than a smal I fraction of the SF6 originally released.
Automobile traverses were conducted on both the east and west sides of Pacheco
Pass. During Airplane Traverse 1-3 tracer concentrations as high as 253 PPT
were detected. The tracer plume detected during this traverse extended for
about 8 miles with concentrations above 30 PPT. This traverse was about 600 ft
above the release height. This suggests that the tracer was carried aloft by
the flow convergence near the release site. The convergence of air at the
release site is consistent with afternoon upslope flows on both sides of the
coastal mountains that form the western boundary of the San Joaquin Valley.
At fixed sampling sites within the San Joaquin Valley, most sites showed
low, essentially background levels of tracer. The concentration data collected
at each of the fixed sampling sites is included in Figure 3.6.5. The
concentrations detected at these sites may be a smal I amount of carryover from
previous tests. Approximately 1240 lbs of SF6 was released in the San Joaquin
Va\ ley between 7/25/79 and 7/30/79.
Summary
The tracer was released from a pass through the coastal mountain range on
the west side of the San Joaquin Valley. The surface layer flow on both the
east and west sides of the pass were converging, indicating that the tracer was
carried aloft. Significant tracer concentrations were detected only during an
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SJV-6 7/30/79 - 7/31/79
CHOWa-lILLA
CDt:t:c:-0 t::::6~11,,1,,111
FIREBAUGH
0jp 50 r
'
HURON~ t- 0 j pd o.J::O 6 6 d o-±:o I n:-q. , J a.. Q..
50 r .., co I tn u. ALPAUGH '-' ~
0 j +*•*b-Ot----r-~t:=bch*,*l 50,
! I
WASCO~ 10 j +cO..o:--CTb ~
50 1 8/IKERSFlEUl~
I
i I I I f7Hrfl:::rn*,*l*,*,*1*,*,*1*,*,*I*+ , l , I , i I ;0'+'''12 15 18 21 24 3 6 9 12 15 18 21 0
PACIFIC DAYLIGHT TIME
RELEASE LOCATION: 536 LBS SF6 AT LOS BANOS ~cLc~~c llMc: i200-i725 PDT, 7/30/79
Figure 3.6.5 3-138
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SJV
6
.. 12' ___,, * -f"'""---""•-'-"I ·- ·-
' ·,
Figure 3.6.6
• INDICATES SAMPLER LOCATIONS <? '.~ IS THE RELEASE SI TE
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airplane traverse conducted about 600 ft above the release site. It was not
possible to determine the transport path of the tracer after being carried
aloft. The tracer concentrations within the San Joaquin Valley were
indistinguishable from background levels.
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4. Conclusions
1. The July 1979 field program was characterized by relatively
warm temperatures at 850 mb compared to average. All tracer tests were ~arried out under above average temperature conditions.
2. Average wind flow into the valley at Stockton and Los Banos
during July is directed from Stockton to Bakersfield at all hours of the day. The principal driving force for this flow is the thermal low pressure area to the east of the Sierras.
3. Average wind direction in the low levels at Visalia and Fresno for the July program was southeasterly during the early morning hours but northwesterly for the balance of the day. The duration of the southeasterly winds was longer at Visalia, associated with northward spreading of the Fresno
Eddy. 4. The Fresno Eddy develops during the night as a result of
stable conditions in the southern end of the valley. The absence of the eddy is associated with the passage of weak, cool troughs through the area.
5. As the eddy develops, the flow above Bakersfield and Visalia (from 1000 to 2000 m, agl) increases compared to the value at Fresno, indicating that some of the northwest flow is displaced upward and over the eddy.
6. The nocturnal wind jet formed to a significant degree during about half of the July 1979 data sample, Peak wind speed occurred at about 300-400 m (agl) at 2100-2300 PDT.
7. Mixing layer depths were observed to range from 600 to 1200 m during the afternoons when tracer tests were conducted.
8. Maximum ozone concentrations ranged between .11 and .17 ppm on the days when tracer releases were carried out.
9. Maximum CO values on tracer days were 2 to 5 ppm while NOx observations ranged between .18 and .32 ppm.
10. NMHC concentrations taken near Stockton averaged less than .2 ppm with iow concentrations attributable to automobile
sources.
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11. The major components of the total particle composition
were silicon, sulfate and carbon. Crustal-like materials
accounted for the largest fraction of the mass.
12, Tracer released between 0700 and 1300 PDT on July 13, 1979 at
Manteca was transported by northwesterly winds along Hwy 99.
Approximately 40 miles south of the release site, the tracer
trajectory shifted westward and followed the San Joaquin
River, the lowest portion of the valley. Pollutants trans
ported into the San Joaquin Valley from the California Delta
and San Francisco Bay area would also have been transported
along the western side of the valley on this day, minimizing
the impact of these plumes on the urban east side of the
valley. Based on a comparison to the Gaussian plume model, the dispersion of the tracer plume was consistent with neutral
or slightly unstable atmospheric conditions and a mixing depth
of about 1650 ft.
13. Tracer released between 1300 and 1900 PDT on July 16, 1979 at
Manteca was transported by northwesterly winds along the San
Joaquin River. As in the previous test, pollutants transported
into the San Joaquin Valley from the San Francisco Bay area
would have had a minimal impact on pollutant levels on the urban
east side of the valley. Based on a comparison to the Gaussian
plume model, both the horizontal and vertical dispersion of the
tracer was consistent with neutral or slightly unstable atmospheric conditions.
14. Tracer released between 1510 and 2030 PDT on July 18, 1979 at
Livermore was transported by westerly winds over Altamont Pass
and into the San Joaquin Valley. The intrusion of tracer into
the San Joaquin Valley was limited due to stabilization (and
comparative stagnation) of the atmosphere after nightfall~ On the day following the release, the tracer "cloud" was
transported down the western side of the valley in a manner
similar to that found during the previous two tests.
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15. Tracer released between 1200 and 1700 PDT on July 25, 1979 at Reedley was transported upslope by the westerly afternoon winds, impacting sites in the National Forest and Park areas in the Sierra Nevada Mountains. The upslope movement of the tracer plume was arrested by the nighttime reverse flow. Some of the tracer carried downslope by the nighttime flow was was transported by flow across the valley floor to Huron on the western side of the valley. The afternoon upslope flow appears to be a mechanism for valley ventilation but its effectiveness is reduced by the corresponding downslope flow at night.
16. Tracer released between 2300, July 27, 1979 and 0215, July 28, 1979 aloft into the nocturnal jet northwest of Fresno was transported to the extreme southern end of the San Joaquin Valley by late morning on the day following the release. Essentially none of the tracer was transported to the ground level during the night of the release. Tracer detected at ground level west of Fresno on the night of the release was apparently carryover from the experiment conducted two days previously. The nocturnal jet appears to be
an efficient mechanism for transport to the southern end of the valley, but minimal ground level impacts occur until the surface mixing layer deepens during the following day.
17. Tracer released between 1200 and 1725 PDT, July 30, 1979 at Pacheco Pass west of Los Banos was carried aloft due to the convergence of a westerly coastal flow and an easterly valley uplsope flow. Essentially none of the tracer was detected at ground level within the valley.
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ll~illlilllill~[l\111111105541