Final Report
LIDAR STUDY OF  STACK  PLUMES
By:  WARREN B. JOHNSON, JR. and EDWARD E. UTHE
Prepared for:

DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
NATIONAL AIR POLLUTION CONTROL ADMINISTRATION
DIVISION OF METEOROLOGY
411  WEST CHAPEL HILL STREET
DURHAM,  NORTH CAROLINA  27701
CONTRACT PH 22-68-33
 STANFORD RESEARCH INSTITUTE
 Menlo Park, California 94025 • U.S.A.

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            STANFORD RESEARCH  INSTITUTE
            Menlo Park, California 94025 • U.S.A.
Final Report
LIDAR STUDY OF STACK PLUMES
By: WARREN B. JOHNSON, JR. and EDWARD E. UTHE
Prepared for:

DEPARTMENT OF  HEALTH, EDUCATION,  AND WELFARE
NATIONAL AIR  POLLUTION CONTROL ADMINISTRATION
DIVISION OF METEOROLOGY
411 WEST CHAPEL HILL STREET
DURHAM,  NORTH  CAROLINA  27701
CONTRACT PH 22-68-33
SRI Project 7289
Approved:

R. T.  H. COLLIS
Director
Aerophysics Laboratory

RAY L. LEADABRAND
Executive Director
Electronics and Radio Sciences Division
                                                             Copy No. -'::.

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                               ABSTRACT
     The feasibility of lidar (laser radar) for stack plume studies is
established from the results of an experimental investigation of plume
behavior from a 245-m power plant stack in western Pennsylvania.  During
this study a total of 175 vertical plume cross sections containing about
3800 separate lidar observations were obtained, of which 64 cross sec-
tions representative of various types of plume behavior were selected
for detailed analysis.  Each vertical cross section was built up from
15 to 30 lidar shots at 5 to 8 second intervals and at elevation angle
increments of 1/3° to 10°.  The selected cross sections are grouped into
series which show the spatial (downwind) and temporal variations in
plume geometry and relative particulate concentration distributions.
     The factors involved in interpreting the lidar data in terms of
plume rise and diffusion are discussed and exemplified.  Although cal-
culated plume-rise values agree reasonably well with the observations,
it is clear from inspection of the cross sections that the important
effects of vertical wind direction shear (plume tilting and fanning)
and vertical changes in stability (plume trapping) should be taken into
account when predicting plume rise and diffusion.  Close correspondence
between plume tops and levels of increased atmospheric stability was
found.  Several cross sections are shown of fumigating plumes, which
occurred frequently.  In a tilted plume, different portions apparently
fumigate at different times.  Optimum use of lidar for diffusion studies
requires provision for obtaining 30-minute or hourly plume concentration
distributions, as well as allowances for the effect of the lidar noise
level upon plume size.
     To investigate the potential of lidar for making quantitative
measurements,  a sample cross section of absolute mass concentration was
computed on the basis of Mie scattering theory and independent particle
size measurements.  The cross-axial integrated mass concentration repre-
sented by this cross section is 680 g/m.  The corresponding value calcu-
lated from the gross power-plant data and wind speed is 875 g/m.
                                  iii

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     The advantages of the mobile lidar technique stem from its ability
to obtain measurements remotely and at a high density in space and time.
The quantitative application of the technique for obtaining absolute
particulate mass concentrations is limited mainly by the accuracy with
which the optical characteristics of the aerosol  are known.  An improved
lidar system for plume studies would incorporate  better signal-to-noise
characteristics and a higher pulse repetition rate than present equip-
ment provides.  in addition, an expanded data processing capability with
 real-time" output is necessary.
                                IV

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                               CONTENTS
ABSTRACT	       iii
LIST OF ILLUSTRATIONS	       vii
LIST OF TABLES	        xi
LIST OF SYMBOLS	      xiii
FOREWORD	        xv
   I INTRODUCTION 	         1
  II SUMMARY AND CONCLUSIONS	         3
     A.   Plume Characteristics 	         3
     B.   Lidar Data Analysis Considerations	         4
     C.   Instrumentation Considerations	         5
 III DESCRIPTION OF THE EXPERIMENTAL PROGRAM	         7
     A.   Instrumentation 	         7
     B.   Experimental Procedures 	         9
     C.   Summary of Lidar Data	        12
  IV BASIC ANALYSIS OF LIDAR BACKSCATTER SIGNATURES 	        15
     A.   General Discussion	        15
     B.   Lidar S-Function Analysis 	        17
   V RELATIVE CONCENTRATION CROSS SECTIONS OF KEYSTONE
     STACK PLUME	        25
     A.   May 1968 Observation Period	        25
     B.   October 1968 Observation Period 	        33
  VI INTERPRETATION OF CROSS SECTIONS IN TERMS
     OF PLUME RISE AND DIFFUSION	        53
 VII EVALUATION OF PARTICULATE MASS CONCENTRATIONS
     FROM LIDAR NORMALIZED SIGNAL RETURN (S) VALUES 	        59
VIII ANALYSIS OF ATTENUATION EFFECT
     USING PARTICLE-SIZE CHARACTERISTICS	        65

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   IX RECOMMENDATIONS FOR FURTHER RESEARCH  	        73
     A.   Lidar Instrumentation 	        73
     B.   Data Handling and Reduction Capabilities	        74
     C.   Experimental and Analytical Techniques	        76
     D.   Advanced Lidar Concepts	        7*>
REFERENCES	        79
Appendix A—DESCRIPTION OF MARK V LIDAR	        81
Appendix B--DETAILED LIDAR DATA SUMMARIES  	        89
Appendix C—LIDAR DATA DIGITIZING AND CONDITIONING DETAILS.  .        97
Appendix D--PLAN VIEWS OF HORIZONTAL PLUME POSITIONS
            FROM LIDAR OBSERVATIONS 	       101
Appendix E--LIDAR EYE-SAFETY CONSIDERATIONS 	       113
                                  vi

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                             ILLUSTRATIONS
Frontispiece

Figure 1
Figure 2
Figure 3
Figure 4

Figure 5
Figure 6

Figure 7

Figure 8

Figure 9

Figure 10


Figure 11


Figure 12


Figure 13

Figure 14
Figure 15
Mark V Lidar in Operation during Keystone
Stack Plume Study near Shelocta, Pennsylvania
SRI Mark V Lidar	
Lidar Sites Used during Field Experiments  .
Basic Lidar Observation of Smoke Plume. .  .
Example of Multiple-Trace Format Used
for Display of Magnetic Disk Records.  . .  .
Lidar Data Analysis Process 	 ,
Effect of Range Correction upon Plume Signal
Return and Receiver Noise Level 	 ,
Comparison of Plume Cross Sections Contoured
in Linear Units (a) and Logarithmic
Units (b)  	
Relative Height Considerations Associated
with Lidar Plume Observations 	 ,
Spatial Series of Lidar-Observed Vertical
Cross Sections under Stable Conditions,
25 May 1968, from Site 1, 3.5 km from Stack
Spatial Series of Lidar-Observed Vertical
Cross Sections under Moderate Diffusion
Conditions, 25 May 1968, from Site 1,
3.5 km Southwest of Stack 	
Spatial Series of Lidar-Observed Vertical
Cross Sections under Stable Conditions,
26 May 1968, from Site 2, 3.5 km North of
Stack 	
Spatial Series of Lidar-Observed Vertical
Cross Sections under Unstable (Looping)
Conditions, 26 May 1968, from Site 2,
3.5 km North of Stack 	
Vertical Temperature Profiles Associated
with Lidar Observations, 25-26 May 1968 .  .  ,
Comparison of Manual and Machine Analyses  .
Time Series of Lidar-Observed Vertical
Cross Sections from Site 6, 3.8 km Northeast
of Stack, Plume Overhead, 15 October 1968  .
 8
10
15

16
18

21

22

26

27


28


29


30

31
34

35
                                  VII

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Figure  16      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, Plume Overhead,
               16 October 1968  	
Figure  17      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, Plume Overhead,
               17 October 1968  	
Figure  18      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 17, 13.7 km
               North-Northwest of Stack, Plume Overhead,
               18 October 1968  	
Figure  19      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 21, 21 km
               East-Southeast of Stack, Plume Overhead,
               20 October 1968  	
Figure  20      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 22, 4.9 km
               Southeast of Stack, 21 October 1968,
               Immediately Prior to Full Precipitator
               Operation 	
Figure  21      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 22, 4.9 km
               Southeast of Stack, 21 October 1968,
               Precipitators in Full Operation 	
Figure  22      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 22, 4.9 km
               Southeast of Stack, 21 October 1968  .  .  .

Figure  23      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, 22 October 1968  .  .  .

Figure  24      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, 22 October 1968,
               Clean Plume 	

Figure  25      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, 22 October 1968  .  .  .

Figure  26      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, 22 October 1968  .  .  .

Figure  27      Spatial Series of Lidar-Observed Vertical
               Cross Sections from Site 6, 3.8 km
               Northeast of Stack, 23 October 1968  .  .  .
37
38
39
40
41
42
44
45
46
47
48
49
                                 viii

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Figure 28      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 11, 4 km
               Northwest of Stack, 24 October 1968  	

Figure 29      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 11, 4 km
               Northwest of Stack, 24 October 1968  	

Figure 30      Time Series of Lidar-Observed Vertical
               Cross Sections from Site 11, 4 km
               Northwest of Stack, 24 October 1968  	

Figure 31      Dependence upon Particle Size of Total
               Scattering (Extinction) Optical Cross
               Section per Unit Mass  (§e) ., and
               Backscattering Optical Cross Section per
               Unit Mass per Steradian (^b) 	
Figure 32      Sample Cumulative Particle Size Distribution
               and Junge-Type Analytical Fit 	  ,
Figure 33      Effect and Magnitude of Correction of Plume
               Mass Concentration Distribution for
               Attenuation  	

Figure 34      Visualization of Intensity-Modulated
               Range/Height Oscilloscope Display of
               Plume Cross Section Observed by Lidar .  .  .  ,

Figure A-l     Optical System of Mark V Lidar	

Figure A-2     Electronics System of Mark V Lidar	

Figure D-l     Plan View of Horizontal Plume Positions,
               15 October 1968 	

Figure D-2     Plan View of Horizontal Plume Positions,
               16 October 1968 	

Figure D-3     Plan View of Horizontal Plume Positions,
               17 October 1968 	

Figure D-4     Plan View of Horizontal Plume Positions,
               18 October 1968 	

Figure D-5     Plan View of Horizontal Plume Positions,
               20 October 1968 	

Figure D-6     Plan View of Horizontal Plume Positions,
               21 October 1968 	

Figure D-7     Plan View of Horizontal Plume Positions,
               22 October 1968 	

Figure D-8     Plan View of Horizontal Plume Positions,
               23 October 1968 	

Figure D-9     Plan View of Horizontal Plume Positions,
               24 October 1968 	
 50
 51
 52
 62


 68



 70



 75

 84

 86


103


104


105


106

107


108


109


110


111
                                    IX

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                                TABLES
Table I        Keystone Precipitator Conditions during
               Lidar Observations of Plume
               (from Single Stack)	,

Table II       Condensed Data Summary, Lidar Observations ,

Table III      Values of Input Parameters Used and Results
               from Plume Rise Calculations Using ASME
               Formula for Stable Conditions	,

Table IV       Summary of MRI Particle-Size Distribution
               Data	,

Table V        Values of Optical Parameters Computed
               from Relative Particle-Size Data 	 ,


Table A-I      Characteristics of SRI Mark V Lidar. ...


Table B-I      Data Summary, 25 May-1 June 1968	,

Table B-II     Data Summary, 15-24 October 1968 	
11

13



55


66


67


85


91

93
                                  XI

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                                SYMBOLS
   a = particle radius
   A = effective receiver area
   c = speed of light
   C = particle number concentration; also parameter in formula for
       Junge fit to particle-size data
   C = optical cross section averaged over particle size interval
   E = lidar site elevation
   F = buoyancy flux
   g = acceleration of gravity (= 9.8 m/s)
   G = stability parameter
H(R) = magnitude of magnetic disk-recorded signal return from atmosphere
       as a function of range
  H  = height of plume axis above lidar
  H  = height of top of stack above lidar
   S
  H, = height of plume top above lidar after maximum rise
  AH = plume rise (height of axis of plume above stack top after reaching
       equilibrium)
   H = distance along the laser pulse propagation path
   i = complex operator (y~-l)
   k = slope parameter in equation for Junge fit to particle-size data
log* = logarithmic amplifier transfer function
   m = refractive index of particles
   M = plume mass concentration
  M  = background mass concentration in "clean" air
   n = number of particles per unit volume per unit radius interval
  n  = relative density of particle-size distribution (fraction of
   y*
       number of particles per unit radius interval)
   N = cumulative particle number concentration (number of particles
       larger than a given radius)
  P  = detector output component due to background and internal noise
  P  = detector output component due to backscattered signal return
   o
  P  = peak power emitted into the atmosphere
                                 Xlll

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Q, = backscatter efficiency factor
  b

Q = extinction efficiency factor
  e

  r = radius of stack orifice (= 4.25 m for Keystone)



  R = range


R = reference range


AR = range increments of digitized lidar data


  S = normalized, range-corrected signal return function



  T = atmospheric transmission factor


T = ambient atmospheric temperature at stack top
  a

T  = beam convergence factor


T  = stack gas exit temperature


T  = air temperature at height of plume top


  U = mean wind speed over height interval where plume rise occurs


U  = wind speed at height of stack top (H )
  8                                       S

U  - wind speed at height of plume top (H ) after maximum rise
  L                                       ^

V  = stack gas exit velocity
  S

 x = particle size parameter (= 2rr a/X)


 P = volume backscatter coefficient (per steradian)


 X = wavelength of the laser energy


 M. = 10   m;  also used generally as 10  ( )



^  = backscattering optical cross section per unit mass per steradian

     (=
   = total scattering (extinction) optical cross section per unit

     mass (= a/M)


 rr = 3.1416


 p = density of the particulate matter


 a = volume extinction coefficient


 T = pulse duration
                                xiv

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                               FOREWORD
     This work was carried out as part of the Large Power Plant Effluent
Study (LAPPES) conducted by the National Air Pollution Control
Administration, and was sponsored by the Division of Meteorology of
that agency under Contract PH 22-68-33.
     We are grateful for the logistical and meteorological support and
experimental coordination provided by Frank Schiermeier, LAPPES Field
Manager, and by Larry Niemeyer and Charles Hosier of the Division of
Meteorology, National Air Pollution Control Administration.
     We also acknowledge the able assistance of the following Stanford
Research Institute personnel:  Hisao Shigeishi, Charles Brabant, and
Stephanie Briggs in the computer data processing and analysis phase;
Al Smith and John Alder in the manual analysis phase; and John Oblanas,
Norman Nielsen, and William Dyer in the experimental program.  Thanks
are also due to Ron Collis, Director of the Aerophysics Laboratory,, for
his helpful suggestions in the writing of this report, and to William
Evans for the contribution of his ideas on data display and analysis
techniques .
                                  xv

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FRONTISPIECE   MARK V LIDAR IN OPERATION DURING
              KEYSTONE STACK PLUME STUDY NEAR
              SHELOCTA, PENNSYLVANIA

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                            I  INTRODUCTION

     The lidar, or laser radar, which was developed for meteorological
use by Stanford Research Institute in 1963, has  important applications
in air pollution research and control activities  (see Johnson, 1969;
                                           *
Hamilton, 1966; Barrett and Bcn-Dov, 1967).   This report covers a
recent experimental program, carried out for the  National Air Pollution
Control Administration, involving mobile lidar observations of the diffu-
sion of the smoke plume from a 245-m stack at Keystone Generating Station
in western Pennsylvania.  Such tall stacks are becoming increasingly
necessary in order to lower the ground concentrations of pollutants from
large plants.  However, these stacks cost in excess of $3000 per meter
to build, and  it is important to determine their  efficiency, in practice,
in preventing  high air-pollution levels.  In addition, in order to refine
diffusion models used to predict pollutant concentrations from high
stacks, more data are needed.  Most existing diffusion models were de-
veloped before the advent of the tall stack, and  the accuracy of the
theoretical predictions for this application has  not yet been adequately
verified due to the shortage of suitable data (Smith, 1968).  The new
lidar technique promises to fill this need and facilitate advances in
the theory of  high-stack diffusion.
     Using a mobile, truck-mounted lidar system,  a field team from
Stanford Research Institute participated in the LAPPES  experimental
program during two periods:  25 May-1 June and 15-24 October 1968.
Lidar observations of the smoke plume from the stack of coal-burning
Keystone Generating Station were obtained on 17 clays; a total of 175
vertical plume cross sections, consisting of 3806 individual lidar ob-
servations,  were collected.  The quality of about one-third of these
data were degraded by poor weather conditions.  Of the remainder,
*
 References are listed at the end of the report.

 Large Power Plant Effluent Study.

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approximately 10 percent were selected for detailed manual analysis (first
field program) and 46 percent were analyzed objectively using computer
techniques.  Representative examples of these derived plume cross sec-
tions will be presented here to illustrate the significant information
which lidar observations can furnish regarding plume geometry and be-
havior.  Although particulate emission is not the major air pollution
problem associated with power plants because of the efficacy of modern
ash removal devices,  the smoke serves as a convenient tracer for the
study of diffusion processes.  Since the particles are small,  their
diffusion should be essentially identical with that of a gas such as SO .

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                      II  SUMMARY AND CONCLUSIONS

     The results of the Keystone plume  study with  regard  to  plume  be-
havior in particular, and lidar capabilities and limitations  in general,
are briefly itemized below, with conclusions included  as  appropriate.
A.   Plume Characteristics
     In general, the lidar observations confirmed  and  underscored  the
known and suspected complexities of  plume behavior.  Complicating  fac-
tors--such as those mentioned below--thnt have been largely  ignored  in
present theories should now be intensively studied for possible incor-
poration, if the theory is to stay abreast of the  experimental state of
the art .
     Plume tilting and fanning caused by vertical  wind direction shear
probably affects plume rise, and definitely requires reconsideration of
the definition of plume rise.
     Fanning is a very common feature of plumes from high stacks ob-
served under stable conditions and must be included in any realistic
diffusion theory.
     The marked effects of elevated  inversions and other  levels of  in-
creasing stability with height were  observed frequently and need thorough
consideration.  Close correspondence was found between such  levels  and
plume tops,  as well as with haze tops when no plume was observed.
     Plume fumigation occurs often,  probably more  often than  previously
suspected.  Typically, however, only a  portion of  the  plume fumigates at
a given time,  with the remainder tilted and elevated.
     The meteorological regime best  suited for model validation, namely
nonstable conditions, also presents  the most difficult observational
situation for lidar.  This is because of the diffuse,  rapidly changing
nature of plumes under these conditions.  (See the instrumentation  dis-
cussion later in this section.)

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 B.    Lidar Data Analysis Considerations
      The value of lidar for observing  plumes  was  clearly established.
 For many applications,  such as  the  use of  particulates  in a plume as
 tracers for the study of diffusion  processes,  lidar-observed relative
 mass concentrations,  uncorrected  for attenuation,  should be sufficient
 to  furnish the required information.
      However,  quantitative results  in  terms of  absolute mass concentra-
 tion were also obtained.  A computed sample cross  section corrected for
 attenuation gave a cross-axial  integrated  mass  concentration of 680 g/m
 of  plume length, compared with  875  g/m as  calculated  from the power
 plant data and wind measurements.
      Our method of calculation  of absolute particulate  mass concentra-
 tions from the lidar  data is based  on  the  following:
      (1)  The  same particulate  relative  size  distribution and
           optical properties are  assumed to hold  in the clean
           air  and plume.  (The  MRI  data  appear  to  confirm
           this.)  This  is a convenient but not  essential
           assumption  for obtaining  a solution.
      (2)  The  relative  size distribution and  optical  properties
           are  assumed  to be known (measured or  estimated) .
      (3)   Mie  scattering theory is  assumed to be valid  (this is
           reasonable, since the fly ash particles  are spherical).
           Thus  5 ,  the  extinction optical  cross section per unit
           mass,  can be  computed.
      (4)   The clean air outside the plume  is  assumed  to be  homo-
           geneous  and to have a known  mass concentration M
                                                          o
           (measured or  estimated).
     The  integration procedure used  in this method is fairly sensitive
to errors  in the values  used for the solution parameters  P   and M  .
                                              H           ^e      o
     The known errors and  limitations  associated with the use  of
collecting-type  particle  samplers tends to make such data incompatible
with lidar data.  Optical  particle  samplers might give  more  comparable

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results, although there could be difficulties with any direct-sampling
instrument that disturbs the medium.
     The best prospects for obtaining routine quantitative data seem to
lie in the direction of deriving additional information on the solution
parameters by means of advanced lidar techniques, such as multiple-
wavelength instruments, which may be able to eliminate the need for in-
dependent particle measurements.
C .   Instrumentation Considerations
     For plume cross sections built up from many individual lidar obser-
vations, an accurate shot-to-shot referencing system is essential to
correct the data for pulse-to-pulse variations in transmitted power.
     Higher pulse repetition rates, on the order of one to ten shots per
second, are needed to observe rapidly changing plumes under unstable
conditions adequately and faithfully.  A water-cooled system is suggested
by this requirement .
     Better data handling, processing, and display capabilities are
necessary to assimilate larger quantities of data properly.  New tech-
niques, ideally of the real-time analog type, are needed to provide a
capability of averaging many cross sections to obtain an hourly mean
concentration distribution with which to check diffusion theories.
     The usefulness of lidar data would be considerably enhanced if in-
strumentation with higher power output and lower noise susceptibility,
and thus greater range, were used.  A lidar with an effective above-
noise range (for the clear-air return) of about 8 km would be ideal for
plume studies.  The neodymium system used in this study has an effective
                                                  *
range for clear-air return of about one to two km,  and thus could ob-
                                     itt
serve only the denser parts of "clean"  plumes at ranges greater than
*
 This range is variable, depending upon the level of background
 illumination.
 When all electrostatic precipitators were operating.

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this.  The Mark V ruby lidar would give much better results in this
respect due to its shorter wavelength, narrower spectral region, and
greater receiver sensitivity, but the pulse repetition rate needs to
be increased.
     In this connection, it is encouraging to note that neither the ruby
nor neodymium versions of the SRI Mark V lidar approach the limits of
current technology, and systems with the recommended performance can
readily be developed.

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             Ill  DESCRIPTION OF THE EXPERIMENTAL PROGRAM

A .   Instrument at ion
     The SRI Mark V lidar (Fig. 1) was used during both field programs
in a mobile, truck-mounted configuration.  The characteristics of this
instrument are detailed  in Appendix A.  As are all lidars, the Mark V
is basically composed of a laser transmitter, which emits a very brief,
high-intensity pulse of coherent monochromatic light, and a receiver,
which detects the energy at that wavelength backscattered from the at-
mospheric aerosol as a function of range.
     The transmitter of  this instrument employs either a neodymium-doped
glass laser rod or a ruby rod, at wavelengths of 1.06 and 0.694 p. re-
spectively.  The neodymium laser was used for the plume study because
of its faster pulse repetition rate (approximately 10 pulses/min vs
3 pulses/min for the ruby).  However, due to the much lower quantum
efficiencies and higher dark currents of the best available photomulti-
plier tubes at 1.06 u, and the wider filter bandpass needed for this
system, overall receiver sensitivity, signal-to-noise ratio, and thus
range is significantly reduced over that obtainable with the ruby system.
                                                                        *
     The lidar data were recorded on both a video magnetic disk recorder
and on an oscilloscope equipped with a 35-mm recording camera.  A second
oscilloscope used in conjunction with the disk recorder permitted an
"instant replay" of each lidar shot, thereby providing real-time moni-
toring of the data.  A 3-MHz low-pass filter is used with the disk re-
                                              t
corder to minimize noise; the range resolution  is about 40 m, while that
for the 35-mm film record is less than 20 m.  The 35-mm film records were
used for the manual analyses, while the machine analyses employed the
magnetic disk records.
 MRV Corp. Model 100M.
+
 The range resolution as used here is defined as the minimum separation
 distance at which two individual targets can be resolved.

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                                                    '--:--   >- r
FIGURE 1   SRI MARK  V LIDAR

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B.   Experimental Procedures
     For each series of observations, the lidar was situated at any one
of a number of preselected points, depending upon the location of the
plume.  The sites used during the two observation periods are depicted
in Fig. 2.  Where possible, the lidar was positioned so that it could be
aimed in a direction approximately perpendicular to the plume axis.  At
each site, vertical cross sections through the plume were normally ob-
                                                    *
tained at several downwind distances from the stack.   The technique
employed consisted of scanning vertically with elevation angle incre-
ments of 0.3° to 10°, depending upon the vertical extent of the plume
as determined from preliminary observations.  Such scans were then re-
peated at other azimuth angles.  The neodymium lidar permitted observa-
tions at intervals as short as five seconds.  A complete vertical scan
of 20 to 30 lidar shots required about two to five minutes to complete,
and a set of three cross sections could be obtained within 10 to 15
minutes.
     When the lidar was located at a considerable distance downwind from
the stack, such as at Sites 16 (9 km), 17 (14 km), and 21 (21 km), the
vertical cross sections were limited to only one azimuth angle (i.e.,
one vertical plane), because of the extended width of the plumes and
the frequently directly overhead plumes.
     In order to make the stack plume visible for direct observations
with aircraft associated with other experiments, 50 percent of the
electrostatic precipitators at Keystone Generating Station were normally
shut down during most of the observations.  However, to test the capa-
bility of the neodymium lidar to observe the "clean" plume, all of the
precipitators were put into operation during certain periods on 21 and
22 October.  As shown in Table I, six lidar plume cross sections were
obtained under these conditions, and the results are presented in Sec. V.
*
 Although the Keystone Generating Station has two stacks, each 245 m
 high, only one stack was in operation during each of the observation
 periods.

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543210
                                                                                    TA-72B9-8
                  FIGURE 2   LIDAR SITES USED DURING FIELD EXPERIMENTS

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                   Table  I
KEYSTONE PRECIPITATOR CONDITIONS  DURING LIDAR



  OBSERVATIONS OF PLUME  (FROM SINGLE STACK)



      (Precipitators on  indicated by X)
Date
(1968)
25 May
26 May
15 October
16 October
17 October
18 October
20 October
21 October
22 October
23 October
24 October
Lidar
Cross Section
Numbers
All
All
All
All
All
All
All
j 46, 47, 48
(All Others
j 60, 61, 62
' All Others
All
All
Bank 1
Inlet
1
X
X
X
X
X
X
X
X
X
X
X
X
X
2
X
X
X
X
X
X
X
X
X
X
X
X
X
3
X
X
X
X
X
X
X
X
X
X
X
X
X
4
X
X
X
X
X
X
X
X
X
X
X
X
X
Outlet
1
X
X
X
X
X
X
X
X
X
X
X
X
X
2 3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
4
X
X
X
X
X
X
X
X
X
X
X
X
X
Bank 2
Inlet
1







X

X


X
2







X

X



3







X

X



4







X

X



Outlet
1







X

X


X
2







X

X



3







X

X



4







X

X




-------
     The lidar observation periods were limited in length by prior
arrangement in order to forestall any possible interference between the
lidar and other experiments utilizing aircraft.  One of the considera-
tions here was lidar eye-safety, which is discussed in Appendix E.
C.   Summary of Lidar Data
     The lidar observations obtained during the two experimental periods,
25 May-1 June 1968 and 15-24 October 1968, are summarized in detail in
Appendix B, and in condensed form in Table II, along with the distribu-
tion of the analytical effort among the data.  Data obtained during
several days during the May period when there was rain, low ceilings or
fog have been omitted, since no analysis was attempted.  Data obtained
on occasions when the cooling tower plume merged  with the smoke plume
also were not analyzed .
                                  12

-------
                                                                   Table  II
                                                 CONDENSED DATA  SUMMARY,  LIDAR OBSERVATIONS
                                                   (For detailed  summaries,  see Appendix B)
to
Date
(1968)
25 May


26 May

15 October


16 October


17 October

18 October

20 October

21 October


22 October


23 October


24 October

Time
(EOT)
0912-0925
1034-1048
1423-1453
0854-0926
1145-1208
0932-1007
1032-1150

0852-0946
1149-1206

0903-0942
1151-1216
0917-0944

0909-0941
1018-1040
0854-0935
1023-1036

0900-0945
1134-1201
1227-1245
0850-0918
0941-0949
1155-1227
0930-1204

Site
Number
1


2

6


16


16

17

21

22


6


6


11

Elevation
(m)
329


387

394


418


418

448

448

448


394


394


418

Location
from Stack
3.5 km SW
(Az. 227°)

3.5 km N
(Az. 002°)
3.75 km NE
(Az. 055°)

8.50 km N
(Az. 355°)

8.50 km N
(Az. 355°)
13.7 km NNW
(Az. 344°)
21 .1 km ESE
(Az. 104°)
4 . 90 km SE
(Az. 120°)

3.75 km NE
(Az. 055°)

3.75 km NE
(Az. 055°)

3.95 km NW
(Az. 306°)
Number of
Cross Sections
Observed
3
3
4
6
5
6
8

6
5

5
3
4

4
2
11
3

9
6
6
7
2
5
19

Analyzed
3
3
0
3
2
3
5

2
0

2
0
2

2
1
6
3

9
0
3
3
0
0
12

Analysis
Method*
M, C
M
—
M
M
C
C

C
—
over
C
—
C

C
C
C
C

C
—
C
C
--
—
C

Remarks
Spatial
series

Spatial
series
Time and
spatial
series
Plume
almost
overhead
Plume
overhead
Plume
overhead
Plume
overhead
Dirty vs
clean
plume
Dirty vs
clean
plume
Time and
spatial
series
Time
series
                      M—Manual Analysis, C—Computer Analysis.

-------
          IV  BASIC ANALYSIS OF LIDAR  BACKSCATTER SIGNATURES

A.   General Discussion
     An example of an  oscilloscope  photograph of  a typical  lidar shot
recorded on the magnetic disk  is  given in  Fig.  3.  Here the magnitude
of the backscattered signal return  from the  airborne aerosol is log-
amplified and displayed on a logarithmic scale  (in order to maintain a
wide dynamic range of  recording)  versus time (or  range)  on  a linear
scale.
                                RANGE —  km
                 0   0.3  0.6   0.9   1.2   1.5   1.8  2.1  2 2   2.7
                 I     I    I     I     I     1    I     I    I
              O
              o
1 1 1
TRANSMITTER
POWER
REFERENCE
PULSE

H

^x^
^\

SIGNAL
RETURN
FROM
PLUME

^"^ c« i /^ m
h



\ \ n IT T i
                      NEAR FIELD
                      CONVERGENCE
                      POINT OF
                      TRANSMITTER
                      AND RECEIVER
SIGNAL RETURN
FROM BACKGROUND
AEROSOL IN "CLEAN"AIR
                                                     TA-7289-9
            FIGURE 3   BASIC LIDAR OBSERVATION OF SMOKE  PLUME

     For  inspection,  inventory,  and  editing purposes,  ten lidar observa-
tions are displayed  simultaneously by the magnetic disk recorder, as
shown in Fig.  4.  One complete  vertical "slice," or cross section,
through the plume  is  represented by  two to four of these ten-trace
                                    15

-------
           0  0.3  0.6  0.9   1.2   1.5   1.8   2.1  2.4  2.7  3.0
                                                        Elevation
                                                        Angle
                                                       TA-7289-10
           FIGURE 4   EXAMPLE OF MULTIPLE-TRACE FORMAT USED
                      FOR EXAMINATION OF MAGNETIC
                      DISK RECORDS

photographs.   The "artificial" peak in the received signal  at  close range
                                                 *
in Figs. 3 and 4 is typical of a bistatic system,  and  is due  to the
oppositely acting effects of signal increase with  increasing degree of
intersection of the transmitter beam and receiver  field  of  view, and
signal drop-off due to increasing range  (a function of  the  square of the
range) .
     These traces represent the basic raw lidar data, which can be used
directly to obtain plume boundaries easily and accurately.  However,
meaningful quantitative  information on the concentration distribution
within the plume requires further reduction and analysis.   For each plume
cross  section consisting of 20 to 40 lidar observations, the  data must
be adjusted and corrected for:
     (1)  Range effect,
     (2)  Log-amplifier  transfer function, and
     (3)  Pulse-to-pulse variations in transmitted power.
 Current lidars have separate, noncoaxial  transmitter and receiver optics
                                   16

-------
Allowance for these factors is fairly straightf orward, and results  in a
cross section of normalized signal return  (S) values.  These S-values
are directly proportional to particulate mass concentrations (expressed
in logarithmic units) ,  if the particle size distribution and optical
properties are spatially uniform, as is often a reasonable assumption
(McCormick and Kurfis,  1966), and if attenuation  is negligible.  Correc-
tion for the attenuation effect requires considerable effort, and is
detailed in Sec. VII.
     Manual analysis was initially employed for the May data.  Using a
specially prepared gridded template, range-corrected values of signal
return (in dB, relative to the background  signal  level from the ambient
aerosol) were extracted from the 35-mm film record.  These values were
then corrected for the  shot-to-shot variations in transmitted power,
plotted, and the resulting cross sections  analyzed by hand at a contour
interval of 6 dB (representing an increase by a factor of four) .  In
line with the preceding discussion, these  S-contours represent (in
logarithmic units) approximate relative mass concentrations within  the
plume .
     These manual analyses are quite tedious, and an objective analysis
procedure was developed to process the October data and to check the
hand analyses of the May observations.  This procedure is documented in
Fig. 5 (and Appendix C) and is discussed below.
B .   Lidar S-Function Analysis
     The signal received on the face of the Mark V detector, originating
from backscattered energy at range R, may  be expressed as

                   P (R) = P^ ^ -^ T (R)  p(R) T2(R)                (1)
where
                            ^
                    s       T  2  R2  c
          P  = peak power emitted into the atmosphere
           c - speed of light
           T = pulse duration
                                   17

-------
STEP 1—ANALOG-TO-DIGITAL CONVERSION
                       I
                     Field
                 Instrumentation
                   Electronics
Oscilloscope
  Camera
Manual  Curve
   Tracing
Calma Model
300 Digitizer


ONE SET
OF LIDAR
OBSERVATIONS

r
i

VIDEO
MAGNETIC
DISK RECORD

—
r
i

35 mm
FILM

1
1

DIGITIZED
DATA
(AR = 3.8 m)

r
i
-»-
DATA IN
ENGINEERING
UNITS
CDC6400
Computer
 STEP 2—CONDITIONING, EDITING, AND BASIC ANALYSIS
DATA 1 N
ENGINEERING
UNITS


T
1
CONDITIONED
AND EDITED DATA
(AR = 15.2m)


r
i
NORMALIZED SIGNAL RETURN (S)
VALUES Data Corrected for Range,
Pulse-to-Pulse Power Variations,
and Log Amplifier Characteristics

1 1
1 1
CDC6400 CDC6400
 STEP 3—CONTOUR ANALYSIS AND ATTENUATION STUDY

S-VALUES

PARTICLE
SIZE DATA


.Selecte

d Cases
1 "
* '
i
CDC6400

MASS
CONCENTRATION
VALUES
I'
1
1
1
) „
p
i
CONTOUR PLOTS OF PLUME
CROSS SECTIONS
S Units

CONTOUR PLOTS OF PLUME
CROSS SECTIONS
Mass Concentration Units
CDC3300, 6400
                                                        CDC280 TV Graphs
                                                          Calcomp Plotter
                                                     SRI  Contouring Program in
                                                         Polar Coordinates
                                                                                       TA-7289-11
     FIGURE  5   LIDAR  DATA ANALYSIS PROCESS.
                  on  Steps 1  and 2.
                 See Appendix C  for additional  details
                                                18

-------
           A = effective receiver area
          T  = beam convergence factor
           3 = volume backscatter coefficient  (per steradian)
           T = atmospheric transmission factor.
As previously mentioned, the resulting detector signal was routed through
a logarithmic (log) amplifier and recorded on  a video magnetic disk, as
well as on a backup 35 -mm recording camera system.
     All signal strengths were referenced to the detector level in the
absence of the applied backscatter signal P ,  which is denoted by P  .
The atmospheric return level recorded on the disk may then be expressed
(in decibel notation) as
                                      P (R) +  P
                       H(R) = 10 log* - - - -                   (2)
                                           N
where log* is the  log amplifier transfer function, which differs slightly
from the true log  function.  As indicated in Fig. 5 and detailed in
Appendix C, the analysis phase was initiated by digitizing recorded H(R)
traces, using a CALMA Model 300 digitizer.  Intensity values at the
digitizer standard increment (equivalent to 4  m) were recorded on mag-
netic tape.  A CDC6400 computer was then employed to obtain a range-
corrected, normalized signal return (S) function defined as
                                      P (R) R2
                        S(R) = 10 log -5- — - - -                    (3)
                                      P  R   R
                                       s \ o I   o
where R  is a reference range [normally chosen as the first data point
       o
of the H(R) digitization], and P  » P .  This S function also incor-
                                S     JN
porates a correction for the transfer function of the log amplifier.
     From Eqs. (1) and (3), the normalized signal return function S(R)
may be related to  the atmospheric optical parameters by
                    6(10 = 10 10.                 ,                (4,
                                  e (Ro) T  W
                                   19

-------
where T (R > R )  = 1 is assumed;  i.e..  the H(R) digitization process
       c      o
was initiated at a point on the trace for which the transmitted beam is
fully encompassed by the diverging receiver field of view.  The S func-
tion then represents a relative backscatter function, which is uncorrected
for atmospheric transmission losses.
     S-function contours were generated from a computer program (developed
at Stanford Research Institute) that uses linear interpolation of data
gridded in polar coordinates.  The polar grid of data points need not be
equal-incremented in range or angle, thus permitting processing of lidar
data collected at unequal increments of elevation angle.  The output from
the contouring program was subsequently machine plotted on a Benson-
Lehner or Calcomp plotter, or electronically graphed on the CDC280 CRT/
film system.  These contour plots and their significance are presented
in Sec. V.
     The lidar S function is dependent  only on the atmospheric optical
properties when P (R) » P,T.  However,  when P (R) ^ ?„ (i.e.,  when the
                 s        N          '        s       N                  _
atmospheric return is at or below the noise level), then S(R)  °c 10 log R .
Invalid data of this type were omitted  from the contouring program.  This
omission, illustrated in Fig. 6,  explains the open contours that may be
expected when plume return occurs at a  range for which the clear-air re-
turn would be below the noise level. While the S-function contour
analyses give a surprisingly good picture of plume relative concentration
distributions from laser energy returns (see Fig. 23), they are biased
to varying degrees by the fact that some energy is lost from the laser
pulse as a function of distance along the path, i.e., the atmospheric
transmission of the laser energy varies along the pulse path.   Accounting
for this attenuation effect requires additional information on the atmo-
spheric scattering particles and/or an  explicit relationship between the
atmospheric transmission and backscatter properties at the laser wave-
length.  This aspect of the analysis is discussed further in Sec. VII.
     Since plume mass concentrations—and thus lidar echoes—cover such
a wide dynamic range, contouring a plume cross section in linear units
presents a problem.  As illustrated in  Fig. 7, the linear display  (a)
                                   20

-------
                                    RAW LIDAR  DATA
      BEAM CONVERGENCE
             AREA
CO
I-
_l
O
<\i o

I
0_
\
o:
a:


o
o
g
CO
                         LIDAR
                        SIGNAL
           PLUME
           RETURN
      BACKGROUND
             REFERENCE
              RANGE  (Ro)
                    V
                                                            SIGNAL RETURN  IN  THE
                                                            ABSENCE OF NOISE
                                                                      RANGE
                                                                   UNKNOWN SCATTERING
                                                                       REGION
                   CORRECTED FOR I/R2 SIGNAL DECREASE WITH RANGE
                   AND LOGARITHMIC AMPLIFIER TRANSFER FUNCTION
                     FLAT UNTIL
                     NOISE LEVEL
                     IS REACHED
                         \
CLOSED
CONTOURS
OPEN
CONTOURS'
BACKGROUND
NOISE  LEVEL
                                                                         RANGE
             REFERENCE
             RANGE (Ro)
                                                                              TA-7289-12
  FIGURE 6   EFFECT OF RANGE CORRECTION  UPON PLUME SIGNAL RETURN AND RECEIVER
             NOISE  LEVEL.  For simplicity, a perfectly transmitting homogeneous medium has been
             assumed for the  clear air.
                                          21

-------
  600
DC
<
Q
o
CD
   400
   200
            Cross section No. 64
            0940:35-0942:00  22 Oct 68
            Azimuth 300 deg mag
                               J.
                  _L
                          _L
                                                         _L
_L
      1.2
   600
 1.4               1.6               1.8
           HORIZONTAL RANGE  FROM  LIDAR — km

          (a)   Linear display—M/MQ—contour interval 25

—I	1	1	1	1	1	
                                                                                           2.2
            Cross section No. 64
            0940:35-0942:00  22 Oct 68
            Azimuth 300 deg mag
   400
IT
<
Q
O
CO
   200
                                _L
                                        J_
                                                 _L
                                                         _L
       1.2
 1.4               1.6               1.8
           HORIZONTAL RANGE  FROM  LIDAR
                                                                          2.0
                                                                     km
                          2.2
                         (b)  Logarithmic display—10 Iog10 (M/M0)— contour interval 3 db


                 FIGURE 7   COMPARISON  OF  PLUME  CROSS SECTIONS CONTOURED
                              IN  LINEAR  UNITS (a)  AND LOGARITHMIC  UNITS  (b)
                                                                        TA-7289-13
                                                  22

-------
loses definition at the boundary of the plume, compared with a logarithmic
display (b) with contours in decibels.  The latter documents the plume
edge more accurately, and permits reasonable contour spacing.
     In the linear display in the figure, the contour units are in mul-
tiples of the clean-air background mass concentration (M ).  or M/M ,
                                                        o '        o'
where M is the plume mass concentration.  [For this case, M  was taken
              3                                            °
to be 100 ng/m , on the basis of the visibility estimate and the work of
Noll, et al. (1968).]  It may be seen that the contour spacing, and thus
the outer contour value, must be set at no lower than about 25 in order
to prevent contour crowding.  On the other hand, the logarithmic display
with units of dB = 10 log   (M/M ) has a contour spacing of 3 dB,  which
gives an outer boundary of M/M  ~ 2 without excessive contour crowding.
                              o
(Each contour increment of 3 dB corresponds to a change by a factor of
approximately two from the adjacent contours.)  Because of these ad-
vantages, logarithmic contour intervals have been used exclusively in
the lidar cross sections.
     Because of the effect of the finite above-noise range of the lidar
as explained in Fig. 6, many contours in the cross sections to follow
later do not close around the plume; with increasing range they begin
contouring the background noise and become meaningless.  In addition,
contours frequently appear in the clear air beneath the plume, which
are usually probably real, but have no particular value.  Both of these
effects are shown in Fig. 7(b).  To add clarity to the plume cross sec-
tions, these extraneous portions of the contours have been deleted from
the illustrations.  Figure 33 in Sec. VIII shows the nature of this
editing process.  Considerable care was taken to ensure that this process
did not remove any portion of the plume cross section or any other in-
formation of value.
                                   23

-------
   V  RELATIVE CONCENTRATION CROSS SECTIONS OF KEYSTONE STACK PLUME

A.   May 1968 Observation Period
     The emphasis during the May observation  period was on  lidar  plume
observations within five miles  (8 km)  of  the  stack.  The  analyses  for
the May data were performed manually.  All lidar observations during
this period were taken when one of the two precipitator banks for  the
active stack was shut down, allowing 50 percent of the effluent to pass
out through the stack untreated.  The  resulting plume color was a  light
gray-brown.
     In the plume cross section illustrations to follow,  both for  the
May and October data, it should be noted  that the lidar is  at the  point
(0,0), and the horizontal range scale  is  usually discontinuous.  Also,
heights are taken above the lidar; Fig. 8 illustrates the height  rela-
tionships  involved.  To facilitate height transformations,  the height of
the top of the stack is indicated on the  ordinate scale for each cross
section by means of a horizontal arrow.   (Lidar site elevations are
given in Table II, Sec. III.)  Calculated plume rise heights (AH)  are
also shown for those cross sections for which reasonably  concurrent
temperature profiles were available, and  will be discussed  in Sec. VI.
     Figures 9-12 show four sets of sequential vertical cross sections
through the smoke plume during  the mornings of 25 May  (Figs. 9 and 10)  and
26 May (Figs. 11 and 12).  The  contours in Figs. 9 through  12 represent
range-corrected signal return in decibels relative to  that  from the  ambient
background aerosol, including background  noise, and can be  taken  to  repre-
sent (approximately) the relative particulate concentrations.  The effects
of attenuation are neglected.   The inset  in each figure indicates the
geometry of the observations.   Poor weather conditions prevailed  during
the 43 cross sections obtained  during  the remainder of the  May period.
The cross sections in Fig. 9 were obtained about 1-1/2 hours earlier than
those in Fig. 10, while the observations  in Fig. 11 precede those  in Fig.
12 by almost three hours.  Vertical temperature profiles  closest  in time
                                    25

-------
   KEYSTONE
   STACK
                245 m
Y////////////////.
                                    H_   570-E
                                                              LIDAR  SITE  t  ELEVATION
                            570 m
                     325 m
                                                  SEA LEVEL
                                                                              TA-7289-14
    FIGURE  8   RELATIVE  HEIGHT CONSIDERATIONS  ASSOCIATED  WITH  LIDAR  PLUME
                OBSERVATIONS.  Lidar site elevations, E, are given in  Table  II; values of HS
                are indicated on each  plume cross  section.

-------
bO
        1000
         800
tr
Q  600
Ij
LU

O  400

I-
X
2  200
LU
I
                                  LIDaR SITE NO I
                 PLAN VIEW OF  HORIZONTAL PLUME POSITION
                                                                                                                 25 MM I968
                                                                                                                 0912-0926 EOT
                                                                                        CROSS SECTION MO

                                                                                        AZIMUTH 000° M
                                                                         AH (calc)_
                                                                         = 206 m
                                                                                                                   CROSS secrtON NO
                                                                                                                   0912 30 - 0916 00 EOT
                0.8
                       1.0
                               1.2
                                      1.4
                                             1.6
                                                     1.8
                                                            2.0
                                                                        -!  f-
                                                             2.2    '    0.8     1.0
                                                                RANGE 	 km
                                                                                            1.2
                                                                                                   1.4
                                                                                                          1.6
                                                                                                                   2.0
                                                                                                                          2.2
                                                                                                                                              1000
                                                                                                                                               800
                                                                                                                                               600
                                                                                                                                              400
                                                                                                                                               200
                                                                                                                                  2.4     2.6
                         0.2
                                  0.4
                                           0.6
                                                     0.8
                                                              1.0     1.17         0      0.2     0.4
                                                            PLUME CROSS-WIND DISTANCE  	 km
                                                                                                       0.6  0.7
                                                                                                                              0.1
                                                                                                                               0.2  0.23

                                                                                                                                  TA-7289-1 5
        FIGURE 9    SPATIAL SERIES  OF  LIDAR-OBSERVED VERTICAL CROSS SECTIONS  UNDER STABLE  CONDITIONS,  25 MAY  1968,
                      FROM SITE 1, 3.5km  FROM STACK.  The  contours represent  range-corrected signal return in decibels  relative to  that from
                      the ambient  background aerosol,  including background noise, and  can be taken  to  approximately represent relative  particulate
                      concentrations.  Attenuation  has  been neglected.   See inset for horizontal  positions of cross  sections.

-------
     1000
to
00
                      CROSS SECTION NO 6
                      1045.00-1048:00 EOT
                         SIS* M
CROSS SECTION NO 4
1034.00-103945 EOT
    000 • M
     4
                                                      0  1/2   I km
                                       LIDAfi SITE NO I

                             PLAN VIEW OF HORIZONTAL PLUME POSITION
CONVERSION TftBL£

dB
0
6
12
18
24
30
MULTIPLE
BACKGROUND
|
4
16
63
251
IOOO
OF
RETURN






                                                                                                                                    25 MAY 1968
                                                                                                                                   1034-1048 EOT
                                                                            AH (calc)
                                                                            = 251 m
                                                      2.8    3.0   3.2   3.4   3.6 1.0   1.2    1.4
                                                                                                             2.0   2.2   22   2.4   2.6   2.8    3.0   3.2
                         1.8    2.0   2.2   2.4
                                                              1.2      1.4  1.5      0    0.2   0.4    0.6    0.8   1.0 1.16 0
                                                           PLUME  CROSS-WIND DISTANCE — km
                                                                                                                                 0.2
                                                                                                                                                    1000
                                                                                                                                                    80O
                                                                                                                                                    600
                                                                                                                                                    400
                                                                                                                                                    200
                                                                                                     0.4  0.48

                                                                                                       TA-7289-16
          FIGURE 10    SPATIAL SERIES OF LIDAR-OBSERVED VERTICAL CROSS SECTIONS  UNDER MODERATE DIFFUSION  CONDITIONS,
                         25 MAY  1968,  FROM  SITE  1, 3.5km SOUTHWEST  OF  STACK

-------
   800
tr
<  600
Q
   400
o
CO
   200
X
(D
                STACK   \X^-/

                        \ ^ Xx  CROSS SECTION NO 12
                INFERRED    N{\   X 0858.00-0902 40 EOT


                        /  \ \
                          HORIZONTAL
                          PROJECTION
                          OF PLUME
                          BOUNDARIES-.^  \
226' M

/
                                                      CROSS SECTION MO 14
                                                      0908 43-0913-00 EOT
                                                         253-M
                        LIOAR SITE NO 2

                             PLAN VIEW OF HORIZONTAL PLUME POSITION
CONVERSION TABLE


-------
00
o
                 1800
                 1600
                1400
              CE
              <
              Q
                1200
                1000
              o
              m
I
(3
UJ
X
                 800
                 600
                 400
                 200
                        INFERRED HORIZONTAL
                        PROJECTION OF PLUME
                        BOUNDARIES
                                                     NFERRED AXIS OF
                                                     BISECTED PLUME
                                           /Z26' M
                                  PLAN  VIEW OF HORIZONTAL PLUME POSITION
                        LIDAR SITE N02
                              CROSS-SECTION NO 17
                              II45'30-II48'30 EOT
                              AZIMUTH 200' M
                       -TOP OF
                        STAXK
                               3.4
                                        3.6
                                                  3.8
                                                           4.0
                                                                                                                                        26 MAY  I968
                                                                                                                                        II4S-II5S EOT
4.2 •>   0  "  2.8
  RANGE  — km
                                            0.2
                                                     0.4
                                                                                          3.0
                                                                                                    3.2
                                                                                               3.4

                                                                                              _|	
                                                                                                                      3.6
                                                                                                                               3.8

                                                                                                                                I	
                                                                                                                                        4.0
                                                                                                                                                       8OO
                                                                                                                                                      1600
                                                                                                                                                      1400
                                                                                                                                                      1200
                                                                                                                                                      1000
                                                                                                                                                       8OO
                                                                                                                                                       600
                                                                                                                                                       400
                                                                                                                                                       200
                                                                                                                                                  4.2
                                              0.57                   0       0.2      0.4
                                                  PLUME CROSS-WIND DISTANCE  — km
                                                                                                             0.6
                                                                                                                      0.8
                                                                                                                               1.0
                                                                                                                                        1.2 1.27
                                                                                                                                                 TA-7289-18
             FIGURE  12    SPATIAL SERIES OF LIDAR-OBSERVED VERTICAL CROSS  SECTIONS  UNSTABLE (LOOPING)  CONDITIONS,
                             26  MAY  1968, FROM  SITE  2,  3.5km  NORTH OF  STACK

-------
to the lidar cross  sections  are  given in Fig.  13.  On both mornings, the
sky was essentially clear.
                 1000
                E 800 -
                 o
                 I-
                 10
                 ,.  600
                UJ
                en
                <
                CD
                UJ
                > 400
                m
                I 200
                                             26 MAY
                                             I 40 EOT
                        TOP OF
                        STACK
                      —  25 MAY-*
                         0946 EOT
                          10
                   FIGURE 13
                               12   14    16   18
                               TEMPERATURE —°C
20
22
                                                TA-7289-19
                               VERTICAL TEMPERATURE
                               PROFILES ASSOCIATED
                               WITH  LIDAR OBSERVATIONS,
                               25-25 MAY 1968
     Several general  features of these cross sections are apparent.  The
contours, which  are  in  logarithmic  units  (decibels), represent approxi-
mate relative  particulate  mass concentrations as previously discussed.
Maximum concentrations  are usually  observed near the top of the plume,
apparently associated with the greater buoyancy there.  This effect was
also found by  Hamilton  (1966),  who  took ruby-lidar observations of the
plume from an  oil-fired  power plant.   There is considerably consistency
in the observed  shape and  structure of the Keystone plume from cross
section to cross  section in each set,  and  individual features may be
followed for several kilometers downwind  from the stack.  This is par-
ticularly pronounced for the early-morning,  nondiffusive cases.  For
                                   31

-------
example, in Fig. 9,  the central clear cavity,  or vault, on the bottom
of the plume, evidently associated with the bifurcation process, is
readily apparent in all three cross sections.
     For the stable cases (Figs. 9 and 11), the characteristic horizontal
spreading (fanning)  and tilting of the plume due to vertical wind direc-
tion shear (wind veering with height) is evident.
     In Fig. 11, there is some evidence that terrain channeling of the
air flow acted to horizontally spread the effluent, in addition to the
effects of wind direction shear.  The northeastern portion of the plume
(nearest the lidar)  appears to follow a valley that is about 100 m lower
than the hills which are traversed by the southwestern portion of the
plume (farthest from the lidar), possibly accounting for part of the
                                                          *
rapid increase in the cross-wind (or cross-axis) dimension  of the plume
from 340 m at 0.8 km downwind to 1450 m at a downwind distance of 2.2 km.
Lifting by the hills could explain the 160-m rise of the southwestern
portion of the plume (at the extreme right in Fig. 11) from Cross Section
12 to Cross Section 14.
     The cross sections pictured in Fig. 10 probably represent a case of
fumigation, in that downward diffusion  is fairly strong, while upward
diffusion of the plume apparently is limited.   This situation could be
caused by a temperature inversion at 900-1000  m, above the maximum height
of the observed temperature profile.  Note that relatively high concen-
trations are brought to very low levels within 3 km from the stack.
     The rapid upward diffusion of a looping plume is illustrated in
Fig. 12.  For the most part, the relative concentrations in Cross Section
19 are less than those in Cross Section 17 by about 6 dB, which repre-
sents a decrease to about one quarter of the previous levels .  The tem-
perature sounding for this time (Fig. 13) shows an approximately dry-
ad iabatic lapse rate up to the maximum height  sampled, 1000 m above the
base of the stack.
*
 This dimension is indicated on the secondary abscissa scale for each
 cross section during the May period.
                                   32

-------
     Since these cross sections were built up from lidar observations
spanning a period of two to five minutes, some distortion is unavoidable
when the plume structure is changing with time, as during unstable con-
ditions (Figs. 10 and 12).  In the future, lidar systems capable of one
or two pulses per second and with automatic positioning should eliminate
such problems by furnishing essentially  instantaneous plume "slices."
B.   October 1968 Observation Period
     Due to the large quantity of lidar  data obtained during this period,
an objective, computer-oriented data reduction and analysis process was
developed, as described in Sec. IV.  This process permitted the analysis
of about half of the cross sections observed.  A number of illustrative
examples have been selected for presentation here.  There are various
minor flaws in these analyses that would not have occurred if the work
had been carried out by hand, but the time saving is quite significant.
     For example, occasional small areas of the cross sections (indicated
in the figures) were not contoured due to a minor program error.  In
addition, the cross sections illustrated do not always represent the
total plume width as recorded on the original data records (photographs),
although the portion shown is correct.   This truncation occurred because
of a problem in digitizing and processing those photographs that were
obtained with an oscilloscope sweep speed of 5 (as/cm, corresponding to
a full-scale range of 7.5 km.
     Because of this difficulty, which could not be overcome within the
time and effort limitations of the project, the photographs taken at
2 |_is/cm were used exclusively, which limits the ranges of the analyzed
data to 3-km maximum.  In order to retain the information on total hori-
zontal plume extent, maximum distances of plume return were scaled off
the original 35-mm film and are indicated on the figures by vertical
arrows (horizontal arrows when off scale) labeled with the range to the
farthest observed edge of the plume.
     Several of the May (hand-prepared)  cross sections were reanalyzed
by machine for comparison purposes.  An  example is given in Fig. 14.
The agreement is good, despite the fact  that two different data records
                                   33

-------
  800
  600
Q
_J
UJ
O
m
  400
111
I
  200
—I	1	1     |
 MANUAL DATA REDUCTION
 AND CONTOURING
 FROM 35-mm FILM
             T/T
                                           MACHINE DATA REDUCTION
                                           AND CONTOURING
                                           FROM MAGNETIC DISK
           Cross Section No. 1
           0912:30-0916:00 25 May 68
           Azimuth 045 deg mag
     2.0
               2.2
   2.4        2.6 "2.0         2.2
HORIZONTAL RANGE FROM LIDAR — km
                                                            2.4
                                                               2.6
                                                         TB-7289-20
    FIGURE 14  COMPARISON OF MANUAL AND  MACHINE ANALYSES.  Note that
               two different records are used, with the 35-mm  film having considerably
               better spatial resolution than the magnetic disk.  One lidar observation
               is missing at the top of the machine cross section.
were used:  the 35-mm film  (spatial  resolution about  20 m), and the mag-
netic disk (spatial resolution  about 40 m).  In  addition, it was later
discovered that some data  (the  uppermost lidar observation) was missing
from the disk record; this  caused  the shape of the machine cross sec-
tion to differ at the top  of  the  plume from that  in  the manual analysis.
      The cross sections  in  Fig. 15 are in the same  (approximately  cross-
wind) vertical plane at  the same  azimuth angle from  the lidar, and are
 spaced about one hour apart;  thus, they document  the  changing crosswind
 structure of the plume with time  during the morning  of 15 October. The
direction to the stack  is  into  the paper.  (See  Appendix D for plan views
of the horizontal plume  positions, to clarify visualization of the lidar/
 stack/plume orientation.)   The  typical tilting and  fanning of the  plume
 in stable conditions, due  to veering (clockwise  rotation) of the wind
direction with height,  is  apparent.   By 1147 EDT,  the height of the
mixed layer had apparently increased to the level of the  lower part of
 the plume, causing fumigation of  that portion.   Unfortunately, no  tem-
 perature profiles are available for this day.
                                    34

-------
E  800
600
>  400
00
I  200
(3
                                                                          Cross Section No. 2
                                                                          0939:00-0943:11  15 Oct 68
                                                                          Azimuth 300 deg mag
         Top of Stack
      0.4     0.6     0.8     1.0     1.2     1.4      1.6     1.8    2.0     2.2     2.4

                                   HORIZONTAL  RANGE  FROM  LIDAR — km
                                                                                     2.6
        2.8
        3.0
E   800
    600
   400
O
m
   200
            • Top of Stack
                                                                       Cross Section No. 8
                                                                       1036:30-1041:00  15 Oct 68
                                                                       Azimuth 300 deg mag
   0.4     0.6     0.8
                             1.0     1.2     1.4     1.6     1.8     2.0     2.2     2.4
                                   HORIZONTAL RANGE  FROM  LIDAR — km
2.6
2.8
                                                                                                    3.0
E   800
                                                                          Cross Section No. 14
                                                                          1147:00-1150:00  15 Oct 68
                                                                          Azimuth  300 deg mag
                                     1.2     1.4    1.6     1.8     2.0     2.2
                                  HORIZONTAL RANGE FROM LIDAR  —  km
                                                                                         2.6
                                                                                             2.8      3.0

                                                                                              TB-7289-52
  FIGURE 15
             TIME SERIES  OF  LIDAR-OBSERVED  VERTICAL CROSS SECTIONS  FROM  SITE 6, 3.8km
             NORTHEAST OF  STACK, PLUME OVERHEAD, 15 OCTOBER 1968.  All  times  EOT.   Lidar
             is located at  Point (0,0). Horizontal arrows represent height of stack; vertical arrows represent
             horizontal extent of plume as indicated by original record.  See also Figure  D-1.
                                                   35

-------
     Figures 16-18 illustrate the large plume widths at 8.5 and 14 km down-
wind caused by stratification and fanning of the plume during the early
morning hours of 16-18 October,  respectively.  The "lumps" appearing in
these cross sections (and in those of other stratified plumes) are caused
                                                   *
by a bias effect in the computer contouring program  due to the particu-
lar gridding technique used.  This bias effect only occurs for very shal-
low plumes.  The vertical plane covered here is directly over the lidar.
     The plume cross sections in Fig. 19 are the farthest downwind (21 km)
that were observed during the experimental program.  These cross sections
are in a vertical plane directly over the lidar.  Of special interest
here is Cross Section 42, which shows no plume, but does show the haze
top associated with the temperature inversion.  Evidently the tenuous
plume either meandered away or lost its identity by mixing downward.
     Figures 20 and 21 illustrate the effect on plume density of all
precipitators being in operation (Fig. 21) compared with 50-percent
operation (Fig. 20 and others).   In each figure, the cross sections are
at different azimuth angles and thus different downwind distances from
the plume.  Cross Sections A44 and 46 are about 3.5 km downwind, Cross
Sections B44 and 47, 4.5 km downwind (and approximately crosswind), and
Cross Sections 45 and 48 are 6 km downwind.  (It should be kept in mind
that as illustrated in Appendix D, these cross sections are sometimes
elongated and do not represent true plume width, except when oriented
in the crosswind direction.  Plume height, however, is always truly
represented.)
     Examining Cross Sections B44 (Fig. 20) and 47 (Fig. 21), the dirty
and clean plume, respectively, we see that the maximum normalized signal
return above the reference for the clean plume is 12 dB, which is 6 dB,
or four times, lower than that for the dirty plume.  The apparent size
of the plume, as observed by the lidar, also shrinks, due to less of the
plume return being above the receiver noise level (see Fig. 6, Sec. IV).
*
 The contouring program, developed recently by S. Briggs of SRI, was
 used in its available form for this work.  This bias effect, as well as
 the cause for the contouring skips, could be eliminated from the program
 in future studies.
                                   36

-------
  800
  600
  400
o
CD
   200
Cross Section No. 16
0916:00-0918:15  16 Oct 68
Azimuth 100 deg mag
                                      Program
                                      Skip
                                                 	AH (calc) = 169 r
            0.2    0.4    0.6     0.8     1.0     1.2     1.4     1.6     1.8
                        HORIZONTAL RANGE FROM  LIDAR  — km
                                                                  8     12     16     20
                                                                  TEMPERATURE  — °C
   800
            Cross Section No. 20
            0943:15-0946:20 16 Oct 68
            Azimuth 100 deg mag
            0.2
        0.4     0.6     0.8     1.0     1.2    1.4
             HORIZONTAL  RANGE FROM LIDAR
                                                                              8     12      16     20
                                                                             TEMPERATURE — "C

                                                                                           TB-7289-21
  FIGURE 16   TIME SERIES OF  LIDAR-OBSERVED  VERTICAL CROSS SECTIONS  FROM SITE 6, 3.8km
               NORTHEAST OF  STACK,  PLUME OVERHEAD, 16 OCTOBER  1968.  See also  Figure D-2.
               Calculated plume-rise heights (AH) are shown as dashed lines.
                                                 37

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HEIGHT ABOVE LIDAR -
*• £
o 8 S
	 . 	 — 	 -y , •••-] |
Cross Section No. 27
091 0:00-091 4:25 17 Oct 68
-, , , _ v Azimuth 090/270 deg mag
/Cjl 1 //^^x^ ••— -i$\
Top of Stack 0911
u — . 1640ml 	 _
I , , , i A I I
u -
\v
- V
, I , , \
-1.6 -1.2 -0.8 -0.4 0 0.4 0.8 |Q 20
HORIZONTAL RANGE FROM LIDAR — km TEMP — °C
  800
Q
LU
X
  400
Cross Section No. 30
0936:00-0942:20 17 Oct 68
Azimuth 090/270 deg mag
        Top of Stack
 Program
'Skip
                                            / Convergence \
                                           /    Zone     \
                                          J	1	L
   -1.6      -1.2      -0.8      -0.4        0       0.4      0.8
                       HORIZONTAL RANGE  FROM LIDAR — km
                                                                            1.2
                                                                            2315ml
                                                  1.6      2.0

                                                      TB-7289-22
  FIGURE  17    TIME SERIES OF LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM SITE  6, 3.8km
               NORTHEAST OF  STACK, PLUME  OVERHEAD,  17 OCTOBER  1968.  See also  Figure D-3.
                                               38

-------
  1600
      0       10      20
       TEMPERATURE  — °C
                                     -0.4      0      0.4     0.8     1.2
                                        HORIZONTAL RANGE FROM  LIDAR
   1600
   1200
LU
>
CO
<
LU
I
   800
   400

Cross Section No. 37
0941:00-0944:20 18 Oct 68
Azimuth 080/260 deg mag
p.s. 4-18— 'ie^S^^-^^F^^Sis^; f _
I I J I I 1 I
-0.8 -0.4 0 0.4 0.8 1.2
HORIZONTAL RANGE FROM LIDAR — km
A .
]/ . | . . v • i • | _
y\
7a\
\
\
1017 EOT \
\
Calculated \
Plume \ ~
Rise \ \
\ \ -
.1, AH(calc) \ \
«^ ^ = 241 m \ \ -
\ V —
i A i t i I i i i f1 i i \
1-6 ^0 10 20
  FIGURE 18
                                                                                      TB-7289-23
               TIME SERIES OF  LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM SITE 17, 13.7km
               NORTH-NORTHWEST OF STACK, PLUME OVERHEAD,  18  OCTOBER 1968.  See also Figure D-4.
               MRI particle sampling (P.S.) altitudes and run numbers are also indicated.
                                                39

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1600
E
I
I
cc 1200
Q


£ 800
o
CO
*£
X 400
O
LLJ
X
0
A
	 ']/ i i i i v ' I
\
Cross Section No. 40 »
0928:00-0932:00 20 Oct 68 *
Azimuth 200/020 deg mag 'a >
\
\
\
. \
\

\
Program \
Skip
#*&^*;mi**&e^ /i^f-^^^^^^^fi, d^1 °833 EDT
An 1 \ 1(=lfi ^^il^gP^^-T&<^* fr^—^ii -^-^ — <^Of\^t~^ i
~~~ , /
-«— Top I 2850 m' — *- )
of Stack | , , , , , A , i I , , < I
L ' 	 ' 	 ' 	 ' 	 ' 	 	 ]/

1 1 1

	
"
~


\
\ -
\
\ —
\
\ -
\ -
r
i i i >
r*tf
                  -0.8
                      HORIZONTAL  RANGE  FROM LIDAR — km
                                                                      TEMPERATURE — °C
1600


. 1200

C
3
J
j 800
>
3
3
C
- 400
I
j
0

Cross Section No. 41
0937:00-0941:30 20 Oct 68
Azimuth 200/020 deg mag



_




,_--,. ^ -*, „ ... 	 _<=--*r=«cfiiJ's''&^'i;?' --=,--- • f '' ( * ^UtT /T®^
TOP '"^- •''•^^^^^i^S^^^^t^''^'1'-^^^^'^-^^
of Stack
~t , , : , 1,
-0.8    -0.4     0      0.4     0.8     1.2      1.6

           HORIZONTAL RANGE  FROM LIDAR — km
2.0
                                                                            2.4
                                                                                   2.8
IT
<
Q
O
m
H-
I
O
LU
I
   1600
   1200
   800
    400

Cross Section No. 42
1018:00-1024:20 20 Oct 68
Azimuth 200/020 deg mag
•*— Top of Stack
iii.
-1.2 -0.8 -0.4 0
A
v ' ' I ' X ' I ' ' '
\ _
3 \
\
\
\ -
^ V \
Q \ \
\\-
^^ 
-------
  800
  600
  400
   200
LLJ
I
         Cross Section No. A44
         0854:00-0855:40  21 Oct 68
         Azimuth 270 deg mag
         - Top of Stack
             _J	L_
      0.4    0.6     0.8
                           1.0     1.2     1.4    1.6     1.8     2.0    2.2
                                HORIZONTAL  RANGE  FROM  LIDAR  —  km
2.4
2.6
2.8
3.0
  800
  600
£  400
O
in
<
t-  200
I
          Cross Section No. B44
          0856:40-0858:35 21 Oct 68
          Azimuth  225 deg mag
          -Top of Stack
                                                                    -A H (calc) = 203 m
     0
                                                                                  0857 EOT
      0.4    0.6     0.8     1.0     1.2     1.4     1.6     1.8     2.0
                    HORIZONTAL RANGE FROM  LIDAR — km
                                                                       2.2      "4      8      12
                                                                                 TEMPERATURE — °C
  800

-------
E 800
  600
  400
o
CD
   200
LLJ
*    0
          Cross Section No. 46
          0903:00-0904:40 21  Oct 68
          Azimuth 270 deg mag
          - Top of Stack
            0.6     0.8    1.0    1.2    1.4     1.6    1.8    2.0    2.2
                               HORIZONTAL RANGE FROM  LIDAR  — km
                                                                            2.4
                                                                                   2.6
2.8
3.0
E 800



\ 600
3
J
i 400
0
£
- 200
L
0
J
C 0
A
V ' | ' y |
Cross Section No. 47 \ \
0906:30-0908:20 21 Oct 68 \ \
\ \
Azimuth 225 deg mag ( 7 \
/— -., j 	 '^f^T/^iST^ \ \
PS 1-21 -•- ^-r^ ^^§^ L^ y^J \
^l^ 5T? ^Zf^-^/ A 	 	 \
	 	 	 	 g^-^r -^^^,.—^.~^—, 	 ^ H (calc) = 206 m \

0857 EOT
- — Top of Stack /
$
f i i i i i i f] i A . \ . . . \
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 "4 8





-

\
\
\
\
\
\
\ —
\
\
V
II I \
12
HORIZONTAL RANGE FROM LIDAR — km TEMPERATURE — °C
  800
cc 600
<
Q
uj 400
O
CO
<
H 200
I
0
LU
x   0
         Cross Section No. 48
         0909:30-0910:50  21 Oct 68
         Azimuth 180 deg mag
                                                                 ?~
                                                                    Y
           Top of Stack
FIGURE 21
            0.6     0.8     1.0    1.2     1.4     1.6     1.8     2.0     2.2
                             HORIZONTAL RANGE  FROM LIDAR — km
                                                                           2.4     2.6     2.8     3.0

                                                                                          TB-7289-26
             SPATIAL SERIES  OF LIDAR-OBSERVED VERTICAL CROSS SECTIONS  FROM SITE 22, 4.9km
             SOUTHEAST OF STACK,  21  OCTOBER  1968, PRECIPITATORS  IN  FULL OPERATION.
             See also  Figure  D-6.
                                                42

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     Later during the same morning, the cross sections in Fig. 22 were
observed on the same azimuth angles.  Here the lower portion of the
plume is fumigating, while the upper portion remains relatively intact,
probably due to the temperature inversion at 470 m.
     Figures 23-26 illustrate various stages in the structure of the
plume during the morning and midday of 22 October.  In these figures the
stack location is into the paper.  Considering the cross sections located
nearly crosswind (Cross Sections 58, 64, and 73), we see that at 0904 EOT
the plume is compact and level (Cross Section 58), at 0941 EDT wind shear
has set in and the plume is tilted, and at 1232 EDT fumigation of the
lower portion is occurring.  For the clean plume (Fig. 24), essentially
no plume is apparent in the cross sections due to the weakness of the
return signal in relation to the background noise level.  Possibly be-
cause of the 3-MHz bandpass of the disk recorder, the data for clean
plumes do not show up as well on these cross sections as on the 35-mm
film, from which the plan views in Appendix D were obtained.
     In Fig. 27, the plume apparently cannot penetrate the 1° C inversion
at 500 m above the lidar, and is spreading out beneath with fumigation
of the lowest portion.  Cross Section 79 shows an interesting bubble at
the top, which could be a thermal which has risen through the plume.
     A series of approximately crosswind-oriented cross sections at about
15-minute intervals is shown in Figs. 28-30.  The rapidly changing struc-
ture of the plume is apparent, as well as the trapping of the effluent
by the stable layer at 400-500 m above the lidar.  On this date, 24
October, the particulate output of the stack was reduced by 25 percent
from previous days, since two additional precipitator sections were
operating.  As shown  in Cross Section 104  (Fig. 29),  there  is some down-
ward diffusion of the plume, but the stable near-ground layer apparently
prevents the plume material from mixing to the ground.
                                   43

-------
         800
         600
         400
      O
      CO
         200
      LLI
      X
               Cross Section No. 54

               1023:00-1025:55 21  Oct 68

               Azimuth 270 deg mag
              AH (calc)
            0      0.2      0.4      0.6     0.8

               HORIZONTAL RANGE FROM  LIDAR  — km
-T	!_,	/L
1.0      1.2      V
                    4      8       12

                 TEMPERATURE  — °C
        800
        600
      LU 400


      O
      CO
      <

      I- 200
      I
      O

      LU
      I
                                                                Cross Section No. 55

                                                                1027:30-1030:30  21 Oct 68

                                                                Azimuth 225 deg mag
                   0.2     0.4     0.6     0.8     1.0      1.2      1.4     1.6     1.8

                            HORIZONTAL  RANGE FROM LIDAR — km
         800
      DC  600
      <
      Q
        400
      O
      CO
      X  200
               Cross Section No. 56

               1033:20-1036:50  21  Oct 68

               Azimuth 180 deg mag
               -Top of Stack
                                                                                2030 m L_»
                   0.2      0.4     0.6     0.8     1.0     1.2      1.4      1.6      1.8

                            HORIZONTAL  RANGE  FROM LIDAR — km
                                                                                TB-7289-27
FIGURE 22   SPATIAL SERIES OF  LIDAR-OBSERVED VERTICAL CROSS SECTIONS  FROM SITE 22, 4.9km

             SOUTHEAST OF STACK, 21 OCTOBER  1968.  See also Figure D-6.
                                                44

-------
           800
           600
       >  400
       o
       DO
X   200
LU
x
      0
                  Cross Section No. 57
                  0900:00-0901:20  22 Oct 68
                  Azimuth 270 deg mag
                  -Top of Stack
       1.0     1.2      1.4      1.6     1.8     2.0     2.2     2.4     2.6
                          HORIZONTAL RANGE FROM  LIDAR — km
                                                                                     2.8
           800
                  Cross Section No. 58
                  0903:00-0904:30  22 Oct 68
                  Azimuth 300 deg mag
              T.O      1.2      1.4     1.6      1.8     2.0     2.2
                   HORIZONTAL RANGE FROM LIDAR — km
                                                                 4.0     8.0     12.0
                                                                TEMPERATURE — °C
       cc
       <
       Q
           800
   600
           400
       X  200
                  Cross Section No. 59
                  0905:20-0907:30 22 Oct 68
                  Azimuth 330 deg mag
               ••—Top of Stack
              1.0      1.2      1.4      1.6      1.8      2.0      2.2      2.4
                              HORIZONTAL RANGE FROM  LIDAR  —  km
                                                                       2.6
                                                                              2.8
                                                                                        TB-7289-28
FIGURE  23    SPATIAL SERIES OF  LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM SITE 6, 3.8km
              NORTHEAST OF  STACK,  22 OCTOBER 1968.  See  also Figure D-7.
                                                  45

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          800
       =  600
       Q
>
O
CO
<
          400
       g 200
                  Cross Section No. 60
                  0921:45-0923:10 22 Oct 68
                  Azimuth 270 deg mag
                                                                        |.
1.0      1.2     1.4     1.6     1.8     2.0     2.2     2.4
                 HORIZONTAL RANGE FROM LIDAR  — km
                                                                         2.6
                                                                         2.8
          800
           600
          400
          200
       cc
       o
HI
O
CO
<
I-
CJ
                  Cross Section No. 61
                  0923:50-0925:10 22 Oct 68
                  Azimuth 300 deg mag
               PS. 4-22^
1.0     1.2     1.4     1.6     1.8     2.0     2.2     2.4
                 HORIZONTAL  RANGE FROM LIDAR — km
                                                                         2.6
                                                                         2.8
       cc
       <
       o
       o
       CO
       <
       I-
       I
       o
       HI
       X
          800
           600
          400
   200 T°P
                            1.4     1.6      1.8     2.0     2.2     2.4
                             HORIZONTAL RANGE  FROM LIDAR — km
                                                                  2.6     2.8

                                                                       TB-7289-29
FIGURE 24   SPATIAL SERIES  OF LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM  SITE  6, 3.8km
             NORTHEAST OF STACK, 22 OCTOBER 1968, CLEAN PLUME.  See also Figure  D-7.
                                              46

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= 600
3
J
> 400
3
Q
I
E 200
1
J
c
0
1
800
c 600
3
J
U> 400
Q
(
E 200
p
u
c
0
1
800
: 600
C
i
j
i 400
D
1
E 200
3
J
C
0
1
Cross Section No. 63
0938:30-0939:45 22 Oct 68
Azimuth 270 deg mag
^^f - ffij
' ^iK^ri^
" — Top of Stack
J , I
0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
HORIZONTAL RANGE FROM LIDAR — km

2.8
Cross Section No. 64
0940:35-0942:00 22 Oct 68
Azimuth 300 deg mag
P.S. 8-22 — «-
_. '•,^i£^^=^-.~^ - -
P.S.7-22— itf^ff^^}^
•« — Top of Stack ~" N^^^z2^r^—
	 1 .
0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
HORIZONTAL RANGE FROM LIDAR — km
Cross Section No. 65
943:45-0945:15 22 Oct 68
Azimuth 330 deg mag
^^^7"";^^~^ 5:"-^
•* — Top of Stack
0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
HORIZONTAL RANGE FROM LIDAR — km
2.8

2.8
TB-7289-30
FIGURE 25   SPATIAL SERIES OF  LIDAR-OBSERVED  VERTICAL CROSS SECTIONS FROM  SITE 6, 3.8km
            NORTHEAST  OF STACK, 22  OCTOBER 1968. See also Figure D-7.
                                            47

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        800
     cc 600
     Q
     _1
     tH 400
        200
              -Top of Stack
                                                               Cross Section No. 72
                                                               1227:00-1229:15  22 Oct 68
                                                               Azimuth 270 deg mag
           1.0   1.2     1.4      1.6      1.8     2.0     2.2      2.4      2.6      2.8      3.0
                            HORIZONTAL RANGE  FROM LIDAR — km
        800
                 Cross Section No. 73
                 1231:00-1233:00  22 Oct 68
                 Azimuth 300 deg mag
          0
           0.8   1.0     1.2     1.4      1.6     1.8     2.0     2.2   '      |6     20
                  HORIZONTAL  RANGE FROM  LIDAR —  km           TEMPERATURE
        800
      DC
      <
      Q
        600
      O
      m
        400
        200
      LU
      X
            -•— Top of Stack
                                                               Cross Section No. 74
                                                               1234:45-1236:55  22 Oct 68
                                                               Azimuth 330 deg mag
                                                                             3500 ml
           0.8  1.0     1.2     1.4     1.6      1.8     2.0     2.2     2.4
                             HORIZONTAL RANGE FROM  LIDAR — km
2.6
        2.8
                                                                                 TA-7289-31
FIGURE 26   SPATIAL SERIES OF  LIDAR-OBSERVED  VERTICAL CROSS SECTIONS FROM SITE  6, 3.8km
             NORTHEAST OF  STACK, 22 OCTOBER 1968.  See also  Figure  D-7.
                                                48

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   800
   600
O
CO
   400
   200
             Cross Section No. 79
             0856:45-0858:30 23 Oct 68
             Azimuth 220 deg mag
        - Top of Stack
      0.4    0.6     0.8     1.0    1.2     1.4     1.6     1.8     2.0     2.2     2.4
                                 HORIZONTAL RANGE FROM  LIDAR — km
                                                                                      2.6    2.8     3.0
   800
             Cross Section No. 80
             0859:45-0901:45 23 Oct
             Azimuth 180 deg mag
       0.4     0.6     0.8     1.0     1.2     1.4     1.6    1.8     2.0     2.2
                       HORIZONTAL RANGE FROM  LIDAR  — km
                                                                                    4      8     12
                                                                                 TEMPERATURE — "C
   800


cc  600
Q
O
m
   400
   200
I
C3
LLJ
     0
             Cross Section No. 81
             0902:40-0904:45 23 Oct 68
             Azimuth 140 deg mag
      0.4    0.6     0.8     1.0     1.2     1.4     1.6     1.8    2.0     2.2     2.4     2.6     2.8     3.0
                                 HORIZONTAL  RANGE  FROM  LIDAR — km                   TA-7289-32

FIGURE  27   SPATIAL SERIES OF LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM SITE 6, 3.8km
              NORTHEAST OF STACK, 23  OCTOBER  1968.   See also  Figure D-8.
                                                  49

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   800
           Cross Section No. 93
           0933:15-0934:40 24 Oct 68
       0     0.2    0.4    0.6     0.8     1.0     1.2     1.4     1.6     1.8
                     HORIZONTAL  RANGE  FROM LIDAR — km
                                                                                4      8      12      16
                                                                                TEMPERATURE — UC
   800
   600
u  400
O
CQ
<
H-  200
I
O
           Cross Section No. 99
           1004:40-1006:00  24 Oct 68
           Azimuth 070 deg mag
           Top of Stack
       0     0.2    0.4
0.6     0.8     1.0    1.2     1.4     1.6     1.8    2.0
     HORIZONTAL RANGE FROM LIDAR — km
2.2
                                                                                            2.4    2.6
E  800
   600
   400
O
CO
I-  200
x
u
LU
I
           Cross Section No. 101
           1020:00-1021:45  24 Oct 68
           Azimuth 070 deg mag
          -Top of Stack
             0.2    0.4     0.6     0.8     1.0     1.2    1.4     1.6     1.8     2.0
                                  HORIZONTAL  RANGE  FROM LIDAR — km
                                                                                     2.2
                                                                 2.4
               2.6
                                                                                             TB-7289-33
  FIGURE 28    TIME SERIES OF  LIDAR-OBSERVED VERTICAL CROSS  SECTIONS FROM SITE 11, 4km
                NORTHWEST  OF STACK, 24 OCTOBER  1968.  See also Figure D-9.
                                                 50

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  800
=  600
Q
_l
£  400
O
CO
   200
I
Hi
X
           Cross Section No. 103
           1035:15-1037:50  24 Oct 68
           Azimuth 070 deg mag
          -Top of Stack
             0.2     0.4     0.6     0.8     1.0     1.2    1.4     1.6     1.8
                                HORIZONTAL RANGE  FROM LIDAR  —  km
                                                                               2.0     2.2    2.4    2.6
   800
oc  600
   400
            Cross Section No. 104
            1047:30-1050:30  24 Oct 68
            Azimuth 070 deg mag
O
CD
   200
I
CD
          -Top of Stack
                                                                      AH(calc)
             0.2     0.4     0.6     0.8     1.0    1.2     1.4     1.6     1.8
                       HORIZONTAL RANGE FROM  LIDAR — km
                                                                                     8      12     16
                                                                                  TEMPERATURE  — °C
   800
 cc 600
 Q
 _J
 LU 400
 O
 CQ
   200
I
CJ
LU
           Cross Section No. 106
           1103:30-1105:45 24 Oct 68
           Azimuth 070 deg mag
          -Top of Stack
       0     0.2    0.4     0.6     0.8     1.0     1.2     1.4     1.6     1.8    2.0     2.2     2.4     2.6
                                 HORIZONTAL RANGE  FROM LIDAR  —  km
                                                                                              TB-7289-34
 FIGURE  29   TIME SERIES OF  LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM SITE  11, 4km
               NORTHWEST OF STACK,  24 OCTOBER 1968.  See also Figure D-9.
                                                  51

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   800
   600
   400
   200
I
(D
LU
I
          Cross Section No. 107
          1117:30-1119:50  24 Oct 68
          Azimuth 070 deg mag
-Top of Stack
             0.2    0.4    0.6     0.8     1.0     1.2     1.4     1.6     1.8
                               HORIZONTAL RANGE FROM LIDAR — km
                                                                    2.0
2.2
                                                                                  2.4
       2.6
   800
   600
>
o
m
<
LU
I
   400
   200
          Cross Section No. 108
          1134:00-1136:30  24 Oct 68
          Azimuth 070 deg mag
          -Top of Stack
             0.2    0.4     0.6     0.8     1.0     1.2    1.4     1.6     1.8
                               HORIZONTAL RANGE FROM  LIDAR  — km
                                                                    2.0
2.2
2.4
2.6
   800
   600
   40°
          Cross Section No. 109
          1145:45-1151:35  24 Oct 68
          Azimuth 070 deg mag
O
CQ
   200

        ••—Top of Stack
                                                                  	AH (calc) = 429 m
   0.2    0.4    0.6     0.8     1.0     1.2    1.4     1.6
            HORIZONTAL RANGE FROM LIDAR — km
                                                                  L
                                                                       1.8
                                                                                    8      12     16
                                                                                 TEMPERATURE —  °C
                                                                                              TB-7289-35
  FIGURE  30   TIME  SERIES  OF LIDAR-OBSERVED VERTICAL CROSS SECTIONS FROM  SITE 11,  4km
                NORTHWEST OF  STACK,  24 OCTOBER 1968.  See also Figure D-9.
                                                 52

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             VI  INTERPRETATION OF CROSS SECTIONS  IN TERMS
                      OF PLUME RISE AND DIFFUSION

     The new capability to "see" the detailed  structure and geometry of
plumes, which lidar makes possible, gives the  instrument decided poten-
tial in plume rise and diffusion studies.  However, as often happens
when a new technique enables us to obtain detailed observations where
only sparse data were available before, the lldar data have underscored
the complexities of plume behavior and made apparent the weaknesses of
certain of the present concepts and theoretical assumptions.
     After examination of the plume cross sections in Sec. V, it is
apparent that plume tilting and fanning caused by wind direction shear
is a characteristic feature of plume behavior  in stable conditions.  It
then becomes difficult to identify any one level of the plume for use
in computing plume rise.  The concept of plume rise also tends to lose
meaning under fumigation conditions, which were frequently observed,
and under unstable (looping) conditions.  Equally  important as compli-
cating factors are the temperature inversions  and stable layers, which
regularly occur aloft and tend to trap the plumes and prevent further
rise.  The lidar data for October show several instances of this.  Thus
the data emphasize that there typically are significant vertical varia-
tions in stability and wind structure that have profound effects upon
plume behavior, and that are not taken into account by the plume rise
theories .
     Plume-rise values (^H) for the stable cases were calculated from
    formula rec
(Smith, 1968):
                                   *
the formula recommended by the ASME  Committee on Air Pollution Controls
                            AH = 2(F/GU)1/3                        (5)
 American Society of Mechanical Engineers.

-------
with
and
F = g r2 Vg (Tg - Ta)/Ta




G = (g/T UAT/AZ + o.oi)
    \   a/



U = (Ut + UJ/2
                      AT = T. - T
                            X    3
                      AZ = H  - H     (after Proudfit, 1969)
                            t    s
where



          F = buoyancy flux



          g = acceleration of gravity (= 9.8 m/s)



          r = radius of stack orifice (= 4.25 m for Keystone)



         V  = stack gas exit velocity
          S


         T  = stack gas exit temperature
          S


         T  = ambient atmospheric temperature at stack top
          a


          G = stability parameter



          U = mean wind speed over height interval where rise occurs



         U  = wind speed at height of plume top (H,) after maximum rise
          L                                        C


         U  = wind speed at height of stack top (H )
          3                                       S


         T  = air temperature at height of plume top.



The  computed values, as well as the values of the  input parameters used,


are  listed  in Table III.



      In  view of  the complications discussed previously with  regard to


defining plume rise in a manner that permits objective determination


from lidar  plume cross sections, the calculated plume rise values have


been indicated directly on the cross sections, Figs. 9-12 and 15-30.




                                   54

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                                               Table III
              VALUES OF  INPUT PARAMETERS  USED  AND RESULTS FROM PLUME RISE CALCULATIONS



                              USING ASME  FORMULA  FOR STABLE CONDITIONS
Date
(1968)
5/25
5/26
10/16
10/17
10/18
10/20
10/21
10/22
10/23
10/24
Time
(EOT)
0919
1036
0900
0917
0945
0912
0920
0942
0928
0857
0907
1024
0903
1232
0900
0934
1049
1148
Cross
Section
Number
2
4
12
16
20
27
34
37
40
B44
47
54
58
73
80
93
104
109
V
s
(ft/s)
73.0
73.0
68.5
68.6
68.6
68.7
65.9
65.9
67.1
67.0
69.0
69.0
59.2
59.2
73.1
61.3
61.3
61 .3
T
s
(°F)
275.0
275.0
270.0
292.0
292 .0
292.0
289.0
289.0
267.0
278.0
278.0
278.0
292.0
292.0
285.0
300.0
300.0
300.0
T
a
(°C)
12.8
12.7
15.4
17.3
17.3
19.7
18.7
20.0
9.6
7.5
7.5
8.6
11.5
15.7
7.3
9.6
9.8
11.0
Tt
(°C)
11.6
9.7
13.4
17.5
17.6
18.3
17.1
16.5
11.0
5.5
5 .8
5 .9
12.1
13.2
4.7
8.3
8.5
7.7
Ht
(m)
590
850
540
470
430
530
550
580
460
620
570
580
430
580
550
560
470
510
H
s
(m)
240
240
160
152
152
152
122
122
122
162
162
162
176
176
176
152
152
152
Ut
(m/s)
7.5 at 84°
5.3 at 89°
11.0 at 157°
9.0 at 186°
10.5 at 187°
12.4 at 176°
10.9 at 168°
14.3 at 165°
6.8 at 248°
9.1 at 326°
7.8 at 328°
8.1 at 325°
7.9 at 193°
14.9 at 218°
9.0*
4.9 at 158°
6.4 at 156°
6.2 at 150°
U
a
(m/s)
6.2 at 70°
4.5 at 49°
3.0 at 111°
5 .9 at 153°
5.2 at 150°
7.2 at 150°
7.2 at 136°
7.2 at 136°
6.4 at 235°
7.5 at 305°
7.5 at 305°
7.4 at 314°
5.5 at 153°
6.0 at 196°
7.5 at 241°
5.7 at 127°
6.9 at 137°
5 .8 at 127°
AH
(m)
206
251
220
169
164
183
185
241
156
203
206
242
161
203
257
218
212
429
AH + H
(m)
446
491
380
321
316
235
307
363
278
365
368
404
337
379
433
370
364
581
Estimated.

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In this way, detailed comparisons with the observed plume heights and
shapes are possible.
     In general, the ASME formula appears to predict plume rise reasonably
well, although of course the frequent presence of temperature inversions
at plume levels diminishes the relevancy of the theory in many instances.
For the few cases where the vertical temperature gradient at plumes
levels is approximately uniform with height, and vertical wind shear—
and thus plume tilting—is weak (e.g., Cross Section 58,  Fig. 23), the
agreement between the theory and the observations is excellent.  On the
whole, there appears to be a weak indication that the ASME formula may
predict slightly lower plume rises than observed.
     The capabilities of lidar in computing diffusion parameters are
fairly obvious, at first glance, from inspection of the horizontal plan
views of plume positions in Figs. 9-12 (insets) and in Appendix D, which
show the horizontal spread of the effluent with downwind  distance.
Again, however, wind direction shear and the attendant spreading of the
plume by shearing are not adequately covered by present theories.  The
best application of current theory is probably for the neutral and un-
stable cases, when vertical wind shear is not usually so pronounced.
Here another problem is encountered, in that most theories are only
valid for mean concentrations over a period of 30 minutes to an hour
(Gifford, 1961).  To be most useful here, then, a lidar should be
capable of taking fast, quasi-instantaneous cross sections through a
plume at frequent intervals for extended periods on the order of an hour.
The results of these cross sections would then be averaged to obtain a
mean concentration distribution to compare with theory.  The present
equipment requires about two to three minutes for a complete cross sec-
tion.  Under unstable conditions when the plume position is rapidly
changing, some distortion is introduced  into the cross sections due to
the lack of instantaneity of the individual lidar observations.
     Another important consideration for studying plume diffusion with
a lidar is the receiver signal-to-noise ratio at the range where the
plume is observed.  As seen in Fig. 6, a portion of the plume return is
                                   56

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truncated when the plume is observed at a range beyond that at which
clear-air return is detected above the noise.  This decreases the ob-
served size of the plume, and hence affects the diffusion calculations
unless suitable allowances are made.  A prime example of this effect is
shown by Figs. 20 and 21 and the corresponding plume plan views in
           *
Appendix D.   Here a series of six cross sections were obtained within a
time period of 15 minutes.  The precipitators were all on when the last
three cross sections were observed, furnishing a clean plume.  Due to
background noise considerations, this clean plume is "seen" by the lidar
to be considerably smaller than the dirty plume.  However, the diffusion
regime was the same.
     The Mark V lidar has an effective above-noise range for clear-air
return on a typical bright day of about one to two km in the neodymium
                                                                  t
version, but this could be readily improved by using a ruby or YAG
laser and/or additional signal-to-noise enhancement equipment and
techniques .
2k
 The effect is not as pronounced in the plan views due to the greater
 recording resolution of the 35-mm film system.

 Ytrrium aluminum garnet, wavelength 1.06 |_i.
                                   57

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          VII  EVALUATION OF PARTICULATE MASS CONCENTRATIONS
            FROM LIDAR NORMALIZED  SIGNAL RETURN  (S) VALUES

     As discussed  in Sec. IV.  the  conversion of  S values  to absolute
mass concentrations requires allowance  for  the effect  of  attenuation of
the laser beam as  it passes through  the atmosphere  and  the plume.  This
problem is best approached by  solving the differential  equation derived
from Eq. (4) (Sec . IV) :

                        dR ~   '    |3  dR     '  a

where Bouquer's law of attenuation

                       T(R) =  exp  -  /   rrU) d S,                    (7)
                                 _  °         _
has been assumed and a(£) is the volume extinction  coefficient at  a dis-
tance i along the  path.  The solution of Eq. (6) for particulate mass
concentration along the laser  beam path requires relating the optical
parameters a and g to the particulate mass  concentration.  For this
purpose the ratio  of each optical  parameter to the  particulate mass con-
centration M(mass/volume) is defined as
                           -
                           M
                                          M
Substitution of Eq .  (8)  into the  lidar differential equation  [Eq .  (6)]
results in an expression relating mass concentration  to  the lidar  nor-
malized signal return:
                   dR
                        4.34
                                            ,0
                                                                    (9)
where
         has been considered  independent of range.  The validity  of  this
assumption will be discussed later.  This nonlinear equation may be
solved by first employing the linearization transform 7] = M   with the
                                   59

-------
result
                                                           -1
M(R) = exp C
]
                             M
                                 - 2 F
                                     =
 /  exp C^SU)
JR
                                                                   (10)
where C  = 1/4.34.  This solution principally assumes that
     (1)
             and ^  are invariant with range and the value of
           G      D
             can be computed, and
     (2)  a boundary or clear-air particulate mass concentration,
          M
              is known or can be estimated.
     Microscopic analysis of the Keystone fly ash clearly shows that the
particles are glass spheres, apparently formed from the mineral content
of the coal by the intense heat of the combustion process; hence, the
use of Mie theory in deriving estimates of ^  and £,   is justified.  To
a high degree of accuracy, the volume extinction coefficient at the
lidar wavelength of 1.06 |_i may be considered to be essentially dependent
only on the atmospheric particulate matter, and the ^ values may be ex-
pressed
         as :
                              n a  Q (x,m) n(a) da
                                    G

                                4    3
                                — TT a  p n(a) da
                                                                    (11)
                              TT a  Q (x,m) n(a) da
                                4    3
                                — TT a  p n(a) da
                                                                    (12)
 To be precise, the parameters ^e and ^b defined by Eqs.  (11)  and  (12)
 are exactly equivalent with those defined by Eq.  (7)  only when  multiple
 scattering effects are absent.  This is a good  assumption for this  study
 because of the narrow field of view of lidar systems  (<1 mrad) .
                                   60

-------
where
          a = particle radius
         Q  = extinction efficiency factor
          G
         Q  = backscatter efficiency factor
          x = size parameter = 2n a/X
          m = refractive index of particles
          X = wavelength of the laser energy
          n = number of particles per unit volume per unit radius
              interval, and
          p = density of the particulate matter.
     The efficiency factors may be computed from Mie theory for a given
particulate matter refractive index, the real part of which in this case
was estimated to have a value of approximately 1.5, based upon the known
mineral composition of coal.  The requirement that ^  and ?  be inde-
                                                    6      u
pendent of range is satisfied when the relative particle-size distribu-
tion is invariant with range; i.e.,

                       n(R,a) = C(R) n (a)                         (13)
                          '           r       '

where C(R) is the number concentration and n (a) is the relative size
distribution.  Also, with this assumption only the relative particle
size distribution is required to evaluate the ^ values.  However, n (a)
is rarely completely independent of range, and the question may be asked
as to how small changes in the relative size distribution are reflected
in the ^ values.  Since the £ values are expressed in terms of integrals
over the range of particle sizes, monodispersed (single-sized) particles
would cause largest ^ variations with slight changes in the particle size.
Mie computations of ^  and ^  are presented in Fig. 31 for the case of
monodispersed particles consisting of material with a density of 2.1 g/cm
(as measured at the Institute from a Keystone fly ash sample) and a re-
fractive index of m = 1.5-iO for incident radiation of wavelength 1.06 u.
                                   61

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                                  4            6
                              PARTICLE RADIUS — microns
                                                8            10

                                                      TA-7289-36
FIGURE  31
DEPENDENCE UPON  PARTICLE SIZE OF TOTAL SCATTERING	
EXTINCTION—OPTICAL CROSS SECTION PER  UNIT MASS  (£ }. AND BACK
BACK-SCATTERING OPTICAL CROSS OPTICAL  CROSS SECTION PER
UNIT MASS PER STERADIAN (^).  For mono-disperse particles with
refractive index of 1.5-iO and density of  2.1  g/cm3
                                      62

-------
     As shown, slight variations in particle size can cause large varia-


tions in F  and smaller but significant variations in F .   Because of
         bb                                           ^e

this, and the fact that P  is more sensitive to variations in p than a
                         s

[Eq.  (1)], the requirement that £  remains constant with range also


satisfies the less stringent requirement that ^  remains invariant.
                                               6


     A real aerosol contains particles of many sizes, so the variations


in the ^ curves tend to be smoothed out when a weighted integral for all


sizes present is computed.  The next section will explain the methods


developed to handle the supplementary particle-size data obtained during


the Keystone study for use with the lidar observations.
                                   63

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                 VIII  ANALYSIS OF ATTENUATION EFFECT
                  USING PARTICLE-SIZE CHARACTERISTICS

     The Keystone stack plume particulates were sampled with an airplane-
mounted Goetz moving slide impactor  (Goetz, 1969) by Meteorology Research,
Inc. (MRI), at times nearly concurrent with the SRI lidar observations.
Tentative relative particle size distribution data for specified sampling
periods were furnished SRI (see Table IV) along with information re-
quired to evaluate the number of particles per unit volume per unit
radius interval for increments of 0.25 p.  in radius.  The relative size
distribution is sufficient to evaluate the optical parameters |  and F
                                                               G      D
for use with the lidar data.
     Ideally, however, one would like to  compare mass concentrations
measured by the MRI sampler with those derived from the lidar data.
This was not possible, since our conversions of the relative particle-
size data to absolute size distributions  (using the furnished sample-
volume values) and then to mass concentrations give unrealistically
                                                               3
large values of concentration for the clear air (M  > 1000 ng/m ) upwind
of the stack.  Hence it has been necessary to use the empirical relation-
ship derived by Noll, et al. (1968)  to determine the clear-air background
mass concentration (M ) from visual  estimates of atmospheric visibility.
     The solution parameter ^  and the parameter ^  were evaluated from
the furnished relative size distributions for each data sample listed in
Table IV; these values are tabulated in Table V.  In these computations,
integrations over particle radii were performed by means of rectangular
integration, with the size distribution assumed constant within each
sampling interval.  The parameters £  and I*  were evaluated from sampling-
                                     G      D
interval-averaged optical cross sections  defined as:
C =
                           Q =  (\ /4rr) fx Q(x)dx/fdx                 (14)
                                \     / J         
-------
                                                                    Table IV
                                                 SUMMARY OF MRI PARTICLE-SIZE DISTRIBUTION DATA
                                                    (Compiled by Stanford Research Institute)
Count
No.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18


19
20
21
22
23
24
Date
(October
1968)

16
17
17
17
17
17
17
17
17
17
17
18
18
18
18
18
18
18


21
22
22
22
22
22
Time
(EDT)

0953
0853
0957
1219
1219
1223
1223
1230
1230
1230
1252
0951
1009
1009
1009
1009
1009
1142


0912
0930
0942
0944
0945
1233
Slide
No.

5-16
2-17
16-17
22-17
22-17
23-17
23-17
24-17
24-17
24-17
26-17
1-18
4-18
4-18
4-18
4-18
4-18
6-18


1-21
4-22
6-22
7-22
8-22
12-22
Slide
Position

2
4
10
17
17
2
12
5
8
17
5
3
2
2
2
7
7
5


10
18
13
13
2
7
Photo
Exposure
Time
(s)

0.5
0.5
0.2
0.2
0.2
0.1
0.5
0.1
0.2
0.5
0.5
0.5
0.5
0.2
0.1
0.5
0.2
0.5


0.5
0.5
0.5
0.2
0.5
0.5
Slide
Exposure
Time
(s)

29
29
109
106
106
106
106
226
226
226
17
116
117
117
117
117
117
244


59
29
27
28
28
7
Aircraft
Radial Position
Relative
to Stack
(km)
*
3 DW
3 DW
16 DW
8 DW
8 DW
8 DW
8 DW
8 DW
8 DW
8 DW
7
14 DW
17 DW
17 DW
17 DW
17 DW
17 DW
5 UW


5 DW
4 DW
4 DW
4 DW
4 DW
4 DW
Relative
to Lidar
(km)
*
6 UW
6 UW
7 DW
Over
Over
Over
Over
Over
Over
Over
7
Over
3 DW
3 DW
3 DW
3 DW
3 DW
20 UW


Over
Over
Over
Over
Over
Over
Aircraft
Altitude
(Ft
MSL)

2320
2750
2650
3000
3000
1800
1800
3000
3000
3000
7
2500
3100
3100
3100
3100
3100
1250
to
3750
2800
2700
2100
2400
2700
2400
(m above
Lidar)

289
420
390
497
497
131
131
497
497
497
7
314
497
497
497
497
497
Below
692

446
429
246
338
429
338
Portion
of Plume
Sampled '

Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
7
Bottom
Top
Top
Top
Top
Top
None"


Middle
Above(?)
Bottom
Middle
Above (?)
Middle
Precipitator
Capacity On
(percent)

50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50


100
100
50
50
50
62
Associated
Lidar
Cross
Section
No.

—
—
—
33
33
33
33
33
33
33
7
37
37
37
37
37
37
—


47
61
64
64
64
73
Ol
    Notes:   DW = downwind, UW  =  upwind.
             Judging from MRI aircraft  data  and  lidar cross sections.
              Clear" air background upwind of  stack.

-------
                                Table V
                 VALUES OF OPTICAL PARAMETERS COMPUTED
                   FROM RELATIVE PARTICLE-SIZE DATA
Count Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
?e
(mV1)
0.63211
0.64544
0.70527
0.56964
0.85449
0.36938
0.93607
0.97728
0.55544
0.51767
0.59043
0.32160
0.37274
0.47949
0.45573
0.54664
0.84976
0.39697
0.35974
0.21364
0.51050
0.25768
0.38903
0.68789
?b
(m2g~1ster~1)
0.03647
0.05744
0.06434
0.06138
0.05519
0.03603
0.05103
0.04638
0.05882
0.05197
0.02630
0.02109
0.02622
0.03176
0.02401
0.02836
0.03571
0.03233
0.02950
0.01382
0.04480
0.02137
0.03518
0.05680
     It was indicated by MRI that the particle counting technique is in-
sensitive to particles with radii less than 0.50 to 0.25 |~i.  The influence
of this on the evaluated quantities, as well as the validity of the rec-
tangular integration, was investigated by fitting a continuous Junge dis-
tribution function to the observed particle counts.  Figure 32 illustrates
the method used to evaluate the Junge parameters from the cumulative
particle-size distribution of Count No. 21, which has been reduced to
absolute values by the tentative MRI information.  This particular sample
has considerably fewer small particles (a < 1.0 |a) and also fewer large
particles (a > 3 |_i) than the indicated Junge model.
                                   67

-------
            1000
          o
          •a
         8.c.
             100
          Q
          UJ
o
o
2
Z
I
t-
cc
LJ
CC
_J

UJ
o
t-
cc
o.
u.
o
cc
LJ
m
              10
              1.0
             O.I
                     0    O
                 METHODOLOGY:
                  n = C Q-k
                  Slope  l-k
                   Intercept =
                                    1	>~
                                     COUNT No. 21
                                     SLIDE 6-22
                                     0942 EOT
                                     22 OCT  1968
                                         n = 201 o
                                                -4.346
               O.I              1.0              10
                      PARTICLE RADIUS, a  	  microns
                                                   100
                                                          TA-7289-37
         FIGURE 32   SAMPLE CUMULATIVE PARTICLE SIZE DISTRIBUTION
                     AND JUNGE-TYPE ANALYTICAL FIT
     Assuming  that  the Junge model is a satisfactory  representation of
the real aerosol,  it  can then be employed with  a more exact trapezoidal
integration of ^  (maintaining 0.1 increments  in x) .   Integration with
                                                     o
limits of  a =1.0  and 10.0 |_L results in g;   = 0.37  m /g,  slightly less
than the rectangular  integrated value (0.51), which is expected because
of the increased number of larger particles in  the Junge model.  Inte-
gration with limits of a =0.1 and 10.0 (j. results  in  F  = 0 87  the in-
                                                       =e     '   '
crease occurring because of the larger number of small particles in the
Junge distribution.
                                    68

-------
     The lidar and particle  sampling of  the Keystone  plume were  best

coordinated for Cross  Section 64} which  is oriented approximately  cross-

wind, and this case was chosen  to apply  the mass  concentration solution

discussed in Sec. VII.  The  boundary parameter M  was  taken  from the

visibility estimate (7 to  10 miles),, which gives  M  =  100 ug/m , using

the relationship of Noll,  et al.  (1968).  The value of  £  was chosen  in
                                                        Q
accordance with the computation  (Table V) for Particle  Count 22  as
     2 ,  *
0.2 m /g .   The results of these  absolute mass concentration computa-

tions are presented in Fig.  33, which also illustrates  the manner  of  the

removal of extraneous clear-air  and background noise contours from  the

plume cross sections, which  is  normally  employed  in order to better de-

fine the plume boundaries  and shape.  Figure 33(c) represents the  re-

sults of the graphical subtraction of Fig. 33(a)  from  33(b), and thus

shows contours of mass concentration in  decibels  added  to the back  side

of the plume by the attenuation  correction.  It may be  noted that  the

maximum correction is  9 dB, which means  that the  mass  concentration at

that point was almost  10 times  too low in the uncorrected cross  section,

Fig. 33(a) .  It may be seen  that  although the attenuation correction

does change concentrations significantly in one part of the cross  sec-

tion, the general shape and  structure of the plume remain the same.

     A planimeter was used to integrate  the total mass  per unit  plume

length (cross-axial integrated mass concentration) represented by  the

cross sections in Fig. 33(a) and  (b) .  The results were as follows:

uncorrected cross section  (a),  350 g/m of plume length; corrected  (b),
 A value of 0.3 m /g was tried also,, but gave no solution due  to  the
 integration becoming unstable.  Although  solutions were not attempted
 for any other cross sections,, many of the high values of £,e shown  in
 Table IV would probably cause similar unsuccessful results.   These high
 values are a consequence of  the surprisingly small modal particle  sizes
 reported by MRI.  The cause  of this apparent discrepancy between the
 lidar data and the particle-size data is  unknown, but there are  a  number
 of possibilities, such as  (1) the free-air particles could have  a  thin
 coating of water, which increases their optical size, (2) particle
 agglomerates may break up when introduced into the sampler, (3)  some of
 the assumptions used in the  lidar data analysis may be faulty, or  (4)
 there may be an error in the particle-size measurements or analyses.
                                   69

-------
         600
     <  400
     LU
     o
     CD
     <
     I-   200
     I
     <£
     LU
     I
                (a) Without attenuation correction
            1.2
                       1.4
                                   1.6
                                              1.8
                                                          2.0
                                                                      2.2
         600
      <  400
      Q
      O
      m
         200
      o
      LU
      I
                 (b)  With attenuation correction
             1.2
                        1.4
                                    1.6
                                               1.8
                                                          2.0
                                                                      2.2
      Q
      _l
      LU

      O
      CD
       LU
       I
         600
          400
          200
                  (c)  (a)-(b)
CROSS SECTION NO. 64
0940.35-0942.00 22 OCT
AZIMUTH 300 DEC MAG
             1.2
         1.4         1.6         1.8         2.0
          HORIZONTAL RANGE FROM LIDAR — km
                                                                      2.2
FIGURE  33   EFFECT AND  MAGNITUDE OF CORRECTION  OF  PLUME MASS
              CONCENTRATION DISTRIBUTIONS FOR ATTENUATION.  Contours
              represent 10 Iog10 (M/M0) and  thus  are labelled in decibels.  Solution
              parameters  for  (b) are clear-air  concentration  M0  = 100 x  10~6 g/m3;
              £e =  0.2 m2/g; dashed  line faired in by hand  separates clear-air and
              background-noise contours from plume contours.
                                         70

-------
680 g/m, which shows that the mass correction was significant.  These
values were compared with an estimate of the particulate emission rate
from the stack, obtained from the following parameters existing at the
time the cross section was obtained:
                                      3
          Coal burning rate = 651 x 10  Ib/hr
                                              *
          Fly ash content of coal = 17 percent
          Precipitator collection efficiency = 50 percent
                                               (half in operation)
          Wind speed at plume level = 8 m/s.
     Using these values gives a stack source strength of 7000 g/s, and
a plume cross-axial integrated mass concentration of 875 g/m, compared
with the 680 g/m measured by the lidar, after allowance for attenuation
Although further evidence will be necessary from other comparisons, the
close agreement of this initial example does indicate strongly that the
lidar technique is capable of useful quantitative measurements.
*
 Full conversion to gas-borne fly ash particles is assumed
                                   71

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               IX  RECOMMENDATIONS FOR FURTHER  RESEARCH

     This first feasibility  study,, although  limited  in scope  and  scale
of effort, has demonstrated  that  lidar  is  of  significant  value  in  plume
studies.  The instrument can furnish  information  about plume  rise  and
dispersion from tall stacks  that  is unobtainable  in  such  detail by any
other means.  To take advantage of the full  potential of  the  technique,
additional work is needed  in a number of areas.   These fall for the most
part within the general categories of
     (1)  Lidar instrumentation improvements,
     (2)  Additional data-handling and reduction  capabilities,
     (3)  Improved experimental and analytical  techniques, and
     (4)  Testing of advanced lidar concepts.
A number of specific suggestions  for  improving  lidar usefulness in plume
studies are itemized below.
A.   Lidar Instrumentation
     •    The observations described  in this  report were  made with SRI's
general-purpose experimental Mark V lidar  operating  in its neodymium
configuration.  Although this provided a higher pulse repetition  frequency
(10-12 pulses/min) than the  ruby  version,  the latter system is more sen-
sitive and could thus have acquired data at  longer ranges, or better
information on "clean" plumes (i.e., with  full  precipitator operation).
The lower pulse rate of the  ruby  system (3-4  pulses/min)  would have
seriously reduced the data rate.
          These considerations well illustrate  the problem confronting
the designer of an optimum system for use  in  plume observations.   It  is
important to recognize, however,  that the  SRI Mark V lidar is a rela-
tively modest unit, and that with current  technology considerably  higher
performance is readily attainable.  The results of the present  investi-
gation, even allowing for the limitations  of  the  equipment, are so
                                   73

-------
encouraging that the development of a more advanced lidar system appears
to be fully justified.
          Such a system could be readily developed with state-of-the-art
technology based upon the experience of the present study.  In selecting
an optimum system,  it would be necessary to investigate carefully the
relative advantages of lasers of different wavelengths.  Prime candidates
are 0.694 [a (ruby), 0.9 |_i (gallium arsenide),  near infrared at 1.06 n
(neodymium glass and YAG—ytrrium aluminum garnet), or 0.53 [i (the second
harmonic of the latter), all of which are immediately available.  In
making the choice,  the factors of pulse repetition rate, availability of
adequately sensitive detectors, and, of course, cost would all have to
be carefully weighed.
          Although at the moment indications are that a well-cooled ruby
laser, system  with a PRF of 1 to 10 pulses per second would provide the
best compromise, a detailed systematic study would be a most valuable
preliminary to building an advanced lidar system for plume studies.
     •    A study should be made of the feasibility of calibrating the
lidar on an absolute basis so that the energy output (in joules) of each
pulse were known.  A completely calibrated lidar could furnish objective
estimates of one of the attenuation solution parameters, M , the abso-
lute particulate mass concentration in the clear air.
B.   Data Handling and Reduction Capabilities
     •    Even at the present lidar firing rates, the large quantity of
data collected is on the verge of becoming unmanageable.  Each lidar
observation is not just a point measurement, but a complete profile.
Making full use of this information, particularly when using higher-PRF
instruments, requires new and better ways of handling and processing
lidar data.
*
 Recent tests with the SRI Mark V ruby system indicate that relatively
 modest improvements could permit it to be operated at a pulse rate
 comparable to that of the neodymium version, which could make this
 system an excellent interim solution.
                                   74

-------
     •    A big  step in the right direction would be  the development of
an intensity-modulated  range-height oscilloscope display of  plume cross
sections.  This  would  be similar to the familiar radar  RHI display,  as
simulated in Fig.  34,  and would give an immediate, operationally useful
photograph showing the  plume shape and boundaries, as well as  the in-
ternal relative  concentration distribution in terms of  varying degrees
of brightness.   For a  more quantitative record, the video magnetic disk
recorder would be  used  to take photos of the same cross section with
                                 (Each line represents one lidar shot;
                                 trace intensity is a function of plume
                                 paniculate concentration)
                       HORIZONTAL DISTANCE FROM LIDAR
                                                             TA-7289-39
      FIGURE 34
VISUALIZATION OF INTENSITY-MODULATED RANGE/HEIGHT
OSCILLOSCOPE DISPLAY  OF  PLUME CROSS SECTION
OBSERVED  BY LIDAR
different  oscilloscope intensity settings, giving  a contour representa-
tion.  Such  a  display would require that each lidar observation be cor-
rected electronically for range and for equipment  nonlinearities.   These
real-time  analog  techniques would greatly simplify the  data-processing
problem  and  reduce the number of digital computer  analyses  required.
     •     Since  some of the lidar data will always need to  be retained
in quantitative  form, an on-line analog-to-digital conversion and  re-
cording  capability in the field would vastly facilitate later digital
analyses.
                                    75

-------
C .   Experimental and Analytical Techniques
     •    For better time continuity of the lidar plume observations,
the limitations on duration of the observation periods, which were in
effect during the experimental phase of this study, are undesirable and
future arrangements should permit uninterrupted operations, if at all
possible.
     •    Observations should also be obtained during the night hours,
when lidar performance is optimum due to the low background illumination
(noise) levels.
     •    Most of the effort in this study went into lidar data collec-
tion, processing, and analysis.  More work is needed on the interpreta-
tion and use of plume cross sections in checking plume rise formulas,
testing diffusion models, studying terrain effects, etc.
     •    In particular, a rationale is needed to deal with the effect
of the background noise threshold in plume cross sections upon the
testing of diffusion models using lidar data.  This methodology could be
similar to that developed by Gifford (1959) for use in diffusion esti-
mates from smoke plume photography.
     •    Some provision for time averaging of the lidar data is required
for use in testing diffusion models, which generally are designed to
furnish one-half- to one-hour averages.  This capability is especially
needed for checking models for neutral and unstable conditions.  It is
possible that an analog means to do this can be devised using the pre-
viously discussed intensity-modulated range-height display.
     •    In future absolute concentration analyses, an attempt should
be made to treat £ , the ratio of the optical volume extinction coeffi-
cient to particle mass, as a variable with range.
D.   Advanced Lidar Concepts
     •    There is great potential for exploiting the wavelength charac-
teristics of laser energy in lidar applications for plume studies.  Two
possibilities warrant early investigation:
                                   76

-------
          (1)   The use of multiwavelength systems to determine
               absolute mass concentrations without independent
               information of the particle size distribution,
               and
          (2)   The extension of the multiwavelength differential
               absorption technique that has been applied to the
               determination of water-vapor (Schotland et al.,
               1962) to the evaluation of plume constituents.
In this connection the development of new types of lasers,  such as the
tunable dye laser, holds great promise.
                                   77

-------
                              REFERENCES
Barrett, E. W., and O. Ben-Dov. 1967:  Applications of the lidar to
     air pollution measurements.  J. Appl. Meteor., 6, 500-515.

Gifford, F. A., Jr., 1959:  Smoke plumes as quantitative air pollution
     indices.  Intern. J. Air Poll., 2, 42-50.

Gifford, F. A., Jr., 1961:  Use of routine meteorological observations
     for estimating atmospheric dispersion.  Nuclear Safety, 2, 48.

Goetz, A., 1969:  A new instrument for the evaluation of environmental
     aerocolloids.  Envir. Science and Tech., 3, 154-160.

Hamilton, P. M.,  1966:  The use of lidar in air pollution studies.
     Intern. J. Air and Water Poll., 10, 427-434.

Johnson, W. B., Jr., 1969:  Lidar applications in air pollution research
     and control.  J. Air Poll. Contr. Assoc., 19,  March 1969.

McCormick, R. A., and K. R. Kurfis, 1966:  Vertical diffusion of aerosols
     over a city.  Quart. J. Roy. Meteor. Soc., 92, 392-396.

Noll, K. E., P. E. Mueller, and M. Imada, 1968:  Visibility and aerosol
     concentration in urban air.  Atmos . Envir., 2, 465-475.

Proundfit, B. W., 1969:  Plume rise from Keystone Plant.  Final Report,
     Contract PH  86-68-94, Sign X Laboratories, Inc., Essex, Connecticut.

Schotland, R. M., A. M. Nathan, E. A. Chermack, and E. E. Uthe, 1962:
     Optical sounding.  Tech. Rpt., Contract DA 36-039 SC-87299, U.S.
     Army Electronics Research and Development Laboratory.

Smith, M. E. (Editor), 1968:  Recommended Guide for the Prediction of
     the Dispersion of Airborne Effluents.  American Society of Mechanical
     Engineers, 345 E. 47th Street, New York.
                                   79

-------
        Appendix A
DESCRIPTION OF MARK  V LIDAR
             81

-------
                              Appendix A
                      DESCRIPTION OF MARK V LIDAR

     The optical system of the Mark V lidar is illustrated in Fig. A-l.
The transmitter consists of a Q-switched, air-cooled, pulsed ruby or
neodymium-doped glass laser with wavelengths at 6943 A  (deep red) or
at 10,600 A (near infrared), respectively.  Since the angular resolution
of the lidar is determined by the transmitted beam divergence, 6-inch-
diameter collimating optics are used to reduce the laser beam divergence
and to produce an output beamwidth of 0.35 mrad.  The corresponding
spatial resolution of this beam is 0.50 m at a range of 1 km in the
cross-beam direction, and about 2.3 m in range.  The pulse repetition
rate of the Mark V lidar is primarily limited by the cooling rate of the
laser cavity.  At present, the maximum firing rate is 3 to 4 pulses per
minute for the ruby laser, and 10 to 12 pulses per minute for the neo-
dymium.  The characteristics of the Mark V lidar are summarized in Table
A-I.
     The lidar receiver consists of a 6-inch-diameter Newtonian tele-
scope, identical to the transmitter optics.  An adjustable field stop
at the focal plane limits the receiver field of view to a maximum of 6
mrad.  A multilayered narrow-band filter with a wavelength interval
(bandwidth) of 13 A (ruby) or 100 A (neodymium) is inserted in the re-
ceiver optical path to reduce the output noise level produced by solar
radiation scattered into the receiver field of view.  The detector con-
sists of an RCA 7265/S-20 photomultiplier tube for the ruby laser, and
an RCA 7102/S-l for the neodymium system.
     The major electronic components of the lidar and the data-recording
system are illustrated in the block diagram shown in Fig. A-2.  A
compressed-air-driven turbine rotates the laser Q-switching prism at
*  4 o
 10  A = 1 l-i.
                                   83

-------
                                                       COLLIMATING LENS
                            NARROW-BAND FILTER
                 RECEIVER SIGNAL
                                                                         PRISM
FIELD STOP
(ADJ USTABLE)
           PRIMARY
           MIRRORS
oo
                                  PHOTOMULTIPLIER
                                   LIGHT GUIDE TO
                                   OPTICAL ATTENUATOR
 DIVERGING LENS
FIBER OPTICLIGHT
GUIDES
                       LASER ROD
                                    _    ;f^_	^_ ^
                          FLASH LAMPS
                              (2)
                                                    PARTIALLY REFLECTING MIRROR
                                                    (FABRY-PEROT ETALON)
                   REFERENCE PATH TO
                   COLLIMATING LENS
                   CALIBRATED
                   OPTICAL ATTENUATOR
                   0-45dB
         RIGGER  PULSE TO OSCILLOSCOPE


               SILICON PHOTO DIODE



                              TA-7289-40
                                    FIGURE A-1   OPTICAL SYSTEM OF MARK V  LIDAR

-------
                               Table A-I
                  CHARACTERISTICS OF SRI MARK V LIDAR
           Characteristics
      Transmitter
        Laser Material
        Beamwidth (mrad)
        Optics
        Peak Power Output (MW)
        Pulse Length (ns)
        Q Switch
        Maximum PRF (pulses/min)
      Receiver
        Optics
        Field of View (mrad)
        Predetection Filter
                              o
        Wavelength Interval (A)
        Detector

        Postdetection
        Filter Bandwidth (MHz)
                                            Wavelength
    6943 A
Ruby
0.35
   10,600 A
Neodymium-Glass
0.2
6-inch f/4 Newtonian Reflector
15
15
Rotating Prism
3 to 4
50
12
Rotating Prism
10 to 12
6-inch Newtonian Reflector
1.5
13
RCA 7265
(S-20 Cathode)
30
3.0
100
RCA 7102
(S-l Cathode)
30
500 revolutions per second.  Upon receipt of a fire signal, the synchro-
nizing generator triggers the flash lamp in step with a signal from the
rotating prism.  A capacitor bank charged to 3 kV supplies energy for
the laser flash lamps.  A photodiode senses the occurrence of the laser
pulse and produces a trigger pulse to start the oscilloscope sweep.  The
output of the photomultiplier in the lidar receiver is fed to a pulse
amplifier having a logarithmic transfer function, and then to an oscillo-
scope.  A Polaroid recording camera mounted on the oscilloscope photo-
graphs the lidar return signal.  Other data-recording options available
include the use of an automatic recording 35-mm camera and a magnetic
disk video recorder.  The latter device furnishes a steady display on
the face of the oscilloscope immediately after each shot,  as well as a
permanent record, and is very useful for real-time monitoring of
observations .
                                   85

-------
                                                 FLASH LAMP


                                             ROTATING PRISM	v  \
.LASER  ROD
             ,BEAM SPLITTER
                                                                          J-fl— -X---X
                                                                             FIRE
                                                                             PULSE
                     ^OUTPUT RADIATION


                 •PHOTO DIODE
00
a
      BACKSCATTERED
      SIGNAL RETURN"
PHOTOMULTIPLIER



i

HIGH VOLTAGE
POWER
SUPPLY



LOGARITHMIC
AMPL IFIER






VIDEO DISC
RECORDER
1



SWEEP TRIGGER
I
OSCILLOSCOPE




»
MONITOR
OSCILLOSCOPE

35 MM
RECORDI NG
CAMERA
POLAROID
* CAMERA

                                                                                                          TA-7289-41
                                    FIGURE A-2   ELECTRONICS SYSTEM OF MARK V LIDAR

-------
     Although the pulse-to-pulse variations of laser power output are
not unduly severe, the presence of this random variation  introduces
a corresponding uncertainty in the amplitude of the received signal un-
less provision for monitoring the transmitter power is made.  The Mark V
lidar incorporates an optical feedback arrangement, using fiber-optic
light guides, that samples the transmitted energy and injects it into
the receiver optical path ahead of the narrow-band predetection filter
(see Fig. A-l).   This arrangement produces a pulse occurring at zero
range on the receiver output.  The pulse height is proportional to trans-
mitted power.  A variable neutral-density filter is inserted in the
fiber-optic path to allow adjustment of the pulse height.
     The use of a logarithmic video amplifier in the receiver is almost
essential in order to compress the wide dynamic range of the detector
(typically four or more orders of magnitude) to enable the received
signal to be displayed on a single oscilloscope trace without loss of
detailed information.
                                   87

-------
         Appendix B
DETAILED LIDAR DATA SUMMARIES
             89

-------
            Table B-I
DATA SUMMARY,  25  MAY-1 JUNE 1968
Date
(1968)
5/25









5/26











5/27











5/28
Site
No.
1









2











3











4
Observational
Period
No.
1


2


3



4





5





6





7





8
Cross
Section
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Azimuth
Angle
045
000
315
000
045
315
000
045
315
045
200
226
252
253
226
200
200

226
226
226
226
065
032
000
065
032
000
065
032
000
065
032
000
020
Elevation
Angle
(First)
13
25
21
30
16
23
89
89
89
60
9
16
20
15
15
9
13

30
30
30
30
12
25
24
15
25
24
15
25
20
15
25
24
89
Time
(Start)
(EOT)
0912 :30
0917:30
0922 :00
1034:00
1040:15
1045:00
1423:00
1431:00
1437:00
1448:00
0854:00
0858:00
0904:30
0908:45
0915:45
0921 :00
1145:30

1151 :30
1154:30
1200:30
1205:00
0908:10
0913:15
0918:00
0923:00
0928:00
0932 :20
1013:45
1019:45
1024:00
1035:30
1040:30
1045:45
0909:45
Elevation
Angle
(Last)
6
11
7
4
4
4
7
5
5
3
1
3
5
5
6
1
5

22
4
4
4
3
1
1
2
1

2
2
2
0
2
2
3
Time
(End)
(EOT)
0916:00
0921:00
0925:25
1039:45
1043:30
1048:00
1428:00
1435:00
1442:15
1453:00
0856:15
0902 :40
0906:30
0913:00
0918:00
0926:00
1148:30

1153:00
1158:30
1204:15
1208:30
0912:00
0916:45
0922:00
0927:00
0931 :30
0935:20
1018:15
1022 :45
1026:45
1039:30
1043:45
1049:00
0913:00
Elevation
Angle
Increment
1/2
1
1
1
1
1
3
3
3
3,1
1/2
1/2
1
1/2
1/2
1/2
1/2

1
1
1
1
1/2
1
1
1/2
1
1
1/2
1
1
1/2
1
1
3
No. of
Lidar
Shots
15
15
15
27
13
20
28
29
29
28
17
26
16
20
19
29
29

9
27
27
27
19
25
24
27
25
24
28
24
21
30
24
23
30
Subtotal
No. of
Shots









219











465











759

Weather, Remarks
0800 : O 1/4 GF C
0900 : O 7 L/V
Plume Hdg ~ 245°



1400: /© 15 140/5
Plume Looping


0800: 100©/dDlO 090/5
Plume Hdg ~ 315°




1000: 1000 vd)/© 7
090/10

Plume Looping


0800 :E25 0 4R-090/15G25
Plume Hdg 270-290°










0800 :E35®8 090/5

-------
                                                              Table B-I (Continued)

Date
(1968)
5/28







5/29






5/30



5/31






6/1







Site
No.
3







5






2



6






6






Observational
Period
No.
9







10



11


12



13



14


15






Cross
Section
No.
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52

53
54
55
56
57
58
59
60
61
62
63
64



Azimuth
Angle
065
032
000
333
065
032
000
333
350
030
070
030
350
350
020
117
117
117

228
199
170
199
228
199
170
170
350
215
305
260


Elevation
Angle
(First)
20
25
25
25
20
25
25
25
15
15
12
12
20
20
20
28
25
28

10
15
15
15
15
20
20
90
85
90
90
90


Time
(Start)
(EOT)
1113:30
1116:30
1121:00
1126:40
1135:45
1139:45
1143:30
1148:20
0855:30
0900:00
0905:00
0912:15
1208:15
1210:10
1213:30
0844:00
0945:15
1018:15

0820:30
0824:45
0828:15
0831:15
0935:15
0940:15
0944:45
1018:00
1025:00
1030 :00
1034:00
1041 :00


Elevation
Angle
(Last)
3
3
3
4
3
2
2
4
2-1/2
2
4
2
2
2
2
4
5
4

1-2/3
2
3-1/2
1-1/2
3-1/3
3
3-1/2
15
6
12
6
5


Time
(End)
(EDT)
1116:00
1119:45
1123:30
1128:00
1138:00
1142:20
1147:00
1150:00
0859:00
0903:45
0908:15
0915:15
1209:30
1212:30
1215:45
0848:00
0948:30
1021:15

0823:30
0827:15
0830:40
0824:25
0938:45
0943:45
0948:15
1020:45
1027:30
1032:15
1037:00
1043:30


Elevation
Angle
Increment
1
1
1
1
1
1
1
1
1/2
1/2
1/2
1/2
2
1
1
1
1
1

1/3
1/2
1/2
1/2
1/2,1/3
1/2
1/2
5
5,3,2,1
5,3
5,3,1
5,3,2,1


No. of
Lidar
Shots
19
23
23
22
18
24
24
22
26
28
17
22
10
19
19
25
23
25

27
27
24
28

34
29
18
23
19
24
25


Subtotal
No. of
Shots







964






1105


1178







1378









Weather, Remarks
(Plume overhead,
shifting EWD, so moved
to Site 3)
Plume turning into water
cloud
1200:E12©3R — F 090/10


0830 :E50 © 5HGFC
Plume moving to ESE





0845; -X10 © 1/4R-FC
0945: E10 © 2R — FC
1015: E8 © 50 © 3R—
F 200/4
0800: E10 © 5H 220/3
Plume becoming water
cloud
0900: A 13 (D 25 © 5H
(Chopper report)


Ground fog till 1000
Plume overhead

Plume rising almost
vertically and then
spreading horizontally —
wind light/variable
Total No. of Shots 1487
CD
CO

-------
                                                                    Table  B-II
                                                         DATA SUMMARY,  15-24 OCTOBER 1968
Date
(1968)
10/15















10/16










10/17







Site
No.
6















16










16







Observational
Period
No.
1















2





3




4




5


Cross
Section
No.
1
2
3
4
5
6
7
8

9
10
11
12
13
14

15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Azimuth
Angle
270
300
330
270
300
330
270
300

330
300
300
300
300
300

145
100
55
100
100
100
255
230
230
230
230
090
090/270
090/270
090/270
090/270
090/270
090/270
090/270
Elevation
Angle
(First)
45
50
50
40
40
36
30
50

36
40
44
70
70
70

90
90
90
90
90
90
30
30
36
15
20
15
15
15
15
15
3
5
15
Time
(Start)
(EOT)
0932:00
0939:00
0945:30
0955:00
0959:00
1004:40
1032:30
1036:30

1044:00
1059:20
1116:00
1138:00
1143:00
1147:00

0852 :20
0916:00
0920:20
0934:00
0938:30
0943:15
1149:30
1153:20
1157:30
1200:10
1204:00
0903:30
0910:00
0916:30
0928:00
0936:00
1151:15
1201:45
1212:00
Elevation
Angle
(Last)
3
4
2
2
2
2
Time
(End)
(EOT)
0936:04
0943:11
0949:40
0957:50
1002:25
1007:25
2 1034:40
2 1041:00
1
2
2
2
1
1
1

40
5
45
5
5
6
2
2
1
1
1
90
6
6
5
5
5
5
5
1047:00
1102 :20
1118:50
1141 :30
1145:45
1150 :00

0855 :00
0918:15
0923:00
0937:00
0941 :50
0946:20
1151 :30
1155 :45
1159:00
1203:00
1206:25
Msg.
0914:25
0922 :20
0934:35
0942 ;20
1157:15
1207:10
1216:25
Elevation
Angle
Increment
2
2
2
2
2
2
2
2

2
2
2
3,2
3
3,2

5
5
5
5
5,2
5,2
2
2
2,1
1
1
5
5,2
5,2
5,2,1
5,3,2
5,3,1
5,4,3,2
5,4,3,2
No . of
Lidar
Shots
22
26
26
20
20
18
15
25

18
20
22
25
24
25

11
18
12
18
24
26
15
15
19
15
20
16
33
34
35
33
33
29
27
Subtotal
No. of
Shots














306











499







739
Weather, Remarks
0915 :Q 3 GF
Plume Hdg 022 ;









Strong vertical wind
shear in direction

1156: O 5-7H
light /variable





0945; O 7 HK 360/5
1145: O 8H 135/8





Plume Hdg 360=

0927: E60(D/dD8 090/5
Plume overhead
1216: 12008 060/8


CO
CO

-------
                                                            Table B-II (Continued)
Date
(1968)
10/18




10/20





10/21













10/22









Site
No.
17




21





22













6









Observational
Period
No.
6




7



8

9










10


11









Cross
Section
No.
34
35
36
37

38
39
40
41
42
43
44A
44B
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65

Azimuth
Angle
080/260
080/260
080/260
080/260

200/020
200/020
200/020
200/020
200/020
200/020
270
225
180
270
225
180
225
180
225
270
225
270
225
180
270
300
330
270
300
330
270
300
330

Elevation
Angle
(First)
3
3
3
3

3
45
14
14
2
20
24
26
16
24
26
16
26
16
26
24
26
45
60
60
15
16
15
15
16
15
15
15
15

Time
(Start)
(EDT)
0917:20
0928:20
0935:20
0941:00

0909:00
0916:15
0928:00
0937:00
1018:00
1038:30
0854:00
0856:40
0859:30
0903:00
0906:30
0909:30
0921:30
0925:00
0928:00
0930:30
0934:00
1023:00
1027:30
1033:20
0900:00
0903:00
0905:20
0921:45
0923:50
0925:45
0938:30
0940:35
0943:45

Elevation
Angle
(Last)
3
3
3
3

2
2
2
2
1
10
5
8
3
5
6
4
9
5
9
7
9
2
3
2
2
3
2
3
3
3
2
2
2

Time
(End)
(EDT)
0922:15
0932:30
0939:45
0944:20

0914:45
0919:00
0932 :00
0941:30
1024:20
1040:50
0855:40
0858:35
0901:20
0904:40
0908:20
0910:50
0923:40
0926:00
0929:40
0932:15
0935:40
1025:55
1030:30
1036:50
0901:20
0904:30
0907:30
0923:10
0925:10
0927:00
0939:45
0942 :00
0945:15

Elevation
Angle
Increment
5,4,3
5,4,3,2
5,4,3
5,4,3

5,4,3,2
5,3,2
5,2
5,2
5,2
10
2,1
2,1
1
2,1
2,1
1
2,1
2,1
2,1
2,1
2,1
3,2,1
5,3,2,1
5,3,2,1
1
1
1
1
1
1
1
1
1

No. of
Lidar
Shots
34
33
33
33

35
24
34
34
42
16
17
18
14
16
18
13
17
10
18
14
15
24
26
27
14
14
14
13
14
13
14
14
14

Subtotal
No. of
Shots



872






1057













1304










Weather, Remarks
0900: SOQD/dDs 110/8
Plume overhead

1100: 15® 80 CD/CDS
130/10
0900 : Ql5


0945: O I5 160/7
1015: O 5H
1100 : O 5H 220/10
0830: 50Q6H 270/3









0945: 400V(H)6H 135/5


1100: 25(D50(|)8 290/10
0840: /0 7 GF
Plume Hdg 020°





1015: /(D 7 080/5
1015: undulations on
top of plume
CD

-------
                                                             Table B-II (Continued)
Date
(1968)
10/22











10/23













10/24









Site
No.












6













11









Observational
Period
No.
12











13






14

15




16









Cross
Section
No.
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
Azimuth
Angle
270
300
330
270
300
330
270
300
330
300
300
300
220
220
180
140
220
180
140
220
180
220
180
140
190
180
110
070
030
110
070
030
070
070
070
070
Elevation
Angle
(First)
20
20
20
20
20
30
26
30
40
34
30
30
16
18
26
24
20
20
26
22
26
24
30
45
50
90
30
34
26
22
30
34
30
26
34
34
Time
(Start)
(EDT)
1134:00
1137:00
1139:15
1151:50
1154:15
1158:45
1227:00
1231:00
1234:45
1238:30
1241:15
1243:45
0850:15
0856:45
0859:45
0902:40
0909:00
0912:45
0916:00
0941:20
0946:30
1155:00
1158:45
1206:00
1218:00
1223:45
0930:00
0933:15
0936:00
0938:30
0941:00
0943:30
1002:00
1004:40
1017:45
1020:00
Elevation
Angle
(Last)
2
3
3
1
0
3
1
1
2
2
2
2
1-1/2
2
2
5
2
1
5
2
2
2
1
5
1
2
3
2
5
5
4
2
5
5
9
6
Time
(End)
(EDT)
1136:10
1138:30
1140:40
1153:25
1157:30
1201:50
1229:15
1233:00
1236:55
1240:30
1242:50
1245:05
0853:15
0858:30
0901:45
0904:45
0911:20
0915:50
0918:00
0943:45
0949:40
1157:40
1201:20
1209:30
1220:30
1227:10
0932:30
0934:40
0937:05
0940 :00
0942:30
0945:20
1003:40
1006:00
1019:30
1021:45
Elevation
Angle
Increment
2,1
2,1
2,1
2,1
1
2,1
2,1
2,1
3,2,1
2
2
2
1,1/2
1
2,1
2,1
1
1
2,1
2,1
2,1
2,1
2,1
5,3,2,1
3,2,1
5,3,2
2,1
2
2,1
2,1
2
2
2,1
2,1
2,1
2,1
No. of
Lidar
Shots
17
15
15
18
25
27
19
20
20
17
15
15
28
17
17
18
19
20
18
20
21
19
23
17
22
27
21
17
16
15
14
17
17
15
17
20
Subtotal
No. of
Shots











1665













1951










Weather, Remarks

1140: /(J)7 090/10

1050: Plume looping

1205: /
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                                                            Table B-II  (Continued)
Date
(1968)
10/24









Site
No.
11









Observational
Period
No.
16









Cross
Section
No.
102
103
104
105
106
107
108
109

110
Azimuth
Angle
070
070
070
070
070
070
070
070

070
Elevation
Angle
(First)
30
30
38
36
46
46
90
90

90
Time
(Start)
(EDT)
1032:30
1035:15
1047:30
1051:30
1103:30
1117:30
1134:00
1145:45

1202:00
Elevation
Angle
(Last)
9
8
5
6
4
2
8
4

4
Time
(End)
(EDT)
1034:10
1037:50
1050:30
1053:25
1105:45
1119:50
1136:30
1151:35

1204:45
Elevation
Angle
Increment
2,1
2,1
2,1
2
2
2
10,5
3,2
10,5
3 2
°,"
10 5
3,2
No. of
Lidar
Shots
15
22
28
16
22
23
23
25

25
Subtotal
No. of
Shots









2319
Weather, Remarks







1150: 80(J)l60©5H
180/10

co
en

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                  Appendix C
LIDAR DATA DIGITIZING AND CONDITIONING DETAILS
                       97

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                              Appendix C
            LIDAR DATA DIGITIZING AND CONDITIONING DETAILS
                          (by C. E. Brabant)

1•   Photographic Processing
     The lidar returns were recorded on Polaroid photographs and on
magnetic disk tracks in analog form.  These signals were then repro-
duced from the magnetic recordings and displayed repetitively on the
screen of a standard laboratory oscilloscope (Tektronix Model 555).  A
photographic transparency on 35-mm film was made of each oscilloscope
trace with an illuminated graticule superimposed on the background to
provide reference axes for scaling the photograph.  The time scales
used in the photographic frames were 2 )j,s/cm (3-km range full scale),
and when appropriate, 5 p,s/cm (7.5-km range full scale).  The vertical
amplitude scale was set at 100 mV/cm.
2.   Graphical-to-Digital Conversion
     A Model 300 CALMA Co. digitizer was used to convert the optically
enlarged photographic trace to numerical increments recorded on digital
magnetic tape.  The data on the photographs were automatically digitized
when the cursor was manually traced over the image of the lidar return
signal amplitude.  Scaling was performed at the beginning of each
digitizing-recording session and immediately preceding a change in
scale whenever this occurred.
     Engineering values in millivolts and microseconds were entered via
the digitizer keyboard, as were all other special control characters.
These were recorded on magnetic tape along with the records of the in-
cremental digital values describing the X and Y Cartesian coordinates
of the analog signal.  These values were recorded for equal increments
in time at a resolution of approximately 25 ns, corresponding to 3.8 m
in range.  The vertical scale resolution was 0.75 mV.  General accuracy
obtained in curve tracing is estimated to be no worse than one-half of
                                  99

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the trace width, which varied from approximately 10 to 20 mV, although
it is possible that larger deviations from the curve occurred infrequently.
3.   Transformation to Engineering Units and Conditioning
     A standard CDC 6400 computer program developed by the CALMA Co. was
used to recover the data, scaled in engineering units.  Much of the data
required special handling because of operator errors in entering control
characters via the keyboard,  foot-treadle,  and console pushbuttons of the
digitizer.  This step produced the first intermediate digital magnetic
tape and a control listing of the decimated data points.  This listing
also provided data for verifying the scaling factors used to convert
incremental values into scaled engineering values.
     A pair of special CDC 6400 computer programs were developed to
select data between predetermined starting and ending ranges (travel
time values for lidar return  signals) at equally spaced intervals.
Adequate spatial resolution was obtained by selecting every fifth point
in the data record, yielding  an increment of approximately 100 ns (15-m
range) between selected sample points.  The second  program of the pair
listed the entire output tape, point-by-point,  as a check for subsequent
processing.
                                   100

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               Appendix D

PLAN VIEWS OF HORIZONTAL PLUME POSITIONS
         FROM LIDAR OBSERVATIONS
                   101

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                               Appendix D
                PLAN VIEWS OF HORIZONTAL PLUME  POSITIONS
                         FROM LIDAR OBSERVATIONS

     To help  clarify the plume cross sections  from the October period
that are presented  in Sec. V, plan views  of  horizontal plume positions
derived from  these  cross sections are shown  on the following pages
(Figs. D-l  to D-9) .  By referring to these plan  views, the elongation
in the cross  sections caused by the lidar azimuth angle being nonper-
pendicular  to the plume axis may be determined.
   r-
           0"
         KEYSTONE
         STACKS
   FIGURE D-1   PLAN VIEW OF HORIZONTAL PLUME POSITIONS, 15 OCTOBER 1968
                Cross section numbers and times in EOT are shown beside each horizontal
                plume position.
                                    103

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     \
LIDAR SITE

  No. 16
                                  20 (0945)
                      \


                       \
     \l


      \l

      0
    KEYSTONE
     STACKS
              i




            I
                                 I
                                   I
                                     I
                                        I





                                      I
                                        I
                                          I
                                              16 OCTOBER 1968
                                          I l  I
                                                    1

                                                SCALE—km
                                                           TA-7289-43
FIGURE  D-2   PLAN VIEW OF HORIZONTAL PLUME  POSITIONS, 16 OCTOBER 1968
                                   104

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                                             30 (0939)
                                           27 (0912)
                                                         17 OCTOBER 1968
                                                  i i i  l
                                                              I	I
                                                       0      1       2
                                                          SCALE—km
                                                                     TA-7289-44
FIGURE D-3   PLAN VIEW OF HORIZONTAL PLUME POSITIONS, 17 OCTOBER 1968
                                     105

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                                    37 (0943)
                                              34 (0920)
    i I l  i
         18 OCTOBER 1968
         0      1      2
            SCALE—km
                                                                  TA-7289-45
FIGURE  D-4   PLAN VIEW OF HORIZONTAL PLUME POSITIONS, 18 OCTOBER  1968
                                  106

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KEYSTONE
 STACKS
                                                                40
                                                              (0930)    42
                                                                     (1021)
            20 OCTOBER 1968
              SCALE—km
                                 10
                                                                   TA-7289-46
    FIGURE D-5   PLAN VIEW OF HORIZONTAL PLUME POSITIONS, 20 OCTOBER 1968

       For those observation series  where the azimuth angle was held con-
  stant and the plume  structure  observed as  a function of time, the  first
  cross section in the series  is shown  at the proper position,  and subse-
  quent cross sections are  displaced slightly for graphic purposes to
  avoid superposition.
       The horizontal  plume boundaries  interpolated between cross sections
  are indicated by dashed lines  in the  figures.   It should be remembered
  that these illustrations  show  the  total horizontal projection of the
  plume.  At any given height, the plume would normally be narrower  than
  this.
       The cross section number  and  time (EDT) are shown beside each
  horizontal plume position.
                                     107

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o
oo
                                                                                                            LIDAR SITE

                                                                                                              No. 22
                                                                                          48

                                                                                         (0910)
                                                                                                              TB-7289-47
                         FIGURE D-6   PLAN VIEWS OF HORIZONTAL PLUME POSITIONS, 21  OCTOBER 1968

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                                                                      LIDAR SITE
                                                                        No. 6
63
(0939)|- 	 /* 	 LIDAR SITE
; / No. 6
//
//
// ''
(*( KEYSTONE Q
STACKS
1 	 IMll 1 1
72
(1228)
/
/
/
KEYSTONE
STACKS
                                                    /
                                                      /
                                                         /
LIDAR SITE
  No. 6
                                                                 22 OCTOBER 1968
                         1
                                                                       TA-7289-48


FIGURE D-7   PLAN  VIEWS OF  HORIZONTAL PLUME POSITIONS, 22 OCTOBER  1968

                                     109

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    23 OCTOBER 1968
                                     LIDAR SITE
                                       No. 6
\-
KEYSTONE S' '
STACKS^ ' 	 — -
0^---
III! 	 1
^ 	
— 79
(0857)
1
	 J 	
80
(0901)
|
               SCALE—km
                                                                   TA-7289-49
FIGURE D-8   PLAN VIEW OF HORIZONTAL PLUME POSITIONS, 23 OCTOBER 1968
                                  110

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                                                109 (1149)
                                                108 (1135)
                                                107 (1119)
                                                106 (1105)
                                                104 (1049)
                                                103 (1036)
                                                101 (1021)
                                                -99 (1005)
                                                 93 (0934)
                 LIDAR SITE
                   No. 11
                 24 OCTOBER 1968
0             1
   SCALE—km
                                                                   ©
                                                                 KEYSTONE
                                                                  STACKS
                                                                     TA-7289-50
FIGURE D-9    PLAN  VIEW  OF HORIZONTAL PLUME POSITIONS,  24  OCTOBER  1968
                                       111

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          Appendix E
LIDAR EYE-SAFETY CONSIDERATIONS
              113

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                              Appendix E
                    LIDAR EYE-SAFETY CONSIDERATIONS

     Although often exaggerated, the question of safety in the use of
experimental lidar systems should be carefully considered.
     The series of observations described in this report were carried
out with careful adherence to the safety procedures that have been de-
veloped and practiced by SRI teams over the last six years of field
experiments.  Some of the more  important aspects of the safety question
are described below.
     The Mark V lidar pulse is harmless to the skin, but could cause
eye damage in the form of a minute retinal lesion if the pulse were
viewed directly.  The lidar pulse takes the form of a cylinder of light,
initially 15 cm in diameter and 6 m long, traveling through the atmo-
sphere at the speed of light.  Each pulse is only 0.00000002 s (0.02 |_LS)
in duration, and the pulses occur approximately 5 s apart.  The lidar
is designed to totally prevent any emission of stray laser light from
any direction other than that in which the unit is pointed.
     Thus an eye hazard exists only at the exact instant of firing and
only in the precise direction the lidar is aimed.  The lidar is highly
directional:  the increase in diameter of the pulse with range (travel
distance) is very slight—from 15 cm at the transmitter to 1.3 m at two
miles range—so that the spatial extent of the hazard is confined to a
very narrow cone.  In this sense, the hazard from a lidar is directly
analogous to that from a rifle or other firearm, except that the magni-
tude of the danger is considerably less for the lidar.  This is because
the pulse can only cause eye damage, and even then, only a partial (lo-
calized)  loss of vision could result.  Generally this loss would take the
form of a blind spot ten times smaller than the natural one already present
(and unnoticed)  in every human eye at the location of the optic nerve.
     Our standard general safety procedures for field experiments (which
have proven worthy by use in many projects) are as follows:

                                  115

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(1)   Mechanical stops are placed on the equipment to con-
     fine the pointing angles to a specific field of view.
(2)   Aiming and firing is accomplished manually by an
     operator who uses an aiming telescope to monitor
     the field of view,  as well  as a large surrounding
     area.  This operator is the only person who can
     fire the lidar,  and he does not trigger the unit
     until he is sure the area is clear.
(3)   A separate observer equipped with binoculars also
     keeps the entire firing area under surveillance.
     This observer is equipped with an override switch
     to prevent firing of the lidar when  any human
     activity (airplane,  ship, etc.) is sighted in the
     firing area.
(4)   When not being fired,  the lidar is always rendered
     completely safe by a switch which discharges the
     capacitor bank furnishing high voltage to the laser
     flash lamps.  Without  this  high voltage supply,  the
     lidar cannot be fired.
(5)   As an additional precaution,  the stowage position
     of the lidar is such that it is never pointed at
     eye level.
                             116

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