United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/4-81-022

May 1981
Air
   USER'S  MANUAL  FOR  MIXING  HEIGHT  COMPUTER PROGRAM

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USER'S MANUAL FOR MIXING HEIGHT COMPUTER PROGRAM
                Robert F.  Kelly
        Air Management Technology Branch
      Monitoring and Data  Analysis Divisic
      U.S. ENVIRONMENTAL PROTECTION AGENCY
       Office of Air, Noise and Radiation
  Office of Air duality Planning and Standards
  Research Triangle Park,  North Carolina  27711
                    May 1981

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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers.  Copies are
available free of charge to Federal employees, current contractors and
grantees, and nonprofit organizations - In limited quantities - from the
Library Services Office (MD-35), Research Triangle Park, North Carolina
27711; or, for a fee, from the National Technical Information Service,
5285 Port Royal Road, Springfield, Virginia  22161.
                   Publication No. EPA-450/4-81-022

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TABLE OF CONTENTS
                                                                          Page
Abstract	      iv
List of Figures	       v
List of Tables	      vi
Acknowledgements 	     vii
1.0  Introduction	      1
2.0  Method Used	      1
3.0  Approximations	      5
4.0  Input Data Format	      6
5.0  Program Output	   13
6.0  References	   18
7.0  Program Listing	   19

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ABSTRACT
     A FORTRAN-!anguage computer program has been developed to estimate mixing
height values for use in the Empirical Kinetic Modeling Approach/Ozone Isopleth
Plotting Package (EKMA/OZIPP).  This program uses temperature, pressure and
height values measured at a surface site, and from atmospheric vertical profiles
(e.g., radiosondes).  The manual contains instructions on how to use the program,
including a description of the data needed, how to format the data, and an
explanation of the output from the program.  Examples of input and output are
also included.

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LIST OF FIGURES
No.                                                                   Page
 1.  Example of a Step-by-step Mathematical  Method for
     Estimating Mixing Heights 	   2
 2.  Graphical Example of How to Estimate a  Mixing Height	   3
 3.  Example of Data Input	10
 4.  Example of Data Output	14

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LIST OF TABLES



No.                                                                    Page



 1.   Examples of Data Needed to Find Mixing Heights	    8



 2.   Input Format Used by Computer Program 	    9



 3.   Example of Input and Output for a Maximum Mixing Height Case.  .   11



 4.   Example of Input and Output for a Mixing Height at 0800 LCT .  .   12

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ACKNOWLEDGMENTS



     Helpful suggestions for this report were given by Dr. Edwin L. Meyer and



Mr.  Norman C. Possiel.  Messrs. Warren P. Frees and William N. Hamilton helped



the author test, debug and punch copies of the computer program.  The User's



Manual was typed by Mrs. Carole J. Mask.
                                       vn

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1.0  INTRODUCTION
     This FORTRAN language computer program has been developed specifically to
estimate mixing height values needed by the Empirical Kinetic Modeling Approach/
Ozone Isopleth Plotting Package (EKMA/OZIPP).   The program was written in standard
FORTRAN and tested on a UNIVAC 1100 computer system.  Urban temperature and
pressure values and data from a nearby upper air sounding site are used to
estimate mixing height values for the urban area.  This program enables non-
meteorologists to estimate mixing heights from available data without using
complex graphs or methods.  The program statements are provided in Section 7.0
and a punched-card deck of the program may be obtained by writing or calling:
Mr. Robert F. Kelly, U.S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Mail Drop 14, Research Triangle Park, North Carolina
27711, (919) 541-5522.

2.0  METHOD USED
     Mixing heights can be found by following a series of mathematical steps
(like the example in Figure 1) or from a graph of temperature plotted against
height or pressure (such as the graph in Figure 2).  The mathematical method can
be a long, tedious procedure.  The graphical method, while easier to do, is less
precise.
     This program applies the mathematical version of the graphical method and is
based on the steps in Figure 1.  Measurements of temperature and pressure at the
surface and at levels aloft are used to calculate values of potential temperature
with height, as needed by the procedure.  Potential temperature is a meteorological

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          Step  1  —  For reference,  the  information at the top of Table A-4  should  be listed
     (e.g.,  date,  city, etc.).   If  the  morning mixing height 1s to  be calculated,  the 0800 LCT
     surface data  are  used.   If the maximum mixing height 1s to be  calculated, the data cor-
     responding to the tine  of  maxima  temperature (I.e., between 800-1800  LCT)  are used.  In
     the  row labeled URBAN SURFACE  DATA,  enter the following Information:   1) the  elevation of
     the  urban  temperature site 1n  meters above  sea level;  2) the surface pressure 1n millibars
     (this value 1s  PSf,j! *nd  3) the  surface temperature 1n degrees Celsus (*C).

               Convert the surface  temperature 1n collar four to degrees Kelvin  (*K) by adding
     273.2,  and enter  the result 1n colunn five.  This  value 1s T ^ ('IC).
Use Equation 1 below and the values just entered to calculate the potential
                                            0.1 *K)


                                             *286
     temperature at  the surface (6,,.  1n *K to  the  nearest  0.1 *K)  and  enter this  value under
     column six '8CK}'.
                                                 (1n mb)
          Step 2 — Using the temperature  sounding  data,  find  the  highest  pressure  level  other
     than the sounding's surface value that 1s  less than  the pressure  at the  urban  surface.*
     Fro* this pressure level  on the sounding,  enter the  height  (1f listed},  pressure  and
     temperature (1n »C) Into tht row marked "(2}"  on Table A-4.

          Step 3 — Convert the temperature at  this leVel  to the Kelvin  scale and enter  1n
     colusn 5.  Compute the potential  temperature  (6 )  to the  nearest  0.1 *K using the  pressure
     (P,  1n mb) and temperature (T  1n *K) at this  level  1n Equation 2 below:

                                       f p  H* mM  1-0.286
               Up C1n •« - Tp (in 1C) l^fljj y J                   (2)


     Enter the value of 9. found fron Equation  (2)  Into the  same row under the column  labeled
     "8CK}".            P

          Step 4 — If the potential temperature,  "Q," of the  last row that was entered  1s
     greater than the potential temperature 6 . .  and this 1s  the  first  level above the  surface,
     then 250 meters should be used as the mixing  height.  Otherwise,  go to Step 5.  If  1t  1s
     less than or equal to Osfc, then enter the height (If given), pressure and temperature of
     the next. lowest pressure Tevel found  on the sounding Into the next  row of Table A-4 and
     return to Step 3.

          Step S~— The rixlng height fs between the last two  levels entered  Into Table  A-4.   If
     height values are given for both of these  levels,  the elevation of  the mixing  height can  be
     found using Step 6.  If one of the levels  does not have  a height  value,  use linear  Inter-
     polation to find the pressure value for the potential temperature value  of C  .  + 0.1 *K.
     Enter this pressure value Into the row marked  "MIXING HEIGHT" at  the  bottom SrTable A-4
     under the column "PRESSURE 1n mb. *  Proceed to Step  7.

          Step 6 — From the two levels where height 1s given  on the sounding surrounding the
     mixing height level, use linear Interpolation  to find the height  (1n  meters ASL)  at the
     value C f  + Q.l'K (I.e., the potential temperature  C at  the  mixing height).   Enter the
     value foufid by linear Interpolation Into the row labeled  "MIXING  HEIGHT" under the  column
     "HEIGHT CmASLl." and proceed to Step 8.

          Step 7 -- Use linear Interpolation to find the  height above  sea  level of the mixing
     height using the pressure at the mixing height (found 1n  Step 5)  and  the pressure levels  on
     the sounding above and below the mixing height pressure  that  have both pressure and height
     values.  Enter the height value found Into the row "MIXING HEIGHT"  under the col USD marked
     "HEIGHT, (mASL)" and proceed to Step 8.

          Step 8 — Subtract the elevation of the urban site (mASL) from the height (mASL)  of
     the nrlxlng height.  The result 1s the height of the  mixing height 1n  meters above the
     surface of the city OaAGL}.  Enter this value Into Table A-4.

     NOTE; Despite the fact that pressure and height, and potential temperature and
           height, are not linearly related, linear Interpolation  does not produce
           significant errors over the limited ranges us*d above.

     *  For example,  1f the urban surface pressure 1s 285 mb,  and  the  sounding pressures are:
        1005, 1000, 963, 850 mb, etc., 9£3 mb 1s the "highest pressure level  that  1s less than
        the pressure  at the urban surface."  850 mb 1s the "next lowest pressure level*  needed
        1n Step 4.


Figure  1.    Example  of  a Step-by-step Mathematical Method  for  Estimating
              Mixing  Heights

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Figure 2.
This is a graphical example of the method in Figure 1.  The solid
line is the temperature sounding and the dashed line is the tempera-
ture the surface air ((&)) would have at different pressures (rising
without exchanging heat with surrounding air).  The air from the
surface will rise as long as it is warmer (i.e., less dense) than_
the surrounding air.  The mixing height according to this method is
where the air rising from the surface becomes colder (i.e., denser)
than the surrounding air and will not rise further.

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term for the temperature a parcel  of air would have if it were  moved  vertically,
without exchanging heat with the surrounding air,  to a pressure of 1000 milli-
bars.  The calculated potential  temperature of the surface air  is  compared with
the potential temperature calculated for the sounding level  nearest to the
surface (i.e., layer 1).  If the potential  temperature at the surface is greater
(i.e., wanner) than the potential  temperature of layer 1, the surface air will
rise through that layer because warm air is less dense than cold air.   The
potential temperature is computed for the next highest layer of air (i.e.,
layer 2) and all the layers above it (i.e., layers 3, 4,  etc.)  until  a layer is
found that has a potential temperature warmer than the surface  potential tempera-
ture.  When the air rising from the surface enters a layer of air that is warmer
(i.e., less dense) than it is, the surface air will stop rising.  This altitude
is the upper limit of the mixing of air from the surface and is called the
mixing height.  The height of the top of this well-mixed layer will determine
the vertical extent to which pollutants emitted near the earth's surface will be
diluted.

     The program described herein defines the mixing height as  the lowest altitude
where the potential temperature is greater than the surface potential temperature.
If a sounding has height values for all the pressure levels needed, the program
estimates the mixing height by linear interpolation from potential temperature
to height.  However, not all atmospheric soundings have  height values for each
pressure level.  Where  height values are missing,  the pressure value at the
mixing height is found  by linear interpolation of  pressure values associated
with potential  temperature values above and below  the mixing height.  The eleva-
tion of the mixing height is then found by  linear  interpolation of heights
associated with the previously described pressure  values.

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3.0  APPROXIMATIONS
     Since the points used to describe a temperature sounding (i.e.,  a vertical
temperature profile) are connected by straight lines, we can assume that tempera-
ture is linear with height between the plotted points.  Potential  temperature is
roughly linear with temperature and therefore no significant error results if
potential temperature is taken as being linear with, height between the reported
sounding levels.

     Some error may occur if height values are not given for each pressure
level.  If a pressure level does not have a height values temperature (and
therefore potential temperature) may not be linear wTth height between the
levels where height "alues are given.  Therefore, this program interpolates from
potential temperature to pressure and then from pressure to height.  Even though
potential temperature is not linear with pressure, the error is not significant
over the small pressure intervals often encountered.  The estimated pressure at
the mixing height is used to find the elevation of the mixing height by linear
interpolation using sounding levels that have both pressure and height.   While
pressure is not linear with height, detailed height and pressure values from
soundings taken for the St. Louis Regional Air Pollution Study show that linear
interpolation from pressure to height over the interval from 1000 to 850 milli-
bars (about 1500 meters) gives a range of 0 to 40 meters above the actual value.
This error will approach zero for low mixing heights and will not be significant
for maximum mixing heights, where accuracy of 50 to 100 meters is acceptable for
most purposes.

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     The change of mixing height due to errors in calculated potential  tempera-
ture cannot be evaluated since the error depends on the rate of change  of
temperature (and thus potential temperature) with height near the mixing height.

4.0  INPUT DATA FORMAT
     To compute the mixing height for the city being modeled, this program needs
the following:

          1)  upper air sounding data (e.g., National Weather Service,  local
urban radiosonde or helicopter spirals);

          2)  urban surface temperature and pressure at 0800 LCT* and at the time
of maximum temperature;

          3)  elevation of the urban temperature measurement in meters above sea
level, and
          4)  the climatological daily maximum mixing height value for summer
nonprecipitation days  (listed for some cities in Reference 1 [page A-3] and for
others in Reference 2).
If the pressure data are not available at the elevation of the temperature data,
other data  can be used if they are adjusted to the elevation of the temperature
measurement.  Additional information on how to obtain these data is given in
*   LCT stands  for Local Civil Time, which is the prevailing local time for a
    location.   In other words, LCT  is  Local Standard Time, unless the locality
    is on Local Daylight Time.

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Appendix A of the EKMA Guideline document.   Also, Table 1 gives the urban
surface and upper air data used in the examples explained below.
     The card format to be used to enter the data tnto the program is in Table 2.
The first number on card 1 tells the program that it is estimating the mixing
height for either 0800 LCT or the maximum mixing height.  The second number on
the first card is the climatological daily maximum mixing height value.  This
value allows the program to check for unusual estimated mixing  heights.  The
urban surface data are contained on the second data card.  Sounding data should
be entered on the following cards, except for the surface data  from the sounding,
which was replaced by the urban surface data entered on card 2.  In Figure 3, the
surface and sounding data used to calculate maximum mixing height is used as an
example to explain the input data.  The sounding data must be entered in order of
decreasing pressure (i.e., increasing height).  Sounding levels with a pressure
greater than the urban surface pressure or a height less than the urban surface
height will be ignored by the program.  Additional instructions and cautions are -
given in the program listing.  Significant comments on program  operation are
marked with an asterisk (*) in the program listing.

     Tables 3 and 4 show the input and output for maximum and 0800 LCT mixing
height examples, respectively.  Users should attempt to replicate the examples
illustrated in Tables 3 and 4 using their own computer system prior to using the
program for general application.

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          Examples of me Date Needed for This Method
Hour Stertinc at, LCT
          9
         10
         11
         12
         13
         14
         15
         16
         17
         18
        Surface Data

           Temperature "C

                22.2
                23.9
                25.8
                27.
                28.
                29.
                30.
                30.4
                30.8
                31.4
                31.2
                  Pressure,  mb

                     1010.3
                     1010.7
                     1010.8
                     1010.6
                     1010.3
                     1010.0
                     1009.6
                     1009.2
                     1008.8
                     1008.6
                     1008.5
                           Soundino Data
          1200 GKT Soundinc
                                    0000 _GMT Sounding
Pressure (mb)  Heloht (m ASL)  Temp. (°C)    Pressure (mb)  Height (rc ASL)  Temp. (°C)
   S 1015*
   K 1000
   S  957
   hi  850
   S  827
   S  817
   hi  700
   S  680
  -S  661
   S  60E
   f,  500
   S  451
   S  ^£2
      43E
   K  400
   S  38£
   S  349
   S  324
   K  300
   S  267
   K  250
   K  200
   hi  1 50
   S  14£
  139

 1550


 3168



 5860



 7560
 22.
 22.
10890
12370
14190
 24.4
 16.2
 14.2
 12.6
  4.6
  5.6
  5.6
  0.4
 -£.3
 -£.3
-12.7
-13.9
-IE.7
-20.1
-26.3
-29.7
-23.7
-39.5
-47.7
-51.7
-60.9
-61.5
 S 1012*
 hi 1000
 K  850
 S  831
 S  791
 S  778
 S  760
 hi  700
-S  628
 S  560
 hi  500
 K  400
 S  371
 y.  300
 S  265
 hi  250
 S  205
 hi  200
 K  150
    127
    120
S
S
M  100
Y.   70
    50
    30
    20
    15
                             hi
                             hi
                             hi
                             S
                    8*
                  114
                 1537
                 3164


                 5860
                 7560

                 9650

                10900

                12370
                14190
                 16690
                 18900
                 21040
                 24350
                 27030
       y, = Mandatory Levels and S = Significant Levels
       The 0000 GMT Sounding is the following day in GMT.
       * The lowest level of the soundinc should not be used in the mixing
         height calculations for EK
 31.0*
 30.6
 16.4
 13.2
 11.8
 11.2
  7.0
  1.6
 -1.5
 -7.3
-18.9
-21.7
-33.1
-39.9
-42.9
-52.9
-53.3
-61.1
-64.9
-61.7
-63.2
-58.5
-54.5
-49.9
-44.7
-42.1
     Printed copies of National Weather Service sounding data can be ordered
     by h-riting to:  National Climatic Center, Federal Building, Asheville,
     Uo'-tn Carolina  26801  or call inc  (704) 258-2850, extension 683.  The  cost
     (.as of April 1981)  is  60 cents per sounding, with a minimum order of  S5.00.
                                             8

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Table 2.  Card Input Format
Card
Number

  1
Variable
  Name

MNMX
           CLIMPM
Column
Number(s)
              5-11
FORTRAN
Format

  II
                F7.0
Data to be Entered

Mixing height to be computed:
0 = 0800 LCT
1 = Maximum

Climatological daily maximum
mixing height value in meters
above ground level
           ELEV


           PRESS

           TEMP
              2-9


             10-17

             18-23
                          URBAN SURFACE DATA

                F8.1       Height in meters above sea
                          level

                F8.1       Pressure in millibars

                F6.1       Temperature in degrees Celsius
  3 to
  last
  card
ELEvS  (As on card 2, except input is the

PRESS) -I sounding data without the sounding

TEMP J /surface data
Note:   Pressure reduced to sea level should not be used unless the height
        of the pressure level is at sea level.

      - This program was designed to use temperatures to the nearest 0.1°C.
        Temperatures measured in degrees Fahrenheit should be converted to
        the nearest 0.1°C.   As explained in Section 2.0, pressure can be
        rounded to the nearest whole millibar and height to the nearest 10 meters.

      - Missing values can  be entered using a height greater than 90000 or a
        temperature greater than 900.  If a level does not have a pressure
        value, do not use that level in the input for the program, since the
        program cannot use  a level unless a pressure value is given.

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Card Number
1.
2.
3.
4.
5.
6.
7.
8.
9.
1 1
62.
114.
1537.
99999.
99999.
99999.
99999.
3164.
700.
0 1008.
0
0
9
9
9
9
0
1000.
850.
831.
791.
778.
760.
700.
6
0
0
0
0
0
0
0
31.
30.
1
1
1
1
1

6.
5.
3.
1.
1.
7.
4
6
4
4
2
8
2
0
Explanation

Card Number
     1.
     2.


     3-9.
"1" indicates that the data is for a maximum mixing height
estimation.  1700 meters is the climatological daily
maximum mixing height.

Urban surface elevation (62.0 meters above sea level),
pressure  (1008.6 millibars) and temperature (31.4°C).

-Sounding data (elevation,-pressure, temperature).
99999.9 = missing height value.
Figure 3.  Data Input for Maximum Mixing Height  Example
                                         10

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Table  3.   Example for Maximum Mixing Height
        INPUT:
               1700.
             62.0
            11*.0
           1537.C
          99999.9
          99999.9
          99999.9
          99999.9
           3164.0
         8EOF
100E.6
100C.O
 850.0
 831. 0
 791.0
 778.0
 760.0
 700.0
31.*
30.6
16.*
15.*
13.2
11.8
11.2
 7.0
         OUTPUT:

HEIGHT
MASL
62. C
1U.O
1537.0
99999.9
99999.9
99999.9
99999.9
316*. 0

PRESSURE
MB
1008.6
1000.0
850.0
831.0
791.0
778.0
76C.C
700.0

TEMP.
OE6.C
31.4
30.6
16.4
15.4
13.2
11.8
11.2
7.0
POTENTIAL
TEMP.
DE6.K
303.9
303.8
303.4
304.3
.0
.0
.0
.0
         MAX. MIXING HEIGHT  1613. METERS AGLi   837.3  MILLIBARS.

         THE CLIMATOL06ICAL MAXIMUM MIXING HEIGHT VALUE  ENTERED WAS  1700. METERS A6L.
                                            11

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Table  4.   Example for  0800 LCT Mixing Height
           INPUT:
                C  1700.
                £2.0  1010.3  23.2
                139.0  100C.O  23.0
99999.9
1550.0
99999.9
99999.9
3168.0
3EOF
967.0
850.0
827.0
817.0
70C.O

24.4
16.2
14.2 ----- - ---- -
13.6
4.6

            OUTPUT:
             HEIGHT  PRESSURE   TEMP.
              MASL       KB     PEG.C
               «.C   1010,3     23.2
              135.0   1000.0     23.0
POTENTIAL
  TEMP.
  DE6.K
  295.5
  296.2
             ACCORDING TO THIS METHOD, THE LOWEST LATER OF THE SOUNDING IS
             NOT WELL MIXED.  THIS IMPLIES * MIXIMC HEIGHT OF ZERO PETERS AGL.
             THE URBAN MIXING HEIGHT IS GREATER THAN THE   0. METER
             MIXING HEIGHT COMPUTED BY THIS METHOD.  250 METERS A6L
             SHOULD BE USED FOR THE EKMA 0800 LXT MIXING HEIGHT.

             THE CLIMATOLOGICAL MAXIMUM MIXING HEIGHT VALUE EKTERED WAS  170C.  METERS
                                             12

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5.0  PROGRAM OUTPUT
     The output from the program gives the height of the mixing height in meters
above the surface elevation entered on data card 2.  Figure 4 explains the
output from the input data in Figure 3.  When unusual situations occur (e.g., not
enough data entered, possibly unrealistic mixing height values), the program
informs the user by various messages displayed at the end of the output.   Most of
these messages direct the user to take some action or to refer to the EKMA Guide-
line document  for further information.  These program warnings and why they
occur are discussed below.  When a problem occurs, the first step should be to
check that the data were entered correctly.
OUTPUT -
   THE URBAN MIXING HEIGHT IS GREATER THAN THE 	 METER
   MIXING HEIGHT COMPUTED BY THIS METHOD.  250 METERS AGL
   SHOULD BE USED FOR THE EKMA 0800 LCT MIXING HEIGHT.

EXPLANATION -
     - A mixing height less than 250 meters above ground level has been estimated
by the program for the 0800 LCT mixing height.  Data from St. Louis and Philadelphia
temperature soundings taken by helicopter indicate that this program's method of
estimating the mixing height underestimates the depth of the early morning urban
mixed layer.
OUTPUT
   MIXING HEIGHT VALUE MAY BE TOO HIGH.
                                        13

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HEI6HT
KASL
62. C
114.0
1537.0
99999.9
99999.9
99999.9
99999.9
3 1 64 . 0
_ -
PRESSURE
KB
1008.6
1000.0
850.0
831.0
791.0
778 .t)
76C.O
700.0
- ^_ ~ -_ - ;-
TEKP.
DE&.C
31,4
30.6
16.4
15.4
13.2
1t.fi
11.2
7.0
POTENTIAL
TEKP.
OEG.K
303.9
303.8
303.4
304.3
.0
.0
.0 -
.0
           I. BUIKG HEIGHT   1612. METERS A6Lt   837.3 KILLIBARS.

        THE CLIBATOL061CAL  HAXIHUK K1XIN6 HEI6KT VALUE EKTEREC UAS   1700. BETERS ACL.
 Explanation -

 - If height values are  input  in meters  above  ground  level  (mAGL),  the output
    n the "height" column will  be  in mAGL  instead  of meters  above sea level
   (mASL) as labeled.  The mixing  height value  is  in meters  above the urban surface
   elevation entered in columsn 2  through  9  of  card  2.

   Values of height, pressure  and  temperature  in  the output  are the same as the
   input values.  The values of potential  temperature  in  degrees Kelvin by the
   program where needed.

   The mixing height is between 850 and 831  millibars  (MB)  at a potential
   temperature of 304. 0°K.  The height values used for interpolation are at
   850 and 700 MB and the mixing height is estimated to be  at 1613. meters above
   the urban surface elevation of  62 tnASL  entered  on card 2  of the input.'   The
   estimated mixing height  is  significant  to the  nearest 10  meters at best.
Figure 4.  Detailed Example of Output  for Maximum Mixing  Height Estimation from
           the Input Shown in Figure 3.
                                         14

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EXPLANATION
     - For 0800 LCT mixing height - estimated value is greater than 500 meters
above ground level.  An incorrect value for urban surface temperature may have
been entered.
     - For the maximum mixing height - estimated value is more than twice the
climatological value entered on card 1.  An incorrect value may have been entered
for the urban surface temperature or the sounding may be unrepresentative of the
region being modeled.
OUTPUT
   MIXING HEIGHT IS LOW FOR A MAXIMUM MIXING HEIGHT.

EXPLANATION
     - The estimated maximum mixing height is less than one-third the climato-
logical value entered on card 1 of the data for the program or is less than
250 meters above ground level.  The sounding may be from a location that is much"
warmer than the urban area being modeled.  If that is true, another more repre-
sentative site should be found.
OUTPUT
   SEE **USE OF CITY-SPECIFIC EKMA FOR OZONE SIPS**
   FOR ALTERNATIVE  PROCEDURES
EXPLANATION
     - This is a followup for other messages when possible solutions are outlined
in the EKMA Guideline document.
                                        15

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OUTPUT



   ACCORDING TO THIS METHOD, THE LOWEST LAYER OF THE SOUNDING IS



   NOT WELL MIXED.  THIS IMPLIES A MIXING HEIGHT OF ZERO METERS AGL.





EXPLANATION



     - Even though this method gives a mixing height of zero meters  above ground



level, either a low morning mixing height exists or a problem has been caused by



the data used for the maximum mixing height values.  See other statements listed



by the program output for possible solutions.  The program prints the statement



because the potential temperature of the surface air is lower (colder) than the



potential temperature of the layer above it.





OUTPUT



   DATA FINISHED BEFORE MIXING HEIGHT FOUND - POSSIBLE BAD SURFACE DATA.





EXPLANATION



     - Check to_ see  ifthe correct urban surface temperature value was entered



on card 2.  Otherwise the mixing height is above the highest sounding level



entered into the program.  Also check to see if the sounding used is representa-



tive of the urban region.





   MIXING HEIGHT WAS FOUND BUT HEIGHT VALUE ABOVE  MIXING HEIGHT LEVEL



   OF 	 MILLIBARS IS NEEDED FOR  INTERPOLATION.





EXPLANATION



     - To do linear  interpolation from pressure to height, the program needs



height values above  and below the estimated mixing height.   If no upper  height
                                        16

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value exists, use a height value from another nearby sounding on the same day or
a height value from the U.S. Standard Atmosphere.
                                        17

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6.0  REFERENCES

 1.  U.S. Environmental Protection Agency, Guideline for Use of City-specific
     EKMA in Preparing Ozone SIPs, EPA-450/4-80-027 (March 1981).

 2.  G. C. Holzworth, Mixing Heights, Wind Speeds, and Potential  for Urban
     Air Pollution Throughout the Contiguous United States, AP-101, U.S.
     Environmental Protection Agency, Research Triangle Park, North Carolina
     (January 1972).
                                         18

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7.0   PROGRAM LISTING
TDS«MXHGT(1
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           ).MXHGT/EKHA
                 • *»••»*»*•»•••••*»•*•»••*»*•»**»**-»•*»*•»•»•*••••****»*»*»»***•••»*HHX00100
                 "•COMPUTERIZED METHOD FOR ESTIMATING ATMOSPHERIC  MIXING  HEl6HTS*«*MHX00200
                 ••••••••••VERSION FOR USE WITH EKHA/OZIPP,  MARCH 25t  1981••••••••••MHX00300
                 ***•*»***•»••*»»••••«»••»»•»»•»•**» • *••**•*••-»»»** ••••••••••••**»»»MHX 00400
                 NOTE: STARRED COMMENTS (•) MUST BE FOLLOWED  FOR THIS  PROGRAM        MHXOC500
                 TO WORK PROPERLT.                                                   MHX00600
                                                                                     MHX00700
                                                                                     MHX00800
                                                                                     MHX00900
                                                                                     MHX01000
                                                                                     MHX01100
                                                                                     MNX01200
                                                                                     RHX01300
                                                                                     MHX01400
                                                                                     MHX01500
                                                                                     HKX01600
                                                                                     MHX01700
                                                                                     MKX01800
                                                                                     MHX01900
                                                                                     MHX02DOD
                                                                                     MHX02100
                                                                                     MHX02200
                                                                                     HHX0230D
                                                                                     M.HX02400
                                                                                     MKXC2500
                                                                                     MHX02600
                                                                                     MHX0270C
                                                                                     MHX0280C
                                                                                     MHX02900
                                                                                     MHX03000
                                                                                     MHX03100
                                                                                     MKX03200
                                                                                     MHX03300
                                                                                     MHX0340C
               •THE URBAN SURFACE DATA MUST BE  INPUT  FIRST IN PLACE OF THE SOUNDING MHX03500
                SURFACE DATA AND MUST HAVE OBSERVED VALUES FOR ELEVATION,  PRESSURE
THE
  THIS PROGRAM FINDS THE MIXING HEIGHT  USING  URBAN  SURFACE  AND
  RADIOSONDE SOUNDING DATA.  THE PROGRAM  WAS  WRITTEN  BT  BOB KELLY
  OF EPA'S AIR MANAGEMENT TECHNOLOGY BRANCH AND  GIVES THE  MIXING
  HEIGHT BY FINDING THE LOWEST HEIGHT ON  THE  SOUNDING WHERE THE
  POTENTIAL TEMPERATURE IS GREATER THAN THE POTENTIAL TEPERATURE
  AT THE SURFACE.
    DIMENSION ELEV(50),PRESS(50),TEMP(50),PT(50)
    REAL M1XHT

  UNIT NUMBERS FOR INPUT AND OUTPUT  FOR THIS  PROGRAM  CAN BE CHANGED
  BT THE USER IF UNIT NUMBERS OTHER  THAN  THE  '5' (FOR CARD  READER)
  AND THE '6' (LINE PRINTER) USED  IN THIS PROGRAM ARE NEEDED.
  THIS CAN BE DONE BY CHANGING THE VALUES
  DATA CARD BELOW TO THE INPUT AND OUTPUT
    INTEGER IN,OUT
    DATA IN/5/,OUT/6/
    NN - 0
    READ(Ih,250)  MNMX, CLIMPM
250 FORMAT (3X,- II, F7.0)
 •'MNMX'- FOR 0800 LCT ENTER '0',  FOR MAXIMUM MIXING  HEIGHT ENTER
 •"CLIMPM' IS THE CLIMATOLOGICAL MAXIMUM  MIXING  HEIGHT
  IN METERS ABOVE GROUND LEVEL.

 •IF MORE THAN 50 LEVELS ARE TO BE USED,  THE  SIZE OF  THE ARRAYS
  IN THE DIMENSION STATEMENT (ABOVE) SHOULD BE INCREASED TO THE
  MAXIMUM NUMBER OF LEVELS TO BE USED.
FOR "IN* AND 'OUT' ON
UNIT NUMBERS NEEDED.
                AND TEMPERATURE.  THE SOUNDING  DATA  MUST BE ENTERED IN ORDER OF
                INCREASING HEIGHT (I.E.  DECREASING PRESSURE).

               •ALL LEVELS ENTERED MUST  HAVE  PRESSURE VALUES.

               •THE LAST LEVEL OF THE SOUNDING  DATA  FOR  THIS PROGRAM MUST
                HAVE OBSERVED VALUES FOR HEIGHT,  PRESSURE AND TEMPERATURE.
                  READ(IN,150) ELEVM),  PRESSd), TEMP(I)
              150 FORMAT (2F8.1, F6.1)
               *     'ELEV  * HEIGHT ABOVE SEA  LEVEL IN METERS.
                     'PRESS' * PRESSURE  IN MILLIBARS.
                     "TEMP"  « TEMPERATURE TO THE NEAREST 0.1 DEGREES CELSIUS.
               •FOR MISSING VALUES USE THE FOLLOWING:
                   FOR HEIGHT      ('ELEV')   USE  '99999.9',
                   FOR PRESSURE    ("PRESS')  MISSING VALUES ARE NOT ALLOWED,
                   FOR TEMPERATURE ('TEMP')   USE   '999.9'.
                  PT(1) * (TEMP(1>+273.2)*((PRESS(1)/1000.>«« -0.286)
                  PT(1) * (AINT((PT<1)f0.05)*10.))/1C.
                'PT' IS THE POTENTIAL TEMPERATURE TO THE NEAREST 0.1 DEGREES
                KELVIN FROM VALUES OF TEMPERATURE AND PRESSURE AT LEVEL (L).
      MHX03600
      MHX03700
      MHX03BOC
      MHX03900
      MHX04000
      MHX04100
      MHX04200
      MHX04300
      MHX044QO
      HHX04500
      MHX04600
      MHX04700
      MHX04800
      MHX04900
      MHX0500C
      MHX05100
      MHX0520C
      MHX05300
      MHX05400
      MHX05500
      MHX05600
                                            19

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  THE URBAN SURFACE DATA  IS  AT  L  *  1.
    L * 2
 20 READCIN,150,  END*55>  E,P,T
    IF 

= N-1 60 TO 33 41 PRESMH = (CPRESS(L)-PRESS(h))»l(PT(1)*0.1)-PT(L))/ 7 (PT(L)-PT(H))>+PRESS(L) PRESRH = (AINT((PRESKH+O.C5)*1C.))/1C. "PRESKH' IS THE PRESSURE AT THE RIXIN6 HEIGHT TO THE NEAREST 0.1 MILLIBARS. 50 IF (ELEVCK) ,6T. 90000) 60 TO 40 60 TO 51 40 K =• K + 1 - READ(1W,15S, EKD«65) ELEVCK), PRESS


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11*           7 *    MASL       MB      DE6.C     DEC.*')                           MHX11400
115            t>0 1001 M « 1,K                                                    MHX11500
116            WRITE
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                                    TECHNICAL REPORT DATA
                             (Please read Insmicrions on The reierse before completing]
        NO.
      EPA-450/4-81-022
                               2.
                                                             3. RECIPIENT'S ACCESSION NO.
U T'TLc AND SUBTITLE

  User's  Manuel  for Mixing  Height Computer Program
                                                          5. REPORT DATE
                                                               May 1981
                                                             6. PERFORMING ORGANIZATION CODE
  AUTHOR1S)
  Robert  F.  Kelly
                                                             8. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
U.S.  Environmental Protection Agency
Office  of  Air Quality  Planning and Standards
Monitoring and Data Analysis  Divisipn/AMTB   (MD-14)
Research Triangle Park,  North Carolina  27711
                                                             10. PROGRAM ELEMENT NO.
                                                             11. CONTRACT/GRANT NO.
 12. SPONSORING AGENCY NAME AND ADDRESS

   Same
                                                           13. TYPE OF REPORT AND PERIOD COVERED
                                                              4. SPONSORING AGENCY CODE
 IE. SUPPLEMENTARY NOTES
   Supplements EPA-450/4-80-027, "Guideline  for Use of City-specific EKMA in Preparing
   Ozone SIPs."
 16. ABSTRACT
       "A FORTRAN-!anguage  computer program  has  been developed  to  estimate mixing
   height, values for  use  in the Empirical  Kinetic Modeling Approach/Ozone Isopleth
   Plotting Package  (EKMA/OZIPP).   This program  uses temperature,  pressure and
   height values measured  at a surface site,  and from atmospheric  vertical profiles
   (e.g., radiosondes).   The manual contains  instructions on how to use the program,
   including a description  of the data needed,  how to format the data, and an
   explanation of the  output from the program.   Examples of input  and output are
   also  included.      ~    	""
                                 KEY WORDS AND DOCUMENT ANALYSIS
                   DESCRIPTORS
                                             b. IDENTIFIERS/OPEN ENDED TERMS  C. COSATI T'ieid/Group
   Mixing Height
   Computer  Program
   EKMA
   OZIPP
 •£ DISTRIBUTION STATEMENT

   Unlimited
                                              19. SECURITY CLASS (This Report)
                                                    Unclassified
                                                                           21. NO. OF PAGES
                                                20 SECURITY CLASS (This page)
                                                      Unclassified
                                                                           22. PRICE
    Forr- I22C-1 (Rev. 4-771    PREVIOUS EDITION is OBSOLETE

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