Running OZIP: Command Options

Overview

The OZIP program has been installed on an SGI workstation at the Shodor Education Foundation. To run the program, a forms-based interface allows the user to specify options and commands for a run. Simply by clicking on the "Submit" button, an input file is created, the program is run, and output files of various types are created "on-the-fly" and displayed, based on the users's desires. Most of the information presented below is designed for the user who is creating input files from scratch, but is useful for users who create input files with the help of the form.

The input file is a text file consisting of a series of options and commands. The input file can contain the names of commonly used "include" files that are inserted into the text of the input file. This is done by inserting the character "@", followed by the complete filename of an "include", or pre-built, file. More than one include file may be used.

Again, the primary purpose of the Web interface is to relieve the modeler of the inconvenience of having to pay attention to coding syntax and structure. We have eliminated several of the available OZIP options in the Web interface to reduce the turn-around time needed for you to get your results.

The information below comes from several program summaries and users guides.

The general rules for the format of an input file and include files are:

the first four letters of a command are usually significant
top level commands must be followed by ">", and commands end with a "<"
case is not important for the version being used in this example. It is important for some versions on some platforms. Lower-case is being used in this version.
comments are allowed between { } and ( ), or on lines where the first character is "!"

Command Options

NOTE: a number of options that are available are not described here. These options, such as ECHO (which lists the input file as it is read by the program) are automatically inserted or eliminated in the forms-based version. Key words that will appear in the input file are in bold print. Capital letters are used to show MANDATORY parts of the commands or options. In some cases, you will not see mandatory key words, since these have been replaced by pre-existing files, which are prefaced by the symbol "@".

Chemical MECHanism

The user is not provided with the option to custom-build a mechanism from this interface; rather, one of two pre-established mechanisms are available:

Carbon-Bond Mechanism IV: this mechanism is described in a separate reading
Regional Acid Deposition Model (RADM) mechanism : this mechanism is described in a separate reading

A detailed description of the input files for chemical mechanims is available for review.

ZENith Angle Dependence of Photolysis Rates

Zenith allows the user to vary the rates of photolytic reactions relative to the angle of solar elevation (which is related to the spectral distribution of actinic flux). The values in these tables are input for 10 zenith angles (0 through 70 in increments of 10, and 78 and 86 degrees from zenith). A cubic spline interpolation is performed to find the factor value for the current zenith angle.

The user is not provided with the option to custom-build a zenith file from this interface; rather, one of two pre-established zenith files are available:

Chemical REACtivities

The user is provided with the option to include one of three pre-built reactivities datasets or to custom-build a reactivities from this interface. Reactivities are described in a separate reading. The options available to the modeler are:

TITLE of simulation

A text field up to 72 characters. This option allows the user to insert a text string defining the simulations.

PLACE of simulation

Place has the following fields:

CITY = name;
LATitude = number, (in degrees north)
LONGitude = number, (in degrees west)
TZone = number, (based on the local time zone, Eastern Daylight Time = 4.0, Pacific Daylight Time = 7.0)
Year = number,
Month = number,
Day = number;

METeorological conditions

DILution = (activates the characteristic mixing height curve based on the following input information:
- MHINit = number, (the initial mixing height in meters)
- MHFinal = number, (the final mixing height in meters)
- TINit = number, (the starting time of mixing height increase)
- TFInal = number; (the ending time of mixing height increase)
TEMPerature [ntemp, tunit] = t1, t2, t3, ... tntemp; (allows input of average column temperature values at the beginning and end of each simulation hour. ntemp is the number of vlaues input, which is usually the number of hours+1. tunit specifies the temperature scale used on input, either Kelvin, Celsius, or Farenheit.)
PRESsure [punit] = number; (the constant pressure to be used throughout the simulation. punit specifies the pressure scale to be used, with choices being atmospheres (AT), Torr (mm of Hg) or inches of Hg.
RH [wnum] = w1, w2, w3, ... wnum; (allows input of relative humidity at the beginning and end of each simulation hour. wnum is the number of values input, which is usually the number of hours+1. Because TEMP and PRES values are needed to calculate water concentrations from RH, this option must follow the TEMP and PRES options or an error will occur. There is no default for RH.

BOUNDARY conditions

This option controls the various concentrations, reactivities, and deposition rates that occur at the physical boundaries of the reactin column and at the beginning of the simulation.

Base Depositions: the forms-based interface requires you to use the base deposition values contained in a fixed file
IFRACTION_NO2 = fraction (this is the NO₂/NO_x fraction for the NO_x that is present due to controllable emissions at the start of the simulation. A unitless value.)
TRANSPORT = (controls the initial concentrations of O₃, NO_x, VOC, and CO in the surface and aloft layers that are due to transport. The SURFace concentrations are used to account for the initially present mass in the surface layer that is due to transport. In the simulation, this is added to the initial mass resulting from controllable emissions (input with the CALC, EKMA, or ISOP options.) and the non-controllable mass input with INIT option. The ALOFT mass is added into the surface layer as the mixing height rises. All units are in parts per million (ppm)
```
O3SURFACE = concentration,
O3ALOFT = concentration,
VOCSurface = concentration,
VOCAloft = concentration,
NOXSurface = concentration,
NOXAloft = concentration,
COSUrface = concentration,
COALoft = concentration;
```

Emissions Inventories

The modeler has the option of describing post-8 a.m. emissions either as fractions or as mass emissions. Regardless, the program converts all values to emissions fractions.

To input emissions, the user has two optional methods: EMIS or MASS. Only one method may be used with each simulation. This option must follow MET and BOUN, and precede CALC, ISOP, and EKMA. Only 3 species (VOC, NO_x and CO) are allowed for EMIS but up to 10 may be used with the MASS option.

The differences between EMIS and MASS are described next. These options have in common the following: In the option command line, the user must include the number of hours that values will be given for. All species must use the same number of hours. VOC, NO_x and CO are unique groups because the emissions of these species are varied in EKMA and ISOP calculations. The species included in the VOC group and the fraction of total VOC that each comprises are input using the BOUN/REAC and MECH options. NO_x consists of NO and NO₂ and the ratio of NO-to-NO₂ for both the initial surface layer and the emissions can be given in BOUN/REAC. An emission ratio table will be printed on output. Regardless of the method used, the output will show the ratio of emissions to initial concentration for all emitted species or groups. These ratios are calculated at the initial mixing height, a temperature of 298.15 K, and the specified simulation pressure. During simulation the program continuously accounts for changes in the volume of the column (changing mixing height) and air density (temperature) before the mass of emissions is added to the air column. A second table is also printed showing the mass emission rates in (kg/km² per hour).

Input of hourly EMISsions EMISsions [numhrs] > VOC = em1, em2, .... emnumhrs, NOX = em1, em2, .... emnumhrs, CO = em1, em2, .... emnumhrs;
EMIS allows the user to input hourly emission fractions that are directly ratioed to the initial surface concentrations of controllable VOC, NO_x and CO emissions (the initial concentrations are input in the CALC, EKMA or ISOP options). The emission fractions should be calculated at the same mixing height as the initial, controllable surface concentrations; the program will automatically account for later changes in mixing height. Since this is a direct ratio to initial values given elsewhere, conc (concentration) is not used and mw (molecular weight) is not needed for conversion. Also, if there are not enough hours of data given to fill the simulation period, values of 0.0 are assumed after the emission period ends.
Input of hourly MASS emissions:
MASS allows the user to input hourly emission mass for up to 10 species or groups in units of kg/km² per hour. An initial concentration (in units of ppm) that is used by the program to convert hourly emission densities into emission fractions, must be included on the species line. For VOC, NO_x and CO, OZIP compares this value to the concentration input in CALC, EKMA or ISOP for consistency. A warning message will print if there is a mismatch, but in some cases a different value is useful so the program does not stop. For species other than VOC, NO_xand CO, the initial concentration (conc) specified in the MASS option is used as the initial mass due to emissions. This mass is then converted to ppm ratios. As noted above, because the calculation of column concentration of emissions also depends on the molecular density of air and the volume of the column, the ppm emission ratio factors printed on output will differ if TEMP and mixing height values vary from 298.15 K and the initial mixing height. If there are not enough hours of data given to fill the simulation period, values of 0.0 are assumed after the emission period ends. conc is used in MASS only. The units are ppmC for VOC and ppmV for all other species, including individual organics that are part of the VOC group. mw is the molecular weight of a species used for conversion of MASS units to ppm. MW is mandatory for all species except VOC, NO_x , and CO in EMIS. For OZIPR molecular weights for these species need not be entered if default values are desired; the defaults are:
- VOC = 14.5
- NO_x = 46
- CO = 28
For OZIP, however, it is necessary to include molecular weight values for these three species in the proper fields. If a different value is desired for VOC, the user should note that mw is the molecular weight of a carbon unit (CH 2.5 ) since the calculation is in ppmC. The default NO_x is the molecular weight of NO₂ because emission inventories are given as 100% NO₂.
Since EKMA does not control species other than VOC, NO_x , and CO, any other emissions input with the MASS option, including specific VOC species, will not be reduced in attainment calculations.
```
MASS [numhrs] >
VOC [mw] = conc, 
   em1, em2, .... emnumhrs, 
NOX [mw] = conc,  
   em1, em2, .... emnumhrs, 
CO [mw] = conc,  
   em1, em2, .... emnumhrs, 
specie3 [mw] = conc,  
   em1, em2, .... emnumhrs, 
specien [mw] = conc,  
   em1, em2, .... emnumhrs;
< (MASS)
```
Individual CALCULATIONS (single simulations)
```
CALCULATE >
VOC = concentration; 
NOX = concentration; 
CO = concentration;
< (CALCULATE)
```
The CALCULATE option allows the user to perform one trajectory simulation with all of the input options previously described. The output options for CALCULATE are rather complex, but are designed to provide the user with the capability of performing detailed analysis of the results. In batch mode, more than one CALC line may follow each other, while in interactive mode, control will return to the screen. All options set for the previous CALC simulation will be retained. Thus, the user need only change the conditions that differ between simulations.
VOC is mandatory. It is the concentration of VOC (ppmC) in the initial surface-layer mixture that is due to emissions and subject to control. This mass is added to any transported or other uncontrollable VOC sources to total the actual concentration that a simulation will begin with (default: VOC = 0.0 ppmC).
NOX is mandatory. It is the concentration of NO_x (ppm) in the initial surface-layer mixture that is due to emissions and subject to control. At the beginning of a simulation this mass is added to any uncontrollable NO or NO₂ (default: NO_x = 0.0 ppm).
CO is the concentration (ppm) in the initial surface-layer mixture that is due to emissions and subject to control. This mass is added to any transported or other uncontrollable CO sources to total the actual concentration that a simulation will begin with (default: CO = 0.0 ppm).
The concentrations listed for VOC, NO_x , and CO in the output file represent all the initial mass of these species that is included in the calculation. That is, the values printed at each time step in the output file include the VOC, NO_x , and CO concentrations listed in the CALC option as well as any VOC, NO_x , and CO transported in the surface layer. It also includes the concentration of individual VOC species included in the MASS option.

EKMA calculations
```
EKMA >
BASE =
O3 = concentration, 
RATIO = number, 
CO = concentration, 
VOC = concentration, 
NOX = concentration;
FUTURE =
DELNOX = number, 
DELCO = number, 
O3ALOFT = concentration, 
VOCALOFT = concentration; 
EXTRA =
VOCLEVEL = number, 
VOCTABLE, NOXTABLE, 
COTABLE, 
TRYS = number;
< (EKMA)
```
BASE controls the base condition simulations. The options are these:
- O₃ is the mandatory design (base case, or daily design value) ozone concentration.
- RATIO is the design VOC/NO_x ratio (ppmC/ppm) for the initial controllable emissions in the base year. If the base year VOC and NO_x concentrations have been previously calculated, RATIO can be substituted for by the following two options. This eliminates the need to converge on the design O₃ along the RATIO (RATIO is calculated from these two option values).
- VOC is the calculated level of controllable VOC (ppmC) emissions that yields the base case O₃ .
- NOX is the calculated level of controllable NO_x emissions that yields the base case O₃ .
- CO is the mass (ppm) in the initial surface-layer that is due to emissions and can be controlled in EKMA. This mass is added to initial transported CO (given in BOUN for the base case, and in FUTURE for the future case) to total the actual initial concentration. Surface transported CO (COSURFACE) is not controlled in EKMA calculations. (DF = 0.0)
FUTURE controls the future condition simulations. The options are these:
- DELNOX allows the user to change future NO_x emissions by a fixed percent. For example, a 20 percent reduction would require input of "DELN = - 20" (DF = 0).
- DELCO allows the user to change future CO emissions by a fixed percent (DF = 0). This replaces the old credit option used in OZIPM-4. Use of this option assumes that the user has included CO information in the EMIS or MASS option.
- O3ALOFT is the future initial concentration of ozone transported aloft (DF = base case value).
- VOCALOFT is the future initial concentration of VOC transported aloft (DF = base case value).
- EXTRA allows additional sub-commands that enable the user to control calculations and output.
- TRYS tells the program how many simulations to attempt when trying to converge on a base or future year solution (DF = 8).
- VOCLEVEL allows the user to specify one level of VOC control to be performed. The VOC level is expressed as a percent change from the base year level (use a minus sign for percent reduction, e.g., 60 percent reduction = -60). This calculation is performed in lieu of an attainment calculation.
- VOCTABLE generates a tabular report of change in ozone as a function of change in VOC emissions. This is done in lieu of an attainment calculation. This calculation uses the future conditions of surface and aloft transported species, deltaCO, and deltaNO_x , and reduces the final base case VOC in 10 percent intervals. The ozone calculated for these conditions is compared to the calculated base case ozone. If base case VOC and NO_x are already known, these values are used in lieu of base case calculations.
- NOXTABLE generates a tabular report of change in ozone as a function of change in NO_x emissions. This is done in lieu of an attainment calculation. This calculation uses the future conditions of surface and aloft transported species and deltaCO, and reduces the final base case NO_x in 10 percent intervals. The ozone calculated for these conditions is compared to the calculated base case ozone. If base case VOC and NO_x are already known, these values are used in lieu of base case calculations.
- COTABLE generates a tabular report of change in ozone as a function of change in CO emissions. This is done in lieu of an attainment calculation. This calculation uses the future conditions of surface and aloft transported species and deltaNO_x , and reduces the final base case CO in 10 percent intervals. The ozone calculated for these conditions is compared to the final calculated base case ozone. If base case VOC and NO_x are already known, these values are used in lieu of base case calculations.
- The concentrations of VOC, NO_x , and CO given in the output file for the attainment calculations include only the mass of these species in the initial surface mix that is subject to control; it does not include any VOC, NO_x , or CO transported in the surface layer or any individual VOC species whose surface transport concentration may be given in the SURF option.
ISOPLETH calculations:
```
ISOP >
VOCMAX = concentration, 
NOXMAX = concentration, 
CO = concentration;
< (ISOP)
```
The ISOPLETH option performs the 121 CALC simulations necessary to provide data for constructing an isopleth diagram. The simulations are performed for all combinations of decade percentages (0 to 100% by 10%) of VOCMAX and NOXMAX. The default situation is to construct an isopleth of the maximum 1-hour average concentrations for any gas-phase species requested. [ISOP cannot currently be done for aerosol species].
The results of the simulations are printed in the output file and in a file named filename.ISO. The .ISO file is then used as input to the graphics program (gnuplot)) to draw isopleths of most species included in the .ISO file.
Even though the ISOP option will generate data in a .ISO file for each species, it may not be possible to draw an isopleth for some species under some conditions.
VOCMAX refers to the maximum VOC concentration on the abscissa of the desired isopleth diagram (the minimum value is always 0). Simulations are performed at decade percentages of this value (default = 2.0 ppmC).
NOXMAX refers to the maximum NO_x concentration on the ordinate of the desired isopleth diagram (the minimum value is always 0). Simulations are performed at decade percentages of this value (default = 0.28 ppmC).
CO is the mass (ppm) in the 6-9 a.m. surface layer that is due to emissions and can be controlled. This mass is added to COSURF (the mass due to initial surface transport) to arrive at the total initial concentration (default = 0.0).