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NASA / TM--1999-209629 Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8: Users Guide C.G. Justus Computer Sciences Corporation, Huntsville, Alabama B.F. James Marshall Space Flight Center, Marshall Space Flight Center, Alabama May 1999

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The NASA STI Program Office...in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program Office plays a key part in helping NASA maintain this important role. The NASA STI Program Office is operated by Langley Research Center, the lead center for NASA's scientific and technical information. The NASA STI Program Office provides access to the NASA STI Database, the largest collection of aeronautical and space science STI in the world. The Program Office is also NASA's institutional mechanism for disseminating the results of its research and development activities. These results are published by NASA in the NASA STI Report Series, which includes the following report types: TECHNICAL PUBLICATION. Reports of completed research or a major significant phase of research that present the results of NASA programs and include extensive data or theoretical analysis. Includes compilations of significant scientific and technical data and information deemed to be of continuing reference value. NASA's counterpart of peer-reviewed formal professional papers but has less stringent limitations on manuscript length and extent of graphic presentations. TECHNICAL MEMORANDUM. Scientific and technical findings that are preliminary or of specialized interest, e.g., quick release reports, working papers, and bibliographies that contain minimal annotation. Does not contain extensive analysis. CONTRACTOR REPORT. Scientific and technical findings by NASA-sponsored contractors and grantees. CONFERENCE PUBLICATION. Collected papers from scientific and technical conferences, symposia, seminars, or other meetings sponsored or cosponsored by NASA. SPECIAL PUBLICATION. Scientific, technical, or historical information from NASA programs, projects, and mission, often concerned with subjects having substantial public interest. TECHNICAL TRANSLATION. English-language translations of foreign scientific i and technical material pertinent to NASA's mission. Specialized services that complement the STI Program Office's diverse offerings include creating custom thesauri, building customized databases, organizing and publishing research results...even providing videos. For more information about the NASA STI Program Office, see the following: • Access the NASA STI Program Home Page at http ://www.sti.nasa.gov • E-mail your question via the Internet to help@sti.nasa.gov • Fax your question to the NASA Access Help Desk at (301) 621-0134 • Telephone the NASA Access Help Desk at (301) 621-0390 Write to: NASA Access Help Desk NASA Center for AeroSpace Information 800 Elkridge Landing Road Linthicum Heights, MD 21090-2934

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NASA/TM--1999-209629 Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8: Users Guide C.G. Justus Computer Sciences Corporation, Huntsville, Alabama B.F. James Marshall Space Flight Center, Marshall Space Flight Center, Alabama National Aeronautics and Space Administration Marshall Space Flight Center ,, MSFC, Alabama 35812 May 1999

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Acknowledgments The authors thank Joe Beerer, NASA Jet Propulsion Laboratory, for support provided through the Mars Global Surveyor Project, and David Spencer, NASA Jet Propulsion Laboratory, for support provided through the Mars Surveryor Program 2001 Mission. Special thanks also go to Belinda Hardin, Computer Sciences Corporation, for her expert assistance in preparing this report and to Margaret Alexander, MSFC Electromagnetics and Aerospace Environments Branch for skillfully editing the draft. Available from: NASA Center for AeroSpace Information 800 Elkridge Landing Road "Linthicum Heights, MD 21090-2934 (301) 621-0390 National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 (703) 487-4650 ii

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PREFACE These improvements to the NASA/MSFC Mars Global Reference Atmospheric Model (Mars- GRAM Version 3.8) were sponsored by the NASA Marshall Space Flight Center through the Electomagnetics and Aerospace Environments Branch, Analysis and Integration Laboratory. Systems Engineering Division of the Systems For those unfamiliar with earlier versions of Mars-GRAM, NASA Technical memorandum 108509 "Mars Global Reference Atmospheric Model (Mars-GRAM 3.34) Programmer's Guide", and NASA TM 108513 "A Revised Thermosphere for the Mars Global Reference Atmospheric Model (Mars-GRAM Version 3.4)" are recommended. These reports are available electronically from the NASA Technical Report Server at Internet address. http://techreports.larc.nasa.gov/cgi-bin[NTRS For information on obtaining Mars-GRAM Version 3.8 code and data, as well as additional copies of this report, contact Electromagnetics and Aerospace Environments Mail Code EL23 Marshall Space Flight Center, AL 35812 Attn: ms. Bonnie James Phone: (256) 544-6985 E-mail: bonnie.james@msfc.nasa.gov 111 Branch

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TABLE OF CONTENTS Title Section Page lo Introduction ................................................................................................................. 2. Changes Made in Mars-GRAM Version 3.8 ............................................................... 3 3. How to Run Mars-GRAM ........................................................................................... 3 How to Obtain the Program ................................................................................ 3 Running the Program ......................................................................................... 4 Program Input ..................................................................................................... 8 Program Output .................................................................................................. 9 o Sample Results ............................................................................................................ 10 ° References ................................................................................................................... 11 Header for new Version 3.8 output Files ..................................................................... Appendix A 14 Appendix B Example NAMELIST Format Input File .................................................................... 15 Appendix C Sample Output LIST File ............................................................................................ Appendix D Summary of Files Provided with Mars-GRAM Version 3.8 ....................................... 20 Example Application of Mars-GRAM Appendix E Appendix F Summary of Changes in Mars-GRAM V in a Trajectory Code ...................................... 21 Versions 3.5, 3.6, and 3.7 .............................. 23

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LIST OF ILLUSTRATIONS Section Title 4.1 Contours of topographic altitude low resolution data °°°°°''°°°'°'°HH°OI°'°°e°°H°°°°°°°°H°.°°.°°..°°°°°°° 4.2 Page (km) from the NASA Ames MGCM °°Hi°.°°.°,°H°°°°°H°°°O.°.°° ...... °°'° Mars-GRAM Version 3.8 height-latitude cross section of temperature at Northern winter solstice (Lsffi270 degrees) at noon local solar time ....................... 10 vi

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Mars Global Reference (Mars-GRAM) Version 1. Introduction The Mars Global Reference Atmospheric Atmospheric Model 3.8: Users Guide Model (Mars-GRAM) is an engineering -oriented model of the atmosphere of Mars, based on data observed by the Mariner and Viking missions. Versions up to and including and Justus, James and Johnson (1996). Version 3.34 were documented by Justus (1991) 3.4 was discussed by Justus, Johnson, and James (1996). Readers unfamiliar with earlier versions of Mars-GRAM are urged to read these reports to familiarize themselves with the scope, capabilities, functionality, and terminology of the program. Changes made for versions 3.5, 3.6, and 3.7 are summarized in Appendix F. Section 2 of this report describes changes made for Mars-GRAM Version 3.8. Section 3 explains how to run Mars-GRAM. Sample results are presented in Section 4. Sample input and output from version 3.8 with descriptive details are presented in Appendices A through E. 2. Changes Made in Mars-GRAM Version 3.8 The following is a summary of new features and changes in Mars-GRAM Version 3.8. A synopsis of changes in versions 3.5 through 3.7 is given in Appendix F. Code line numbers iin parentheses) give approximate starting line number(s) where changes appear in the Mars-GRAM code. Changed former batch version main program code line numbers from "MARB" to "MGRM" (MGRM 1) Reduced the number of graphics output files and included more variables in each file (SETU 36, SETU 90, DSTP 280) See header descriptions for the new graphics output files in Appendix A. Changed to NASA Ames Mars Global Circulation Model (MGCM) low resolution topography (SETU 15) (Figure 4.1) Topographic height at the poles was corrected to apply at all longitudes. Decreased temperature gradient at polar cap edge (ALBL 26, TSRF 53a) This has the effect of reducing the magnitude of thermal winds aloft. Revised procedure whereby input heights <= -5 km are treated as being at the topographic surface (ATM2 54b, ATM2 82, DSTF 14)

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Revisedlapserateat surfacefor surfacetemperaturecalculation(ATM2 67, ATM2 99) Revisedperturbationmagnitudesversusheight(ATM2 217b,DSTP50a,DSTP 199b) Introduceda newiterativeprocedurefor finding ZF (heightof 1.26nbarlevel) for the hydrostaticinterpolationoption (ATM2 2144a) Addedpressurescaleheightto DATASTEP output(DSTP2a) Addedcorlim factor(ratioof trajectorystepsizeto minimumsizefor assured perturbationaccuracy)with warningmessagesif corlim < 1 (DSTP80) Addedgradientwind (curvature)correctionto winds (DSTP 160g) Addedcheckto limit wind componentsto lessthansoundspeeddividedby square root of two (DSTP 151a,DSTP 160h) Treated"surface"winds asbeingat 10cm, ratherthanViking level of 1.6m (DSTP165) Addednewwind perturbationmodel,includingtidal winds (DSTP229,DSTP 244c,WAVE 91, MGRM 88) Includedcomputationof F1 ionizationpeakaltitudeandmolecularweight.F1peak heighthasalsobeenaddedto outputfiles (DSTP246i,DSTP290,DSTP254d, STRA47a) Addedclimatefactorsto LIST output(DSTP256a) Convertedsurfacepressurelatitudevariationto cosineterms,to insurediurnal amplitudegoesto zeroatthe poles(PSRF61) Changedto newvaluesof referenceellipsoidradii, gravityterm,androtationrate (consistentwith currentJPLvalues)(RLPS9a,RLPS 18a) Addedcentrifugaltermto gravity (RLPS22) Usedmolecularscaletemperaturein stratosphericinterpolationto accountfor heightvariationof molecularweight (STRA 16,STRA47h) RemovedES(8)andES(9) termsfrom calculationof ZF, but not TF. This makes perturbationstandarddeviationsmoreconsistentin the thermosphere(STW2 37d)

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Includedeffectof heightchangeof molecularweight in computationof density scaleheight (STW261a,THRM 133b) AddedPathfinderlandingsiteto setof locationsthathaveterrainheightspecified (TERN 12a) Appliedclimatefactorsto minimum,maximum,andaveragesurfacetemperatures (TMPS 138e) IncludedCos(LAT)/Cos(75)factorin waveperturbationsto insurezeroamplitude at thepoles(WAVE 77a) Allowed variableclimatefactorsto be passedfrom trajectoryprogramto Mars- GRAM subroutines(CFIN l, MART 58b) Allowed optionalhigh resolutionsolarpositionsto bepassedfrom trajectory programto Mars-GRAM subroutines(DUMT 35a,MGRM 72, DSTP35) AddedsubroutineSublTchkto assurethattemperaturesdo not go below CO2 sublimationtemperature(ATM2 72d,ATM2 106b,PRES29a,STCK 1,STRA 47k, THRM 132b) 3. How to Run Mars-GRAM How to Obtain the Program All source code and required data files are available from a file transfer protocol (tip) server at NASA Marshall Space Flight Center. The ftp site also contains example input and output files and "readme" files. To obtain the program source code and data files by tip, see contact information in the preface. See Appendix files available on the ftp site. Runnin2 the Program There are two ways to run Mars-GRAM: D for a summary of the program and data (1) as a subroutine in a (user-provided) main driver program (such as a trajectory program) and (2) as a stand alone program, using a NAMELIST format input file, in which values for all input options are provided. To use Mars-GRAM 3.8 as a subroutine, see discussion dumytraj.f (available in the ftp file distribution) in Appendix E and use example file as a guide. File README2.txt (available in

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the ftp file distribution) also discusses use of dumytraj.f as an example for using Mars- GRAM as a subroutine. The steps involved in setting up and running Mars-GRAM in stand alone mode are the following: (1) Compile and link the three FORTRAN source code files marsgram.f, marssubs.f, and setup.f into an executable program (assumed to be called marsgram) (2) Make sure that necessary data files ARCHGTS.DAT (topographic height information) and COSPAR.DAT (COSPAR model atmosphere data) are in the same file directory as the executable program (3) Prepare a NAMELIST format input file (called INPUT) with the desired values of all input options. See example in Appendix B. (4) If trajectory input mode (rather than automatic profile mode) is desired, prepare a trajectory input file (called TRAJDATA) containing time, height, latitude, longitude, and climate factor values (further discussion below). (5) Run the program by entering its executable name (e.g., marsgram). The program automatically opens and reads the INPUT file (and the TRAJDATA file, if trajectory mode is used) and the data files ARCHGTS.DAT and COSPAR.DAT. If the program is run in profile mode, the user inputs values of fixed increments of time, height, latitude, and longitude. In this mode, the program automatically increments the position until the desired number of positions (NPOS) are evaluated. In trajectory mode, Mars-GRAM reads time and position information from the TRAJDATA file. Two auxiliary z programs are provided on the ftp server for building or modifying trajectory files. Program rdmgt.f is a FORTRAN program to read a trajectory file that contains one value of time, height, latitude, and longitude per line. The program adds climate factors to each line. Program bldmgt.f builds a trajectory file that consists of fixed steps in height, latitude, longitude, or time. Program bldmgt.f provides a means for generating "trajectory" positions on a height-latitude cross section or a latitude-longitude map, for example. See discussion in comment lines of these two programs for details about their use. Program Input Appendix B gives a sample of the NAMELIST file INPUT for Mars-GRAM 3.8. Whether the subroutine or stand alone version is used, the input variables whose values must be supplied in the INPUT file are as follows: LSTFL name of the LIST file (see example LIST file in Appendix C). For a listing to the console in the stand alone version enter the filename CON.

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OUTFL nameof the OUTPUTfile (seediscussionof this file in AppendixA). MONTH month(1 through12)for the initial time MDAY dayof the monthfor the initial time MYEAR yearfor thestartingtime,a 4-digit number Alternatelythe years1970-2069 canbe inputasa 2-digit number NPOS maximumnumberof positionsto evaluate,if anautomatically-generated profile is to beproduced.Use0 if the trajectorypositionsareto be readin from a TRAJDATA file. IHR initial time,hourof the dayGMT IMIN initial time, minuteof thehour SEC initial time, secondsof the minute ALSO valueof the areocentriclongitudeof theSun(Ls, in degrees)atwhich a dust stormis to start Usea valueof 0 if nodust stormis to be simulated. Dust stormcanbe simulatedonly duringthe seasonof theMars yearfor which Ls is between180and320degrees. INTENS duststormintensity,anarbitraryintensityscale,with allowablevalues rangingfrom 0.0 (noduststorm)to 3.0 (maximumintensitydust storm) RADMAX maximumradius(km) a duststormcanattain,developingaccordingto the parameterizedspaceandtime profile of build-up anddecayin theprogram If a valueof 0 or morethan 10000km is used,the stormis takento beof globaldimensions(uniformly coveringthe planet),but still assumedto build up anddecayin intensityaccordingto the sametemporalprofile. DUSTLAT latitude (degrees,North positive)for the centerof the dust storm. DUSTLON longitude(degrees,Westpositive)for the centerof the duststorm. F107 the 10.7cm solarflux in its usualunits of 10-22W/cm2 at the averageEarth orbit position(1 AU) The solarflux is automaticallyconvertedby the programto its valueatthe positionof Mars in its orbit. STDL standarddeviationparameterfor short-termvariationsin the Stewartmodel thermosphereThe normalvalueis 0; the allowablerangeis from -3.0 to +3.0. 5

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MODPERT model number for the perturbations to be computed: 1 is for the random (mountain wave) model, 2 is for the Zurek (tidal) wave model, and 3 means to use combined perturbations from both models. NR1 seed value (integer) for the random number generator The allowable range is I to 29999. To do Monte-Carlo simulations with a variety of perturbations, use a different random number seed on each model run. To repeat a given perturbation random number seed value. sequence on a later model run, use the same NVARX x-code for the plotable output (x-y pairs for 1-D line graphs or x-y-z triplets for 2-D contour plots) See Appendix A for a list of the variables associated with the x code (e.g., if NVARX = 1, output is for plotting versus the height above the reference ellipsoid). NVARY y-code for 2-D contour plot output (x-y-z triplets) Use a y-code value of 0 for 1-D line graph (x-y pair) plots. See Appendix A for a list of y-code values and parameters represented. LOGSCALE parameter to control the units of the output values of density and pressure on the output plot files A value of 0 means use regular density and pressure units (kg/m 3 and N/m2); 1 means to output the logarithm (base-10) of the regular units; and 2 means to output the percentage deviation from the COSPAR values of density and pressure. FLAT latitude of the initial point to simulate (degrees, North positive) FLON longitude of the initial point to simulate (degrees, West positive) FHGT height (km) of the initial point to simulate above the reference ellipsoid DELHGT height increment (km) between successive steps in an automatically generated profile (positive upward) DELLAT latitude increment (degrees, Northward positive) between successive steps in an automatically generated profile DELLON longitude increment (degrees, Westward positive) between successive steps in an automatically generated profile DELTIME time increment (seconds) profile between steps in an automatically generated CF0 climate adjustment factor at the surface (multiplier to be used to increase or decrease the nominal Mars-GRAM surface temperature, nominal = 1)

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CF5 climateadjustmentfactorat 5-km altitude(multiplier to beusedto increase or decreasethe nominalMars-GRAMtemperatureat 5-km significantlevel, nominal= 1) CF15 climateadjustmentfactorat 15-kmaltitude(multiplier to beusedto increase or decreasethe nominalMars-GRAMtemperatureat 15-kmsignificant level,nominal= 1) CF30 climateadjustmentfactorat 30-kmaltitude(multiplier to beusedto increase or decreasethenominalMars-GRAM temperatureat 30-kmsignificant level,nominal= I) CF50 climateadjustmentfactorat 50-kmaltitude(multiplier to beusedto increase or decreasethe nominalMars-GRAM temperatureat 50-kmsignificant level, nominal= 1) CF75 climateadjustmentfactorat75-km altitude(multiplier to be usedto increase or decreasethe nominalMars-GRAM temperatureat75-km significant level,nominal= 1) deltaZF additiveadjustmentto modify the height(km) of the 1.26-nbarpressure level (ZF altitude),nominal= 0 deltaTF additiveadjustmentto modify the temperature(K) at theZF altitude, nominal= 0 deltaTEX additiveadjustmentto modify thetemperature(K) of the exosphere (asymptotictemperatureapproachedatvery high altitudes),nominal= 0 CFp climateadjustmentfactorfor surfacepressure(multiplier to beusedto increaseor decreasethenominalMars-GRAM surfacepressurevalue, nominal= 1) ipopt option for interpolatingbetween75-km significantlevel andaltitudeof 1.26-nbarlevel (heightZF): 0 meansuseregressionto setZF andusenonhydrostaticinterpolation,1meansusehydrostaticinterpolationbetween75 km andZF height(with ZF heightdeterminedby the hydrostaticsof the temperatureprofile) rpscale multiplicative factorfor densityandwind perturbations(1 = nominal) NMONTE numberof MonteCarlorunsduringoneexecutionof the program. New/differentstartingrandomnumbersareautomaticallygeneratedfor eachof theMonte Carloprofiles (or trajectories) 7

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iup option controlling outputof LIST file andgraphicsoutputfiles (0 = none, otherthan0 (default)indicatesgeneratethesefiles) Two auxiliary input files arerequired.The file ARCHGTS.DATcontainsthe topographicheight dataarray(topographicheight,km, abovethereferenceellipsoid). The file COSPAR.DATcontainstheheightprofile of COSPARtemperature,density,andpressure values. If the (pre-computed)trajectorymodeis used(NPOS=0),trajectorydatamustbe read from the TRAJDATA file. Eachline of theTRAJDATA file is a positionandtime for which to computeatmosphericparameters.The inputlinescontaintime (seconds,from the initial time), height(km, relativeto the referenceellipsoid), latitude(degrees,North positive),and longitude(degrees,Westpositive). Eachline of theTRAJDATA file mustalsocontain climatefactors(CF0- CF75,deltaZF,deltaTF,deltaTEX,andCFp; seeabovedefinitions). Programsrdmgt.f andbldmgt.f (providedon theftp file server)assisttheuserin building a trajectoryfile andaddingclimatefactorvalues. Seecommentsembeddedin the sourcecode of theseprogramsfor details. For automatically-generatedprofiles,outputis generateduntil themaximumnumberof positions(NPOS)is reached.For trajectorypositionsreadin from the TRAJDATA file, output is generateduntil theendof thefile is reached. Program Output There are three general types of program output (1) a "LIST" file containing header and descriptor information, suitable for printing or viewing by an analyst (example LIST file in Appendix C), (2) an "OUTPUT" file containing one header line and one line per output position, suitable for reading into another program for additional analysis (example OUTPUT file in Appendix A), and (3) a set of "plotable" output files, or graphics output files, i.e., text files suitable for input to a graphics program (descriptions in Appendix A). The graphics output files contain either x-y data pairs or x-y-z data triplets, determined by the selected values for the x-code (NVARX) and y-code (NVARY). If 1-D line-graph (x-y pair) data is the selected plot output option then y-code = 0 is input. If 2-D contour plot (x-y-z triplet) data is the selected plot output option, then a non-zero value of ycode is input. See the list of codes for x-code and y-code below. If the user desires to suppress the LIST, OUTPUT and graphics output files (so that output can be handled in a user-provided program), this is done by setting the LIST file unit number (iup) to 0 in the NAMELIST format INPUT file. The unit number associated with the "screen" output (iu0), normally 6 in the stand alone version, can be set to any other value, by changing it at program code line BLKD 16, and re-compiling the program.

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1. Sample Results Earlier versions of Mars-GRAM used topographic height data manually read from U.S. Geological Survey maps of Mars surface topography. With version 3.8, the low resolution topography used by the NASA Ames Mars Global Circulation Model (MGCM) is employed. Data at each pole was averaged over longitude, so that a common polar value for each pole would be approached regardless of which longitude a trajectory is approaching a given pole. Figure 4.1 shows contours of the Ames MGCM topography at 1 km contour intervals. Although this figure displays East longitude, Mars-GRAM continues to use West longitude for its input and output. Figure 4.2 shows a height-latitude cross section of temperature for northern winter solstice (Ls = 270 degrees) at noon local solar time. Altitude is height above local topographic surface. Despite the several changes and improvements noted in Section 2, this cross section is still similar to one from earlier versions of Mars-GRAM (compare Figure 11 in Appendix B of Justus, James, and Johnson, 1996). NASA Ames MGCM Topography, km 8O 60 40 11) 20 no -20 "J -40 -6O ".----....._..__ -80 I I I I , I _ I -150 -100 -50 0 .------------ 0 I z 1 i I 50. 100 150 Longitude, degrees East Figure 4.1 Contours of topographic low resolution data altitude (km) from the NASA Ames MGCM

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Mars-GRAM Height-Latitude Cross Section of Temperature (K) Northern Winter Solstice (Ls = 270), Noon Local Solar Time 80 60 40 L_0|tua_ de °egreyd 0 40 60 80 Figure 4.2 Mars-GRAM Version 3.8 height-latitude cross section of temperature at Northern winter solstice (_ = 270 degrees) at noon local solar time. 5. References ° Justus, C.G. (1991): "Mars Global Reference Atmospheric Model for Mission Planning and Analysis", J. Spacecraft and Rockets, 28(2), 216-221. , Justus, C.G., B.F. James, and D.L. Johnson (1996): "Mars Global Reference Atmospheric Model (Mars-GRAM 3.34): Programmer's Guide", NASA Technical Memorandum 108509. . Justus, C.G., D.L. Johnson, and B.F. James (1996): "A Revised Thermosphere for the Mars Global Reference Atmospheric Model (Mars-GRAM Version 3.4)", NASA Technical Memorandum 108513. 10

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Appendix A Headers for New Version 3.8 Output Files Earlier versions of Mars-GRAM graphics output files had single model output variables in the format of Var_X Variable or Var_X VaLY Variable These files are read into a graphics program to produce 2-dimensional (Variable versus VaLX) or 3-dimensional (Variable versus Var_X and Var_Y) graphs. For Mars-GRAM 3.8 several output variables were combined into fewer graphics output files, since most plotting programs now allow the user to select from among several data items per line for plotting. To aid in interpretation, the new graphics output files now contain header information describing the output variables. New graphics outputs files and headers for Mars-GRAM 3.8 are File = OUTPUT (or other name, as prescribed in the NAMELIST INPUT file) Time = time after initial input time (sec) Height = altitude above reference ellipsoid (km) Lat = latitude (degrees, North positive) LonW = longitude (degrees, West positive) DensAV = average density (kg/m3) Temp = average temperature (K) EWind = eastward wind component (m/s, positive toward East) NWind = northward wind component (m/s, positive toward North) sigD = standard deviation for density perturbations (% of mean) sigwa = standard deviation of density wave perturbations (% of mean) Ls = areocentric longitude of Sun from Mars (degrees) File = Density.txt Var_X = user-selected plot variable (determined by NVARX value) VarY = (Optional) user-selected plot variable (from NVARY value) DENSLO = low (- mean - 1 standard deviation) density (kg/m3) DENSAV = average (mean) density (kg/m3) DENSHI = high (- mean + 1 standard deviation) density (kg/m3) DENSTOT = total (mean plus perturbed) density (kg/m**3) 11

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File = Perturb.txt Var_X = user-selected plot variable (determined by NVARX value) Var_Y = (Optional) user-selected plot variable (from NVARY value) SigD = standard deviation of density perturbations (% of mean) DensP = density perturbation value (% of mean) corlim = fraction of minimum step size for accuracy of perturbations (should be > 1 for insured accuracy of perturbations) SigU = standard deviation of wind perturbations (m/s) DensWA = density perturbation amplitude from wave model (% of mean) AmpWind = wind perturbation amplitude from wave model (m/s) File = Surftemp.txt Var_X = user-selected plot variable (determined by NVARX value) Var_Y = (Optional) user-selected plot variable (from NVARY value) Tmin = daily minimum surface temperature for this lat-lon (K) Tavg = daily average surface temperature for this lat-lon (K) Tmax = daily maximum surface temperature for this lat-lon (K) TminC = daily minimum surface temperature for this lat-lon (degrees C) TavgC = daily average surface temperature for this lat-lon (degrees C) TmaxC = daily maximum surface temperature for this lat-lon (degrees C) File = Thrmdata.txt Var_X = user-selected plot variable (determined by NVARX value) Var_Y = (Optional) user-selected plot variable (from NVARY value) Tbase = temperature at 1.26 nbar level (K) Zbase = altitude of 1.26 nbar level (km) Flpeak = altitude of F1 ionization peak (km) MolWgt = mean molecular weight (kg/kg.mole) File = Tpreshgt.txt Var_X = user-selected plot variable (determined by NVARX value) Var_Y = (Optional) user-selected plot variable (from NVARY value) Temp = mean temperature (K) Pres = mean pressure (N/m**2) TdegC = mean temperature (degrees C) Pres_mb = mean pressure (mb) 12

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Hrho = densityscaleheight(km) Psurf= surfacepressurefor this lat-lon-time(mb) File = Winds.txt Var_X = user-selected plot variable (determined by NVARX value) VarY = (Optional) user-selected plot variable (from NVARY value) EWmean = mean eastward wind component (m/s, positive toward East) EWpert = eastward wind perturbation (m/s) EWtot = total (mean plus perturbed) eastward wind (m/s) NSmean = mean northward wind component (m/s, positive toward North) NSpert = northward wind perturbation (m/s) NStot = total (mean plus perturbed) northward wind (m/s) Model input codes used to select the plotable x and y parameters (Var_X and Var_Y) are as follows: Code Parameter ................................................. 1 Height (above reference ellipsoid, km) 2 Height (above local terrain, km) 3 Latitude (deg.) 4 West Longitude (deg.) 5 Time from start (Earth seconds) 6 Time from start (Martian Sols) 7 Areocentric Longitude of Sun, Ls (deg.) 8 Local Solar Time (Mars hours = 1/24 Sols) 9 Pressure (mb) 13

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Appendix B Example NAMELIST Format Input File The following is an example of the NAMELIST format input file required by Mars-GRAM 3.8. Values given are the default values assigned by the program. Only values that differ from the defaults actually have to be included in the NAMELIST file. Note that some compilers do not allow the use of inline descriptive comments (following the !). Some compilers use other formats for the first and last lines of the NAMELIST format file. Check your compiler user's guide for details. $ INPUT LSTFL = 'LIST' ! List file name OUTFL = 'OUTPUT' ! Output file name MONTH = 7 ! month of year MDAY = 20 ! day of month MYEAR = 76 ! year (4-digit; NPOS = 21 ' max # positions IHR = 12 [ GMT hour of day IMIN = 30 ! minute of hour SEC = 0.0 ! second of minute (CON for console listing) 1970-2069 can be 2-digit) to evaluate (0 = read data from file) (for initial position) ALSO = 0.0 ! starting Ls value (degrees) for dust storm (0 = none) INTENS = 0.0 ! dust storm intensity (0.0 - 3.0) RADMAX = 0.0 ! max. radius (km) of dust storm (0 or >10000 = global) DUSTLAT = 0.0 i latitude (deg) DUSTLON = 0.0 ! West longitude for center of dust storm (deg) for center of dust storm FI07 = 68.0 ! 10.7 cm solar flux (10"*-22 W/cm**2, at 1 AU) STDL = 0.0 [ std. dev. for thermosphere variation (-3.0 to +3.0) MODPERT = 3 [ perturbation model; l=random, 2=wave, 3=both NRI = i001 ! starting random NVARX = 1 ! number (0 < NRI < 30000) x-code for plotable output (l=hgt above ref. ellipse) NVARY = 0 ! y-code for 2-D plotable output (0 for I-D plots) LOGSCALE = 0 ! 0=regular density, l=log(density), 2=COSPAR deviations FLAT = 22.0 ! initial latitude FLON = 48.0 initial longitude FHGT = -0.5 ! initial height DELHGT = I0.0 ! height increment DELLAT = 0.0 ! latitude increment (N positive), degrees (West positive), degrees (km), above ref. ellipse (km) between steps (deg) between steps DELLON = 0.0 ! West longitude increment (deg) between steps DELTIME = 0.0 ! time increment CF0 = 1.0 ! climate adjustment CF5 = 1.0 climate adjustment CFI5 = 1.0 ! climate adjustment CF30 = 1.0 ! climate adjustment CF50 = 1.0 ! climate adjustment CF75 = 1.0 ! climate adjustment (sec) between steps factor at surface factor at 5 km factor at 15 km factor at 30 km factor at 50 km factor at 75 km deltaZF = 0.0 [ adjustment for height of 1.26 nbar level (ZF, km) deltaTF = 0.0 [ adjustment for temperature at height ZF (K) deltaTEX = 0.0 [ adjustment for exospheric temperature (K) CFp = 1.0 ! climate adjustment factor for surface pressure ipopt = 1 ! interpolation option 0=regression, l=hydrostatic rpscale = 1.0 ! scale factor for perturbations (i = nominal) NMONTE =I number of Monte iup = 1 l LIST and graphics Carlo runs to do file output option (0 = none) ! [.he. 0 means normal output of files (default)] SEND 14

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Appendix C Sample Output LIST File The following is the LIST file output produced by the standard input parameters as given in Appendix B. The standard input is also provided to users (along with the program code and other data files) as file "input.std". Output data given here are provided as file "listref3.8". Availability of these files allows users to make a test run after compiling Mars-GRAM on their own machine, and to electronically check their output by a filecompare process (e.g. the "diff" command in UNIX or the "fc" command in DOS). Note that, due to machine-dependent or compiler-dependent rounding differences, some output values may differ slightly from those shown here. These differences are usually no more than one unit in the last significant digit displayed. As shown here, the listing gives numbers in the DOS convention of not displaying zero-valued leading digits before the decimal place. Leading zeroes are given in the UNIX version of listref3.8 provided. If necessary for performing the output test, changes from UNIX format to DOS format can be accomplished with an editing program (e.g. changing all character strings "0." to " ." and changing all "-0." to " -.", where "_" indicates a blank space) Mars-GRAM version 3.8 - February, 1998 Date = 7/20/1976 Julian Date = 2442980.0 Height of 1.26 nbar level from hydrostatic CFO,CF5,CFI5,CF30,CF50,CF75= 1.000 1.000 GMT Time = 12:30: .0 interpolation 1.000 1.000 1.000 1.000 CFp,deltaZF,deltaTF,deltaTEX= 1.000 .0 .0 .0 FI0.7 flux = 68.0 (i AU) 25.0 (Mars), Perturbation model = 3 Random seed = Time (rel. to T0) = .0 sec. ( standard deviation = .0 1001 Scale factor = 1.0 .000 sols) Ls = 97.0 deg. Scale Hgt H(p) = 12.74 H(rho) = 14.29 km Height = -1.54 km ( .00 km) Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU Sun Longitude = 108.77 deg. Local Time = 16.05 Mars hours Pressure Temperature = 247.6 K Density (Low, Avg., High) = i. 599E-02 -10.7 Departure, COSPAR NH Mean = Total Density = 1.886E-02 kg/m3 Density Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to TO) = .0 sec. ( Height = 8.46 km ( i0.00 km) Scale = 8.233E+02 N/m2 1.739E-02 i. 880E-02 kg/m3 % -2.8 % 5.0 % Perturbation = 8.42 % of mean = 1.6 -1.5 .I m/s = -.i .9 .8 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 10.61 H(rho) = 11.89 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU Local Sun Longitude = 108.77 deg. Pressure Temperature = 206.1 K 8.310E-03 Density (Low, Avg., High) = 12.8 Departure, COSPAR NH Mean = Total Density = 8.653E-03 kg/m3 Density Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to T0) = .0 sec. ( Height = 18.46 km ( 20.00 km) Scale Time = 16.05 Mars hours = 3.425E+02 N/m2 8.691E-03 9.072E-03 kg/m3 % 18.0 % 23.2 % Perturbation = -.43 % of mean = 4.7 -7.9 -3.2 m/s = -5.1 2.8 -2.3 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 9.68 H(rho) = 10.57 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU 15

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Sun Longitude = 108.77 deg. Local Time = 16.05 Mars hours Temperature = 188.0 K Pressure = 1.283E+02 N/m2 Density (Low, Avg., High) = 3.395E-03 3.568E-03 3.742E-03 kg/m3 Departure, COSPAR NH Mean = 11.7 % 17.5 % 23.2 % Total Density = 3.479E-03 kg/m3 Density Perturbatlon = -2.51% of mean Eastward Wind (Mean, Perturbed, Total) = 1.7 -10.5 -8.8 m/s Northward Wind (Mean, Perturbed, Total) = -8.5 -2.7 -11.2 m/s .......................................................................... Time (rel. to T0) = .0 sec. ( .000 sols) Ls = 97.0 deg. Height = 28.46 km ( 30.00 km) Scale Hgt H(p) = 8.89 H(rho) = 9.71 km Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Longitude = 47.970 degrees Orbital Radius = 1.649 AU Sun Longitude = 108.77 deg. Local Time = 16.05 Mars hours Temperature = Iq2.7 K Pressure = 4.431E+01 N/m2 Density (Low, Avg., High) = 1.242E-03 I. 342E-03 1.442E-03 kg/m3 Departure, COSPAR NH Mean = 8.1% 16.9 % 25.6 % Total Density = 1.533E-03 kg/m3 Density Perturbation = 14.26 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) ........... . .............................................................. Time (rel. to TO) = .0 sec. ( = -1.4 -21.4 -22.7 m/s = -13.2 1.0 -12.2 m/s .000 sols) Ls = 97.0 deg. Height = 38.46 km ( 40.00 km) Scale Hgt H(p) = 8.21 H(rho) = 8.75 km Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Longitude = 47.970 degrees Orbital Radius = 1.649 AU Sun Longitude = 108.77 deg. Local Time = 16.05 Mars hours Temperature = 159.6 K Pressure = 1.407E+01 N/m2 Density (Low, Avg., High) = 4. 272E-04 4. 612E-04 4. 951E-04 kg/m 3 Departure, COSPAR NH Mean = 6.2 % 14.7 % 23.1% Total Density = 4.837E-04 kg/m3 Density Perturbation = 4.89 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to T0) = .0 sec. ( Height = 48.46 km ( 50.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local = -5.1 4.1 -i.0 m/s = -19.2 -17.3 -36.5 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 7.54 H(rho) = 8.04 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours Temperature = 146.5 K Pressure = 4.079E+00 N/m2 Density (Low, Avg., High) = 1.291E-04 1.456E-04 i. 621E-04 kg/m* "3 Departure, COSPAR NH Mean = -.6 % 12.1% 24.8 % Total Density = 1.543E-04 kg/m3 Density Perturbatlon = 5.99 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to T0) = .0 sec. ( Height = 58.46 km ( 60.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local = -9.2 -i.0 -10.2 m/s = -25.7 -.4 -26.1 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 7.23 H(rho) = 7.40 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours Temperature = 140.5 K Pressure = 1.096E+00 N/m2 Density (Low, Avg., High) = 3. 402E-05 4. 079E-05 4.756E-05 kg/m3 Departure, COSPAR NH Mean = -11.9 % 5.6 % 23.1% Total Density = 3.864E-05 kg/m3 Density Perturbation = -5.27 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to T0) = .0 sec. ( Height = 68.46 km ( 70.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local = -14.1 6.2 -7.9 m/s = -33.3 21.7 -11.6 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 6.95 H(rho) = 7.12 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours Temperature = 135.1 K Pressure = 2.817E-01 N/m2 Density (Low, Avg., High) = 8. 988E-06 I. 091E-05 i. 283E-05 kg/m3 Departure, COSPAR NH Mean = -16.1% 1.8 % 19.7 % Total Density = 1.005E-05 kg/m**3 Density Perturbation = -7.90 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) = -19.3 14.3 -5.0 m/s = -39.8 43.9 4.2 m/s 16

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Time (rel. to TO) = .0 sec. ( .000 sols) Ls = 97.0 deg. Height = 78.46 km ( 80.00 km) Scale Hgt H(p) = 7.05 H(rho) = 7.14 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Mars Orbital Radius = 1.649 AU Sun Latitude = 25.00 deg. Local Time = 16.05 Mars hours Sun Longitude = 108.77 deg. Tbase = 128.6 K Zbase = 122.7 km Exospheric Temp. = 211.1 K Solar Zenith Angle = 55.2 deg F1 peak Pressure Temperature = 130.8 K 2.253E-06 Density (Low, Avg., High) = = 126.6 km Mol.Wgt. = 43.49 = 6.922E-02 N/m2 2.768E-06 3.283E-06 kg/m3 -19.9 % -1.6 % 16.7 % Departure, COSPAR NH Mean = Total Density = 3.364E-06 kg/m3 Density Perturbation = 21.51% of mean Eastward Wind (Mean, Perturbed, Total) = -25.5 19.4 -6.1 m/s Northward Wind (Mean, Perturbed, Total) = -45.5 15.9 -29.6 m/s .......................................................................... Time (rel. to T0) = .0 sec. ( .000 sols) Ls = 97.0 deg. Scale Hgt H(p) = 6.97 H(rho) = 7.06 km Height = 88.46 km ( 90.00 km) Latitude = 22.480 degrees West Longitude = 47.970 degrees Mars Orbital Radius = 1.649 AU Sun Latitude = 25.00 deg. Local Time = 16.05 Mars hours Sun Longitude = 108.77 deg. Tbase Exospheric Temp. = 211.1 K Solar Zenith Angle = 55.2 deg F1 peak Pressure Temperature = 128.6 K 5.351E-07 Density (Low, Avg., High) = Departure, COSPAR NH Mean = -27.5 Total Density = 6.826E-07 kg/m3 Density Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to TO) = .0 sec. ( Scale Height = 98.46 km ( i00.00 km) = 128.6 K Zbase = 122.7 km = 126.6 km Mol.Wgt. = 43.49 = 1.663E-02 N/m2 6.763E-07 8.174E-07 kg/m3 % -8.4 % 10.7 % Perturbation = .94 % of mean = -39.1 12.6 -26.4 m/s = -52.2 -16.7 -69.0 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 6.90 H(rho) = 6.98 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU Local Sun Longitude = 108.77 deg. Tbase Exospheric Temp. = 211.1 K Solar Zenith Angle = 55.2 deg F1 peak Pressure Temperature = 126.5 K 1.247E-07 Density (Low, Avg., High) = Departure, COSPAR NH Mean = -36.3 Total Density = 1.529E-07 kg/m3 Density Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to TO) = .0 sec. ( Height = 108.46 km ( ii0.00 km) Scale Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km = 126.5 km Mol.Wgt. = 43.49 = 3.934E-03 N/m2 1.627E-07 2.007E-07 kg/m3 % -16.8 % 2.6 % Perturbation = -6.02 % of mean = -62.9 -10.3 -73.2 m/s = -60.1 -44.3 -104.4 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 7.02 H(rho) = 6.96 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Mars orbital Radius = 1.649 AU Sun Latitude = 25.00 deg. Local Sun Longitude = 108.77 deg. Tbase Exospheric Temp. = 211.1 K Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 126.6 km Mol.Wgt. = 43.27 Pressure Temperature = 127.3 K 2.913E-08 Density (Low, Avg., High) = Departure, COSPAR NH Mean = -42.5 = 9.345E-04 N/m2 3.820E-08 4.728E-08 kg/m3 % -24.6 % -6.7 % Total Density = 2.961E-08 kg/m3 Density Perturbation = -22.50 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to TO) = .0 sec. ( Scale Height = 118.46 km ( 120.00 km) = -104.2 45.9 -58.2 m/s = -71.7 -37.5 -109.2 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 7.14 H(rho) = 7.08 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Mars orbital Radius = 1.649 AU Sun Latitude = 25.00 deg. Local Sun Longitude = 108.77 deg. Tbase Exospheric Temp. = 211.1 K Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 126.7 km Mol.Wgt. = 43.05 Pressure = 2.277E-04 N/m2 Temperature = 128.2 K 6.929E-09 Density (Low, Avg., High) = -51.9 Departure, COSPAR NH Mean = 17 9.197E-09 1.147E-08 kg/m3 % -36.1% -20.3 %

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Total Density = 9.490E-09 kg/m3 Density Perturbation = 3.18 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to TO) = .0 sec. ( = -121.3 .0 -121.3 m/s = -89.6 -2.6 -92.2 m/s .000 sols) Ls = 97.0 deg. Height = 128.46 km ( 130.00 km) Scale Hgt H(p) = 9.25 H(rho) = 7.28 km Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Longitude = 47.970 degrees Orbital Radius = 1.649 AU Sun Longitude = 108.77 deg. Local Time = 16.05 Mars hours Exospheric Temp. = 211.1 K Tbase = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 127.9 km Mol.Wgt. = 42.60 Temperature _ 163.4 K Pressure = 6.267E-05 N/m2 Density (Low, Avg., High) = 1.499E-09 1.966E-09 2.433E-09 kg/m3 Departure, COSPAR NH Mean = -66.4 % -55.9 % -45.5 % Total Density = 2.429E-09 kg/m3 Density Perturbation = 23.57 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to T0) = .0 sec. ( Height = 138.46 km ( 140.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local Exospheric Temp. = 211.1 K Tbase = -139.4 .8 -138.5 m/s = -114.1 19.6 -94.5 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 11.16 H(rho) = 9.92 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 128.9 km Mol.Wgt. = 41.85 Temperature = 192.5 K Pressure = 2.372E-05 N/m2 Density (Low, Avg., High) = 4.731E-10 6.205E-I0 7.679E-10 kg/m3 Departure, COSPAR NH Mean = -63.2 % -51.7 % -40.2 % Total Density = 5.363E-10 kg/m3 Density Perturbation = -13.57 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) ............... -- .......................................................... Time (rel. to TO) = .0 sec. ( Height = 148.46 km ( 150.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local Exospheric Temp. = 211.1 K Tbase = -153.8 7.2 -146.7 m/s = -153.8 .0 -153.8 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 12.18 H(rho) = 11.31 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 129.5 km Mol.Wgt. = 40.85 Temperature = 203.8 K Pressure = 1.009E-05 N/m2 Density (Low, Avg., High) = 1.855E-10 2.433E-10 3.011E-I0 kg/m3 Departure, COSPAR NH Mean = -65.2 % -54.4 % -43.6 % Total Density = 2.881E-10 kg/m3 Density Perturbation = 18.44 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) = -159.4 .0 -159.4 m/s = -159.4 20.4 -139.0 m/s .............................. _ ........................................... Time (tel. to TO) = .0 sec. ( Height = 158.46 km ( 160.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local Exospheric Temp. = 211.1 K Tbase .000 sols) Ls = 97.0 deg. Hgt H(p) = 12.95 H(rho) = 12.10 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 129.9 km Mol.Wgt. = 39.46 Temperature = 208.2 K Pressure = 4.550E-06 N/m2 Density (Low, Avg., High) = 7.445E-II i.038E-10 1.345E-10 kg/m3 Departure, COSPAR NH Mean = -72.3 % -61.3 % -49.9 % Total Density = 9.328E-II kg/m**3 Density Perturbation = -10.10 % of mean Eastward Wind (Mean, Perturbed, Total) Northward Wind (Mean, Perturbed, Total) .......................................................................... Time (rel. to T0) = .0 sec. ( Height = 168.46 km ( 170.00 km) Scale Latitude = 22.480 degrees West Sun Latitude = 25.00 deg. Mars Sun Longitude = 108.77 deg. Local Exospheric Temp. = 211.1 K Tbase = -91.4 -23.8 -115.3 m/s = -161.5 .0 -161.5 m/s .000 sols) Ls = 97.0 deg. Hgt H(p) = 13.78 H(rho) = 12.70 km Longitude = 47.970 degrees Orbital Radius = 1.649 AU Time = 16.05 Mars hours = 128.6 K Zbase = 122.7 km Solar Zenith Angle = 55.2 deg F1 peak = 130.4 km Mol.Wgt. = 37.61 ]8

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Temperature= 209.9 K Pressure Density (Low, Avg., High) = 2.998E-II Departure, COSPAR NH Mean = -79.7 % Total Density = 3.196E-II kg/m3 Density Eastward Wind (Mean, Perturbed, Total) = Northward Wind (Mean, Perturbed, Total) = .......................................................................... = 2.150E-06 N/m'_2 4.635E-II 6.496E-II kg/m3 -68.6 % -56.0 % Perturbation = -31.03 % of mean -21.5 -61.3 -82.9 m/s -158.8 24.3 -134.5 m/s Time (rel. to T0) = .0 sec. ( .000 sols) Ls = 97.0 deg. Height = 178.46 km ( 180.00 km) Scale Hgt H(p) = 14.83 H(rho) = 13.32 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU Local Time = 16.05 Mars hours Sun Longitude = 108.77 deg. Tbase = Exospheric Temp. = 211.1 K Solar Zenith Angle = 55.2 deg F1 peak Pressure Temperature = 210.6 K 1.264E-II Density (Low, Avg., High) = Departure, COSPAR NH Mean = -85.3 % Total Density = 2.826E-II kg/m3 Density Eastward Wind (Mean, Perturbed, Total) = Northward Wind (Mean, Perturbed, Total) = .......................................................................... 128.6 K Zbase = 122.7 km = 131.0 km Mol.Wgt. = 35.26 = 1.066E-06 N/m2 2.148E-II 3.088E-II kg/m3 -74.9 % -64.0 % Perturbation = 31.56 % of mean 18.0 -37.6 -19.6 m/s -108.5 -54.2 -162.7 m/s Time (rel. to TO) = .0 sec. ( .000 sols) Ls = 97.0 deg. Height = 188.46 km ( 190.00 km) Scale Hgt H(p) = 16.21 H(rho) = 14.11 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU Local Time = 16.05 Mars hours Sun Longitude = 108.77 deg. Tbase = 128.6 K Zbase = 122.7 km Exospheric Temp. = 211.1 K Solar Zenith Angle = 55.2 deg F1 peak Pressure Temperature = 210.9 K 5.823E-12 Density (Low, Avg., High) = = 131.7 km Mol.Wgt. = 32.48 = 5.586E-07 N/m2 1.035E-II 1.488E-II kg/m3 -88.6 % -79.8 % -71.0 % Departure, COSPAR NH Mean = Total Density = 1.180E-II kg/m3 Density Perturbation = 13.97 % of mean Eastward Wind (Mean, Perturbed, Total) = 29.1 23.6 52.6 m/s Northward Wind (Mean, Perturbed, Total) = -66.7 49.6 -17.1 m/s .......................................................................... Time (rel. to T0) = .0 sec. ( .000 sols) Ls = 97.0 deg. Height = 198.46 km ( 200.00 km) Scale Hgt H(p) = 17.98 H(rho) = 15.15 km Latitude = 22.480 degrees West Longitude = 47.970 degrees Sun Latitude = 25.00 deg. Mars Orbital Radius = 1.649 AU Local Time = 16.05 Mars hours Sun Longitude = 108.77 deg. Tbase = 128.6 K Zbase = 122.7 km Exospheric Temp. = 211.1 K Solar Zenith Angle = 55.2 deg F1 peak Temperature = 211.0 K Pressure 2.935E-12 Density (Low, Avg., High) = = 132.7 km Mol.Wgt. = 29.46 = 3.105E-07 N/m2 5.218E-12 7.501E-12 kg/m3 Departure, COSPAR NH Mean = -90.7 % -83.4 % -76.2 % Total Density = 5.218E-13 kg/m**3 Density Perturbation = -90.00 % of mean Eastward Wind (Mean, Perturbed, Total) = 25.6 -23.7 1.9 m/s Northward Wind (Mean, Perturbed, Total) = -40.5 60.9 20.4 m/s .......................................................................... 19

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Appendix D Summary of Files Provided Provided to the user of Mars-GRAM marsgram.hst - the history file summarizing with Mars-GRAM Version 3.8 program and data files are the following: various versions and changes marsgram.f - source code for the "stand alone" version main program dumytraj.f - source code for the dummy trajectory version main program marssubs.f - subroutines used by both marsgram and dumytraj versions setup.f - setup subroutines used by both marsgram and dumytraj versions ARCHGTS.DAT - data file for low resolution Ames MGCM topographic heights COSPAR.DAT - data file for the COSPAR reference model atmosphere INPUT.REF - commented test input file for reference case (see Appendix B) INPUT.STD - non-commented test input file for reference case listref3.8 - test list output file for the reference case (see Appendix C) headers.txt - list of plotable output files and file header definitions (see Appendix A) README.txt - this general program introduction file README2.txt - discussion of the dumytraj.f dummy trajectory program bldmgt.f - auxiliary program to build trajectory file with variable CFs rdmgt.f - auxiliary program to read trajectory file & add variable CFs Version 3.8 now includes the capability for time- or latitude-dependent climate factors (CFs) on trajectory input data and in the trajectory version. CFs include (CF0, CF5, CF15, CF30, CF50, CF75, CFp, deltaZF, deltaTF, and deltaTEX). To use CFs from the INPUT file, use CFs of 0.0 on the trajectory input file. Non-zero CFs on the trajectory input file or from a trajectory main program will supersede those on the INPUT file. Two auxiliary programs are provided for adding CFs to trajectory files: Program bldmgt.f will generate a "trajectory" consisting of user-defined steps in height, latitude, longitude, and time. Program rdmgt.f will read a previously generated trajectory data file (TRAJDATA, containing time, height, latitude, and longitude) and will add CFs. Both bldmgt and rdmgt programs interpolate CFs from an auxiliary CF data file (cfinfo.txt, see description in bldmgt.f or rdmgt.f source code). NOTE: BEGINNING WITH VERSION 3.6, NO INTERACTIVE VERSION IS INCLUDED. Plotable output files can be generated with data given versus several selected parameters. Generation of LIST file output and plotable on input. For version 3.8, a reduced number output files is now controlled by value of iup of plotable output files are generated, each containing several parameters suitable for plotting. These new plotable files have headers to help identify parameters in the files. File names and definitions of headers are given in the file headers.txt (Appendix A). 20

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Appendix E Example Application of Mars-GRAM in a Trajectory Code With earlier versions of Mars-GRAM a dummy trajectory program, marstraj.f, was supplied. With version 3.8 an alternate version of (double precision) dummy trajectory calculating program (dumytraj.f) is included. Although similar in general function to the original marstraj.f code, the following details of dumytraj.f are different, i.e., (1) In marstraj.f, interaction with Mars-GRAM Call Setup(...) Call Randinit(...) Call Datastep(...) was via calls to three subroutines - These three subroutines are part of the Mars-GRAM code and are automatically available to be called whenever the Mars-GRAM code (marssubs.f and setup.f) is linked to the user's main trajectory driver program. If you already have a trajectory, program built like this, with calls to Setup, R.andinit, and Datastep it might be easily modified to incorporate version 3.8 subroutines without using the approach taken in dumytrai.f. (2) In dumytraj.f, interaction with Mars-GRAM is via three calls to one subroutine (named Marstraj), but with different values of three control parameters (isetup, jmonte, and istep) - Call Marstraj(...) with isetup=l Call Marstraj(...) with isetup=0, jmonte>0, istep=0 Call Marstraj(...) with isetup=0, jmonte=0, istep>0 whereisetup = 1 triggers the call to the Setup subroutine, jmonte>0 triggers the call to the reinitialization process (including the call to the Randinit subroutine), and istep = 1 to MAXNUM is a counter for steps along the trajectory (with a call to the Datastep subroutine at each step). Marstraj is a new subroutine ihat must be included (along with the basic Mars-GRAM code) as a subroutine in the user's calling trajectory program. (3) In the original marstraj.f dummy trajectory main code, transfer of double precision (trajectory) variables to and from single precision to be done within the user's main trajectory code. (Mars-GRAM) variables was assumed In the dumytraj.f code this transfer is handled within the Marstraj subroutine (which must be included as a subroutine in the user's trajectory program). (4) In the original marstraj.f, (single precision) position increments (DELHGT, DELLAT, and DELLON) were presumed to be calculated within the user's main trajectory program. In the dumytraj.f code, input variables to the Marstraj subroutine are 21

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current and next (double precision) position values (height, latitude, and longitude) and the position increments to be passed to the Datastep subroutine are computed within the Marstraj subroutine. Regardless of which dummy trajectory code you decide to use as your starting model from which to build the interface to Mars-GRAM for your own trajectory code, it is worthwhile to read the comments embedded in the code for the dumytraj.f version." These comments give more explicit descriptions of the functions that are being performed. They also provide better hints about what to do if you are using predictorcorrector (or other) trajectory approaches that require mid-point corrections along trajectory steps and/or the use of density variations that occur within each trajectory step. Two new features of dumytraj.f are (1) allows high precision Mars ephemeris values for sun latitude and longitude and Ls angle to be passed from the trajectory program for use by Mars-GRAM subroutines and (2) allows variable climate factors to be evaluated within the calling trajectory program and passed to Mars-GRAM subroutines for use. Interpolation of climate factors, as necessary, is done by the cfinterp subroutine, supplied as part of the dumytraj.f code. 22

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Appendix F Summary of Changes in Mars-GRAM Versions 3.5, 3.6, and 3.7 Mars-GRAM Version 3.5 (July, 1996) • changed temperature renormalization to be at 25 km above reference ellipsoid datum, not 25 km above local terrain height • removed terms producing large gradient in surface pressure poleward of 55 deg • added option (ipopt) to do hydrostatic interpolation from 75 km to 1.26 nbar • added climate adjustment factor for surface pressure (CFp) added calculation of density scale height [H(rho), retaining pressure scale height H(p)] added plot output files for density scale height [file=HGTrho, unit=35, files(18)], temperature of 1.26 nbar level [file=Tbase, unit=36, files(19)], and height of 1.2¢5 nbar level [file=Zbase, unit=37, files(20)] added option for plot output versus pressure level (NVARX or NVARY = 9) increased minimum and maximum allowed random perturbation magnitudes (by about a factor of 2), and added input of random perturbation scale factor (rpscale) with allowable values 0-3 changed lapse rates 30-50 km and 50-75 km (to 1.19 K/km and 0.44 K/km, respectively) corrected problem with computing position displacements (DELHGT, DELLAT and DELLON) in mode when trajectory file (TRAJDATA) is read in Mars-GRAM Version 3.6 (November, 1996) • added Monte Carlo feature in Batch version and created new dummy trajectorycomputing version (marstraj) 23

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optionalNAMELIST formatINPUT now includesNMONTE = numberonMonte Carlo runs andiup [0 to suppressLIST andgraphicsoutputfiles; iup not equalto zero causesoutputof LIST andgraphicsfiles (default)] addedrandomseed(NR1) andNMONTE to argumentlist of SETUPsubroutine rewindtrajectoryinput datafile (TRAJDATA) whenend-of-fileis encountered • apply randomperturbationscalingfactor(rpscale)to SIGD,DENSHI, andDENSLO • includenew subroutineRandinitto re-initializetherandomnumberseed(NR1)for eachMonte Carlorun NOTE: NO INTERACTIVE VERSION3.6IS PROVIDED. Batch(anddummy trajectory)version3.6 andinteractiveversion3.5 shouldgivethe sameoutputif identicalinputparametersareused[includingNMONTE=I (the defaultcase)]. Mars-GRAM Version 3.7 (June, 1997) added time- or latitude-dependent climate factors (CFs) on trajectory input data CFs include (CF0, CF5, CF15, CF30, CF50, CF75, CFp, deltaZF, deltaTF, and deltaTEX). To use CFs from the INPUT file, use CFs of 0.0 on the trajectory input file. Non-zero CFs on the trajectory input file will supersede those on the INPUT file two auxiliary programs are provided for adding CFs to trajectory files, i.e., program bldmgt.f generates a "trajectory" consisting of user-defined steps in height, latitude, longitude, and time and program rdmgt.f reads a previously-generated trajectory data file (TRAJDATA, containing time, height, latitude, and longitude) and will add CFs. Both bldmgt and rdmgt programs interpolate CFs from an auxiliary CF data file (cfinfo.txt, see description in bldmgt.f or rdmgt.f source code) 24

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REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this coll_d;, of o-,ation is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Infon'nation Operation and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-43, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503 1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED May 1999 Technical Memorandum 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8: Users Guide 6. AUTHORS C.G Justus* and B.F. James r. PERFORMINGORGANIZATIONNAMES(S)ANDADDRESS(ES) 8. PERFORMING ORGANIZATION George C. Marshall Space Flight Center Marshall Space Flight Center, Alabama 35812 REPORT NUMBER M-940 9. SPONSORING/MONITORINGAGENCYNAME(S)ANDADDRESS(ES) 10. SPONSORING/MONITORING National Aeronautics and Space Administration Washington, DC 20546-O001 11. SUPPLEMENTARY NOTES AGENCY REPORT NUMBER NASA/TM--1999-209629 Prepared for Electromagnetics and Aerospace Environments Branch, Systems Analysis and Integration Laboratory, Science and Engineering Directorate. *Computer Science Corporation 12a. DISTRIBUTION/AVAILABILITYSTATEMENT Unclassified-Unlimited Subject Category 18 Nonstandard Distribution 13. ABSTRACT (Maximum 200 words) 12b. DISTRIBUTION CODE Mars Global Reference Atmospheric Model (Mars-GRAM) Version 3.8 is presented and its new features are discussed. Mars-GRAM uses new values of planetary reference ellipsoid radii, gravity term, and rotation rate (consistent with current JPL values) and includes centrifugal effects on gravity. The model now uses NASA Ames Global Circulation Model low resolution topography. Curvature corrections are applied to winds and limits based on speed of sound are applied. Altitude of the F1 ionization peak and density scale height, including effects of change of molecular weight with altitude are computed. A check is performed to disallow temperatures below CO2 sublimination. This memorandum includes instructions on obtaining Mars-GRAM source code and data files and running the program. Sample input and output are provided. An example of incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code is also given. 14. SUBJECT TERMS Mars-GRAM, Atmospheric 32 Mars Global Reference Atmospheric Model, 15. NUMBER OF PAGES 16. PRICE CODE Density, Atmospheric Temperature, Atmospheric Models, Winds 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION OF REPORT OF THIS PAGE Unclassified Unclassified NSN 7540-01-280-5500 A03 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF ABSTRACT Unclassified Unlimited Standard Form 298 (Rev. 2-89) Prescn_ed by ANSI Std. 239-18 9QR.1no