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Module constants_mod

Contact:  Bruce Wyman
Reviewers: 
Change History: WebCVS Log

OVERVIEW

Defines useful constants for Earth.

Constants are defined as real parameters. Constants are accessed through the "use" statement.

OTHER MODULES USED










PUBLIC INTERFACE














PUBLIC DATA








 Name   Type   Value   Units   Description  




 RADIUS   real   6371.e3   m      radius of the earth   




 OMEGA   real   7.292e-5   1/s      rotation rate of the planet (earth)   




 GRAV   real   9.80   m/s^2      acceleration due to gravity   




 RDGAS   real   287.04   J/kg/deg      gas constant for dry air   




 KAPPA   real   2./7.   ---      RDGAS / CP_AIR   




 CP_AIR   real   RDGAS/KAPPA   J/kg/deg      specific heat capacity of dry air at constant pressure   




 CP_OCEAN   real   3989.24495292815   J/kg/deg      specific heat capacity taken from McDougall (2002) "Potential Enthalpy ..."   




 RHO0   real   1.035e3   kg/m^3      average density of sea water   




 RHO0R   real   1.0/RHO0   m^3/kg      reciprocal of average density of sea water   




 RHO_CP   real   RHO0*CP_OCEAN   J/m^3/deg      (kg/m^3)*(cal/kg/deg C)(joules/cal) = (joules/m^3/deg C)   




 RVGAS   real   461.50   J/kg/deg      gas constant for water vapor   




 CP_VAPOR   real   4.0*RVGAS   J/kg/deg      specific heat capacity of water vapor at constant pressure   




 DENS_H2O   real   1000.   kg/m^3      density of liquid water   




 HLV   real   2.500e6   J/kg      latent heat of evaporation   




 HLF   real   3.34e5   J/kg      latent heat of fusion   




 HLS   real   2.834e6   J/kg      latent heat of sublimation   




 TFREEZE   real   273.16   degK      temp where fresh water freezes   




 WTMAIR   real   2.896440E+01   AMU      molecular weight of air   




 WTMH2O   real   1.801534E+01   AMU      molecular weight of water   




 WTMO3   real   47.99820E+01   AMU      molecular weight of ozone   




 DIFFAC   real   1.660000E+00   ---      diffusivity factor   




 SECONDS_PER_DAY   real   8.640000E+04   seconds      seconds in a day   




 AVOGNO   real   6.023000E+23   atoms/mole      Avogadro's number   




 PSTD   real   1.013250E+06   dynes/cm^2      mean sea level pressure   




 PSTD_MKS   real   101325.0   Newtons/m^2      mean sea level pressure   




 RADCON   real   ((1.0E+02*GRAV)/(1.0E+04*CP_AIR))*SECONDS_PER_DAY   deg sec/(cm day)      factor used to convert flux divergence to heating rate in degrees per day   




 RADCON_MKS   real   (GRAV/CP_AIR)*SECONDS_PER_DAY   deg sec/(m day)      factor used to convert flux divergence to heating rate in degrees per day   




 O2MIXRAT   real   2.0953E-01   ---      mixing ratio of molecular oxygen in air   




 RHOAIR   real   1.292269   kg/m^3      reference atmospheric density   




 ALOGMIN   real   -50.0   ---      minimum value allowed as argument to log function   




 STEFAN   real   5.6734e-8   W/m^2/deg^4      Stefan-Boltzmann constant   




 VONKARM   real   0.40   ---      Von Karman constant   




 PI   real   3.14159265358979323846   ---      ratio of circle circumference to diameter   




 RAD_TO_DEG   real   180.0/PI   ---      degrees per radian   




 DEG_TO_RAD   real   PI/180.0   ---      radians per degree   




 RADIAN   real   180.0/PI   ---      equal to RAD_TO_DEG. Named RADIAN for backward compatability.   




 C2DBARS   real   1.e-4   dbars      converts rho*g*z (in mks) to dbars: 1dbar = 10^4 (kg/m^3)(m/s^2)m   




 KELVIN   real   273.15   ---      degrees Kelvin at zero Celsius   




 EPSLN   real   1.0e-40   ---      a small number to prevent divide by zero exceptions   













PUBLIC ROUTINES



    










    

    DATA SETS
    

    None.
    

    

    






    

    ERROR MESSAGES
    

    None.
    

    

    



    

    REFERENCES
    


    
        None.
      
    

    



    

    COMPILER SPECIFICS
    


    
        None.
      
    

    



    

    PRECOMPILER OPTIONS
    


    
        None.
      
    

    



    

    LOADER OPTIONS
    


    None.
    

    

    



    

    TEST PROGRAM
    


    None.
    

    

    



    

    KNOWN BUGS
    


    
        None.
      
    

    



    

    NOTES
    


       Constants have been declared as type REAL, PARAMETER.
   
    

    
   The value a constant can not be changed in a users program.
   New constants can be defined in terms of values from the
   constants module using a parameter statement.<br><br>
   
    

    
   The name given to a particular constant may be changed.<br><br>
   
    

    
   Constants can be used on the right side on an assignment statement
   (their value can not be reassigned). 
   
    

     

    

    EXAMPLE
    

     

        use constants_mod, only:  TFREEZE, grav_new => GRAV
    real, parameter :: grav_inv = 1.0 / grav_new
    tempc(:,:,:) = tempk(:,:,:) - TFREEZE
    geopotential(:,:) = height(:,:) * grav_new
     

    

     

    

    



    

    FUTURE PLANS
    


    

       1.  Renaming of constants. 
    

       2.  Additional constants. 
    

    

    


    

    
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