!***********************************************************************
!* GNU Lesser General Public License
!*
!* This file is part of the GFDL Flexible Modeling System (FMS).
!*
!* FMS is free software: you can redistribute it and/or modify it under
!* the terms of the GNU Lesser General Public License as published by
!* the Free Software Foundation, either version 3 of the License, or (at
!* your option) any later version.
!*
!* FMS is distributed in the hope that it will be useful, but WITHOUT
!* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
!* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
!* for more details.
!*
!* You should have received a copy of the GNU Lesser General Public
!* License along with FMS. If not, see <http://www.gnu.org/licenses/>.
!***********************************************************************
!! \brief Defines useful constants for Earth. Constants are defined as real
!! parameters. Constants are accessed through the "use" statement.
!!
!! \author Bruce Wyman <Bruce.Wyman@noaa.gov>
module constants_mod
!---variable for strong typing grid parameters
use platform_mod, only: r8_kind
implicit none
private
! Include variable "version" to be written to log file.
#include<file_version.h>
!-----------------------------------------------------------------------
! version is public so that write_version_number can be called for constants_mod
! by fms_init
public :: version
real :: realnumber !< dummy variable to use in HUGE initializations
#ifdef GFS_PHYS
! SJL: the following are from fv3_gfsphysics/gfs_physics/physics/physcons.f90
real, public, parameter :: RADIUS = 6.3712e+6_r8_kind !< Radius of the Earth [m]
real(kind=r8_kind), public, parameter :: PI_8 = 3.1415926535897931_r8_kind !< Ratio of circle circumference to diameter [N/A]
real, public, parameter :: PI = 3.1415926535897931_r8_kind !< Ratio of circle circumference to diameter [N/A] (REAL(KIND=8))
real, public, parameter :: OMEGA = 7.2921e-5_r8_kind !< Rotation rate of the Earth [1/s]
real, public, parameter :: GRAV = 9.80665_r8_kind !< Acceleration due to gravity [m/s^2]
real(kind=r8_kind), public, parameter :: GRAV_8 = 9.80665_r8_kind !< Acceleration due to gravity [m/s^2] (REAL(KIND=8))
real, public, parameter :: RDGAS = 287.05_r8_kind !< Gas constant for dry air [J/kg/deg]
real, public, parameter :: RVGAS = 461.50_r8_kind !< Gas constant for water vapor [J/kg/deg]
! Extra:
real, public, parameter :: HLV = 2.5e6_r8_kind !< Latent heat of evaporation [J/kg]
real, public, parameter :: HLF = 3.3358e5_r8_kind !< Latent heat of fusion [J/kg]
real, public, parameter :: con_cliq = 4.1855e+3_r8_kind !< spec heat H2O liq [J/kg/K]
real, public, parameter :: con_csol = 2.1060e+3_r8_kind !< spec heat H2O ice [J/kg/K]
real, public, parameter :: CP_AIR = 1004.6_r8_kind !< Specific heat capacity of dry air at constant pressure [J/kg/deg]
real, public, parameter :: KAPPA = RDGAS/CP_AIR !< RDGAS / CP_AIR [dimensionless]
real, public, parameter :: TFREEZE = 273.15_r8_kind !< Freezing temperature of fresh water [K]
#else
#ifdef SMALL_EARTH
#if defined(DCMIP) || (defined(HIWPP) && defined(SUPER_K))
real, private, parameter :: small_fac = 1._r8_kind / 120._r8_kind #only needed for supercell test
#elif defined(HIWPP)
real, private, parameter :: small_fac = 1._r8_kind / 166.7_r8_kind
#else
real, private, parameter :: small_fac = 1._r8_kind / 10._r8_kind
#endif
#else
real, private, parameter :: small_fac = 1._r8_kind
#endif
real, public, parameter :: RADIUS = 6371.0e+3_r8_kind * small_fac !< Radius of the Earth [m]
real(kind=8), public, parameter :: PI_8 = 3.14159265358979323846_r8_kind !< Ratio of circle circumference to diameter [N/A]
real, public, parameter :: PI = 3.14159265358979323846_r8_kind !< Ratio of circle circumference to diameter [N/A]
real, public, parameter :: OMEGA = 7.292e-5_r8_kind / small_fac !< Rotation rate of the Earth [1/s]
real, public, parameter :: GRAV = 9.80_r8_kind !< Acceleration due to gravity [m/s^2]
real, public, parameter :: RDGAS = 287.04_r8_kind !< Gas constant for dry air [J/kg/deg]
real, public, parameter :: RVGAS = 461.50_r8_kind !< Gas constant for water vapor [J/kg/deg]
! Extra:
real, public, parameter :: HLV = 2.500e6_r8_kind !< Latent heat of evaporation [J/kg]
real, public, parameter :: HLF = 3.34e5_r8_kind !< Latent heat of fusion [J/kg]
real, public, parameter :: KAPPA = 2.0_r8_kind/7.0_r8_kind !< RDGAS / CP_AIR [dimensionless]
real, public, parameter :: CP_AIR = RDGAS/KAPPA !< Specific heat capacity of dry air at constant pressure [J/kg/deg]
real, public, parameter :: TFREEZE = 273.16_r8_kind !< Freezing temperature of fresh water [K]
#endif
real, public, parameter :: STEFAN = 5.6734e-8_r8_kind !< Stefan-Boltzmann constant [W/m^2/deg^4]
real, public, parameter :: CP_VAPOR = 4.0_r8_kind*RVGAS !< Specific heat capacity of water vapor at constant pressure [J/kg/deg]
real, public, parameter :: CP_OCEAN = 3989.24495292815_r8_kind !< Specific heat capacity taken from McDougall (2002)
!! "Potential Enthalpy ..." [J/kg/deg]
real, public, parameter :: RHO0 = 1.035e3_r8_kind !< Average density of sea water [kg/m^3]
real, public, parameter :: RHO0R = 1.0_r8_kind/RHO0 !< Reciprocal of average density of sea water [m^3/kg]
real, public, parameter :: RHO_CP = RHO0*CP_OCEAN !< (kg/m^3)*(cal/kg/deg C)(joules/cal) = (joules/m^3/deg C) [J/m^3/deg]
real, public, parameter :: ES0 = 1.0_r8_kind !< Humidity factor. Controls the humidity content of the atmosphere through
!! the Saturation Vapour Pressure expression when using DO_SIMPLE. [dimensionless]
real, public, parameter :: DENS_H2O = 1000._r8_kind !< Density of liquid water [kg/m^3]
real, public, parameter :: HLS = HLV + HLF !< Latent heat of sublimation [J/kg]
real, public, parameter :: WTMAIR = 2.896440E+01_r8_kind !< Molecular weight of air [AMU]
real, public, parameter :: WTMH2O = WTMAIR*(RDGAS/RVGAS) !< Molecular weight of water [AMU]
real, public, parameter :: WTMOZONE = 47.99820_r8_kind !< Molecular weight of ozone [AMU]
real, public, parameter :: WTMC = 12.00000_r8_kind !< Molecular weight of carbon [AMU]
real, public, parameter :: WTMCO2 = 44.00995_r8_kind !< Molecular weight of carbon dioxide [AMU]
real, public, parameter :: WTMCH4 = 16.0425_r8_kind !< Molecular weight of methane [AMU]
real, public, parameter :: WTMO2 = 31.9988_r8_kind !< Molecular weight of molecular oxygen [AMU]
real, public, parameter :: WTMCFC11 = 137.3681_r8_kind !< Molecular weight of CFC-11 (CCl3F) [AMU]
real, public, parameter :: WTMCFC12 = 120.9135_r8_kind !< Molecular weight of CFC-21 (CCl2F2) [AMU]
real, public, parameter :: WTMN = 14.0067_r8_kind !< Molecular weight of Nitrogen [AMU]
real, public, parameter :: DIFFAC = 1.660000E+00_r8_kind !< Diffusivity factor [dimensionless]
real, public, parameter :: AVOGNO = 6.023000E+23_r8_kind !< Avogadro's number [atoms/mole]
real, public, parameter :: PSTD = 1.013250E+06_r8_kind !< Mean sea level pressure [dynes/cm^2]
real, public, parameter :: PSTD_MKS = 101325.0_r8_kind !< Mean sea level pressure [N/m^2]
real, public, parameter :: SECONDS_PER_DAY = 8.640000E+04_r8_kind !< Seconds in a day [s]
real, public, parameter :: SECONDS_PER_HOUR = 3600._r8_kind !< Seconds in an hour [s]
real, public, parameter :: SECONDS_PER_MINUTE = 60._r8_kind !< Seconds in a minute [s]
real, public, parameter :: RAD_TO_DEG = 180._r8_kind/PI !< Degrees per radian [deg/rad]
real, public, parameter :: DEG_TO_RAD = PI/180._r8_kind !< Radians per degree [rad/deg]
real, public, parameter :: RADIAN = RAD_TO_DEG !< Equal to RAD_TO_DEG for backward compatability. [rad/deg]
real, public, parameter :: ALOGMIN = -50.0_r8_kind !< Minimum value allowed as argument to log function [N/A]
real, public, parameter :: EPSLN = 1.0e-40_r8_kind !< A small number to prevent divide by zero exceptions [N/A]
real, public, parameter :: RADCON = ((1.0E+02*GRAV)/(1.0E+04*CP_AIR))*SECONDS_PER_DAY !< Factor used to convert flux divergence to
!! heating rate in degrees per day [deg sec/(cm day)]
real, public, parameter :: RADCON_MKS = (GRAV/CP_AIR)*SECONDS_PER_DAY !< Factor used to convert flux divergence to
!! heating rate in degrees per day [deg sec/(m day)]
real, public, parameter :: O2MIXRAT = 2.0953E-01_r8_kind !< Mixing ratio of molecular oxygen in air [dimensionless]
real, public, parameter :: RHOAIR = 1.292269_r8_kind !< Reference atmospheric density [kg/m^3]
real, public, parameter :: VONKARM = 0.40_r8_kind !< Von Karman constant [dimensionless]
real, public, parameter :: C2DBARS = 1.e-4_r8_kind !< Converts rho*g*z (in mks) to dbars: 1dbar = 10^4 (kg/m^3)(m/s^2)m [dbars]
real, public, parameter :: KELVIN = 273.15_r8_kind !< Degrees Kelvin at zero Celsius [K]
public :: constants_init
contains
!> \brief dummy routine.
subroutine constants_init
end subroutine constants_init
end module constants_mod
! <FUTURE>
! 1. Renaming of constants.
! </FUTURE>
! <FUTURE>
! 2. Additional constants.
! </FUTURE>
! <NOTE>
! 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).
!
!
!<TESTPROGRAM NAME="EXAMPLE">
!<PRE>
! use constants_mod, only: TFREEZE, grav_new => GRAV
! real, parameter :: grav_inv = 1.0 / grav_new
! tempc(:,:,:) = tempk(:,:,:) - TFREEZE
! geopotential(:,:) = height(:,:) * grav_new
!</PRE>
!</TESTPROGRAM>
! </NOTE>