module physconst 109,2
! Physical constants. Use CCSM shared values whenever available.
use shr_kind_mod
, only: r8 => shr_kind_r8
use shr_const_mod, only: shr_const_g, shr_const_stebol, shr_const_tkfrz, &
shr_const_mwdair, shr_const_rdair, shr_const_mwwv, &
shr_const_latice, shr_const_latvap, shr_const_cpdair, &
shr_const_rhofw, shr_const_cpwv, shr_const_rgas, &
shr_const_karman, shr_const_pstd, shr_const_rhodair,&
shr_const_avogad, shr_const_boltz, shr_const_cpfw, &
shr_const_rwv, shr_const_zvir, shr_const_pi, &
shr_const_rearth, shr_const_sday, shr_const_cday, &
shr_const_spval
implicit none
private
public :: physconst_readnl
save
! Constants based off share code or defined in physconst
real(r8), public, parameter :: avogad = shr_const_avogad ! Avogadro's number (molecules/kmole)
real(r8), public, parameter :: boltz = shr_const_boltz ! Boltzman's constant (J/K/molecule)
real(r8), public, parameter :: cday = shr_const_cday ! sec in calendar day ~ sec
real(r8), public, parameter :: cpair = shr_const_cpdair ! specific heat of dry air (J/K/kg)
real(r8), public, parameter :: cpliq = shr_const_cpfw ! specific heat of fresh h2o (J/K/kg)
real(r8), public, parameter :: karman = shr_const_karman ! Von Karman constant
real(r8), public, parameter :: latice = shr_const_latice ! Latent heat of fusion (J/kg)
real(r8), public, parameter :: latvap = shr_const_latvap ! Latent heat of vaporization (J/kg)
real(r8), public, parameter :: pi = shr_const_pi ! 3.14...
real(r8), public, parameter :: pstd = shr_const_pstd ! Standard pressure (Pascals)
real(r8), public, parameter :: r_universal = shr_const_rgas ! Universal gas constant (J/K/kmol)
real(r8), public, parameter :: rhoh2o = shr_const_rhofw ! Density of liquid water (STP)
real(r8), public, parameter :: spval = shr_const_spval !special value
real(r8), public, parameter :: stebol = shr_const_stebol ! Stefan-Boltzmann's constant (W/m^2/K^4)
real(r8), public, parameter :: tmelt = shr_const_tkfrz ! Freezing point of water (K)
real(r8), public, parameter :: c0 = 2.99792458e8_r8 ! Speed of light in a vacuum (m/s)
real(r8), public, parameter :: planck = 6.6260755e-34_r8 ! Planck's constant (J.s)
! Molecular weights
real(r8), public, parameter :: mwco2 = 44._r8 ! molecular weight co2
real(r8), public, parameter :: mwn2o = 44._r8 ! molecular weight n2o
real(r8), public, parameter :: mwch4 = 16._r8 ! molecular weight ch4
real(r8), public, parameter :: mwf11 = 136._r8 ! molecular weight cfc11
real(r8), public, parameter :: mwf12 = 120._r8 ! molecular weight cfc12
real(r8), public, parameter :: mwo3 = 48._r8 ! molecular weight O3
real(r8), public, parameter :: mwso2 = 64._r8
real(r8), public, parameter :: mwso4 = 96._r8
real(r8), public, parameter :: mwh2o2 = 34._r8
real(r8), public, parameter :: mwdms = 62._r8
! modifiable physical constants for aquaplanet
real(r8), public :: gravit = shr_const_g ! gravitational acceleration (m/s**2)
real(r8), public :: sday = shr_const_sday ! sec in siderial day ~ sec
real(r8), public :: mwh2o = shr_const_mwwv ! molecular weight h2o
real(r8), public :: cpwv = shr_const_cpwv ! specific heat of water vapor (J/K/kg)
real(r8), public :: mwdry = shr_const_mwdair! molecular weight dry air
real(r8), public :: rearth = shr_const_rearth! radius of earth (m)
!--------------- Variables below here are derived from those above -----------------------
real(r8), public :: rga = 1._r8/shr_const_g ! reciprocal of gravit
real(r8), public :: ra = 1._r8/shr_const_rearth ! reciprocal of earth radius
real(r8), public :: omega = 2.0_R8*shr_const_pi/shr_const_sday! earth rot ~ rad/sec
real(r8), public :: rh2o = shr_const_rgas/shr_const_mwwv ! Water vapor gas constant ~ J/K/kg
real(r8), public :: rair = shr_const_rdair ! Dry air gas constant ~ J/K/kg
real(r8), public :: epsilo = shr_const_mwwv/shr_const_mwdair ! ratio of h2o to dry air molecular weights
real(r8), public :: zvir = (shr_const_rwv/shr_const_rdair)-1.0_R8 ! (rh2o/rair) - 1
real(r8), public :: cpvir = (shr_const_cpwv/shr_const_cpdair)-1.0_R8 ! CPWV/CPDAIR - 1.0
real(r8), public :: rhodair = shr_const_pstd/(shr_const_rdair*shr_const_tkfrz)
real(r8), public :: cappa = (shr_const_rgas/shr_const_mwdair)/shr_const_cpdair ! R/Cp
real(r8), public :: ez ! Coriolis expansion coeff -> omega/sqrt(0.375)
real(r8), public :: Cpd_on_Cpv = shr_const_cpdair/shr_const_cpwv
!================================================================================================
contains
!================================================================================================
! Read namelist variables.
subroutine physconst_readnl(nlfile) 1,16
use namelist_utils, only: find_group_name
use units, only: getunit, freeunit
use mpishorthand
use spmd_utils, only: masterproc
use abortutils, only: endrun
use cam_logfile, only: iulog
character(len=*), intent(in) :: nlfile ! filepath for file containing namelist input
! Local variables
integer :: unitn, ierr
character(len=*), parameter :: subname = 'physconst_readnl'
logical newg, newsday, newmwh2o, newcpwv, newmwdry, newrearth
! Physical constants needing to be reset (ie. for aqua planet experiments)
namelist /physconst_nl/ cpwv, gravit, mwdry, mwh2o, rearth, sday
!-----------------------------------------------------------------------------
if (masterproc) then
unitn = getunit()
open( unitn, file=trim(nlfile), status='old' )
call find_group_name(unitn, 'physconst_nl', status=ierr)
if (ierr == 0) then
read(unitn, physconst_nl, iostat=ierr)
if (ierr /= 0) then
call endrun(subname // ':: ERROR reading namelist')
end if
end if
close(unitn)
call freeunit(unitn)
end if
#ifdef SPMD
! Broadcast namelist variables
call mpibcast(cpwv, 1, mpir8, 0, mpicom)
call mpibcast(gravit, 1, mpir8, 0, mpicom)
call mpibcast(mwdry, 1, mpir8, 0, mpicom)
call mpibcast(mwh2o, 1, mpir8, 0, mpicom)
call mpibcast(rearth, 1, mpir8, 0, mpicom)
call mpibcast(sday, 1, mpir8, 0, mpicom)
#endif
newg = gravit .ne. shr_const_g
newsday = sday .ne. shr_const_sday
newmwh2o = mwh2o .ne. shr_const_mwwv
newcpwv = cpwv .ne. shr_const_cpwv
newmwdry = mwdry .ne. shr_const_mwdair
newrearth= rearth .ne. shr_const_rearth
if (newg .or. newsday .or. newmwh2o .or. newcpwv .or. newmwdry .or. newrearth) then
if (masterproc) then
write(iulog,*)'****************************************************************************'
write(iulog,*)'*** New Physical Constant Values set via namelist ***'
write(iulog,*)'*** ***'
write(iulog,*)'*** Physical Constant Old Value New Value ***'
if (newg) write(iulog,*)'*** GRAVITY ',shr_const_g,gravit,'***'
if (newsday) write(iulog,*)'*** SDAY ',shr_const_sday,sday,'***'
if (newmwh2o) write(iulog,*)'*** MWH20 ',shr_const_mwwv,mwh2o,'***'
if (newcpwv) write(iulog,*)'*** CPWV ',shr_const_cpwv,cpwv,'***'
if (newmwdry) write(iulog,*)'*** MWDRY ',shr_const_mwdair,mwdry,'***'
if (newrearth) write(iulog,*)'*** REARTH ',shr_const_rearth,rearth,'***'
write(iulog,*)'****************************************************************************'
end if
rga = 1._r8/gravit
ra = 1._r8/rearth
omega = 2.0_R8*pi/sday
cpvir = cpwv/cpair - 1._r8
epsilo = mwh2o/mwdry
! rair and rh2o have to be defined before any of the variables that use them
rair = r_universal/mwdry
rh2o = r_universal/mwh2o
cappa = rair/cpair
rhodair = pstd/(rair*tmelt)
zvir = (rh2o/rair)-1.0_R8
ez = omega / sqrt(0.375_r8)
Cpd_on_Cpv = cpair/cpwv
else
ez = omega / sqrt(0.375_r8)
end if
end subroutine physconst_readnl
end module physconst