MODULE physics
!-----------------------------------------------------------------------
! NAME
!     physics
!
! DESCRIPTION
!     Fundamental constants read from file and used across PEM modules.
!
! AUTHORS & DATE
!     JB Clement, 12/2025
!
! NOTES
!
!-----------------------------------------------------------------------

! DEPENDENCIES
! ------------
use numerics, only: dp

! DECLARATION
! -----------
implicit none

! PARAMETERS
! ----------
real(dp), parameter :: sigmaB = 5.678e-8_dp            ! Stefan-Boltzmann constant [W/m^2/K^4]
real(dp), parameter :: m_co2 = 44.01e-3_dp             ! CO2 molecular mass [kg/mol], Franz et al. 2017
real(dp), parameter :: m_noco2 = 33.37e-3_dp           ! Non-condensible molecular mass [kg/mol], Franz et al. 2017
real(dp), parameter :: m_h2o = 18.01528e-3_dp          ! H2O molecular mass [kg/mol], Franz et al. 2017
real(dp), parameter :: A = 1._dp/m_co2 - 1._dp/m_noco2 ! MMR/VMR conversion factor
real(dp), parameter :: B = 1._dp/m_noco2               ! MMR/VMR conversion factor

! H2O coefficients for Clausius-Clapeyron law for psat (psat = exp(beta/Th2o + alpha)), following Murphy and Koop 2005
real(dp), parameter :: alpha_clap_h2o = 28.9074_dp
real(dp), parameter :: beta_clap_h2o = -6143.7_dp  ! [K]
! CO2 coefficients for Clausius-Clapeyron law for CO2 condensation temperature (Tco2 = beta/(alpha-log(vmr)),following James et al. 1992
real(dp), parameter :: alpha_clap_co2 = 23.3494_dp
real(dp), parameter :: beta_clap_co2 = 3182.48_dp  ! [K]

real(dp), parameter :: Lco2 = 5.71e5_dp ! CO2 latent heat [J/kg], Pilorget and Forget 2016

real(dp), protected :: g     ! Gravity [m/s2]
real(dp), protected :: r     ! Reduced gas constant,r = 8.314511/[mugaz/1000.0]
real(dp), protected :: mugaz ! Molar mass of the atmosphere [g/mol]
real(dp), protected :: rad   ! Radius of the planet [m]
real(dp), protected :: cpp   ! Cp of the atmosphere
real(dp), protected :: rcp   ! r/cpp (= kappa in the dynamics)

contains
!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

!=======================================================================
SUBROUTINE init_physics(rad_in,g_in,mugaz_in,rcp_in)
!-----------------------------------------------------------------------
! NAME
!     init_physics
!
! DESCRIPTION
!     Initialize physical constants.
!
! AUTHORS & DATE
!     JB Clement, 01/2026
!
! NOTES
!
!-----------------------------------------------------------------------

! DECLARATION
! -----------
implicit none

! ARGUMENTS
! ---------
real(dp), intent(in) :: rad_in, g_in, mugaz_in, rcp_in

! CODE
! ----
rad = rad_in
g = g_in
mugaz = mugaz_in
rcp = rcp_in
r = 8.314511_dp*1000._dp/mugaz
cpp = r/rcp

END SUBROUTINE init_physics
!=======================================================================

END MODULE physics