!
      module argon_module
!
! Advance argon by one time step.
!
      use addfld_module,only: addfld
      implicit none

      contains
!-----------------------------------------------------------------------
      subroutine comp_ar(
     |  lev0,lev1,lon0,lon1,lat)
      use compdat_module,only: war ! need to define this as in tgcm24
!
! Input args:
      integer,intent(in) :: lev0,lev1,lon0,lon1,lat
!
! Local:
      integer :: i
      real :: ar_lbc(lon0:lon1,3,lat0:lat1)
      real :: ar_ubc(lon0:lon1,lat0:lat1)


      do i=lon0,lon1 
        ar_lbc(i,1,lat) = 0.
        ar_lbc(i,2,lat) = 1.
        ar_lbc(i,3,lat) = -sqrt(war(1)*war(2)) ! from tgcm24
        ar_ubc(i,lat)   = 0.
      enddo

      end subroutine comp_ar
!-----------------------------------------------------------------------
      subroutine minor_ar(tn,o2,ox,n2,he,w,difkk,ar,ar_nm,hdar,
     |  ar_out,arnm_out,lev0,lev1,lon0,lon1,lat0,lat1)
      use compdat_module,only: war ! (nlevp1)
!
! Input args:
      integer,intent(in) :: lev0,lev1,lon0,lon1,lat0,lat1
      real,dimension(lev0:lev1,lon0-2:lon1+2,lat0-2:lat1+2),
     |  intent(in) ::
     |  tn,      ! neutral temperature (deg K)
     |  o2,      ! molecular oxygen (mmr)
     |  ox,      ! oxygen family (mmr)
     |  n2,      ! molecular nitrogen (mmr)
     |  he,      ! helium (mmr)
     |  w,       ! omega (vertical velocity)
     |  difkk,   ! eddy viscosity (from mgw)
     |  ar ,     ! argon (mmr)
     |  ar_nm,   ! argon at time n-1
     |  hdar     ! horizontal diffusion
!
! Local:
      integer :: i,k,ibndbot,ibndtop,i0,i1,lat
      real,parameter :: phi_ar(3) = (/1.042,1.509,1.176/)
      real,parameter :: alfa_ar = 0.17 ! thermal diffusion coefficient
      real,parameter :: xyar = 1.e-10
      real :: ar_prod(lev0:lev1,lon0:lon1,lat0:lat1)
      real :: ar_loss(lev0:lev1,lon0:lon1,lat0:lat1)

      ibndbot = 0 ! ilbc in minor
      ibndtop = 1 ! iubc in minor

      ar_prod = 0.
      ar_loss = 0.

!     call minor(tn,o2,ox,n2,he,w,difkk,ar,ar_nm,hdar,ar_lbc,
!    |  ar_ubc,ar_loss,ar_prod,war,rmass_ar,phi_ar,alfa_ar,
!    |  xyar,ibndbot,ibndtop,ar_out,arnm_out,
!    |  lev0,lev1,lon0,lon1,lat0,lat1,0)

      end subroutine minor_ar
!-----------------------------------------------------------------------
      end module argon_module