anchor.diff:       omega => CNST_EOHM,    &
        g     => CNST_EGRAV,   &
        Rd    => CNST_RAIR,    &
  +     Rv    => CNST_RVAP,    &
        Cp    => CNST_CP,      &
        KAPPA => CNST_KAPPA,   &
        PRE00 => CNST_PRE00
  
positive.code: 
      logical, parameter :: hybrid_eta = .false. ! dont use hybrid sigma-p (eta) coordinate
      integer, parameter :: zcoords    = 1       ! if zcoords = 1, then we use z and output p
      integer, parameter :: cfv        = 2       ! if cfv = 2 then our velocities follow Gal-Chen coordinates and we need to specify w
      real(DP)           :: hyam       = 0.0_DP  ! dont use hybrid sigma-p (eta) coordinate
      real(DP)           :: hybm       = 0.0_DP  ! dont use hybrid sigma-p (eta) coordinate
      real(DP)           :: DP_gc                ! bar{z} for Gal-Chen coordinate
  
negative.code:        if ( z(k) < 1.0D-7 ) then
            prs(k) = ps
         else
            prs(k) = rho(k) * t(k) * ( (1.0_RP-q(k))*Rd + q(k)*Rv )
         endif
      enddo
  
      return
    end subroutine diag_pressure
  
  