Stomata

INTERFACE:

    subroutine Stomata (fn, filterp, lbp, ubp, lbc, ubc, lbg, ubg, &
                        apar, ei, ea, tgcm, forc_pbot, &
                        tl, o2, co2, btran, rb, &
                        rs, psn, annpsnpot, annpsn)

DESCRIPTION:

   Leaf stomatal resistance and leaf photosynthesis.

USES:

      use shr_kind_mod , only : r8 => shr_kind_r8
      use shr_const_mod, only : SHR_CONST_TKFRZ, SHR_CONST_RGAS
      use clmtype

ARGUMENTS:

      implicit none
      integer , intent(in)    :: fn                 ! size of pft filter
      integer , intent(in)    :: filterp(fn)        ! pft filter
      integer , intent(in)    :: lbp, ubp           ! pft bounds
      integer , intent(in)    :: lbc, ubc           ! column bounds
      integer , intent(in)    :: lbg, ubg           ! gridcell bounds
      real(r8), intent(in)    :: apar(lbp:ubp)      ! par absorbed per unit la
      real(r8), intent(in)    :: ei(lbp:ubp)        ! vapor pressure inside le
      real(r8), intent(in)    :: ea(lbp:ubp)        ! vapor pressure of canopy
      real(r8), intent(in)    :: tgcm(lbc:ubc)      ! air temperature at agcm 
      real(r8), intent(in)    :: forc_pbot(lbg:ubg) ! atmospheric pressure (Pa
      real(r8), intent(in)    :: tl(lbp:ubp)        ! leaf temperature (Kelvin
      real(r8), intent(in)    :: o2(lbp:ubp)        ! atmospheric o2 concentra
      real(r8), intent(in)    :: co2(lbp:ubp)       ! atmospheric co2 concentr
      real(r8), intent(in)    :: btran(lbp:ubp)     ! soil water transpiration
      real(r8), intent(inout) :: rb(lbp:ubp)        ! boundary layer resistanc
      real(r8), intent(inout) :: rs(lbp:ubp)        ! leaf stomatal resistance
      real(r8), intent(inout) :: psn(lbp:ubp)       ! foliage photosynthesis (
      real(r8), intent(inout) :: annpsnpot(lbp:ubp) ! annual potential photosy
      real(r8), intent(inout) :: annpsn(lbp:ubp)    ! annual photosynthesis (u

CALLED FROM:

   subroutine CanopyFluxes in this modeul

REVISION HISTORY:

   author:            Gordon Bonan
   standardized:      J. Truesdale, Feb. 1996
   reviewed:          G. Bonan, Feb. 1996
   15 September 1999: Yongjiu Dai; Initial code
   15 December 1999:  Paul Houser and Jon Radakovich; F90 Revision
   1/30/02, PET  Made all input and output parameters explicit (removed refere

LOCAL VARIABLES:

   local pointers to implicit in variables
      integer , pointer :: pcolumn(:)     ! pft's column index
      integer , pointer :: pgridcell(:)   ! pft's gridcell index
      integer , pointer :: ivt(:)         ! pft vegetation type
      real(r8), pointer :: qe25(:)        ! quantum efficiency at 25C (umol CO
      real(r8), pointer :: vcmx25(:)      ! max rate of carboxylation at 25C (
      real(r8), pointer :: c3psn(:)       ! photosynthetic pathway: 0. = c4, 1
      real(r8), pointer :: mp(:)          ! slope of conductance-to-photosynth