#if defined(L08_1A) ! *****************************COPYRIGHT******************************* ! (C) Crown copyright Met Office. All rights reserved. ! For further details please refer to the file COPYRIGHT.txt ! which you should have received as part of this distribution. ! *****************************COPYRIGHT******************************* ! Purpose: ! Subroutine to calculate gridbox mean values of surface conductance ! and carbon fluxes. Also returns net primary productivity, leaf ! turnover and wood respiration of each plant functional type for ! driving TRIFFID. ! Calculates the leaf resistance and net photosynthesis using: ! (i) Collatz et al. (1992) C3 photosynthesis model, and the ! Collatz et al. (1991) C4 photosynthesis model. ! (ii) Jacobs (1994) CI/CA closure. ! Written by Peter Cox (February 1996) ! Adapted for MOSES II tile model by Richard Essery (July 1997) ! Coded into UMVN 6.2 by Pete Falloon (July 2006) !********************************************************************** SUBROUTINE leaf (land_field,veg_pts,veg_index,ft & , clos_pts,open_pts,clos_index,open_index & , o3mol,ra,flux_o3 & , fsmc,tl,ca,ci,rd,wcarb,wexpt,wlite & , gl,al,fo3) USE pftparm USE c_rmol USE surf_param, ONLY : beta1,beta2,ratio,ratio_o3 USE switches, ONLY : l_o3_damage USE parkind1, ONLY: jprb, jpim USE yomhook, ONLY: lhook, dr_hook IMPLICIT NONE INTEGER & land_field & ! IN Total number of land points. ,veg_pts & ! IN Number of vegetated points. ,veg_index(land_field) & ! IN Index of vegetated points ! on the land grid. ,ft & ! IN Plant functional type. ,clos_index(land_field) & ! IN Index of land points ! with closed stomata. ,clos_pts & ! IN Number of land points ! with closed stomata. ,open_index(land_field) & ! IN Index of land points ! with open stomata. ,open_pts ! IN Number of land points ! with open stomata. REAL & fsmc(land_field) & ! IN Soil water factor. ,tl(land_field) & ! IN Leaf temperature (K). ,rd(land_field) & ! IN Dark respiration (mol CO2/m2/s). ,ca(land_field) & ! IN Canopy CO2 pressure (Pa). ,ci(land_field) & ! IN Internal CO2 pressure (Pa). ,wcarb(land_field) & ,wlite(land_field) & ,wexpt(land_field) & ! IN Carboxylation, ! Light, and ! export limited gross ! photosynthetic rates ! (mol CO2/m2/s). ! Ozone-related variables ,o3mol(land_field) & ! IN Molar concentration of ozone ! at reference level (nmol/m3). ,ra(land_field) & ! IN Total aerodynamic+boundary layer resistance ! between leaf surface and reference level (s/m). ,gl(land_field) & ! OUT Leaf conductance for H2O (m/s). ,al(land_field) & ! OUT Net Leaf photosynthesis ! ! (mol CO2/m2/s). ,flux_o3(land_field) & ! OUT Flux of O3 to stomata (nmol O3/m2/s). ,fo3(land_field) & ! OUT Ozone exposure factor. ,b1(land_field) & ,b2(land_field) & ,b3(land_field) & ! WORK Coefficients of the quadratic. ,conv(land_field) & ! WORK Factor for converting mol/m3 ! ! into Pa (J/mol). ,glco2(land_field) & ! WORK Leaf conductance for CO2 (m/s). ,wl(land_field) & ! WORK Gross leaf phtosynthesis ! ! (mol CO2/m2/s). ,wp(land_field) ! WORK Smoothed minimum of ! ! Carboxylation and Light ! ! limited gross photosynthesis ! ! (mol CO2/m2/s). ! Work variables for ozone calculations REAL :: b,c INTEGER & j,l ! WORK Loop counters. INTEGER(KIND=jpim), PARAMETER :: zhook_in = 0 INTEGER(KIND=jpim), PARAMETER :: zhook_out = 1 REAL(KIND=jprb) :: zhook_handle IF (lhook) CALL dr_hook('LEAF',zhook_in,zhook_handle) !---------------------------------------------------------------------- ! Calculate the co-limited rate of gross photosynthesis !---------------------------------------------------------------------- !DIR$ IVDEP DO j=1,open_pts l = veg_index(open_index(j)) b1(l) = beta1 b2(l) = - (wcarb(l) + wlite(l)) b3(l) = wcarb(l) * wlite(l) wp(l) = -b2(l)/(2*b1(l)) & - SQRT(b2(l)*b2(l)/(4*b1(l)*b1(l)) - b3(l)/b1(l)) END DO !DIR$ IVDEP DO j=1,open_pts l = veg_index(open_index(j)) b1(l) = beta2 b2(l) = - (wp(l) + wexpt(l)) b3(l) = wp(l) * wexpt(l) wl(l) = -b2(l)/(2*b1(l)) & - SQRT(b2(l)*b2(l)/(4*b1(l)*b1(l)) - b3(l)/b1(l)) END DO !---------------------------------------------------------------------- ! Carry out calculations for points with open stomata !---------------------------------------------------------------------- !DIR$ IVDEP DO j=1,open_pts l = veg_index(open_index(j)) !---------------------------------------------------------------------- ! Calculate the net rate of photosynthesis !---------------------------------------------------------------------- al(l) = (wl(l) - rd(l)) * fsmc(l) !---------------------------------------------------------------------- ! Calculate the factor for converting mol/m3 into Pa (J/m3). !---------------------------------------------------------------------- conv(l) = rmol * tl(l) !---------------------------------------------------------------------- ! Diagnose the leaf conductance !---------------------------------------------------------------------- !DSM glco2(l) = (al(l) * conv(l)) / (ca(l) - ci(l)) if (ca(l) - ci(l) /= 0.) glco2(l) = (al(l) * conv(l)) / (ca(l) - ci(l)) !DSM gl(l) = ratio * glco2(l) END DO !---------------------------------------------------------------------- ! Close stomata at points with negative or zero net photosynthesis ! or where the leaf resistance exceeds its maximum value. !---------------------------------------------------------------------- !DIR$ IVDEP DO j=1,open_pts l = veg_index(open_index(j)) IF (gl(l) <= glmin(ft) .OR. al(l) <= 0.0) THEN gl(l) = glmin(ft) glco2(l) = gl(l) / ratio al(l) = -rd(l)*fsmc(l) END IF END DO IF ( l_o3_damage ) THEN !----------------------------------------------------------------------- ! Modify the stomatal conductance and photosynthesis for ozone effects ! (Peter Cox, 12/11/04) !----------------------------------------------------------------------- DO j=1,open_pts l = veg_index(open_index(j)) !----------------------------------------------------------------------- ! Flux of O3 without ozone effects (for use in analytical eqn) !----------------------------------------------------------------------- flux_o3(l) = o3mol(l) / (ra(l) + (ratio_o3 / gl(l))) !----------------------------------------------------------------------- ! Analytic solution for the ozone exposure factor !----------------------------------------------------------------------- IF (ra(l) == 0.0) THEN fo3(l) = (1 + dfp_dcuo(ft) * fl_o3_ct(ft)) & / (1 + dfp_dcuo(ft) * flux_o3(l)) ELSE b = ratio_o3 / (gl(l) * ra(l)) & + dfp_dcuo(ft) * o3mol(l) / ra(l) & - (1 + dfp_dcuo(ft) * fl_o3_ct(ft)) c = -ratio_o3 / (gl(l) * ra(l)) & * (1 + dfp_dcuo(ft) * fl_o3_ct(ft)) fo3(l) = -0.5 * b + 0.5 * SQRT(b * b - 4.0 * c) END IF fo3(l) = MIN(MAX(fo3(l),0.0),1.0) !----------------------------------------------------------------------- ! Update the leaf conductance and photosynthesis !----------------------------------------------------------------------- gl(l) = gl(l) * fo3(l) al(l) = al(l) * fo3(l) END DO !---------------------------------------------------------------------- ! Close stomata at points with negative or zero net photosynthesis ! or where the leaf resistance exceeds its maximum value. !---------------------------------------------------------------------- !DIR$ IVDEP DO j=1,open_pts l = veg_index(open_index(j)) IF (gl(l) <= glmin(ft) .OR. al(l) <= 0.0) THEN gl(l) = glmin(ft) glco2(l) = gl(l) / ratio al(l) = -rd(l) * fsmc(l) * fo3(l) END IF END DO END IF ! o3 damage !---------------------------------------------------------------------- ! Define fluxes and conductances for points with closed stomata !---------------------------------------------------------------------- !DIR$ IVDEP DO j=1,clos_pts l = veg_index(clos_index(j)) gl(l) = glmin(ft) glco2(l) = gl(l) / ratio al(l) = -rd(l) * fsmc(l) ! Add the contribution from ozone if enabled IF (l_o3_damage) al(l) = al(l) * fo3(l) END DO IF ( l_o3_damage ) THEN !----------------------------------------------------------------------- ! Diagnose the ozone deposition flux on all points !----------------------------------------------------------------------- DO j=1,veg_pts l = veg_index(j) flux_o3(l) = o3mol(l) / (ra(l) + (ratio_o3 / gl(l))) rd(l) = rd(l) * fo3(l) END DO END IF IF (lhook) CALL dr_hook('LEAF',zhook_out,zhook_handle) RETURN END SUBROUTINE leaf #endif