DGVM problems

[dsolyga]

Here a list of the problems found recently :

lpj_establish :

• see ticket 6 ​http://forge.ipsl.jussieu.fr/orchidee/ticket/6
• The following test is always false (found by Nicolas Vuichard):

 sm2(:) = biomass(:,j,isapabove) + biomass(:,j,isapbelow)

 WHERE ( ( d_ind(:,j) .GT. min_stomate ) .AND. &
 ( biomass(:,j,isapabove) + biomass(:,j,isapbelow) ) .GT. sm2(:) )

because we have

   sm2(:) > sm2(:) !!!

lpj_light

• this module should be called also when ok_dgvm or (.NOT.lpj_gap_const_mort). We should add in stomate_lpj.f90 (found

by Sebastiaan Luyssaert and Nicolas Viovy):

   IF ( control%ok_dgvm  .OR. .NOT.(lpj_gap_const_mort)) THEN

       !
       ! 11.1 do light competition
       !

       CALL light (npts, dt_days, &
         veget_max, fpc_max, PFTpresent, cn_ind, lai,     maxfpc_lastyear, &
            lm_lastyearmax, ind, biomass, veget_lastlight, bm_to_litter, mortality)

• fpc_max should be calculated when we have a static vegetation. For the moment, fpc_max = 0 in stomate_lpj so we have always light_death equals to 1! This problem is counter-balanced by the previous point.(found by Sebastiaan Luyssaert-Nicolas Viovy)

   light_death(:,j) = MIN(un, un - fpc_max(:,j)/fpc_nat(:,j))
  

• mortality is not used in this routine. Is this important? (Didier Solyga)
• At the beginning of the module, the calculations of fpc_nat for trees and grasses are the same : (found by Nicolas Vuichard - Didier Solyga)

  IF ( tree(j) ) THEN
  
                  ! 2.1.1.1 trees: minimum cover due to stems, branches etc.
  
                  !          DO i = 1, npts
                  !             IF (lai(i,j) == val_exp) THEN
                  !                fpc_nat(i,j) = cn_ind(i,j) * ind(i,j)
                  !             ELSE
                  !                fpc_nat(i,j) = cn_ind(i,j) * ind(i,j) * &
                  !                     MAX( ( 1._r_std - exp( -lai(i,j) * ext_coeff(j) ) ), min_cover )
                  !             ENDIF
                  !          ENDDO
  
                  !NV : modif from SZ version : fpc is based on veget_max, not veget.
                  WHERE(fracnat(:).GE.min_stomate)
                     !            WHERE(LAI(:,j) == val_exp)
                     !               fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) / fracnat(:)
                     !            ELSEWHERE
                     !               fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) / fracnat(:) * &
                     !                    MAX( ( 1._r_std - exp( - lm_lastyearmax(:,j) * sla(j) * ext_coeff(j) ) ), min_cover )
                     !            ENDWHERE
                     fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) / fracnat(:)
                  ENDWHERE
  
               ELSE
  
                  !NV : modif from SZ version : fpc is based on veget_max, not veget.
                  WHERE(fracnat(:).GE.min_stomate)
                     !            WHERE(LAI(:,j) == val_exp)
                     !               fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) / fracnat(:)
                     !            ELSEWHERE
                     !               fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) / fracnat(:) * &
                     !                    ( 1._r_std - exp( - lm_lastyearmax(:,j) * sla(j) * ext_coeff(j) ) )
                     !            ENDWHERE
                     fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) / fracnat(:)
                  ENDWHERE
  
  !!$                ! 2.1.1.2 bare ground 
  !!$                IF (j == ibare_sechiba) THEN
  !!$                   fpc_nat(:,j) = cn_ind(:,j) * ind(:,j) 
  !!$
  !!$                   ! 2.1.1.3 grasses
  !!$                ELSE
  !!$                   DO i = 1, npts
  !!$                      IF (lai(i,j) == val_exp) THEN
  !!$                         fpc_nat(i,j) = cn_ind(i,j) * ind(i,j)
  !!$                      ELSE
  !!$                         fpc_nat(i,j) = cn_ind(i,j) * ind(i,j) * &
  !!$                              ( 1._r_std - exp( -lai(i,j) * ext_coeff(j) ) )
  !!$                      ENDIF
  !!$                   ENDDO
  !!$                ENDIF
  
               ENDIF  ! tree/grass
  
  

stomate_lpj

• the argument EndOfMonth? is not used : it was added in the last tag (1.9.5.2). Important ? (Didier Solyga)

[jgipsl]

lpj_established : commit done in rev [1890]

[peylin]

To be treated with all DGVM ticket summer 2014