Toy moss model

biogeochem/EDCanopyStructureMod.F90

@@ -12,6 +12,7 @@ module EDCanopyStructureMod
   use FatesConstantsMod     , only : rsnbl_math_prec
   use FatesConstantsMod     , only : nocomp_bareground
   use FatesConstantsMod,      only : i_term_mort_type_canlev
+  use FatesConstantsMod,      only : m2_per_ha
   use FatesGlobals          , only : fates_log
   use EDPftvarcon           , only : EDPftvarcon_inst
   use PRTParametersMod      , only : prt_params
@@ -2232,7 +2233,9 @@ end subroutine UpdatePatchLAI
   subroutine UpdateCohortLAI(currentCohort, canopy_layer_tlai, total_canopy_area)
 
    ! Update LAI and related variables for a given cohort
-
+
+   use FatesMossMod, only : SLA_M2LEAF_PER_KGMOSS
+
    ! Arguments
    type(fates_cohort_type),intent(inout), target   :: currentCohort
    real(r8), intent(in) :: canopy_layer_tlai(nclmax)  ! total leaf area index of each canopy layer
@@ -2244,20 +2247,26 @@ subroutine UpdateCohortLAI(currentCohort, canopy_layer_tlai, total_canopy_area)
 
    ! Obtain the leaf carbon
    leaf_c = currentCohort%prt%GetState(leaf_organ,carbon12_element)
-
-   ! Note that tree_lai has an internal check on the canopy location
-   call  tree_lai_sai(leaf_c, currentCohort%pft, currentCohort%c_area, currentCohort%n,           &
-          currentCohort%canopy_layer, canopy_layer_tlai, currentCohort%vcmax25top, currentCohort%dbh, currentCohort%crowndamage,          &
-          currentCohort%canopy_trim, currentCohort%efstem_coh, 4, currentCohort%treelai, treesai )
-
-   ! Do not update stem area index of SP vegetation
-   if (hlm_use_sp .eq. ifalse) then
-      currentCohort%treesai = treesai
-   end if
 
-   ! Number of actual vegetation layers in this cohort's crown
-   currentCohort%nv = GetNVegLayers(currentCohort%treelai+currentCohort%treesai)
+   if (prt_params%moss(currentCohort%pft) == itrue) then
+      currentCohort%treelai = leaf_c * currentCohort%n / m2_per_ha * SLA_M2LEAF_PER_KGMOSS
+      currentCohort%treesai = 0._r8
+      currentCohort%nv = 1
+   else
+
+      ! Note that tree_lai has an internal check on the canopy location
+      call  tree_lai_sai(leaf_c, currentCohort%pft, currentCohort%c_area, currentCohort%n,           &
+             currentCohort%canopy_layer, canopy_layer_tlai, currentCohort%vcmax25top, currentCohort%dbh,    currentCohort%crowndamage,          &
+             currentCohort%canopy_trim, currentCohort%efstem_coh, 4, currentCohort%treelai, treesai )
+
+      ! Do not update stem area index of SP vegetation
+      if (hlm_use_sp .eq. ifalse) then
+         currentCohort%treesai = treesai
+      end if
 
+      ! Number of actual vegetation layers in this cohort's crown
+      currentCohort%nv = GetNVegLayers(currentCohort%treelai+currentCohort%treesai)
+   end if
   end subroutine UpdateCohortLAI
 
   ! ===============================================================================================

biogeochem/EDPatchDynamicsMod.F90

@@ -3191,7 +3191,28 @@ subroutine fuse_2_patches(csite, dp, rp)
     rp%frac_burnt           = (dp%frac_burnt*dp%area + rp%frac_burnt*rp%area) * inv_sum_area
     rp%btran_ft(:)          = (dp%btran_ft(:)*dp%area + rp%btran_ft(:)*rp%area) * inv_sum_area
     rp%zstar                = (dp%zstar*dp%area + rp%zstar*rp%area) * inv_sum_area
-    rp%c_stomata            = (dp%c_stomata*dp%area + rp%c_stomata*rp%area) * inv_sum_area
+    if (dp%IsAllMoss() .or. rp%IsAllMoss()) then
+       ! We set c_stomata to the unset real value in FatesPlantRespPhotosynthDrive() because mosses
+       ! are expected to have zero resistance. If exactly one fusing patch is all moss, take
+       ! c_stomata from that. This is not accurate, but it's only a diagnostic and for
+       ! one timestep at most (until the next call of FatesPlantRespPhotosynthDrive).
+       ! TODO:
+       !    * If keeping fates_unset_r8 kludge in FatesPlantRespPhotosynthDrive(), code up a way
+       !      to quickly recalculate c_stomata without having to call FatesPlantRespPhotosynthDrive()
+       !      again.
+       !    * Otherwise, c_stomata should always have meaningful values, so remove this special
+       !      handling and just calculate the new value as the area-weighted mean of the donor and
+       !      recipient patches.
+       if (.not. dp%IsAllMoss()) then
+          rp%c_stomata      = dp%c_stomata
+       else if (.not. rp%IsAllMoss()) then
+          rp%c_stomata      = rp%c_stomata
+       else
+          rp%c_stomata      = fates_unset_r8
+       end if
+    else
+       rp%c_stomata         = (dp%c_stomata*dp%area + rp%c_stomata*rp%area) * inv_sum_area
+    end if
     rp%c_lblayer            = (dp%c_lblayer*dp%area + rp%c_lblayer*rp%area) * inv_sum_area
 
     ! Radiation

biogeochem/EDPhysiologyMod.F90

@@ -702,7 +702,12 @@ subroutine trim_canopy( currentSite )
                currentCohort%dbh, currentCohort%crowndamage, currentCohort%canopy_trim, &
                currentCohort%efstem_coh, 0, currentCohort%treelai, currentCohort%treesai )
 
-          currentCohort%nv = GetNVegLayers(currentCohort%treelai+currentCohort%treesai)
+          ! TODO: Would be safer to add this handling to GetNVegLayers()
+          if (prt_params%moss(ipft) == itrue) then
+             currentCohort%nv = 1
+          else
+             currentCohort%nv = GetNVegLayers(currentCohort%treelai+currentCohort%treesai)
+          end if
 
           leaf_veg_frac = currentCohort%treelai/(currentCohort%treelai+currentCohort%treesai)
 
@@ -1885,6 +1890,11 @@ subroutine satellite_phenology(currentSite, bc_in)
              call endrun(msg=errMsg(sourcefile, __LINE__))
           end if
 
+          if (prt_params%moss(fates_pft) == itrue) then
+             write(fates_log(),*) 'Moss in SP mode'
+             call endrun(msg=errMsg(sourcefile, __LINE__))
+          end if
+
           ! Call routine to invert SP drivers into cohort properites.
           call assign_cohort_SP_properties(currentCohort, currentSite%sp_htop(fates_pft), currentSite%sp_tlai(fates_pft)     , currentSite%sp_tsai(fates_pft),currentPatch%area,ifalse,leaf_c)
 

biogeochem/FatesPatchMod.F90

@@ -241,6 +241,7 @@ module FatesPatchMod
       procedure :: FreeMemory
       procedure :: Dump
       procedure :: CheckVars
+      procedure :: IsAllMoss
 
   end type fates_patch_type
 
@@ -1286,6 +1287,33 @@ subroutine CheckVars(this, var_aliases, return_code)
 
     end subroutine CheckVars
 
+    !===========================================================================
+
+    function IsAllMoss(this)
+      !
+      ! DESCRIPTION:
+      !  Checks whether all cohorts on patch are moss
+
+      ! ARGUMENTS:
+      class(fates_patch_type), intent(inout) :: this
+
+      ! LOCALS:
+      type(fates_cohort_type), pointer :: currentCohort ! cohort object
+
+      ! RESULT:
+      logical :: IsAllMoss
+
+      currentCohort => this%tallest
+      IsAllMoss = associated(currentCohort)  ! If patch has no cohorts, it's not all moss
+      do while(associated(currentCohort) .and. IsAllMoss)
+        if (prt_params%moss(currentCohort%pft) == ifalse) then
+          IsAllMoss = .false.
+        end if
+        currentCohort => currentCohort%shorter
+      end do
+
+    end function IsAllMoss
+
     !===========================================================================  
 
 end module FatesPatchMod

biogeophys/CMakeLists.txt

@@ -1,5 +1,6 @@
 list(APPEND fates_sources
   FatesHydroWTFMod.F90
+  FatesMossMod.F90
   LeafBiophysicsMod.F90
   FatesPlantHydraulicsMod.F90)