Summary: sets prescribed albedo in vegetated patches of the cell (skips bare soil)
This subroutine assumes one cohort per patch !!!
- Calculate vegetation, v, and soil, s, carbon/area, c, for non-crop patches, k.
c_v,k + c_s,k where k ranges over non-crop patches.
- Calculate vegetation and soil carbon/area for crop patch, cr.
c_v,cr + c_s,cr
Crops area changes by df_c:
(if df_c>0, the crops area increase; if df_c<0, then crops area decreases)
- Decrease non-crop patch fractional areas,f_k, proportionally by crop fraction
area increase, df_cr.
f_k,new = f_k - (f_k/sum_f_k)*df_cr
s.th. sum_k((f_k/sum_f_k)*df_c) = df_cr
- Increase crop area (or if new, insert crop patch).
f_c,new = f_c + df_cr
- If df_c>0:
Update crop soil carbon to be sum of acquired non-crop patch soils:
I.e. soil carbon from non-crop patches is merged into the new crop area.
(sum each soil carbon pool, p, then divide by new crop area).
c_s,c,p,new = { sum_k(c_s,k,p * df_cr*f_k/sum_f_k) + c_s,cr,p*f_c }/f_c,new
- If df_c<0:
Update non-crop patch soil carbon to merge in crop patch increment soil carbon.
(sum each soil carbon pool, p, then divide by new patch area).
c_s,k,p,new = { c_s,k,p*f_k + c_s,c,p*f_k/sum_f_k*df_cr }/f_k,new
- Net carbon to atmosphere is:
C_to_atm = loss from non-crop patch veg - gain from crop patch increment
= sum_k( c_v,k * df_cr*f_k/sum_f_k) - c_v,cr*df_cr
- Where to put a net loss in biomass carbon (all soil carbon stays in the soil):
Option 1: Put it all as litter into the crop patch.
This will require partitioning the lost biomass pools into litter
pools with relevant ligning content and C:N ratios.
Option 2: Put it into a slow-release pool to send it all to the atmosphere
over a few months or the next year.
Option 1 is more strictly correct, but involves a little more computation of
litter pools, and allows also an option to sequester, e.g. wood harvest.
- Where to put a net gain in biomass carbon:
Option 1: There's only one option: to suck it all from the atmosphere at
once. Given the net sum of gains and losses over the entire
land surface, hopefully this shouldn't cause a dramatic dent in
atmospheric CO2 over one time step.
Author :
Version:
Declaration:
subroutine entcell_update_crops( ecp, cropsdata)
Variables:
- entcell_extract_pfts : used from entcells
- summarize_entcell : used from entcells
- patch_has_pft : used from patches
- patch_split : used from patches
- patch_merge : used from patches
- delete_patch : used from patches
- patch_set_pft : used from patches
- patch_delete_cohort : used from patches
- albedo :
- for all PFTs
- ecp :
type(entcelltype)
- cropsdata :
real*8, intent(in)
- pft_crops :
integer, parameter
- Initial Value
= 8
- pp :
type(patch), pointer
- pp_crops :
type(patch), pointer
- pp_tmp :
type(patch), pointer
- pp_end :
type(patch), pointer
- crops_old :
real*8
- dcrops :
real*8
- dfr :
real*8
- vdata :
real*8, dimension(12)
