CLM5 NBP variable question

[Danbi]

Dear All,

I have a question regarding the NBP variable.
I would like to compare the NBP variable with the calculated NBP.
The commonly known equation is 'NBP = NPP - HR - Fire'.
However, when calculating NBP with each variable (NPP - HR - COL_FIRE_CLOSS), it differs from the actual NBP variable.

The definitions for the variables are as follows:
NBP : net biome production includes fire landuse harvest and hrv_xsmrpool flux (latter smoothed over the year)
NPP : net primary production
HR : total heterotrophic respiration
COL_FIRE_CLOSS : total column-level fire C loss for non-peat fires outside land-type converted region

Accordingly, it seems that other variables (e.g. land use, harvest, and hrv_xsmrpool flux) are not included in this calculation.
Therefore, which variables should additionally be taken into account? (For example, WOOD_HARVESTC: wood harvest carbon (to product pools)).

Thanks!

 

[oleson]

I don't have answers to these questions offhand, but I would start by grepping in the code for NBP, which yields:

call hist_addfld1d (fname='NBP', units='gC/m^2/s', &
avgflag='A', long_name='net biome production, includes fire, landuse,'&
//' harvest and hrv_xsmrpool flux (latter smoothed over the year), positive for sink'&
//' (same as net carbon exchange between land and atmosphere)', &
ptr_gcell=this%nbp_grc)

And then grep for nbp_grc which yields:

! net biome production of carbon, positive for sink
this%nbp_grc(g) = &
-this%nee_grc(g) - &
this%landuseflux_grc(g)
if ( this%dribble_crophrv_xsmrpool_2atm ) this%nbp_grc(g) = this%nbp_grc(g) - this%xsmrpool_to_atm_grc(g)

and then go from there.

 

[Danbi]

Thank you very much, Mr. Oleson, for your response.

Best regards,
Danbi