Inconsistency between PCT_NAT_PFT and fates_pftname in E3SM-FATES

[yanyanchengHydro]

I found the PCT_NAT_PFT values in the output history files are not corresponding to the fates_pftname values in the fates parameter file for a E3SM-FATES run.

For example, when the fates_pftname values are: fates_pftname = "broadleaf_evergreen_tropical_tree ", "broadleaf_evergreen_tropical_tree " ;

the PCT_NAT_PFT values in history files looks like: PCT_NAT_PFT = 0.0002442335, 24.83469, 0.004291027, 6.979313, 11.29983, 11.18025, 10.14186, 15.85443, 17.76597, 0.812268, 1.126857, 0, 0, 0, 0, 0, 0 ;

Ryan commented the information for PCT_NAT_PFT is not meaningful in a FATES run, but it will be helpful to have these diagnostics correctly populated when couple with crops and landuse later.

@rgknox @ckoven

[rgknox]

When FATES is on, I feel like fraction of how much of one natural PFT is there, versus another, is more nuanced.

Therefore, my sense is that the solution here is to turn off this diagnostic when fates is active.

Although, we will want to keep diagnostics that describe what fraction of the land is occupied by natural vegetation versus land-use designated.

[rosiealice]

PCT_NAT_PFT is essentially the same information that FATES is now reading to drive the fixed biogeogaphy runs (#632) (EDIT by @glemieux: I think flipped the 32 and 23). It makes sense to have those values being output when FBG is on, but I agree, probably not the remainder of the time.

If we wanted to calculate something that -did- correspond to PCT_NAT_PFT, the closest thing I can think of would be the proportion of the canopy that is occupied by each PFT. This would ignore the contributions of understorey plants.

@yanyanchengHydro - what were you wanting to get out of the diagnostics which made you look at PCT_NAT_PFT? We can calculate the % of biomass or leaves in each PFT from PFTbiomass and PFTleafbiomass. Do we need another output stream?

[yanyanchengHydro]

PCT_NAT_PFT is essentially the same information that FATES is now reading to drive the fixed biogeogaphy runs (#632) (EDIT @glemieux: see above) . It makes sense to have those values being output when FBG is on, but I agree, probably not the remainder of the time.

If we wanted to calculate something that -did- correspond to PCT_NAT_PFT, the closest thing I can think of would be the proportion of the canopy that is occupied by each PFT. This would ignore the contributions of understorey plants.

@yanyanchengHydro - what were you wanting to get out of the diagnostics which made you look at PCT_NAT_PFT? We can calculate the % of biomass or leaves in each PFT from PFTbiomass and PFTleafbiomass. Do we need another output stream?

@rosiealice Thank you very much Rosie. I was debugging other problems while accidentally found this one. Ryan thinks it will be good to open an issue to keep it on record. So later when couple with crops and landuse, it will be helpful to have these diagnostics correctly populated.

[rosiealice]

In that case we should probably just turn it off when FATES is on, given it has no real meaning.

[jenniferholm]

FWIW - I agree to also turn off PCT_NAT_PFT when FATES is running (I thought it was off to begin with, ha). And it makes sense to have the diagnostic with fixed biogeography runs, and potentially for other things connected to the HLMs.

On Thu, Apr 23, 2020 at 12:47 AM Rosie Fisher notifications@github.com wrote:

In that case we should probably just turn it off when FATES is on, given it has no real meaning.

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