elai and esai for non-SP runs should use frac_sno

[billsacks]

Brief summary of bug

I noticed that the formulation for elai and esai includes frac_sno for satellite phenology runs, but not for CN/BGC runs. @dlawrenncar thinks this is a bug, and that CN/BGC should include frac_sno (see #1112 (comment)).

General bug information

CTSM version you are using: Latest master

Does this bug cause significantly incorrect results in the model's science? Yes

Configurations affected: All non-SP cases

Details of bug

For Satellite Phenology, I see:

CTSM/src/biogeochem/SatellitePhenologyMod.F90

Lines 419 to 420 in 32964a8

	elai(p) = max(tlai(p)*(1.0_r8 - frac_sno(c)) + tlai(p)*fb*frac_sno(c), 0.0_r8)
	esai(p) = max(tsai(p)*(1.0_r8 - frac_sno(c)) + tsai(p)*fb*frac_sno(c), 0.0_r8)

whereas for BGC, there is no accounting for frac_sno in the similar lines:

CTSM/src/biogeochem/CNVegStructUpdateMod.F90

Lines 295 to 296 in 32964a8

	elai(p) = max(tlai(p)*fb, 0.0_r8)
	esai(p) = max(tsai(p)*fb, 0.0_r8)

[billsacks]

@danicalombardozzi @swensosc would one of you want to confirm @dlawrenncar 's feelings that this is a bug, and that CNVegStructUpdate should use the same formulation as in SatellitePhenologyMod?

@danicalombardozzi I'm thinking we could fold this bug fix into #1112 .

[swensosc]

I agree that it should be the weighted average of the snow-covered and snow-free areas, like in satellite phenology.

…

On Thu, Aug 20, 2020 at 11:41 AM Bill Sacks ***@***.***> wrote: @danicalombardozzi <https://github.com/danicalombardozzi> @swensosc <https://github.com/swensosc> would one of you want to confirm @dlawrenncar <https://github.com/dlawrenncar> 's feelings that this is a bug, and that CNVegStructUpdate should use the same formulation as in SatellitePhenologyMod? @danicalombardozzi <https://github.com/danicalombardozzi> I'm thinking we could fold this bug fix into #1112 <#1112> . — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1116 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGRN57BIV4NQRYOOGUCXO7LSBVN5VANCNFSM4QGNHZZQ> .

[danicalombardozzi]

Yes, this looks like a bug, and I can fold it into #1112