Revisit PFT optical properties per Majasalmi and Bright (2019)

[olyson]

As discussed in our CLM meeting, we are recommending revisiting the PFT optical property values in CLM and possibly FATES as recommended in a recent paper:

Majasalmi, T. and R. M. Bright, 2019: Evaluation of leaf-level optical properties employed in land surface models. Geoscientific Model Development, 12, 3923-3938.

This paper utilizes various spectral databases to synthesize and harmonize optical property information for PFTs. The paper suggests that CLM optical properties in the visible band fall within the range of measured values. However, there are notable differences between CLM and measured values in the NIR, particularly for conifer trees. Leaf angle values for crops may also be in need of updating.

I'm assigning this to myself:

1. Based on the paper, update the CLM parameter file
2. Conduct control and experiment runs to evaluate the impact (regular diagnostics + ILAMB)

Tagging @jkshuman

[olyson]

I had a 2 degree historical (1989-2014) laying around which can serve as a control.
I ran another simulation with the PFT optical properties changes according to Table S1 of Majasalmi and Bright.
I've attached plots of the control and new pft optical properties (xl: leaf orientation angle, rholvis/rholnir: leaf visible and near-IR reflectance, rhosvis/rhosnir: stem visible and near-IR reflectance, taulvis/taulnir: leaf visible and near-IR transmittance).

plot_PFT_OP.pdf

Diagnostics comparing these runs are here

I've also run ILAMB on these, results are here

We can discuss, but ILAMB doesn't seem to care too much about these new properties. Although scores are slightly better for some variables, particularly most of the relationships.

[dlawrenncar]

Are the changes in albedo similar to what are seen in Majasalmi and Bright, or is that not the right question to as? According to ILAMB Looks like most significant changes (improvements) are seen in tropical regions, which makes sense since it is mainly the tropical PFT properties that are adjusted.

[olyson]

They didn't actually run any simulations.

[olyson]

Took another look at this because the ILAMB results weren't quite consistent with the changes in the optical properties themselves. Looks like the labels on the ILAMB diagnostics were reversed. Albedo changes in the tropics (albedos are a bit higher) are a bit worse in the new simulation (according to CERES, and to a lesser extent GEWEX.SRB).

[dlawrenncar]

Even if ILAMB results show a degradation, I think we should update to new parameters, presuming we believe the results of Majasalmi and Bright since the albedo error could derive from something other than optical properties (LAI, soil albedo, 2-stream calculations, etc). Perhaps a topic for discussion at a future group meeting.

…

On Wed, Mar 18, 2020 at 4:24 PM Keith Oleson ***@***.***> wrote: Took another look at this because the ILAMB results weren't quite consistent with the changes in the optical properties themselves. Looks like the labels on the ILAMB diagnostics were reversed. Albedo changes in the tropics (albedos are a bit higher) are a bit worse in the new simulation (according to CERES, and to a lesser extent GEWEX.SRB). — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#807 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFABYVFDHR4CBOMA7I7TJN3RIFCZPANCNFSM4I27K5WQ> .

[olyson]

Yes, I agree. For example, I think we (Peter?) kind of tuned the soil albedos for a better match with MODIS albedo. Although this probably shouldn't have that much of an effect in denser canopies.

[ekluzek]

Should this come in as part of the changes for CTSM5.1.0?

[wwieder]

Yes, do we have a list of PRs that we want on CTSM5.1?

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On Thu, May 21, 2020 at 12:46 PM Erik Kluzek ***@***.***> wrote: Should this come in as part of the changes for CTSM5.1.0? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#807 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AB5IWJDZ4FXWG7L6RJHQNDTRSVZJHANCNFSM4I27K5WQ> .

-- Will Wieder Project Scientist CGD, NCAR 303-497-1352

[ekluzek]

Yes, do we have a list of PRs that we want on CLM5.1?

CTSM5.1 rather than CLM...

I created a milestone for CTSM5.1.0 and assigned it to the PR's and issues that I thought appropriate. But, @wwieder and others should go through that list as will, so we mark the right things as coming in. If it would be helpful we could create a milestone for CTSM5.2.0 so we could mark the things that are going to come in later.

[wwieder]

@dlawrenncar and @ekluzek, should this go into the PPE tag?

[ekluzek]

Yes, I think it should. It would just have modified parameters for CTSM5.1 that would change what the default settings for the PPE work would start off with.

[dlawrenncar]

Yes. This should definitely go if possible. Rosie based the parameter ranges for several of the radiation parameters based on this paper.

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On Fri, Jun 26, 2020 at 4:11 PM Erik Kluzek ***@***.***> wrote: Yes, I think it should. It would just have modified parameters for CTSM5.1 that would change what the default settings for the PPE work would start off with. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#807 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFABYVFT2OTFTZM4DRH7QXLRYUMIXANCNFSM4I27K5WQ> .

[wwieder]

This should go under a 5.1 flag, but not critical for a PPE tag

[wwieder]

@dlawrenncar suggested that @olyson will be the keeper of the default parameter file for the PPE. @djk2120 should coordinate to make sure where using the right optical parameters.

[olyson]

Note that we've decided to also change the optical properties for the newly added miscanthus and switchgrass crop types per Majasalmi and Bright for crop, unless we find a specific reason not to do so.

[wwieder]

I see this is on the PPE branch, but is it included in CTSM5.1?

[ekluzek]

Currently it's in the paramsfile that will be used for the PPE branch. We will bring this in as an update to CTSM5.1 as we bring the PPE changes to master. So it's not in there yet -- but is planned to come in.