This PR allows for variable vertical scaling of leaf maintenance respiration when using the Atkin et al. 2017 leaf MR model. The current model calculates top of canopy leaf MR following Atkin et al. 2017 and then scales through the canopy using the leaf nitrogen scaler from Lloyd et al. 2010. Recent observational evidence from Lamour et al. 2023 suggest that respiration might decrease more rapidly than photosynthesis through the canopy. In Lamour et al. 2023 they fit a linear model to observations of leaf MR by LAI, but here to avoid negative leaf MR we use the same negative exponential function as in Lloyd et al. 2010 but allow the curve to vary according to a new parameter fates_maintresp_leaf_decay. This should in principle improve the carbon budget of understory plants, and as a result increase LAI which has been biased low when using the Atkin respiration model.
Collaborators:
@ckoven @mpaiao @jenniferholm @jennykowalcz
Expectation of Answer Changes:
With the new parameter set to its default value of 2.43 results should be bfb with main. Decreasing this parameter decreases understory respiration and should decrease carbon starvation mortality in understory cohorts. I’m running a control and test with a version up to date with API 29 now and will post results.
Checklist
If this is your first time contributing, please read the CONTRIBUTING document.
All checklist items must be checked to enable merging this pull request:
Contributor
[x ] The in-code documentation has been updated with descriptive comments
[ x] The documentation has been assessed to determine if updates are necessary
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[ ] FATES PASS/FAIL regression tests were run
[ ] Evaluation of test results for answer changes was performed and results provided
This PR allows for variable vertical scaling of leaf maintenance respiration when using the Atkin et al. 2017 leaf MR model. The current model calculates top of canopy leaf MR following Atkin et al. 2017 and then scales through the canopy using the leaf nitrogen scaler from Lloyd et al. 2010. Recent observational evidence from Lamour et al. 2023 suggest that respiration might decrease more rapidly than photosynthesis through the canopy. In Lamour et al. 2023 they fit a linear model to observations of leaf MR by LAI, but here to avoid negative leaf MR we use the same negative exponential function as in Lloyd et al. 2010 but allow the curve to vary according to a new parameter fates_maintresp_leaf_decay. This should in principle improve the carbon budget of understory plants, and as a result increase LAI which has been biased low when using the Atkin respiration model.
Collaborators:
@ckoven @mpaiao @jenniferholm @jennykowalcz
Expectation of Answer Changes:
With the new parameter set to its default value of 2.43 results should be bfb with main. Decreasing this parameter decreases understory respiration and should decrease carbon starvation mortality in understory cohorts. I’m running a control and test with a version up to date with API 29 now and will post results.
Checklist
If this is your first time contributing, please read the CONTRIBUTING document.
All checklist items must be checked to enable merging this pull request:
Contributor
Integrator
Documentation
Test Results:
CTSM (or) E3SM (specify which) test hash-tag:
CTSM (or) E3SM (specify which) baseline hash-tag:
FATES baseline hash-tag:
Test Output: