Summary by Nicolas Vuichard on the current status and ongoing actions : 23 Nov 2018

What has been done the last 2 weeks ?

• About the model (​https://forge.ipsl.jussieu.fr/orchidee/browser/branches/ORCHIDEE-CN)

+ Update of the branch based on the latest trunk version (commit 5578 : ​https://forge.ipsl.jussieu.fr/orchidee/changeset?reponame=&new=5578%40branches%2FORCHIDEE-CN&old=5569%40branches%2FORCHIDEE-CN) + Add the possibiliy of reading a 2D leaf CN map for being use with the IMPOSE_CN conifugaration (commit 5562 : ​https://forge.ipsl.jussieu.fr/orchidee/changeset?reponame=&new=5562%40branches%2FORCHIDEE-CN&old=5538%40branches%2FORCHIDEE-CN) + Update of the default parametrization using the latest run.def file used for ORCHIDEE-CN (commit 5590 : ​https://forge.ipsl.jussieu.fr/orchidee/changeset?reponame=&new=5590%40branches%2FORCHIDEE-CN&old=5589%40branches%2FORCHIDEE-CN) + The term of respiration associated to an excess of carbon in the labile or reserve pool is output separately (commit 5620 : ​https://forge.ipsl.jussieu.fr/orchidee/changeset?reponame=&new=5620%40branches%2FORCHIDEE-CN&old=5606%40branches%2FORCHIDEE-CN). All output variables with Growth (like RESP_GROWTH or rGrowth) are duplicated, with Excess "instead" of "Growth" in the output name.

• About the configurations used for running the model:

+ A svn branch has been created for versioning these configurations prior to move them on the trunk (​https://forge.ipsl.jussieu.fr/orchidee/browser/branches/ORCHIDEE-CN_CONFIG) + In particular, we can now use FG1 (SPINUP_ANALYTIC_FG1 config), FG1trans (OOL_SEC_STO_FG1trans config) and FG2 (OOL_SEC_STO_FG2 config) for global runs and ENSEMBLE configuration for in-situ simulations at fluxnet stations.

What could be done based on these developments ?

+ Developments related to the Permafrost done by Bertrand could be updated with the latest version of ORCHIDEE-CN and commited (if every is working when the flag for permafrost is set to "no"). @Bertrand: At first, you may try to copy your local repository of ORCHIDEE-CN with your modifications and to do a 'svn update'. Let us (Josefine + me) if you need help for that. + Check the parameter values of the ORCHIDEE-CN version: prior commit 5590, several parameters were set in the run.def, in particular for N-related and CAN-related parameters. These values correspond to those from the first run.def I got from ORCHIDEE-DOFOCO or to changes we have done over time on the ORCHIDEE-CN branch. You (in particular Sebastiaan) may look at these values that are now set as default values in the code by looking at this diff between r5589 and r5590). + Still about the change in parametrization, and in particular about some changes done recently in the trunk : if these parameters still exist in ORCHIDEE-CN, the changes have been accounted for when we have updated the branch with the trunk. If the parameters do not exist anymore but have still a significance nothing has been done so far. Maybe there are more parameters but i have at least these 2 params in mind: carbon_tau_ipassive and carbon_tau_islow. They have changed on the trunk, the parameters do not exist anymore in ORCHIDEE-CN, they have been replaced by : som_turn_islow and som_turn_ipassive (=1/carbon_tau) but their values have not been changed in ORCHIDEE-CN. Maybe there are other parameters like those two... We may want to check that. + Re-running test simulations for the grassland sites (Fabienne I guess you are ok for continuing that action with the updated version ?) + Performing a set of global simulations FG1, FG1trans, FG2 with the latest version of ORCHIDEE-CN. Vlad, could you be in charge of these simulations. Please, if you need help or advice, come to see me. + Maintaining a wiki page for documenting the work arount ORCHIDEE-CN (I don't think I'm good for that): ​https://forge.ipsl.jussieu.fr/orchidee/wiki/DevelopmentActivities/CMIP6/DevelopmentsCMIP6/V2/Nitrogen. Philippe could help for that action ?

Practically, how to get the model version and the configuations ?

+ Download modipsl + Replace the 2 following lines in the mod.def file for ORCHIDEE_trunk config for instance:

#-C- ORCHIDEE_trunk trunk/ORCHIDEE HEAD 14 ORCHIDEE modeles #-C- ORCHIDEE_trunk trunk/ORCHIDEE_OL HEAD 14 ORCHIDEE_OL config by #-C- ORCHIDEE_trunk branches/ORCHIDEE-CN HEAD 14 ORCHIDEE modeles #-C- ORCHIDEE_trunk branches/ORCHIDEE-CN_CONFIG HEAD 14 ORCHIDEE_OL config

+ Download the model by "./model ORCHIDEE_trunk

Minutes of the meeting of August 30, 2018

Presents: Fabienne, Nicolas Viovy, Bertrand, Sebastiaan, Nicolas Vuichard

We discuss about the phenology of grasslands based on the diagnostic of the simulation done bt Fabienne for Laqueuille site.

This figure shows LAI. Black curves are two remote-sensed. Red line is the current CN version. Green curve shows LAI with CN but with evergreen phenology and default settings. And blue curve shows the lai for CN evergreen with modified values of klatosa.

Minutes of the meeting of August 23, 2018

Presents: Sebastiaan, Fabienne, Bertrand, Nicolas Viovy, Nicolas Vuichard

• Phenology problem
  • Where we are about the problem of phenology ?
    • The update of the code to overpass the maximum CN ratio in order to avoid blocking the allocation has not significantly changed the results in terms of phenology
    • Optimization performed by Vlad @ fluxnet stations minimizing error on GPP improves the fit to the data, but NVui notes that the prior parametrization gives also good results when looking at the GPP but probably not in terms of LAI. One should maybe focusing on LAI (in order to improve its seasonal cycle for some PFTs/regions) not indirectly to GPP.
  • What to do to improve the seasonal cycle of LAI ?
    • Sebastiaan recalls that in CN-CAN grasslands are considered as evergreen species. The main reason was for maintaining lai in winter and increasing the albedo in winter. This could be test into ORCHIDEE-CN. Fabienne shows a preliminary test @ Laqueuille grassland site which shows that LAI is significantly incresed when grassland are considered as evergreen (LAI varies between 5 and 8). We propose to do a global test simulation with this setting (grasslands as evergreen), but prior to that one needs to modify the klatosa parameter in order to decrease the LAI
    • As an alternative to set the grasslands as evergreen, one may continue to think at some adaptation of the allocation scheme for herbaceaous species. Maybe there are some difficulties to increase LAI at leaf onset because sap biomass is also too low or badly initialized => Nicolas Vui will look at this with test simulation @ Laqueuille with Fabienne.

• Problem with the autotrophic respiration
  • Nicolas Vui reminds that the share between the maintenance and growth respiration are almost the opposite of what they should be.
  • In addition, the tuning of these respiration terms are a bit problematic because in the current version, the growth respiration output combined the "true" growth respiration and the respiration term associated to the excess of labile pool when this pool reaches a certain threshold.
  • Prior to work on the tuning of the growth and maitenance respirations, we propose to remove the respiration term associated to the excess of labile Carbon. In replacement of this patch, we propose to downregulate the photosynthesis when the labile C becomes too high. Sebastiaan will ask to some Finish colleagues what could be the labile C level above which a downregulation may act.

• Bertrand mentions that he has finish implementing the "permafrost" into the CN version. He is now testing it. There is a flag to switch on/off this feature. Vlad should do (or already did) a test to ensure that this version gives the same results when this flag is set to NO compared to the former version of CN. If this is the case, we agree to commit this in the branch, to work all with a single version.

• Nicolas Vui mentions also that there are few modifications/bugs that should be commited
  • One bug detected by Bertrand (missing initialization of a variable)
  • One bug related to the land-use change detected by NVui
  • Optionally, NVui added an option to read a map of CN ratio, in order to work globally with the CN fix configuration. This could be also commited.

Minutes of the meeting of June 14, 2018

Presents: Phlippe P., Sebastiaan, Bertrand and Nicolas Vui

We looked at the CL4 simulation performed by Vladislav with C/N dynamic. In particular to the mean seasonal cycle of LAI for each PFT. Although there are similar behavior than with the forced simulation with C/N dynamic (on PFT6 or PFT10), ther "performances look nevertheless better in coupled mode than in force mode. This is not explained so far (might be due to the different set-up).

Philippe asked for producing a list of the most sensitivie parameters regarding the N cycle in order to be able to perform some optimization/tuning at site level but also at global scale.

Minutes of the meeting of June, 7

Presents: Patricia, Sebastiaan, Fabienne, Vladislav, Nicolas Viovy, Philippe P., Nicolas Vuichard

• Problem of phenology of grasslands
  • About the differences in the routine dealing with allocation (stomate_growth_fun_all) between the CN version and CN-CAN version, Sebestiaan don’t think there are significant changes. The main difference is a difference in the parametrisation: In CN-CAN, grasslands are evergreen vegetation while they are deciduous in the CN version.
    

=> one test simulation could be launched in force mode, setting the grasslands as evergreen

• The new diagnostic for looking at seasonal variation of LAI per PFT over specific regions developed by Vlad is not ready yet.
• Instead, we looked at the LAI maps generated per season (DJF,MAM,JJA,...) which are available on the mapper. We have seen that the LAI of PFT 10 for the coupled simulation with CN version and CN fix compares relatively well to the one from the coupled simulation with the standard ORCHIDEE.
  

LMDzOR Trunk	LMDzOR CNfix

In contrast, the LAI from the simulation in force mode with CN version and CNdyn is much lower than the one with the ORCHIDEE standard.

ORCHIDEE Trunk	ORCHIDEE CNdynamic

This may indicate that the problem in the phenology of grasslands is not strictly speaking a phenology problem but a problem of N availability which indirectly impacts on the LAI development.

=> We could run a new simulation with CN version and CN fix in force mode, in order to compare it with the simulation with CN dyn and also with the gimms product.

=> Check how is set the flag ALWAYS_INIT in our simulations with CN dynamic. One may wonder if the low LAI simulation with CNdyn are due to past conditions (ie early 20th or late 19th) for N fertilisation and N deposition or if also for present day conditions, the grasses have difficulties for growing.

Minutes of the meeting of May 31, 2018

• Presents: Fabienne, Vladislav, Philippe P, Nicolas Viovy, Nicolas Vuichard
• Problem in the phenology:
  • Here an illustration of the problem:
  • Problem in the way to compute the mean LAI per PFT in the mapper: The new diagnostic developed by Vlad shows the contribution of each PFT to the total LAI for specific regions (latitudinal bands, continents, ...). This is sensitive to the land use map used and is not the diagnostic expected (ie mean LAI for each PFT for a specific region).
    Action => Vlad will correct this in order to clearly identify which PFT(s) have a very bad phenology
  • Fabienne agrees on working on this issue. Nicolas Vui will give her the information needed for running this version of ORCHIDEE (next Thursday morning)
  • Several actions related to this problem of phenology
    • To modify specific parameters related to the allocation and/or the senescence. Based on the diagnostic, the problem might be only related to the leaf onset, which seems to slow in the temperate areas. Because the leaf onset is not enough abrupt, due to the residence time of the biomass, the problem at the leaf onset may impact as well the senescence phase.
    • To ensure that there is no change in the allocation module of the CN-CAN version compared to the CN version
    • And/or : To switch on the allocation module of CN and to switch on the one from CN-CAN

• Set-up of the coupled simulations LMDzOR:
  • For the moment, only one LMDzOR simulation has been done, in which the leaf C/N ratio was precribed with default values.
  • Simulations with dynamical C/N ratio have to be launched: Vlad will do one soon, starting from scratch. One may also envisage to launch one but starting from a restart file for orchidee component.
  • A simulation with C/N fix could also be done but with more realistic C/N ratio (spatialized) than those used in the first simulation.
• Problem in the autotrophic respiration
  • The share between maintenance and growth respiration is almost the opposite than the one expected.
  • There is an additional source of respiration related to the excess of labile Carbon when this pool reaches too high values. The respiration term is included into the growth respiration. This does not help to tune the maintenance and growth respiration terms.
  • Action: to remove the addition respiration related to the labile C and to diagnose the contribution of growth and maintenance respiration to the autotrophic respiration