Utilising blank PFTs no. 12 and 13

Land Surface CABLE
1

Plant functional type numbers 12 and 13 in CABLE are unused. These PFT slots have the potential for experiments with unique vegetation types. For example, I’m interested in using these slots to copy an existing PFT and modify some of its parameters such as leaf reflectance or perhaps to create a vegetation type more representative of Australia’s semi-arid regions.

This post is to gather thoughts from the community on a procedure to implement this.

CABLE2/ACCESS-ESM1.5

Procedure

  1. Modify the PFT parameters file so that PFT13 has desired parameters
  2. Modify CASA biome file so that PFT13 has desired parameters
  3. Point cable.nml to the above files for filename%veg and casafile%cnpbiome
  4. Edit an UM restart file to copy an existing PFT into slot 13. I wrote a script to do copy shrubs to PFT13, it ensures PFT fractions add to 1 by replacing crops.
  5. Add parameter files and restart file to a payu configuration.
  6. Run a spin-up.

PFT parameter files

CABLE2 uses a different PFT parameter file than CABLE3, which uses a namelist file.
THe CASACNP parameter file is still a .csv file in CABLE3, however. These contain the PFT specific parameters to be modified.

CABLE2 CABLE3
filename%veg pft_params.nml
casafile%cnpbiome casafile%cnpbiome

Restart files

There are many fields in the UM restart file that are passed to CABLE.
Soil physical fields would probably need to be initialized with something realistic.
Anything else?

I will need to revise the work already done here, here, and here

Script here.

PFT specific code

CABLE typically decides how to treat each PFT using iveg variable. For example,
for woody PFTs it might say if (iveg<5) then … If I want the new PFT to be woody can I simply set iveg(12)=1 to 4 in the restart file or elsewhere? or are there parts of the CABLE code where this wouldn’t work?

Spin up

Payu’s pre-industrial configuration is broken at the moment (and also this). I can’t do this step until this is fixed. I’m working with the historical configuration for the moment with land use change disabled.

Any thoughts and help would be much appreciated. I might add a help tag to this post later once it’s clearer what needs to be done.

2

@tammasloughran this:

can I simply set iveg(12)=1 to 4 in the restart file

doesn’t make sense to me. I would think iveg is an array on the number of tiles/patches and not on the number of PFTs. So what you are proposing is to change the PFT of the 12th patch to a woody type… I could be wrong there (I’m not confident about what is in the restart file for the coupled model).
With the current implementation, I don’t think you can avoid modifying the conditions directly to something like IF (iveg < 5 .OR. iveg == 12) THEN