Use of irrigated crop PFT in CLM SP mode

[pesieber]

I am using CLM in SP mode and wonder how the irrigated crop PFT is used.

It has a fraction on the surface dataset (e.g. surfdata_0.5x0.5_hist_16pfts_Irrig_CMIP6_simyr2000_c190418.nc), its LAI is identical to that of the unirrigated crop, and its parameters are also identical to the unirrigated crop except for leafcn which is 25 for irrigated crop and 28 for unirrigated crop (clm5_params.cpbiomass.c190103.nc).

So, since irrigation is not active in SP mode, does the irrigated crop PFT run independently like any other PFT, with the only difference to the unirrigated crop being the lower leafcn? Is there any reason for this value, or could the irrigated crop safely be merged with the unirrigated crop? And could I then safely use the "freed up PFT" for a custom PFT, e.g. a bioenergy crop that I parameterize myself? Of course, with correctly calculated fraction and suitable LAI.

Thanks!

 

[slevis]

I don't know when leafcn was made different for pfts 15 versus 16 and the reasoning for the change. I think that when irrigation is off, the irrigated and unirrigated crop areas merge during the simulation. If so, you may not be able to do what you suggested without some code modification.

 

[slevis]

Oh, by the way... leafcn should not matter in SP simulations because I'm pretty sure that it's for BGC simulations.

 

[pesieber]

Ok thanks! That makes sense. I saw in the CLM5-PPE list that leafcn was active in SP mode, but it might be an error there.

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[akhtert]

Hello, I am reposting a similar query here.

I am doing a Global simulation in SP (no crop model) using the compset I2000CLM50SPGs. I did irrigation in one simulation with irrigate= .true. in the namelist file. Now I want to turn irrigation off. I am using irrigate= .false. in the namelist, but still there is irrigation. DO I need to change something in the surface dataset? Please provide any suggestion or comments. Thank you for your help.

 

[oleson]

When I set irrigate = .false. in usr_nl_clm for that compset using release-cesm2.1.4, I get the error:

ERROR: Command /glade/work/oleson/release-cesm2.1.4/components/clm/bld/build-namelist failed rc=255
out=CLM adding use_case 2000_control defaults for var 'sim_year' with val '2000'
CLM adding use_case 2000_control defaults for var 'sim_year_range' with val 'constant'
CLM adding use_case 2000_control defaults for var 'stream_year_first_urbantv' with val '2000'
CLM adding use_case 2000_control defaults for var 'stream_year_last_urbantv' with val '2000'
CLM adding use_case 2000_control defaults for var 'use_case_desc' with val 'Conditions to simulate 2000 land-use'
err=ERROR : CLM build-namelist::CLMBuildNamelist::add_default() : No default value found for fsurdat.
Are defaults provided for this resolution and land mask?

Is that the error you get?

This was my answer to a similar post, perhaps you can try one of these options (Modifications to IrrigationMod.F90 and namelist variable):

"I tried this myself with various versions (cesm2.1.0, cesm2.1.1, 2.1.3) and had the same problem.
However, I was able to shut off irrigation with cesm2.2.0 by setting irrigate = .false. and adding in the same fsurdat that would be used if irrigate was true.
So, your options seem to be:
1) Use cesm2.2.0
2) Using the version of cesm you are using now, use your method of setting the deficits to zero.
3) I couldn't find a surface dataset without irrigated cropland that is compatible with the dataset you are using. So, you could create a surface dataset manually by assigning irrigated crop areas to the non-irrigated crop areas in that dataset. There may be a way to do this using the mksurfdata tool, but I'm not sure what that is."

 

[akhtert]

When I set irrigate = .false. in usr_nl_clm for that compset using release-cesm2.1.4, I get the error:

ERROR: Command /glade/work/oleson/release-cesm2.1.4/components/clm/bld/build-namelist failed rc=255
out=CLM adding use_case 2000_control defaults for var 'sim_year' with val '2000'
CLM adding use_case 2000_control defaults for var 'sim_year_range' with val 'constant'
CLM adding use_case 2000_control defaults for var 'stream_year_first_urbantv' with val '2000'
CLM adding use_case 2000_control defaults for var 'stream_year_last_urbantv' with val '2000'
CLM adding use_case 2000_control defaults for var 'use_case_desc' with val 'Conditions to simulate 2000 land-use'
err=ERROR : CLM build-namelist::CLMBuildNamelist::add_default() : No default value found for fsurdat.
Are defaults provided for this resolution and land mask?

Is that the error you get?

This was my answer to a similar post, perhaps you can try one of these options (Modifications to IrrigationMod.F90 and namelist variable):

"I tried this myself with various versions (cesm2.1.0, cesm2.1.1, 2.1.3) and had the same problem.
However, I was able to shut off irrigation with cesm2.2.0 by setting irrigate = .false. and adding in the same fsurdat that would be used if irrigate was true.
So, your options seem to be:
1) Use cesm2.2.0
2) Using the version of cesm you are using now, use your method of setting the deficits to zero.
3) I couldn't find a surface dataset without irrigated cropland that is compatible with the dataset you are using. So, you could create a surface dataset manually by assigning irrigated crop areas to the non-irrigated crop areas in that dataset. There may be a way to do this using the mksurfdata tool, but I'm not sure what that is."

I do not get any error, the model runs, but it irrigates.
I assume I have to manually make the irrigated crop type to non-irrigated. I am also trying to find an way to do it.

 

[oleson]

What version of the model are you using?

 

[akhtert]

What version of the model are you using?

I am using CLM5 (cesm 2.1) but I have the aquifer layer active from CLM 4.5 and some groundwater parameterization including pumping.

 

[slevis]

In this version, the irrigated PFT gets merged with the unirrigated PFT during runtime, as far as I remember. How did you determine that the soil was still irrigated?

 

[slevis]

Is the groundwater parameterization + pumping new? I wonder whether it needs some if-statement around it, so as to bypass it when irrigation = .false.

 

[akhtert]

In this version, the irrigated PFT gets merged with the unirrigated PFT during runtime, as far as I remember. How did you determine that the soil was still irrigated?

I saved and checked the QIRRIG variable and there is irigation.

 

[akhtert]

Is the groundwater parameterization + pumping new? I wonder whether it needs some if-statement around it, so as to bypass it when irrigation = .false.

It is not yet available with the default CLM, it was modified by a member in our lab (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020WR027531). The irrigation = .false. works for BGCcrop compsets, however, it seems irrigation is hardwired to the SP compsets and that is why it is not working.