How to output surface roughness (e.g., Z0MV) in the CLM5.0 land surface model?

[Shuai Li]

What version of the code are you using?
- I ran CESM 2.1.4 on NCAR HPC.


Have you made any changes to files in the source tree?
- I only changed the default “fsurdat”


Describe every step you took leading up to the problem:
- Specific steps: 1) create a new case with F2000climo compset
2) case setup
3) vi user_nl_clm, and specified on "hist_fincl1 = 'Z0MV'", "hist_fincl2 = ...", "hist_nhtfrq = 0, -24" "hist_mfilt = 1, 365" "fsurdat = ..." "use_init_interp = .true."
4) vi user_nl_cam, and specified on "fincl2", "mfilt = 1, 365", "nhtfrq = 0, -24"
5) ./preview_namelists
6) ./case.build

Describe your problem or question:
I want to output the roughness variable (e.g., Z0MV). I saw the solution in the previous post and tried it out. I used hist_finl1 = 'Z0MV' in user_nl_clm to specify its output.
But when I try to comment out the "use_cn" if statement to get Z0MV output:

if (use_cn) then
this%z0mv_patch(begp:endp) = spval
call hist_addfld1d (fname='Z0MV', units='m', &
avgflag='A', long_name='roughness length over vegetation, momentum', &
ptr_patch=this%z0mv_patch, default='inactive')
end if

I can't find which file or script for this statement ()
Can you tell me where I can find this statement?

I attached the log file if need it.

 

[slevis]

I typed
git grep -i "call hist_addfld1d (fname='z0mv'"
in my ctsm checkout and got
src/biogeophys/FrictionVelocityMod.F90: call hist_addfld1d (fname='Z0MV', units='m', &

This seems to be the line that you're looking for.

 

[Shuai Li]

I typed
git grep -i "call hist_addfld1d (fname='z0mv'"
in my ctsm checkout and got
src/biogeophys/FrictionVelocityMod.F90: call hist_addfld1d (fname='Z0MV', units='m', &

This seems to be the line that you're looking for.

When I tried to type the command you mentioned in my case folder, there was no response. Is it because I am running CESM2.1.4 on Derecho instead of a local machine?

 

[oleson]

You need to do it in your source code, e.g.,

cd /glade/work/oleson/release-cesm2.1.4/components/clm/src
grep -r Z0MV *

gives:

biogeophys/FrictionVelocityMod.F90: call hist_addfld1d (fname='Z0MV', units='m', &

 

[Shuai Li]

You need to do it in your source code, e.g.,

cd /glade/work/oleson/release-cesm2.1.4/components/clm/src
grep -r Z0MV *

gives:

biogeophys/FrictionVelocityMod.F90: call hist_addfld1d (fname='Z0MV', units='m', &

Hi Oleson,

Thanks a lot for your detailed response. I have found that file.

In addition, I am studying the climate effects of land cover change by replacing the default surface conditions (fsurdat) in CESM2. If I activate the output of Z0MV, will the simulated results (e.g., temperature, precipitation) be different from not activating it?

 

[oleson]

Turning on and off history fields should have no effect on model results.