Reducing the levels in the CAM model using CAM_CONFIG_OPTS

[Sreerag]

Hey,
I am currently using CESM1 for a spun-up ocean simulation, where the initialization files are based on data from 0983 (from the input cams_inti). However, these files are set to 26 vertical levels in CAM, whereas CAM5 uses 30 levels. As a result, I encountered the error:

hycoef_read: ERROR: file lev does not match model. lev (file, model): 26 30.

To resolve this, I used the following command to reduce the vertical levels in the model from 30 to 26:

/xmlchange --append CAM_CONFIG_OPTS nlev=26

This change removed the error. My question is, would this approach be appropriate? By reducing the number of levels in CAM5, will the model be consistent with the initialization file?

Thank you in advance for your assistance.

 

[slevis]

Moving to the CAM Forum.

 

[hplin]

Hello Sreerag,

Thanks for writing. Could you please confirm the CESM version you are using? At this time, CESM1.2 and iCESM1.2 are only supported for deep time paleoclimate and water isotope applications, respectively. Are you using the model for one of those purposes? If so, I will direct this to the appropriate forum. If not, I apologize that we are no longer able to provide support for CESM1; we encourage you to update to the CESM2 series. See Support Policy | Community Earth System Model for support details.

 

[Sreerag]

Hello

I sincerely appreciate your prompt response and support.

After further investigation, I believe the issue stems from using a CAM4 initialization file to initialize CAM5, as they have different vertical levels, leading to inconsistencies. I understand that CESM1 is no longer officially supported, but I came across some initialisation files in the input directory of CESM 2
that may be suitable for my needs. However, they begin at year 402.
Would it be possible to obtain a restart file from year 1000 instead? I would be truly grateful for any guidance or assistance you could provide.
Thank you for your time and consideration.

Yours sincerely

 

[hplin]

Hello Sreerag,

To get restart files for year 1000, you could run the model from year 402 (using the initialization file you linked) and run the model forward, using the inithist namelist option to write out the restart files for desired times.