Doubt with FDH switch in PORT (CAM4)

[deepashree_dutta@student_unsw_edu_au]

Hi all,
I'm trying to use PORT offline with CAM4.

I was wondering what happens when I don't specify the FDH (fixed dynamic heating) switch in user_nl_cam while running PORT.
PORT runs without any error and provides output. But the results don't match with either offline_driver_do_fdh = .true. or .false.

Thank you.
Deepashree

 

[nusbaume]

Hi Deepashree,

Can you let me know which version of CESM you are using? I was unable to find a namelist variable called offline_driver_do_fdh in CESM2.1.3 or later.

However, I did find a namelist variable called rad_data_fdh which sounds like it does the same thing, and in CESM2.1.3 it defaults to False if not included in user_nl_cam. So you shouldn't really get different behavior between setting rad_data_fdh = .false. and not including it at all in user_nl_cam. If you are than there is likely something else that is different between your two model simulations that is causing the different results.

Anyways, hopefully that helps some? If you can let me know the specific CESM model version then I can try and look for the defaults there as well.

Thanks, and have a great day!

Jesse

 

[deepashree_dutta@student_unsw_edu_au]

Hi Jesse,
Thank you so much for your reply.

I'm using CESM1.2.2. If you don't mind can you please have a look at this version of CESM and let me know?
I looked at this particular script to find about fdh switch: ~/models/atm/cam/src/unit_drivers/rad/camrt/radiation.F90.
Am I looking at the right code?

Thanks again for your help.
Deepashree

 

[nusbaume]

Hi Deepashree,

Thanks for the model version! You are looking at the correct code. It looks like offline_driver_do_fdh defaults to False when not included in user_nl_cam, so it should match the run where offline_driver_do_fdh = .false. . If not then it likely means there is some other setting that is different between the two simulations.

Hope that helps!

Jesse

 

[deepashree_dutta@student_unsw_edu_au]

Hi Jesse,

Thank you so much.
You are right. I reanalyzed everything, and FDH false and the defaults match.

Thanks again for your help.
Deepashree