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[Question] Different namelist for CO2 concentration in F compset and B compset ?

Min-Seok Kim

Min-Seok Kim
New Member
Hello,
I'm PhD student who just start studying CESM2 modeling.
Basically, I've studied and followed CESM2 Tutorial materials which are available freely online.
I could learn the way to change CO2 concentration by changing "co2vmr" namelist with B compset example.
Then now, I would like to change CO2 concentration in F compset, but I couldn't find "co2vmr" namelist in 'CaseDocs/atm_in' file.
So I wonder whether there is difference of namelist for CO2 concentration between B compset and F compset.
Or I missed some other important points?

Could you help me?
I would like to know the way how I can change CO2 concentration in F compset simulation.
Thanks in advance for your help.
 

cacraig

Cheryl Craig
CSEG and Liaisons
Staff member
The namelist "co2vmr" is available for F compsets. All of the namelist variables for CAM can be found at:

To set any CAM namelist, you will edit the user_nl_cam file and add a line for each namelist variable you wish to set:
"namelist_var = new_namelist_value"
 

Min-Seok Kim

Min-Seok Kim
New Member
I appreciate with your reply.
But can I ask you one more thing?

Actually, I've tried F2000climo compset simulation.
Under the simulation, I couldn't find co2vmr namelist in CaseDocs/atm_in.
But when I try F1850 simulation now, I could find co2vmr namelist in CaseDocs/atm_in.

So may I ask you that F2000climo compset doesn't have co2vmr namelist?
If right, could I ask you why it doesn't have the namelist, but F1850 has?

Thanks in advance for your help.
 

cacraig

Cheryl Craig
CSEG and Liaisons
Staff member
There are two ways to set CO2 values in CAM, either with co2vmr or via an flbc file (fixed lower boundary conditions) and only one way is permitted in a run. F2000climo use an flbc file and F1850 uses co2vmr. These initial states are set by the compset from a use case file. To see what use_case file is used, do `./xmlquery CAM_NML_USE_CASE` in your case directory anytime after you've run case.setup. The use_case files are usually found in bld/namelist_files/use_cases and you may view the contents of the file specified by your compset.

Since flbc is set for an F2000climo case, you are not able to override it by setting co2vmr in your user_nl_cam file. If you want to do that, you will need to create your own use_case file. If you create your own use case, we also recommend your create your own user_defined compset. Setting these up is not something that we recommend a beginner to do as it is very easy to setup a case which does not work scientifically.
 
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