How to calculate the Geopotential in CESM

[zhendf]

Hi, everyone
Due to my carelessness, I forgot to output the variable geo-potential in the daily file xxx.h1.nc, but I have got the PS output. Could anyone tell me how the geo-potential calculated in the CESM？ Thanks！！！

 

[brianpm]

You might be able to approximate it if you have temperature and specific humidity saved. I think the way that CESM computes it is in:

$CAMROOT/src/atmos_phys/utilities/geopotential_t.F90

 

[cacraig]

You can also trace the variable you wanted to output in the CAM code itself to see what would have been output. For instance, the variable "Z3" which is "Geopotential Height above sea level" is output in src/physics/cam/cam_diagnostics with an "outfld" call and is calculated as follows:

z3(:ncol,k) = state%zm(:ncol,k) + state%phis(:ncol)*rga

There is also a file which contains the geopotential calculations: src/physics/cam/geopotential.F90. I believe this is very similar to the file that brianpm mentioned above.

Hopefully one of these suggestions will help you.

 

[zhendf]

You can also trace the variable you wanted to output in the CAM code itself to see what would have been output. For instance, the variable "Z3" which is "Geopotential Height above sea level" is output in src/physics/cam/cam_diagnostics with an "outfld" call and is calculated as follows:


There is also a file which contains the geopotential calculations: src/physics/cam/geopotential.F90. I believe this is very similar to the file that brianpm mentioned above.

Hopefully one of these suggestions will help you.

Thank you very much，I will try it later！