time step sizes for FV dynamical core

[skkim@cum_snu_ac_kr]

Dear CAM users,

I want to run CAM with FV 1x1.25 and 0.5x0.625 resolutions.
I would like to know the default time step sizes for these resolutions.

Thank you.

 

[hannay]

In finite volume, the default physics timestep is 1800s for every resolution.
The namelist defaults are defined in:
models/atm/cam/bld/namelist_files/namelist_defaults_cam.xml
Cecile

 

[skkim@cum_snu_ac_kr]

Thank you for your reply.

I have one more question.
Through the web surfing, I got a ppt file which title is "The Lin-Rood Finite Volume Dynamical Core: Tutorial". In according to the file(page of "Typical horizontal resolutions"), it were used dtime of 7200 sec at the fv4x5 resolution ,3600 sec at the fv2x2.5 resolution, and 1800 sec at the fv1x1.25 resolution. It looks that the smaller dtime should be used when the resolution become finer.

I wonder if using same dtime (1800 s) at the different resolutions is O.K.

 

[hannay]

in FV, CAM uses the same timestep for the physics (1800s) at different resolutions but it uses different timesteps for the dynamics at the different resolutions. It is automatically set in CAM and you should not have to worry about it.

 

[skkim@cum_snu_ac_kr]

Thank you very much.
Your reply is very helpful to me.