Welcome to the new DiscussCESM forum!
We are still working on the website migration, so you may experience downtime during this process.

Existing users, please reset your password before logging in here: https://xenforo.cgd.ucar.edu/cesm/index.php?lost-password/

How to change CESM2 radiation calculation frequency



Does anybody know which namelist variable should be changed to let CESM2 calculate radiation at each time step? The default frequency is one day (if I remember correctly) but I want to change it. Thank you!


Jesse Nusbaumer
CSEG and Liaisons
Staff member
Hi Eric,

I believe the namelist variables you need to change are iradsw and iradlw, which should both be set to 1 in order to have the radiation run every time step (currently the default for CESM2.1.3 is to run every hour, which is usually two model timesteps).

You can find more info on the radiation timestep namelist variables by searching for "irad" here:

Hope that helps, and have a great day!