lnd_export ERROR: One or more of the output from CLM to the coupler are NaN

[arti-14]

Hi,
Hi.
I am running the CAM simulation in single column mode for the Mid-latitude Continental Convective Clouds Experiment (MC3E).

The model runs succesfully when "scm_relaxation = .true."

But when I try to run the model with no relaxation, the model fails to run with the error " lnd_export ERROR: One or more of the output from CLM to the coupler are NaN"

I have attached the log files generated during the run for reference.

I really appreciate help regarding it.

Best Regards,
Arti Jadav

 

[arti-14]

Hi,
I am adding the user_nl_cam file , which I use during the run of the model.

Best Regards,
Arti Jadav

 

[jet]

Hi Arti. I'm not familiar with that case but my guess is that some forcing in the IOP is driving the model unstable (wrong units for one of the fields maybe?) The error most likely lies with the atmosphere and it moves into a unphysical state after a few steps which causes CLM to error out first. Unfortunately, this is one of those cases where you need to debug to see what is going wrong. Here we use the totalview debugger but print statements work just as well. I would print out T and Q as well as the advective forcing on those variables inside of forecast.F90. Most likely one of those values is going haywire probably near the surface if land is crashing. When you use relaxation the model alters the prognosed state sometimes preventing the model from crashing even though something is wrong.

jt