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Setting adaptive time steps for LES runs with very short time steps

fafrifa

New member
Hello I am trying to complete my 100m LES runs for a case from the SNOWIE field campaign. To save some computational costs, I have an hour and 30 minutes of simulation left to complete the wrf les run which I want to complete these restart runs with adaptive time stepping option.

However, it seems the adaptive time step is not configured or set up to work with base time step <1s (which is necessary in my case to get wrf to run) as I received this error when I tried just a 2 minutes run to see if this works:

-------------- FATAL CALLED ---------------
normalize_basetime: denominator of seconds cannot be negative
-------------------------------------------

Is it possible to complete these 100m LES with the adaptive time step option?
I have attached my namelist.input and one of the rsl.error files here:
 

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Please change your namelist options as:
Code:
 adaptation_domain                       = 1
 time_step                           = 1,
 time_step_fract_num                 = 8,
 time_step_fract_den                 = 10,
Then rerun this case. let me know whether you still get the same error.
 
Please change your namelist options as:
Code:
 adaptation_domain                       = 1
 time_step                           = 1,
 time_step_fract_num                 = 8,
 time_step_fract_den                 = 10,
Then rerun this case. let me know whether you still get the same error.
Hello Ming,

I just made the changes and resubmitted the job. Same problem persists. It terminates in less than 3 mins with the same error.
 
I would suggest that you switch to newest version of WRF and try again. Hope it works but I am not that sure. Your case is special with such a high resolution and adaptive option. Honestly we have little experiences running such cases.
 
I would suggest that you switch to newest version of WRF and try again. Hope it works but I am not that sure. Your case is special with such a high resolution and adaptive option. Honestly we have little experiences running such cases.
Sure, thanks.
 
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