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How to resolve cfl errors?

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I have been trying to run the model for 24 hours over a month (September 2018). I am using three two way nested domains (9km, 3km and 1km) with 63 explicitly defined vertical levels over a part of peninsular India. My timestep is 30. I am getting cfl errors only on some days, while for others the model run is completed without any errors. I have used the same domains and other runtime options for the month of January, 2019 as well and had no issues there. What might be the issue here and how can I attempt to resolve it? Please help me out.
There are two ways we often use to control CFL violation: turn on w_damping and reduce time step.If the model domain is over complex terrain area with large topography gradient, you can also increase epssm. Please try and let me know if you still have CFL issue.
Hi Ming,
Thanks a lot! I shall try your suggestions out.
However, I'm not able to understand why, for the same configuration and runtime options, there are errors only on certain days, while it works fine for others. Would you have any thoughts on that?
This is related to the meteorological condition. For some cases with severe weather, for example, strong convection and large vertical velocity, the model may have trouble to steadily integrate.
Hi g_vijayan,
If you conduct climate simulation, then it is better to use adaptive time step, which will save lots of computation time. However, if you just want to simulate a specific weather event, it doesn't really matter to turn on or turn off the adaptive time step option.