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Domains with 1:1 grid ratio cause segfault?

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I have been trying to run WRF using 3 nested domains at 15-3-3 km resolution (see map), i.e. the second and third nest have the same resolution. This is because I need to be able to make modifications to the output of the second domain, and then run the third domain using ndown. But before doing that with ndown, I tried just running all 3 domains at once (as normally done when not using ndown).

WRF crashes almost immediately with a segfault (see the rsl.error.0000 file attached). WPS and real seemed to run ok and produce the appropriate files.

I have tried steps that would typically help with segfault:
- Reduce the time step (down to 1 second, which seems very small)
- Increase epssm and use 6th order diffusion
- Move the innermost domain away from mountainous terrain

Is it not ok to have 2 domains at the same resolution? Or am I making a mistake elsewhere?


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I believe this is because your D03 is not really a 'nested' domain. It is just a sub-region of D02 and the model is get confused how to process this domain.
I would suggest you run two-domain nesting, and you can always extract the data over the "D03" from model out for D02, i.e.,

ix = 174, 174+165
iy = 165, 165+ 265

Results of D02 over the above range are exactly what you want for D03.