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segmentation fault appears when running unipost

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Hi all,

I tried to convert WRF-Chem v4.2.2 output to grib2 format using UPP. However, there is a segmentation fault appearing when I use it and I am not sure where it goes wrong. I've attached the error log and my run script. I wonder if anyone could help with it?

In addition to the error, I also have two questions related to UPP:

1) Does UPP can process both WRF and WRF-Chem output files?

2) Do I need to make any modification to the default postxconfig-NT-WRF.txt file before running the UPP?

Many Thanks,



  • postxconfig-NT.txt
    16.7 KB · Views: 28
  • unipost_d01.00.out.txt
    37.3 KB · Views: 29
  • run_unipost.txt
    17.9 KB · Views: 30
In general, UPP can read WRF-Chem files, though it is hard coded to read certain variables for wrfout files, so since it wasn't developed specifically for WRF-Chem it's possible the code isn't updated to read everything you have in your wrfout file. You could, in theory, add those variables to the code which is described in Appendix B of the last WRF supported Users Guide: But I wouldn't tackle that until you have a successful run of UPP processing your existing wrfout files.

In your unipost log the error at the end indicates it can't open the params_grib2_tbl_new file, I would first make sure that exists and is being properly linked via the run script. There is also a seg fault memory reference error in your log file, this could be due to the missing params_grib2_tbl_new or could be something else entirely...potentially related to this being a WRF-Chem application. It might helpful to first see if you can process a pretty basic WRF file, like one for the online tutorial, once that is working then see if you can get the WRF-Chem to run as well.

Unfortunately UPP support of WRF applications has ended, so we're not able to dig into these runtime errors in detail any more. But I hope these tips or suggestions can help!
Thanks for your response. I am now using UPPV3.2 and it works fine. I suspect UPPV4.1might have some bugs.