Create ICON file

Hi!
I am trying to create an ICON file base on two ICON file with netCDF4 package in python. then I checked new ICON file in a test run, But there is an ERROR :

“”""GR_EM_SYM_DATE_0 | F
Error opening file at path-name:
netCDF error number -51 processing file “INIT_CONC_1”
NetCDF: Unknown file format
NetCDF: Unknown file format
/home/wrf-cmaq/CMAQ/data/Global_Tehran/icon/ICON_v532_Tehran_6km

 *** ERROR ABORT in subroutine gridded_files_se on PE 000
 Open failure for INIT_CONC_1

PM3EXIT: date&time specified as 0
Date&time specified as 0"""""

I checked the structure of new ICON file with other ICON files but it’s the same. I don’t know how to fix this ERROR and where is I am wrong?!
you can download new ICON file and the LOG file (point_down:)
CTM_LOG_000.v532_gcc_Tehran-6km_20210124.txt (9.1 KB)
ICON file:
https://drive.google.com/file/d/1LmxW0GP26piwLuOMVVESCzzIbc42djKq/view?usp=sharing

See https://cjcoats.github.io/ioapi/AVAIL.html#ncf4.
There have been problems with netCDF not being compatible with itself, especially with Version 4.
Make sure that your python package is creating “netCDF Classic” format.
By the way, The Models-3 I/O API is A programming interface, not a data format !! I/O API files are not synonymous with “netCDF files” !!. Treating it as a data format (as you are doing with your python stuff) is NOT SUPPORTED.

As Carlie notes above, the error you are seeing is likely from your python code writing files using a form of netCDF that is incompatible with the version compiled with your version of IOAPI.

But even if you fix that issue, you will likely run into other problems. IOAPI is an interface, and you should use that interface to create the files. If you want to combine species from different existing ICON files (assuming they have the same time stamp and are on the same domain), then you can use EPA’s combine program, or one of the IOAPI tools, perhaps m3combo.

thank you for your reply this is really helpful for me