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Correct format emiss input files for WRFv4

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New member
Dear colleagues,

Currently, we run WRF-Chem v3.9.1 and we get our prepared emissions files (wrfchemi_dXX, wrffirechemi_dXX) from different programs (python, fortran..), so that means that we do not use fire_emiss nor anthro_emiss WRF-Chem tools. We would like to know what are the special requirements or file format that we need to have to be able to run WRF-Chem v4.1.5 WITHOUT having to set to TRUE * force_use_old_data. (We have found that when using old input data, one should also set hybrid_opt =0 and use_theta_m = 0 in &dynamics, since the defaults for V4 are hybrid_opt =2 and use_theta_m = 1, and this way our model runs, but we don´t want to switch those options to 0).

Thank you very much!

Best wishes,

We apologize that the WRF-Chem user guide has not been updated in some time. We expect to have an update out later this year.

In the meantime, please see these lines in share/input_wrf.F

IF ( INDEX(TRIM(input_title_char),' V4.' ) .NE. 0 ) THEN
yes_use_this_data = .TRUE.
WRITE(wrf_err_message,*)'This input data is not V4: ' // TRIM(input_title_char)
CALL wrf_debug( 0 , wrf_err_message )
yes_use_this_data = .FALSE.

So, it looks like in order to bypass this check, one would simply need to make sure that ("V4") is in the netcdf attribute "TITLE"

Please let me know if this works for you.


Dear Jordan,

Thank you for your reply. We will try what you suggested us and also wait for the update on the user guide for this regard, in case there is something else we should take into account.

Thanks again and best regards!
please I will like to request for the python and the fortran script to generate emission data sets for wrf-chem simulation.
thank you