Cutting down on outputted species

[laura-hyesung-yang]

I'm currently running 12km WRF-GC over the continental US and one month output results in 3TB. This file is too big to postprocess it and requires lots of storage if I wish to make the runs go for different months simultaneously. I wish to hence trim down on number of species that are outputted. However, eventually I have to run one-way nested 4km run and conduct ndown.exe which means I would need some meteorological and chemical species from my 12km outputs.

I found this helpful post that helps to distinguish what variables are needed and what are not for ndown.exe UCAR thread.

I generated below text files that compare wrfinput and wrfoutput files. Then I used the different between the two to identify which variables I can remove and still make ndown.exe work (removable_vars.txt). Do you think this is good approach? Also, is there any limitation in getting rid of some of these variables from the output?
input_vars.txt
output_vars.txt
removable_vars.txt

Thank you!

[jimmielin]

I don't think we ever supported nup and ndown.exe - this was probably last discussed in 2018 with @fengx7. If it works with WRF-Chem maybe it could be made to work with WRF-GC.

One-way nesting at 4km could probably be possible by post-processing the wrfout into something mozbc can ingest. The non-advected species (see geoschem_config.yml) are too short lived and could be cut out. Not sure if real.exe can ingest the meteorological data output from wrfout at 12km or if it'll only ingest FNL...

You could cut down the 12km output using https://wrfgc.readthedocs.io/en/latest/faq.html#can-i-select-what-variables-wrf-gc-outputs (more details here https://github.com/NCAR/WRFV3/blob/master/README.io_config). I am not sure if WRF has a subsetting method to 'cut down' the domain of the output, but probably not.

[laura-hyesung-yang]

Hi Haipeng, thank you! I previously thought this method ([wrfgc documentation])(https://wrfgc.readthedocs.io/en/latest/faq.html#can-i-select-what-variables-wrf-gc-outputs) could only work for chemical species and was thinking of just touching files in Registry to get rid of none chemical species like WRF variables.

I was able to use ndown.exe to generate the IC/BC for nested domain using coarser resolution and made the nested run work. So I think it works with WRF-GC!