No MEGAN mass emissions diagnostic file in CMAQ v5.4 similar to BEIS?

Hi there,
I am using CMAQv5.4 with enabling MEGAN, and how to output the MEGAN mass emissions diagnostic files similar to enabling BEIS modules?
Any recommendations for how to solve this or investigate further?


You can use the DESID diagnostic output framework described in section B.3.7.2 here: CMAQ/ at main · USEPA/CMAQ · GitHub

For the Stream name, use ‘MIOG’ for MEGAN. For BEIS, use ‘BIOG’.

Best wishes,
Ben Murphy


Thanks, @Ben_Murphy for responding so quickly!

To add to this response, please note that the diagnostic emission output files generated through the DESID framework will be mole based rather than mass based (unless I am missing an option in DESID to control that), so if you want to compare MEGAN diagnostic mole-based emissions from the DESID1_MIOG file to existing non-DESID B3GTS mass-based BEIS diagnostic emissions generated using the B3GTS_DIAG flag, you’ll have to do some unit conversions using molecular weights, though for some lumped mechanism species there may be some issues with that. In that case, it’d be cleaner to also generate BEIS mole-based diagnostic emission files through DESID.

Here is an example of the modification to CMAQ_Control_DESID.nml needed to implement MEGAN diagnostic mole-based emission files through DESID, as documented in the link posted by @Ben_Murphy above:

> diff CMAQ_Control_DESID.nml CMAQ_Control_DESID_MEGAN.nml
> 188c188
> <   Desid_N_Diag_Rules = 0    ! Exact Number of Diagnostic Rules Below
> ---
> >   Desid_N_Diag_Rules = 1    ! Exact Number of Diagnostic Rules Below
> 196c196,200
> <
> ---
> >
> >     Desid_Diag_Streams_Nml(1,:)= 'MIOG'
> >     Desid_Diag_Fmt_Nml(1)      = 'COLSUM'    ! Options: 2D, 2DCOL, 3D
> >     Desid_Diag_Spec_Nml(1,:)   = 'ALL'
> >

Thx. Based on your suggestions, CCTM_DESID1_MIOG file can be created.

Hi, @hogrefe.christian.

I still cannot create the CCTM_DESID1_MIOG files. And the CTM files show that the name of first variable is always mistaken code whether I choose ‘ALL’ or ‘ISOP’, 'TERP'.

The figure shows that log when I set Desid_Diag_Spec_Nml(1, :) = 'ALL'.

Yikes. I’m sorry for this frustration. I’ve tried to reproduce this error using our Benchmark scenario and everything seems to be working ok. Can you post your version of the CMAQ_Control_DESID.nml file that is prescribing the diagnostic output?

Thx, I have solved this problem by using another computer.

Hm, I’m not sure why the behavior would go away on a new system. Perhaps the reinstall/recompile step ironed out potential problems. If you end up looking further into this a figuring out system-to-system issues or differences, please report them if possible.

Thank you and happy coding!