Which species are read from a gridded emission file?

I’m trying to figure out why some species are read from a gridded emission file, whereas others seem to be ignored. [Before I forget, I’m using CMAQv5.4]. For example, SO2 or CO are picked up and the results reflect this (versus a similar simulation but without an emission file). However, ECH4 and several other species seem to have been ignored and the results are the same as the simulation w/o an emission file. Looking at the variable VNAME in the subroutine GR3D of the DESID_MODULE, something is not clicking with me: Some variables have their names, but others seem to have been assigned as either POC or PNCOM (not really sure why). Of course, these variables are the ones with no changes in the results with the addition of the emission file. What am I missing here?

Hi Arturo,

You can find the mapping of emissions to CMAQ species within the DESID namelist. For example, if you are running with CB6R5, look for CMAQ_Control_DESID_cb6r5_ae7_aq.nml. For more information on how to interpret this file please see: https://github.com/USEPA/CMAQ/blob/main/DOCS/Users_Guide/Appendix/CMAQ_UG_appendixB_emissions_control.md.

A list of the CMAQ species can be found in the GC_cb6r5_ae7_aq.nml, AE_cb6r5_ae7_aq.nml, NR_cb6r5_ae7_aq.nml, or Species_Table_TR_0.nml for CB6R5.

Within CCTM, the DESID module simply interprets the mapping in the above namelist so you will not find any mappings there.

If there are species you want mapped to CMAQ species for certain emissions sources, it must be done through the namelist file mentioned above. Please note, that CMAQ species names may not match the species names in an emissions file, so some mapping must be determined. For example, the default CMAQ_Control_DESID_cb6r5_ae7_aq.nml will map the emissions species ‘CH4’ to the CMAQ species ‘ECH4’. So if your emissions file has a species called ‘ECH4’ it will won’t map it to the CMAQ species ‘ECH4’ automatically because no mapping in that namelist exists for that species.

Hope that helps you connect the dots!