Generating NEI2020 CMAQ-ready emission data

SMOKE Emissions Inventory
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1

Hi everyone,

I am using CMAQ over these two domains with 36 km and 12 km resolution:
‘21JuneD01’
‘LAM_40N97W’ -1152000.000 -1368000.000 36000.000 36000.000 108 78 1
‘21JuneD02’
‘LAM_40N97W’ 48000.000 -708000.000 12000.000 12000.000 184 154 1

I have noticed the released CMAQ-ready emission data for 12US1 domain with 12 km resolution (https://dataverse.unc.edu/dataset.xhtml?persistentId=doi:10.15139/S3/W4HCMV).
I can successfully use the m3wndw utility and the Regrid utility to create the gridded emission data for my two domains.
I think I can directly use the 12US1 inline emissions to run CMAQ with a smaller domain with the same resolution, right? However, how can I use the 12US1 inline emissions files with 12 km resolution to generate the inline emissions files with 36 km? Appreciating your help in advance!

All the best,
Lingyun

2

Hello Lingyun,

the assignment of inline point sources to a grid cell in CMAQ is based on the XLOCA and YLOCA variables from the stack parameter file(s). These variables represent the distance from the center of the projection and are therefore projection-specific but grid-independent.

As long as you are using the same projection in your CMAQ runs that was defined when processing the emissions, you can use the same inline emission files for any grid defined on that projection without having to reprocess those emissions, as long as your grid is fully contained within the spatial extent of the domain for which emission processing was performed (which does appear to be the case for your 21JuneD01 domain).

To verify that you are indeed correctly reading in all inline emissions, it might be a good idea to turn on the DESID emission diagnostic files when running CMAQ.

1 Like
3

Hi Chris,

Thank you very much for your reply! It helps me a lot and saves much time for me!

Best wishes,
Lingyun

4

Hello Chris,
If I want to run CMAQ for June 2021 using NEI2020, how can I generate smk_merge_dates file for June 2021? Thank you!

All the best,
Lingyun

5

Hello Lingyun,

@eyth.alison 's answers in this thread should be helpful.

Christian

6

Hi Chris,

Thanks very much for your help!
I have successfully generate the smk_dates for June 2021. However, the smk_dates_202106 file need the point source data from some days (e.g., June 7) that are not included in the released CMAQ-ready emission data (AWS S3 Explorer).
For example:
The generated smk_dates_202106 file:

1745847631393
1745847631393829×729 7.92 KB

The available ptnonipm data for June 2020:
1745847732986
1745847732986935×206 18.4 KB

How can I resolve this problem? Should I manually change the smk_dates file? Thank you!

Lingyun

7

I have a newer script that does the cross-year mapping for reading emissions files from one year and modeling in another. I have it already set up to map 2020 emissions dates to 2021. Note that a clean day-to-day mapping could not be performed for Jan 2nd and 3rd. The “all” columns will need to be manually filled with nearby dates based on your modeling needs.
The output file is annual. Splitting to individual months, if required, will need to be done from the annual file.

merge_date_map.py (9.7 KB)

1 Like
8

Hi James,

Thank you very much!

Best wishes,
Lingyun

9

We are wondering are you trying to prepare emissions for 2021 or 2020? But maybe you already answered that earlier in the thread…

If you are running for 2021, you need to use the smk_dates file for 2021, not the one for 2020 even when running ptnonipm.

There are emissions processed for 2021 also released so you don’t need to use the 2020 files:

https://dataverse.unc.edu/dataset.xhtml?persistentId=doi:10.15139/S3/1CLSWK

10

Hi Alison,

That’s great! Thanks for sharing me with the updated CMAQ-ready emission data for 2021 that I ignored before.

Best regards,
Lingyun