Low Aerosol Concentration from CMAQ

CMAQ
1

Hi all,

I am running CMAQ for central florida region to get the particle concentration from Feb 1,2023 through May 1,2024. But the output aerosol concentration is unexpectedly low considering the test case concentration. Please find attached the cmaq cctm run file and a part of the log file. Thank you for your help.
run_cctm_202302_4FL.csh (35.7 KB)
log.txt (83.1 KB)

Hasibul

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2

Hi Hasibul,

This could be a variety of things but a few things I noticed from your runscript:

  • You have your point sources commented out. Do you want to have those turned off?

  • There are also a number of species that are not being used (search for unused in your log file) from your gridded emissions, seaspray emissions, and dust emissions. This may be due to your EMISSCTRL_NML variable in your run script being commented out. I would uncomment that and then just make sure any of the species not being used is properly mapped in that file.

-Sara

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3

Hi Hasibul,

Sara hit the nail on the head when she pointed to the commented-out EMISSCTRL_NML variable in your run script as the reason for your low simulated concentrations.

As noted in the run script:

#> Emissions Control File
#>
#> IMPORTANT NOTE
#>
#> The emissions control file defined below is an integral part of controlling the behavior of the model simulation.
#> Among other things, it controls the mapping of species in the emission files to chemical species in the model

Without providing an EMISSCTRL_NML file, none of the emissions in your input file or specified inline emission streams (windblown dust, sea spray aerosols, lightning NO) are mapped to any model species, i.e. you are effectively running a simulation without any emissions.

As Sara pointed out, this lack of mapping instructions between your emitted species (“surrogates”) and CMAQ chemical mechanism species is reported in the log file under the section

|> Checking for unused Emissions Surrogates:

In your case, it reports that all 86 species present in your GR_EMIS_001 input file are unused, as are the 1 / 29 / 38 species associated with the inline lightning / sea spray / windblown dust emission modules.

Christian

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