How to convert this unit to kg m^-3?

geoschem / geos-chem

GEOS-Chem "Science Codebase" repository. Contains GEOS-Chem science routines, run directory generation scripts, and interface code. This repository is used as a submodule within the GCClassic and GCHP wrappers, as well as in other modeling contexts (external ESMs).

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Your name

Baihua Chen

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Xiamen University

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Dear @yantosca

In GEOSChem.SpeciesConc.20190xxxx_0000z.nc4 file, the following is displayed. This file should only contain emission data, not transport, right? Additionally, I also want to know about the marine organic aerosols. But I couldn't find MOPI and MOPO in GEOSChem.SpeciesConc.2019xxxx_0000z.nc4. I find MOPI and MOPO in the HEMCO_diagnostics.2019xxxx0000.nc file, but their units are mod mod-1 dry? How to convert this unit to ng m^-3 or kg m^-3? Just like Figure 2. Moreover, does the GEOS-Chem model not include marine secondary organic aerosol (SOA)?

These questions are very important to me.

Thank you for your help! Have a nice weekend!

Best regard Baihua Chen 微信截图_20241128112028 35542f1a309c75e2ef46b890b33b189

Thanks for writing @ChenBHXMU and thanks for your patience. We had a long holiday weekend here.

In GEOSChem.SpeciesConc.20190xxxx_0000z.nc4 file, the following is displayed. This file should only contain emission data, not transport, right?

The SpeciesConc collection contains species concentrations, not emissions data.

Additionally, I also want to know about the marine organic aerosols. But I couldn't find MOPI and MOPO in GEOSChem.SpeciesConc.2019xxxx_0000z.nc4. I find MOPI and MOPO in the HEMCO_diagnostics.2019xxxx0000.nc file, but their units are mod mod-1 dry? How to convert this unit to ng m^-3 or kg m^-3? Just like Figure 2.

Did you create a run directory with the marine organic aerosol extra option? If so, your simulation should contain the MOPO and MOPI species in the SpeciesConc collection.

The HEMCO diagnostics file contains emissions in flux units kg/m2/s (mass/area/time), not mol/mol dry.

To convert concentration units (mol/mol dry) to ug/m3 (which I presume is what you want), you can use this conversion:

            # Convert values from ppb to ug/m3:
            # ug/m3 = mol/mol * mol/g air * kg/m3 air * 1e3g/kg
            #         * g/mol spc * 1e6ug/g
            #       = ppb * air density * (spc MW / air MW)

Moreover, does the GEOS-Chem model not include marine secondary organic aerosol (SOA)?

That is correct. The original developers only added MOPO and MOPI primary aerosols but not marine organic SOA.

geoschem / geos-chem