Problem running CBMZ-MOSAIC (4 bins) with AFWA dust scheme

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Problem running CBMZ-MOSAIC (4 bins) with AFWA dust scheme

Post by Rui_Silva » Mon Jun 07, 2021 5:53 pm

Dear all,

I am using WRF-Chem V3.9.1 to simulate a dust event that affected Portugal between 22June and 30 June 2012.
Chemical initial and boundary conditions are provided by CAM-CHEM data, while meteorological initial and boundary conditions are given by ERA5 reanalysis, with 72 hours spin up period.

After running the model using chem_opt = 9 (i.e. CBMZ-MOSAIC 4 bins) with dust_opt = 3 (i.e. AFWA scheme), I've noticed big differences between AOD at 550 nm between the model and CAMS reanalysis fields, although the spatial patterns look similar. Does anyone know what can be causing this differences?

Another issue with my simulation is that the outputs for DRY_DEP_FLUX, WET_DEP_FLUX, DRYDEP_X, and GRASET_X, are all zero. Is this normal?
By the way, AFWA_DUST_LOFT, EDUSTX, DUSTLOAD_X, TOT_DUST, and TOT_EDUST variables have values in them, although I don't know if they are correct.
I've tried dust_opt = 1 (GOCART dust emissions) and the results are pretty much the same, which is strange.

Attached is my namelist.input file, a .gif file with the simulated AOD at 550 nm, and two figures comparing simulated and CAMS AOD at 550 nm at the same instant (Note that figures have different color limits).

Thanks for your help.

Kind regards,
Rui Silva
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Re: Problem running CBMZ-MOSAIC (4 bins) with AFWA dust scheme

Post by jordanschnell » Wed Jun 09, 2021 5:01 pm

Hi Rui,

Unfortunately neither of the GOCART based dust schemes are properly coupled to MOSAIC aerosol schemes.

For example, look at lines 303-326 in chem/module_gocart_dust_afwa.F

Note that there are only a few cases where the 5 size bins of dust emissions (tc) are added to the chem array. For CB05_SORG_AQ_KPP and B05_SORG_VBS_AQ_KPP, the five bins in tc are assiged to the i,j,coarse modes in the MADE/SORGAM aerosol mechanism. For mechansims that have dust_1-5 in their mechanism, the translation is straightforward.

If you look at Registry/registry.chem, you'll see that only a few mechanisms have dust_1-5 listed (i.e., chem_opt = 112, 300, 301, 401).

If you want to use MOSAIC, you will need to modify the code to add the tc dust emissions to aerosols defined in MOSAIC.


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