Sea-salt emissions with chem_opt=9 or chem_opt=11

[Rui_Silva]

Hi,

I would like to know if there is any possibility of using sea-salt emissions with CBMZ/MOSAIC 4bins (chem_opt=9) or RADM2-MADE/SORGAM mechanisms (chem_opt=11) in WRF-Chem v3.9.1?
I know this was possible in versions prior to 3.8, however seas_opt=2 was disabled after that.

Thank you.

Kind regards,
Rui Silva

 

[jordanschnell]

Hi Rui,

I'm looking at WRF v3.9.1.1 and see that you still should be able to use seas_opt = 2 despite what the UG says. HOWEVER, it is possible there are errors associated with the scheme and thus not recommended. In the code, it lists: ! William.Gustafson@pnl.gov; 10-May-2007. as the developer but you may want to contact others (it has been nearly 15 years!). See the subroutine starting on line 8073: SUBROUTINE sorgam_seasalt_emiss. You can always try the scheme out, and apply tuning factors informed by obs.

Jordan

 

[Rui_Silva]

Hi Jordan,

Thanks for your reply and suggestion.

Here is what I found after checking module_aerosols_sorgam.F (subroutine sorgam_seasalt_emiss) and module_mosaic_addemiss.F (subroutine mosaic_seasalt_emiss):

1. SORGAM has two options for activating sea salt emissions - seasalt_emiss_active == 1 and seasalt_emiss_active == 2. The second option is commented in the code, and for this reason I think that only seas_opt=1 is working for SORGAM. If seas_opt=1 (i.e., seasalt_emiss_active == 1), the module distributes emissions through naai, naaj, clai, claj aerosol species, assuming that sea salt is pure NaCl.

2. MOSAIC does the same thing, but for bins instead of modes, however seas_opt=2 works contrary to SORGAM. I've done some test simulations with seas_opt=0 and seas_opt=2, and I can confirm that seas_opt=2 is working for MOSAIC.

In short, seas_opt=1 works for both SORGAM and MOSAIC, while seas_opt=2 only works for MOSAIC.

Best regards,
Rui Silva

 

[jordanschnell]

Hi,

Note that seas_opt is not the same as seasalt_emiss_active. See this line(s) In emissions_driver.F :

if(config_flags%seas_opt == 2 )seasalt_emiss_active = 1

So setting seas_opt = 2 should work for both. I'm looking at 3.9.1.1.

Jordan

 

[Rui_Silva]

Hi Jordan,

Thank you for the explanation.
You are right, seas_opt = 2 works for both mechanisms.

Best regards,
Rui Silva