Guidance on Issue in WRF-Chem (version 4.6, chem_opt=202)

[Setareh Rahimi]

Dear all,

I hope this message finds you well. I am currently using WRF-Chem version 4.6 with chem_opt = 202 [namelist and mozbc script attached] for my research, and I have encountered an issue during the simulation.

The message I received is as follows, and it continuously repeats in rsl.out file:

calculate megan emissions at ktau, gmtp, tmidh = 20 0.00000000 0.108333334 mieaer_sc: radius_wet set to rmax,id,i,j,k,m,rm(m,k) 2 21 1 3 4 0.1274e-02

From my understanding, this output pertains to the wet radius calculation for aerosols within the chemistry module, particularly related to MEGAN emissions. However, I am unsure about the implications of this message and whether it indicates any potential errors or misconfigurations in my setup.

Additionally, I have noticed unusually high values for num a01 through num a04, and also for oin a04. I am concerned that this might be linked to the issue at hand, but I am uncertain about the cause or how to resolve it (attached).

I would greatly appreciate any guidance or suggestions on how to address this issue or if there are specific settings or adjustments that I might need to consider.

Thank you in advance for your assistance. I look forward to your insights.

Best regards,

[Mary Barth]

Hi Setareh,

I am on travel and could only take a quick look at your question. 

I noticed that you are running 2 domains at the same time and it is not clear whether the plots you provided are from d01 or d02. Nevertheless, since you are having an issue, it would be good to continue testing running just one domain. 

My first guess is that the dust scheme is over active. You are using the correct dust option for 202 (i.e., dust_opt=13) but maybe it needs to be scaled.

However, the high values are at a coastal location. I see that the seas_opt=1.  I use seas_opt=3 but I am not sure if the choice of seasalt option makes a difference. 

I would suggest the following. Try a run with no dust emissions and see if you get the same behavior. Also try a second run with no sea salt emissions to see if you get the same behavior.  In other words, I do not see anything obvious in the namelist suggesting that you are not configuring the model properly, but it would be good if others could review your namelist as well. 

I think you will just need to do some science and determine what dust and sea salt options are best to use. 

Also, that might be an anthropogenic source. If so, please check your wrfchemi files to see if they may have very high PM emissions at that location. 

Mary

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Mary Barth 

Senior Scientist   

phone: 303-497-8186    email: bar...@ucar.edu

NSF - National Center for Atmospheric Research

P.O. Box 3000

Boulder, CO 80307

Staff web page

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