WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

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chunchih
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Joined: Tue Sep 08, 2020 3:52 pm

WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by chunchih » Tue Nov 03, 2020 9:57 pm

Hi, I am using the Thompson aerosol-aware MP scheme (MP option=28) in WRFv4.1.2 and WPS 4.1 for a real-case simulation over southcentral Canada. I have two domains in my simulation and I am using the 12-km NAM analysis as my meteorological forcing dataset. I downloaded the climatological aerosol input dataset from https://www2.mmm.ucar.edu/wrf/users/wrf ... dated.html and followed the instructions to set up my namelist.wps and namelist.input files for this scheme option (please see attached). I was able to run geogrid.exe, ungrib.exe, and finally metgrid.exe to get the met_em files in WPS. I could see I_WIF_month*, W_WIF_month*, and P_WIF_month* variables in my met_em files, which should mean that the climatological aerosol dataset was correctly ingested into my met_em files. Then I ran real.exe and was able to get wrfinput files for both domains and wrfbdy_d01. Finally, I ran my simulation with wrf.exe and wrfout_d0* files were produced for both domains.

However, when I checked the QNWFA variable in my wrfout_d01 files some time into my simulation, I noticed something went wrong in the QNWFA field. A box denoting my inner nested domain is clearly visible when visualizing the output from the wrfout_d01 files using ncview (please see attached for example). If working properly, I should see a smooth transition going from d01 to the inner nested domain d02 (i.e, no visible box). Upon further inspection, I found that the QNWFA2D variable (surface aerosol number concentration emission) is the likely source of the problem. For some reason, the magnitude of this variable in the inner nested domain is almost an order of magnitude smaller than that in the surrounding parent domain. Therefore, after some model integration time, the low-level QNWFA over areas covered by d02 is significantly lower (not zero though) than that in the surrounding d01 domain, hence the "box" feature when visualizing my wrfout_d01 files. If I have three domains, the problem would get progressively worse in each successive nested domain. That is, the QNWFA2D variable in d03 is another order of magnitude smaller than that in d02 (therefore, two-orders of magnitude smaller than that in d01). The same problem also exists when I use the use_aero_icbc = .false. option. I have attached a PDF file below that demonstrates this issue. The other variable produced by the Thompson aerosol-aware scheme, QNIFA, looks fine in my output files though, but it may be due to the fact that QNIFA2D is zero at all times.

I updated my WRF version to WRFv4.2.1 and WPS version to WPSv4.2 to see if this problem has been resolved, but it still exists in the newer version. I did, however, modify my GEOGRID.TBL.ARW to make geogrid.exe work better with my application in both versions of WRF and WPS. I wonder if that's what's causing the problem. I thought that METGRID.TBL was the only relevant file for this portion (metgrid.exe) of WPS.

Did I make a mistake during my model set up or there was a bug in the WRF source code? Any suggestions would be greatly appreciated.
Attachments
QNWFA_problem.pdf
(708.35 KiB) Downloaded 31 times
QNWFA_wrfout_d01_2007-06-22_010000_1stlev.png
namelist.input
(5.95 KiB) Downloaded 35 times
namelist.wps
(1.78 KiB) Downloaded 37 times

Ming Chen
Posts: 1577
Joined: Mon Apr 23, 2018 9:42 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by Ming Chen » Wed Nov 04, 2020 3:45 pm

Thanks for reporting this issue. We will take a look and get back to you. It may take some time, and we appreciate your patience.
WRF Help Desk

Ming Chen
Posts: 1577
Joined: Mon Apr 23, 2018 9:42 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by Ming Chen » Wed Nov 04, 2020 10:46 pm

I found severe problems when using the following options:

mp_physics = 28
use_aero_icbc = .true.

It turns out that the data QNWFA_QNIFA_SIGMA_MONTHLY.dat is not processed correctly. The feedback between parent and child domains are also possibly wrong.

Please avoid using the above options at present.
WRF Help Desk

chunchih
Posts: 21
Joined: Tue Sep 08, 2020 3:52 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by chunchih » Wed Nov 04, 2020 11:11 pm

OK. Thanks for looking into this problem!

As a note, I also found that mp_physics=28 and use_aero_icbc=.false. (with idealized, horizontally-homogenous CCN/IN profiles) also produces the same problem. So I have switched back to using the regular Thompson MP scheme (mp_physics=8) for my simulation for now.

parisa
Posts: 10
Joined: Thu Oct 08, 2020 11:13 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by parisa » Thu May 27, 2021 7:21 am

Hi, I have exactly this problem with my wrfouts, does anybody solve this problem with mp option =28 and use_aero_icbc=True?

stormchasegenie
Posts: 36
Joined: Wed Oct 10, 2018 5:42 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by stormchasegenie » Thu Jun 03, 2021 7:11 pm

Greetings,

Has this problem been fixed as of WRF4.1.3?

Thanks,
-Stefan

Ming Chen
Posts: 1577
Joined: Mon Apr 23, 2018 9:42 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by Ming Chen » Mon Jun 14, 2021 9:28 pm

Hi Stefan,
I am sorry that there is no fix for this issue yet.
WRF Help Desk

Ming Chen
Posts: 1577
Joined: Mon Apr 23, 2018 9:42 pm

Re: WRF v4.1.2 Thompson Aerosol-Aware scheme QNWFA2D

Post by Ming Chen » Mon Jun 28, 2021 9:05 pm

Hi Stefan,
I found the problem related to ANWFA2D. This is because in dyn_em/module_initialize_real.F, we have the following piece of code:

4329
4330 IF ( config_flags%use_aero_icbc .AND. ( flag_qnwfa .EQ. 1 ) .AND. &
4331 ( config_flags%mp_physics .EQ. THOMPSONAERO ) ) THEN
4332 do j = jts, min(jde-1,jte)
4333 do i = its, min(ide-1,ite)
4334 z1 = (grid%phb(i,2,j)-grid%phb(i,1,j))/g
4335 airmass = 1./grid%alt(i,1,j) * z1 * config_flags%dx*config_flags%dy ! kg
4336 grid%qnwfa2d(i,j) = grid%QNWFA_now(i,1,j) * 0.000196 * (airmass*5.E-11)
4337 enddo
4346 enddo
4347 ENDIF
4348

Note that "airmass" is dependent on dx * dy, while QNWFA_now, alt, z1 etc. have similar magnitude. WIth a nesting ratio of 1:3, we may have the magnitude of qnwfa2d to be different by 1 order ( i.e., D01 value will be around 10 times that of D02)

I will talk to our expert and fix this issue as soon as possible.

Ming
WRF Help Desk

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