ACM2 pbl error

Hi,
I am getting this error:

RIBX never exceeds RIC, RIB(i,kte) = NaN THETAV(i,1) = 309.9481 MOL= -0.5745613 TCONV = NaN WST = -1.994674 KMIX = 1 UST = -0.1035916 TST = -0.9554436 U,V = 0.4300827 0.2205904 I,J= 206 57

Click to expand...

I am using,
sf_sfclay_physics = 7, 7, 7,
sf_surface_physics = 2, 2, 2,
bl_pbl_physics = 7, 7, 7,
with MCD12Q1, 17 category data. The model crashes in d02 after running for 96 hours.
There are similar topics in this forum but the solutions aren't working for me. I only have issue with this pbl scheme, other pbl schemes are working. I am using the latest versions of WPS and WRF.

Hi,
Have you tested this with the following settings?
sf_sfclay_physics = 7, 7, 7,
sf_surface_physics = 7, 7, 7,
bl_pbl_physics = 7, 7, 7,

The Pleim-Xu sfclay scheme was designed to work specifically with the Pleim-Xu surface scheme, and the ACM2 PBL scheme. There is no testing that has taken place with other combinations, and therefore we cannot guarantee success with others.

Hi,
Yes I have tried that combination but it doesn't work for me since PXLSM requires MODIS 20 or 21 category data whereas I am using 17. I had got another error for that.

Is there any way to make the 17 category work for PXLSM, since in my domain categories 18-21 in MODIS are almost non existant or taken care by other categories?

Also I have been able to run successfully with
sf_sfclay_physics = 1,1,1,
sf_surface_physics = 2, 2, 2,
bl_pbl_physics = 7, 7, 7
But mixing ratio is very much underestimated. Could you suggest some changes with the namelist to improve the mixing ratio without changing the above configuration.

Can you let me know which version of WRF you are using? Thanks.

I am using 4.1.3.

Hi,
It's possible that you could change any land categories above 18 in your domain to values >=17, so that you only have 17 categories.
As for the problems you are seeing with mixing ratio, it again could be the combination you're using. It's hard to say. Take a look at this document from the developers of the Pleim-Xu and ACM2 schemes to see if it's helpful to you in any way:
https://www2.mmm.ucar.edu/wrf/users/docs/PX-ACM.pdf

Hi,
I encountered the problem and solved it without using modis_30s. I am using usgs_30s and corine land use with 100m resolution.
For people facing the same issue you may want to lower the nudging coefficient values guv, gt and gq.
For guv=gt=qg > 0.01 I faced RIBX never exceeds RIC, RIB(i,kte) . I finally setlled up with following parameters:

grid_fdda = 1,
grid_sfdda = 1,
pxlsm_soil_nudge = 1,
gfdda_interval_m = 180,
guv = 0.0001,
gt = 0.0001,
gq = 0.00001,
guv_sfc = 0.0000,
gt_sfc = 0.0000,
gq_sfc = 0.0000,

Sincerely yours

@momodialiosn,
Thank you for posting your fix to the problem!