ACM2 pbl error

[neel14]

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

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.

 

[kwerner]

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.

 

[neel14]

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.

 

[kwerner]

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

 

[neel14]

I am using 4.1.3.

 

[kwerner]

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

 

[momodiallosn]

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

 

[kwerner]

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