WRF Bug (from wrfhelp)

Questions and other topics related to UEMS 15.
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Joined: Wed Nov 30, 2011 4:34 pm

WRF Bug (from wrfhelp)

Post by lcana » Fri Sep 09, 2016 8:54 am

Hi all,

I've received yesterday one mail about a bug for WRf versions 3.7, 3.7.1, 3.8, 3.8.1. This is the mail:

"Dear WRF Users,

We have become aware that there is a problem when using the tmn_update option.

An error was introduced beginning with WRF Version 3.7 in a restart run when the tmn_update option is used. This error is present in WRF Versions 3.7, 3.7.1, 3.8 and 3.8.1. When tmn_update is activated, a moving-averaged skin temperature (TLAG) is used as a lower boundary condition for the land model. Since TLAG is left out of the restart file, any restart using the tmn_update option will start with 0 K as the lower boundary condition for the land model. This will cause the soil temperature to cool gradually, eventually affecting the skin and atmospheric temperature. The tmn_update option can be used for the following land models: SLAB, Noah, NoahMP, RUC and CLM.

The fix is to add the letter 'r' (for restart) in the 8th column of the Registry.EM_COMMON file, for the variable TLAG, so that the original line:

state real TLAG i&j misc 1 - d=(interp_mask_field:lu_index,iswater)u=(copy_fcnm) "TLAG" "DAILY MEAN SFC TEMPERATURE OF PRIOR DAYS" "K"


state real TLAG i&j misc 1 - rd=(interp_mask_field:lu_index,iswater)u=(copy_fcnm) "TLAG" "DAILY MEAN SFC TEMPERATURE OF PRIOR DAYS" "K"

One must do 'clean -a', reconfigure, and recompile the code after making this registry change.

If you have not previously made any changes to your Registry.EM_COMMON file and you are okay with replacing it, instead of making the above change, you can simply replace your current file with the corrected Registry.EM_COMMON.v3* file (attached to this email). Once you download the file, you will need to unpack it, change the name to Registry.EM_COMMON and place it in your WRFV3/Registry/ directory. After this, go back to WRFV3/, issue a 'clean -a', reconfigure, and recompile.

(Thanks to Heimo Truhetz of University of Graz, Austria, for reporting and finding the fix for the problem.)

We apologize for any inconvenience this may have caused.


I suppose this bug is present also in WRF-EMS and I understand that we shoud recompile the code. Has anyone tried to do this?

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Joined: Wed Aug 19, 2009 10:05 am

Re: WRF Bug (from wrfhelp)

Post by meteoadriatic » Fri Sep 09, 2016 10:24 am

I don't think many of us should be concerned with that.

tmn_update has effect only for multi-year runs, in other words for climatology runs. For meteorology purporses that option is useless. Then, this bug affects only restart runs, normal runs are not affected. And only Robert can tell if he did patched his builds or not in EMS. I guess not so if you are doing climatological runs, use restarts and use tmn_update = 1, then you should take actions to correct. In all other cases just ignore.

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