[Wrf-users] tmn_update leads do unrealistic soil temperatures

[Fan, Xingang]

Hi, Heimo:

Thank you so much for sharing the finding and fix!

Xingang Fan
-- 
Xingang Fan, Ph. D.,        |      Department of Geography and Geology
Associate Professor         |      Western Kentucky University
of Meteorology                |      1906 College Heights Blvd., #31066
270-745-5980                 |      Bowling Green, KY 42101-1066
xingang.fan at wku.edu
http://people.wku.edu/xingang.fan




On 8/18/16 6:05 AM, "wrf-users-bounces at ucar.edu on behalf of Heimo
Truhetz" <wrf-users-bounces at ucar.edu on behalf of
heimo.truhetz at uni-graz.at> wrote:

>Dear all,
>
>I was able to fix this issue.
>
>The problem is related to the variable TLAG, which is missing in the
>restart files since model version 3.7.
>
>When the model is restarted (as it is frequently done in climate
>simulations) TLAG is set to zero because it cannot be found in the
>restart file. But TLAG is an essential variable for calculating the soil
>temperature of the lowest layer and if it is set to zero the soil
>temperature of the lowest layer sharply drops. After a few restarts (I
>restart the model every simulated month) the soil temperature of the
>lowest layer becomes unrealistically low.
>
>The solution is to correct the Registry file by adding TLAG to the
>restart stream.
>
>TLAG can be found in Registry.EM_COMMON and the erroneous 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"
>
>should be changed to
>
>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"
>
>(a "r" needs to be added to the entry "d=(interp..."; it should read
>"rd=(interp...")
>
>
>All model versions from 3.7 onwards are affected.
>
>Cheers,
>Heimo
>
>
>
>On 08/11/2016 10:59 AM, Heimo Truhetz wrote:
>> Dear all,
>>
>> when I make use of the tmn_update option in the NOAH LSM (WRF-ARW
>> v3.7.1), the lowest soil layer becomes unrealistically cold after a
>> simulation period of about two and a half months: for instance, the
>> lowest soil layer freezes in Northern Africa (Sahara).
>>
>> Is there somebody else, who has seen this strange behavior?
>>
>> Does anybody have a clue on this?
>>
>>
>> I use the WRF-ARW v3.7.1 and drive it with ERA-Interim. The model domain
>> covers an extended area over Europe.
>>
>>
>> Cheers,
>>
>> Heimo
>>
>> _______________________________________________
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>> Wrf-users at ucar.edu
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>
>-- 
>---------------------------------------------------------
>Heimo Truhetz, PhD - Vice Head of ReLoClim
>Wegener Center for Climate and Global Change (WEGC),
>University of Graz,
>Brandhofgasse 5, A-8010 Graz, Austria
>phone: +43-316-380-8442
>  fax: +43-316-380-9830
>eMail: heimo.truhetz at uni-graz.at
>  web: http://www.wegcenter.at
>---------------------------------------------------------
>
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