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Usage of the newly added SMS-3DTKE PBL

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S

sekluzia

Member
Dear Colleges,

Would you recommend to use the recently added (in the WRF V4.2) three dimensional scale-adaptive TKE subgrid mixing parameterization scheme (SMS-3DTKE, km_opt=5) for my all domains with spatial resolution ranging from 9 km (d01) to 333 m (d04)?

Kind regards,
Artur
 
Artur,
Yes, you can use it for all domains. It's meant to be used in the LES, mesoscale, and gray-zone.
 
Hi,
I have some question about how to use the SMS-3D-TKE (3DTKE) scheme.

My supervisor suggest me to do some files modification before i can use the 3DTKE scheme.
Could you tell me which files did i have to modify before i can use the 3DTKE scheme? or maybe i just simply need to do bl_pbl_physics = 0, diff_opt = 2, and km_opt = 5 in the namelist.input.

Best,
Rahman
 
SMS-3DTKE is a scale-aware PBL scheme, which is especially useful for nest cases with large differences in grid size between domains. You are right that to implement this scheme, you need to set bl_pbl_physics = 0, diff_opt = 2, and km_opt = 5.
Since this is a relatively new feature in WRF, we will appreciate if you can post results using this scheme, especially its performance compared to other 'old' PBL schemes. Thanks in advance.
 
Hello everybody,
I have a question related to this topic :
If I set bl_pbl_physics = 0, what will happen for cumulus scheme and coarse grid size such as 25 km ? In a multi-nest simulation the parent nest can have such a large grid size. Can I still use a cumulus physics or shall I set cu_physics = 0 for ALL domains.

Thank you
 
The SMS-3DTKE scheme will treat the PBL process at coarse resolution (such as 25km) in a way more similar to traditional PBL scheme. When the grid interval becomes smaller, this scheme gradually transfer to LES mode.
cumuls parameterization must be turned on for grid intervals larger than 10km, and it can be on or off for the grey zone (4-10km), and it should be off for grid intervals smaller than 3km. It does't have to be the same for all domains.
 
Thank you for your answer. I have just read it.
In doubt, I kept cumulus parametrization for the coarse grid domain (25 km), for the 5 km grid size, and switched it off for the fine grid domain (1km). The results seem realistic in terms of temperature, cloud and precipitation.
 
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