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WRF-UCM

KevinInJNU

New member
In this case, I set the WRF namelist option: SF_URBAN_PHYSICS = 3 (BEM+BEP) and swtiched on the green roof.
I noticed that some papers change the values of Leaf Area Index(LAI) and stomatal resistance(Rs) to indicate the species of the plants(Sedum), so I attempted to use the command 'grep -I 'LAI'* . How to replace the values observed from the local expreriment.
 

Ming Chen

Moderator
Staff member
The values of these variables are specified based on landuse type. Please take a look at "VEGPARM.TBL".
 

KevinInJNU

New member
Thanks for your reply. An additional question is, will I be able to extract the air temperature above the roof? If I use a green roof (BEM+BEP), can this air temperature variable be affected accordingly? I found some variables like TGRL_URB, TRL_URB. So,Which is the variable represented for the air temperature above the roof.
 

Ming Chen

Moderator
Staff member
TGRL_URB is the green roof layer temperature, which is a 3D variable. WRF doesn't output air temperature above the roof. 2 m temperature is commonly used to represent surface air temperature.
 

KevinInJNU

New member
TGRL_URB is the green roof layer temperature, which is a 3D variable. WRF doesn't output air temperature above the roof. 2 m temperature is commonly used to represent surface air temperature.
Thanks for your previous reply and now I have a new problem, I tried to use UCM (BEM+BEP) to compare the green roof scenario as well as the green roof scenario without turning it on, and I found that at two different times of day, there is a slight warming of the city's grid points during the night time hours(T2 greenroof - T2 base). I would like to ask where I should consider the cause of the appearance.
 

htan2013

Member
Thanks for your previous reply and now I have a new problem, I tried to use UCM (BEM+BEP) to compare the green roof scenario as well as the green roof scenario without turning it on, and I found that at two different times of day, there is a slight warming of the city's grid points during the night time hours(T2 greenroof - T2 base). I would like to ask where I should consider the cause of the appearance.
The green roof tends to have a warming effect at night. Basically, GR has additional soil layers that are able to store more heat during the daytime compared to other roofs and release it at night. Another explanation could be vertical mixing over urban layer. There are tons of papers that you can find.
 

Ming Chen

Moderator
Staff member
This might be related to urban heat island effect.

T2 is diagnosed based on similarity theory. Please take a look at the code "phys/module_sf_sfcdiags.F", in which T2 is calcul;ated in the SUBROUTINE SFCDIAGS.

Hope this is helpful for you.
 

KevinInJNU

New member
The green roof tends to have a warming effect at night. Basically, GR has additional soil layers that are able to store more heat during the daytime compared to other roofs and release it at night. Another explanation could be vertical mixing over urban layer. There are tons of papers that you can find.
Thank you so much for your reply, I've also seen papers mentioning vertical mixing over urban layer, I will keep working on it.
 
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