Discussion on Enabling the Green Roof Diagnostic Variable

[KevinInJNU1220]

Hi, I have a few questions regarding the urban canopy model.

1. When I set UCM=1, I enabled the green roof scheme by setting “GROPTION=1” with FGR=0.5, which means the green roof is activated. In module_NoahMP_hrldas_driver.F, I tried to activate “TGRL_URB3D.” How do I activate this 3D variable? All other variables are successfully output to the file.

2. You previously mentioned that I need to add a variable "T2M". I’d like to confirm whether this modification is correct:

if (NoahmpIO%SF_URBAN_PHYSICS == 1) then
                   NoahmpIO%T2MUXY = (NoahmpIO%FVEGXY*NoahmpIO%T2MVXY + &
                        (1.0 - NoahmpIO%FVEGXY) * NoahmpIO%T2MBXY) * (1.0 - NoahmpIO%FRC_URB2D) + &
                        (NoahmpIO%TH2_URB2D / ((1.e5/NoahmpIO%FORCPLSM)**0.285856574)) * NoahmpIO%FRC_URB2D

3. I’d really like to know which diagnostic variable represents the 2-meter temperature when SF_URBAN_PHYSICS == 3. I used theta_urban(:,1:), and enabling the green roof scenario does not change the 2-meter temperature.

if (NoahmpIO%SF_URBAN_PHYSICS == 3) then
NoahmpIO%T2MUXY =  ((NoahmpIO%theta_urban(:,NoahmpIO%kds,:)

[KevinInJNU1220]

First question: Just add “Soil” at the end, and it will run. For example: add_to_output(NoahmpIO%TGRL_URB3D, “TGRL_URB”, “green roof layer temperature”, ‘K’, “SOIL”)

[KevinInJNU1220]

Here’s a new question: Why is the difference in TGRL_URB zero when comparing “GR” (green roof fraction = 0.5) to “BR” (green roof fraction = 0)?

[tslin2]

Yes, please follow the dimension used in the restart file to output these urban related variables:

hrldas/hrldas/IO_code/module_NoahMP_hrldas_driver.F

Line 1617 in cd96df4

call add_to_restart( NoahmpIO%TGRL_URB3D , "TGRL_URB3D", layers="SOIL" )

[tslin2]

Here’s a new question: Why is the difference in TGRL_URB zero when comparing “GR” (green roof fraction = 0.5) to “BR” (green roof fraction = 0)?

when “BR” (green roof fraction = 0), there is zero green roof fraction, so the TGRL_URB should not be used. Do you compare green roof fraction to other values but not zero?

[KevinInJNU1220]

Okay, thanks for your answer. If I want to make my experiment more relevant to my actual situation by measuring the temperature difference between a green roof and a base roof, aside from the 2-meter temperature reading I’ve set, how should I go about comparing the roof temperatures?

[tslin2]

you can comapre between TGR: green roof surface temperatur and TR: roof temperature or compare land surface temperature

[cenlinhe]

@tslin2 could you please take a look when you have time? Thanks!

[tslin2]

Hi, I have a few questions regarding the urban canopy model.

1. When I set UCM=1, I enabled the green roof scheme by setting “GROPTION=1” with FGR=0.5, which means the green roof is activated. In module_NoahMP_hrldas_driver.F, I tried to activate “TGRL_URB3D.” How do I activate this 3D variable? All other variables are successfully output to the file.

2. You previously mentioned that I need to add a variable "T2M". I’d like to confirm whether this modification is correct:

if (NoahmpIO%SF_URBAN_PHYSICS == 1) then
                   NoahmpIO%T2MUXY = (NoahmpIO%FVEGXY*NoahmpIO%T2MVXY + &
                        (1.0 - NoahmpIO%FVEGXY) * NoahmpIO%T2MBXY) * (1.0 - NoahmpIO%FRC_URB2D) + &
                        (NoahmpIO%TH2_URB2D / ((1.e5/NoahmpIO%FORCPLSM)**0.285856574)) * NoahmpIO%FRC_URB2D

3. I’d really like to know which diagnostic variable represents the 2-meter temperature when SF_URBAN_PHYSICS == 3. I used theta_urban(:,1:), and enabling the green roof scenario does not change the 2-meter temperature.

if (NoahmpIO%SF_URBAN_PHYSICS == 3) then
NoahmpIO%T2MUXY =  ((NoahmpIO%theta_urban(:,NoahmpIO%kds,:)

Regarding the T2MUXY for SLUCM (NoahmpIO%SF_URBAN_PHYSICS == 1), please see the discussion: wrf-model/WRF#2093

Essentially the codes used the air temperature although some annotations in the codes were not clear, TH2_URB2D should be treated as air temperature.
Also based on the comment here:

hrldas/urban/wrf/module_sf_urban.F

Lines 1643 to 1645 in cd96df4

	! TH2 = TS + (TA-TS)*(PSIT2/PSIT) ! Fei: this seems to be temp (not potential) at 2 m [K]
	!Fei: consistant with M-O theory
	TH2 = TS + (TA-TS) *(CHS/CHS2)

Please refer to the method used in the LSP-DS version of HRLDAS:
https://github.com/xuelingbo/LSP-DS/blob/9f9c400091a9e55d30f86ad0eb300411647e53bc/modified/module_NoahMP_hrldas_driver.F#L1088-L1090et