Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

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todor_Gai
Posts: 12
Joined: Wed Jun 17, 2020 12:48 pm

Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

Post by todor_Gai » Wed Jul 22, 2020 7:42 am

Hello,
for some time I am trying to obtain data for cloud optical thickness from wrf model.
However, the output values for the TAUCLDI (CLOUD OPTICAL THICKNESS FOR ICE) and TAUCLDC (CLOUD OPTICAL THICKNESS FOR WATER) are always 0. As far as I know this means that the model is not computing these values.
I've tried different parameters in the &physics block in namelist.input but still cannot understand what I am missing.
I am using data from GFS 0.25 data for initial conditions.
Is it possible that the model needs some additional data to calculate the thickness output ?
Can somebody help me understand what I am doing wrong ?
I am using v4 of the WRF model and these are the physics configs:

Code: Select all

&physics                 
mp_physics               = 7,        7,
use_aero_icbc            = .true.,
use_rap_aero_icbc        = .true.,
aer_opt                  = 2,
aer_aod550_opt           = 1,
aer_aod550_val           = 0.12,
aer_angexp_opt           = 1,
aer_angexp_val           = 1.7,
aer_ssa_opt              = 1,
aer_asy_opt              = 1,
shcu_physics             = 2,        2,
ra_lw_physics            = 5,        5,
ra_sw_physics            = 5,        5,
radt                     = 30,       30,
bl_mynn_edmf             = 0,        0,
sf_sfclay_physics        = 5,        5,
sf_surface_physics       = 2,        2,
bl_pbl_physics           = 5,        5,
bldt                     = 0,        0,
cu_physics               = 1,        1,
cudt                     = 5,        5,
isfflx                   = 1,
ifsnow                   = 0,
icloud                   = 1,
surface_input_source     = 1,
num_soil_layers          = 4,
sf_urban_physics         = 0,        0,
maxiens                  = 1,
maxens                   = 3,
maxens2                  = 3,
maxens3                  = 16,
ensdim                   = 144,
/
Thank you in advance
Todor

Ming Chen
Posts: 963
Joined: Mon Apr 23, 2018 9:42 pm

Re: Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

Post by Ming Chen » Mon Jul 27, 2020 5:28 pm

Todor,
These two variables should have valid values for Goddard radiation scheme, which is what you activated based on your namelist.
I wonder whether you have modified Registry.EM_COMMON, changing the following two lines from:

state real taucldi ikj misc 1 - r "TAUCLDI" "CLOUD OPTICAL THICKNESS FOR ICE" ""
state real taucldc ikj misc 1 - r "TAUCLDC" "CLOUD OPTICAL THICKNESS FOR WATER"

to

state real taucldi ikj misc 1 - rh "TAUCLDI" "CLOUD OPTICAL THICKNESS FOR ICE" ""
state real taucldc ikj misc 1 - rh "TAUCLDC" "CLOUD OPTICAL THICKNESS FOR WATER"

Then recompile and rerun the case. Please also use the newer version of WRF (e.g., WRFv4.2)
WRF Help Desk

todor_Gai
Posts: 12
Joined: Wed Jun 17, 2020 12:48 pm

Re: Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

Post by todor_Gai » Tue Jul 28, 2020 7:29 am

Hi,
yes I have modified the lines that you've mentioned in the same way but the values of TAUCLDI and TAUCLDC are always zero for each point, each time.
I tried the model with that config at different times of the year but the result is always the same. And that makes me think that the model is not calculating the values. Also I hardly find any information about these properties on the web and the model setup for them.
I will be extremely grateful if somebody share some resources.

P.S.
Also I've checked and I am using the latest version WRF and it is 4.2 .
Ming Chen wrote:
Mon Jul 27, 2020 5:28 pm
Todor,
These two variables should have valid values for Goddard radiation scheme, which is what you activated based on your namelist.
I wonder whether you have modified Registry.EM_COMMON, changing the following two lines from:

state real taucldi ikj misc 1 - r "TAUCLDI" "CLOUD OPTICAL THICKNESS FOR ICE" ""
state real taucldc ikj misc 1 - r "TAUCLDC" "CLOUD OPTICAL THICKNESS FOR WATER"

to

state real taucldi ikj misc 1 - rh "TAUCLDI" "CLOUD OPTICAL THICKNESS FOR ICE" ""
state real taucldc ikj misc 1 - rh "TAUCLDC" "CLOUD OPTICAL THICKNESS FOR WATER"

Then recompile and rerun the case. Please also use the newer version of WRF (e.g., WRFv4.2)

todor_Gai
Posts: 12
Joined: Wed Jun 17, 2020 12:48 pm

Re: Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

Post by todor_Gai » Thu Jul 30, 2020 10:44 am

Hi,
I think I found a solution. In case somebody else has the same problem I tried with the CAM (code 3) scheme both for ra_sw/lw_physics.
With this scheme I got non-zero values for the properties.

Now I have to check if the values are correct.
If somebody has an idea how to do that, I will be very grateful.

Thank you

Ming Chen
Posts: 963
Joined: Mon Apr 23, 2018 9:42 pm

Re: Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

Post by Ming Chen » Thu Jul 30, 2020 5:42 pm

Thanks for the kind post. Hope it is helpful for other users.
However, these variables should be calculated in goddard and cam radiation schemes. I am not sure why they are zero in goddard. We will take a look at this issue.
WRF Help Desk

todor_Gai
Posts: 12
Joined: Wed Jun 17, 2020 12:48 pm

Re: Cloud optical thickness output (TAUCLDI and TAUCLDC) is always 0

Post by todor_Gai » Mon Aug 03, 2020 6:26 am

Thank you !

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