No change with spectral nudging.

[Abhi_nav]

Hello,

I am trying to use spectral nudging for my WRF V4 run with chemistry. I am trying to see the effects of spectral nudging in the two test simulation (met only) without (grid_fdda=0) and with nudging (grid_fdda = 2). Although I see the wrffdda file is created and have set the namelist options, the following get printed in rsl files suggesting WRF does not consider the file during the simulation.

From rsl file:
rsl.error.0000 : 01 Spectral nudging for wind is turned off and Guv= 0.0000E+00
rsl.error.0000: 01 Spectral nudging for temperature is turned off and Gt= 0.0000E+00
rsl.error.0000: 01 Spectral nudging for geopotential is turned off and Gph= 0.0000E+00
rsl.error.0000: 01 Spectral nudging for water vapor mixing ratio is turned off and Gq= 0.0000E+00

In the namelist:
&fdda
grid_fdda = 2, ! 0: no nudge, 1: grid nudge, 2: spectral nudge
gfdda_inname = "wrffdda_d<domain>,
gfdda_interval_m = 360,
io_form_gfdda = 2,
!fgdtzero = 0,
if_no_pbl_nudging_ph = 1,
if_no_pbl_nudging_t = 1,
if_no_pbl_nudging_uv = 0, ! nudge wind in all levels
if_zfac_uv = 0,
gph = 0.0003,
gt = 0.0003,
guv = 0.0003,
xwavenum = 2,
ywavenum = 2,

I have tried to change the value of coeff. and x,y wavenum in Registry.EM_COMMON but model runs into some error. Please help.

 

[Ming Chen]

How did you set "gfdda_end_h" in your namelist.input?

 

[Abhi_nav]

How did you set "gfdda_end_h" in your namelist.input?

Dear Ming,

I noticed I have not used that option in my namelist. Also, I cannot find any default value in the Registry, so I guess this field is not passed to WRF.

After checking my namelist I found the error in the line gfdda_inname = "wrffdda_d<domain>
which should be gfdda_inname = 'wrffdda_d<domain>',
The nudging is working after this correction.
From rsl file:
D01 Spectral nudging for wind is turned on and Guv= 0.3000E-03 xwave= 2 ywavenum= 2
D01 Spectral nudging for temperature is turned on and Gt= 0.3000E-03 xwave= 2 ywavenum= 2
D01 Spectral nudging for geopotential is turned on and Gph= 0.3000E-03 xwave= 2 ywavenum= 2
D01 Spectral nudging for water vapor mixing ratio is turned off and Gq= 0.0000E+00
D01 Spectral nudging for temperature is turned off within the PBL.
D01 Spectral nudging for geopotential is turned off within the PBL.

Thanks.