Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

gwd_opt not working in WRFV4.3.2

bomarty

New member
Hello everyone!
When I run wrf.exe (Version 4.3.2) with gwd_opt equals to 3 in namelist.input, all the relevant diagnostic variables are zero, and the wind fields of all three domains (25km, 5km, and 1km)are exactly the same with gwd_opt equals to 0.
1675136721547

According to the users' guide, gwd_opt equals to 3 indicates all four drag parameterization schemes (large-scale gravity wave drag, small-scale gravity wave drag, blocking drag, topographic form drag) are used in wrf.exe, and gwd_opt equals to 0 indicates no drag parameterization schemes. The result seems quite strange since the parameterization schemes should have effected the wind field obviously, especially to the surface layers. Here follows the namelist.input.

&domains
time_step = 100,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 3,
e_we = 80, 221, 601,
e_sn = 80, 231, 651,
e_vert = 51, 51, 51
p_top_requested = 3000,
num_metgrid_levels = 34,
num_metgrid_soil_levels = 4,
dx = 25000, 5000, 1000
dy = 25000, 5000, 1000
grid_id = 1, 2, 3,
parent_id = 1, 1, 2,
i_parent_start = 1, 20, 55,
j_parent_start = 3, 25, 47,
parent_grid_ratio = 1, 5, 5,
parent_time_step_ratio = 1, 5, 5,
feedback = 1,
smooth_option = 2
/

&physics
mp_physics = 8, 8, 8,
ra_lw_physics = 4, 4, 4,
ra_sw_physics = 4, 4, 4,
radt = 30, 30, 30,
sf_sfclay_physics = 1, 1, 1,
sf_surface_physics = 2, 2, 2,
bl_pbl_physics = 1, 1, 1,
topo_wind = 0, 0, 0,
bldt = 0, 0, 0,
cu_physics = 1, 0, 0,
cudt = 5, 0, 0,
isfflx = 1,
ifsnow = 1,
icloud = 1,
surface_input_source = 1,
num_soil_layers = 4,
num_land_cat = 21,
sf_urban_physics = 0, 0, 0,
/

&dynamics
hybrid_opt = 0,
w_damping = 1,
diff_opt = 1, 1, 1,
km_opt = 4, 4, 4,
diff_6th_opt = 0, 0, 0,
diff_6th_factor = 0.12, 0.12, 0.12,
base_temp = 290.
damp_opt = 0,
zdamp = 5000., 5000., 5000.,
dampcoef = 0.2, 0.2, 0.2
khdif = 0, 0, 0,
kvdif = 0, 0, 0,
non_hydrostatic = .true., .true., .true.,
moist_adv_opt = 1, 1, 1,
scalar_adv_opt = 1, 1, 1,
gwd_opt = 3
gwd_diags = 1

/

&bdy_control
spec_bdy_width = 7,
spec_zone = 1,
relax_zone = 6,
specified = .true., .false.,.false.,
nested = .false., .true., .true.,
/

&grib2
/

&namelist_quilt
poll_servers = T,
nio_tasks_per_group = 0,
nio_groups = 1,
/

My problem is how to turn on the gwd_opt and are there any other steps to use the drag parameterization schemes appropriately in wrf.exe?
Thanks.
 
I believe your settings are correct.

Can you find the variables below in your wrfout files:

taux3d_ls,dtauy3d_ls,dtaux3d_bl,dtauy3d_bl,dtaux3d_ss,dtauy3d_ss,dtaux3d_fd,dtauy3d_fd,dusfcg_ls,dvsfcg_ls,dusfcg_bl,dvsfcg_bl,dusfcg_ss,dvsfcg_ss,dusfcg_fd,dvsfcg_fd

If so, what are their values?
 
Hello Ming,
Thank you for your response. Wrfout files have all these variables you mentioned, and they are all equal to zero.
FYI, I've tried with gwd_opt equals to 1 which did change the wind field slightly while gwd_opt equals to 3 still not working.
Thank you.
 
Top