Ojesutofunmi
New member
Hello WRF community,
I am running the em_hill2d_x idealized case at dx=400m (reduced from the standard dx=2km) for a model comparison study, and I am having difficulty reproducing the analytic solution cleanly at the higher resolution. The link to the test case: NWPdesign. Attached is the plot that compares the w′ field at dx=2km and dx=400m against the analytic solution.
Setup:
Namelist:
&domains
time_step = 4,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 1,
s_we = 1,
e_we = 201,
s_sn = 1,
e_sn = 3,
s_vert = 1,
e_vert = 121,
dx = 400,
dy = 400,
ztop = 30000.,
/
&physics
mp_physics = 0,
ra_lw_physics = 0,
ra_sw_physics = 0,
radt = 0,
sf_sfclay_physics = 0,
sf_surface_physics = 0,
bl_pbl_physics = 0,
bldt = 0,
cu_physics = 0,
cudt = 0,
/
&fdda
/
&dynamics
hybrid_opt = 2,
rk_ord = 3,
diff_opt = 2,
km_opt = 1,
damp_opt = 3,
zdamp = 10000.,
dampcoef = .1,
khdif = 0,
kvdif = 0,
smdiv = 0.1,
emdiv = 0.01,
epssm = 0.1,
time_step_sound = 6,
h_mom_adv_order = 5,
v_mom_adv_order = 3,
h_sca_adv_order = 5,
v_sca_adv_order = 3,
non_hydrostatic = .true.,
mix_full_fields = .false.,
moist_adv_opt = 0,
scalar_adv_opt = 0,
/
&bdy_control
periodic_x = .true.,
periodic_y = .true.,
symmetric_xs = .false.,
symmetric_xe = .false.,
symmetric_ys = .false.,
symmetric_ye = .false.,
open_xs = .false.,
open_xe = .false.,
open_ys = .false.,
open_ye = .false.,
/
&grib2
/
&namelist_quilt
nio_tasks_per_group = 0,
nio_groups = 1,
/
&ideal
ideal_case = 1
/
Problem: At dx = 2 km, the w′ field matches the analytic linear hydrostatic solution well. At dx=400 m with the same basic configuration, the upper domain (above ~7km) develops a spurious large-scale structure that does not exist in the analytic solution. This persists across many configurations tested.
What I have tried:
None of these produced a clean match to the analytic solution at dx=400m.
Question: Has anyone successfully run em_hill2d_x at dx = 400 m or finer and obtained a clean w′ field that matches the analytical solution? Is there a recommended namelist configuration for this resolution?
Thank you in advance.
Note on attachments: I was unable to attach the comparison plot due to a temporary upload issue on the forum ("temporary directory missing"). I am happy to share the images directly if anyone is willing to assist: please feel free to reply or send a private message, and I will send them over.
I am running the em_hill2d_x idealized case at dx=400m (reduced from the standard dx=2km) for a model comparison study, and I am having difficulty reproducing the analytic solution cleanly at the higher resolution. The link to the test case: NWPdesign. Attached is the plot that compares the w′ field at dx=2km and dx=400m against the analytic solution.
Setup:
- WRF 4.6.0, em_hill2d_x
- dx=400m, dt=4s, e_we = 201, ztop = 30 km
- damp_opt=3, zdamp=10km, dampcoef = 0.1
- khdif=0, kvdif=0
- diff_opt=2, hybrid_opt=2
- periodic_x/y boundaries
- Run duration: 5 hours
Namelist:
&domains
time_step = 4,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 1,
s_we = 1,
e_we = 201,
s_sn = 1,
e_sn = 3,
s_vert = 1,
e_vert = 121,
dx = 400,
dy = 400,
ztop = 30000.,
/
&physics
mp_physics = 0,
ra_lw_physics = 0,
ra_sw_physics = 0,
radt = 0,
sf_sfclay_physics = 0,
sf_surface_physics = 0,
bl_pbl_physics = 0,
bldt = 0,
cu_physics = 0,
cudt = 0,
/
&fdda
/
&dynamics
hybrid_opt = 2,
rk_ord = 3,
diff_opt = 2,
km_opt = 1,
damp_opt = 3,
zdamp = 10000.,
dampcoef = .1,
khdif = 0,
kvdif = 0,
smdiv = 0.1,
emdiv = 0.01,
epssm = 0.1,
time_step_sound = 6,
h_mom_adv_order = 5,
v_mom_adv_order = 3,
h_sca_adv_order = 5,
v_sca_adv_order = 3,
non_hydrostatic = .true.,
mix_full_fields = .false.,
moist_adv_opt = 0,
scalar_adv_opt = 0,
/
&bdy_control
periodic_x = .true.,
periodic_y = .true.,
symmetric_xs = .false.,
symmetric_xe = .false.,
symmetric_ys = .false.,
symmetric_ye = .false.,
open_xs = .false.,
open_xe = .false.,
open_ys = .false.,
open_ye = .false.,
/
&grib2
/
&namelist_quilt
nio_tasks_per_group = 0,
nio_groups = 1,
/
&ideal
ideal_case = 1
/
Problem: At dx = 2 km, the w′ field matches the analytic linear hydrostatic solution well. At dx=400 m with the same basic configuration, the upper domain (above ~7km) develops a spurious large-scale structure that does not exist in the analytic solution. This persists across many configurations tested.
What I have tried:
- diff_opt = 1, 2, 3
- e_vert = 121, 241, 301
- zdamp = 10000–15000m
- khdif = 0–10, kvdif = 0–50
- dampcoef = 0.1–0.2
- smdiv = 0.01–0.2
- diff_6th_opt = 2, diff_6th_factor = 0.12 (tested, did not resolve the issue)
None of these produced a clean match to the analytic solution at dx=400m.
Question: Has anyone successfully run em_hill2d_x at dx = 400 m or finer and obtained a clean w′ field that matches the analytical solution? Is there a recommended namelist configuration for this resolution?
Thank you in advance.
Note on attachments: I was unable to attach the comparison plot due to a temporary upload issue on the forum ("temporary directory missing"). I am happy to share the images directly if anyone is willing to assist: please feel free to reply or send a private message, and I will send them over.