Boundary discontinuity after data assimilation

Post Reply
Jiwon Lee
Posts: 6
Joined: Mon Dec 17, 2018 7:27 am

Boundary discontinuity after data assimilation

Post by Jiwon Lee » Wed Feb 27, 2019 4:42 am

Discontinuity occurs severely at the boundary between domain 1 and domain 2 after data is transferred to domain 2.

The discontinuity is too large to explain as a result of data assimilation.

I used the same namelist, but I did not have any problems in V3, but this happened in V4.

The physics of both domains are the same

What is the problem?

&domains
time_step = 20,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 3,Image
e_we = 352, 250, 226,
e_sn = 352, 361, 196,
e_vert = 60, 60, 60,
p_top_requested = 5000,
num_metgrid_levels = 32,
num_metgrid_soil_levels = 4,
dx = 9000, 3000, 1000,
dy = 9000, 3000, 1000,
grid_id = 1, 2, 3,
parent_id = 0, 1, 2,
i_parent_start = 1, 145, 78,
j_parent_start = 1, 127, 155,
parent_grid_ratio = 1, 3, 3,
parent_time_step_ratio = 1, 1, 1,
feedback = 1,
smooth_option = 0,
/

&physics
mp_physics = 16, 16, 16,
ra_lw_physics = 1, 1, 1,
ra_sw_physics = 1, 1, 1,
radt = 10, 10, 10,
sf_sfclay_physics = 1, 1, 1,
sf_surface_physics = 2, 2, 2,
bl_pbl_physics = 1, 1, 1,
bldt = 0, 0, 0,
cu_physics = 11, 11, 11,
cudt = 5, 5, 5,
isfflx = 1,
ifsnow = 1,
icloud = 1,
surface_input_source = 1,
num_soil_layers = 4,
sf_urban_physics = 0, 0, 0,
sst_update = 0,
do_radar_ref = 1,
num_land_cat = 33,
/

&fdda
/

&dynamics
hybrid_opt = 0,
w_damping = 0,
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 = 3,
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 = 1,
/

&bdy_control
spec_bdy_width = 5,
spec_zone = 1,
relax_zone = 4,
specified = .true., .false.,.false.,
nested = .false., .true., .true.,
/

&grib2
/

&namelist_quilt
nio_tasks_per_group = 0,
nio_groups = 1,
/
Attachments
problem.png
Discontinuity boundary
problem.png (83.13 KiB) Viewed 2245 times

Ming Chen
Posts: 1456
Joined: Mon Apr 23, 2018 9:42 pm

Re: Boundary discontinuity after data assimilation

Post by Ming Chen » Thu Feb 28, 2019 11:24 pm

If you run the case without data assimilation, do you still see the large discrepancy between the parent - child domain?
WRF Help Desk

Ming Chen
Posts: 1456
Joined: Mon Apr 23, 2018 9:42 pm

Re: Boundary discontinuity after data assimilation

Post by Ming Chen » Thu Feb 28, 2019 11:27 pm

I notice the setting parent_time_step_ratio =1, 1, 1 and time_step=20.
Can you change time_step=54 and parent_time_step_ratio =1, 3, 3?
WRF Help Desk

Jiwon Lee
Posts: 6
Joined: Mon Dec 17, 2018 7:27 am

Re: Boundary discontinuity after data assimilation

Post by Jiwon Lee » Mon Mar 04, 2019 2:05 am

Ming Chen wrote:
Thu Feb 28, 2019 11:24 pm
If you run the case without data assimilation, do you still see the large discrepancy between the parent - child domain?
If I do not use material assimilation, the above problem does not occur.

I compared WRFRUN in V3 and V4 using the same data assimilation output, boundary problem occurs only in V4.

Jiwon Lee
Posts: 6
Joined: Mon Dec 17, 2018 7:27 am

Re: Boundary discontinuity after data assimilation

Post by Jiwon Lee » Mon Mar 04, 2019 2:06 am

Ming Chen wrote:
Thu Feb 28, 2019 11:27 pm
I notice the setting parent_time_step_ratio =1, 1, 1 and time_step=20.
Can you change time_step=54 and parent_time_step_ratio =1, 3, 3?
The same problem occurs with parent_time_step_ratio = 1, 3, 3.

I will increase the time_step.

Good advice thanks !!!!

Ming Chen
Posts: 1456
Joined: Mon Apr 23, 2018 9:42 pm

Re: Boundary discontinuity after data assimilation

Post by Ming Chen » Wed Mar 06, 2019 12:23 am

I will forward your message to our experts in data assimilation. This is a problem caused by data assimilation. Hope they can get back to you soon.
WRF Help Desk

kwerner
Posts: 2287
Joined: Wed Feb 14, 2018 9:21 pm

Re: Boundary discontinuity after data assimilation

Post by kwerner » Tue Mar 26, 2019 3:02 pm

I have moved this topic to the data assimilation section of the forum, as this is a problem that is specifically related to DA.
NCAR/MMM

JJGuerrette
Posts: 19
Joined: Mon Feb 25, 2019 8:14 pm

Re: Boundary discontinuity after data assimilation

Post by JJGuerrette » Mon Jun 03, 2019 4:53 pm

To the original poster, would you please specify at what point during your workflow this error arises? You will have a forecast (simultaneous for both domains) and a data assimilation execution for each domain, for a total of three different executions. Thank you.


Post Reply

Return to “Miscellaneous DA Topics”