[Wrf-users] Upper boundary cfl error (UNCLASSIFIED)
Dumais, Bob (Civ, ARL/CISD)
robert.dumaisjr at us.army.mil
Thu Mar 4 11:47:40 MST 2010
Classification: UNCLASSIFIED
Caveats: NONE
All,
I found this issue as well, over very steep terrain regions.
For example, I tried running WRF in triple nest to 300 m grid spacing
over the White Sands Missile Range, Nm area (2.7 km; 900m; 300 m using
NAM 218 ICs and LBCs). Simply interpolating to 300 m from the default
USGS 1 km data worked fine. However, trying to run with 300 m terrain
generated from higher resolution NEDS arc 1 sec data causes the model to
crash everytime no matter which case/external dataset I try. It always
happens within the first 2 min of model integration. It looks like a
singular point blows up/produces an instability where there is a very
steep model terrain slope. In fact, trying to run a grid recently for
the Olympic venue region near Whistler, BC the same thing happened. Blow
ups (CFL violations due to big values of W) in low levels at a single
steep slope point in the domain, within 2 min of integration. This was
for a 1 km grid spacing domain where the terrain was generated from the
default 1 km USGS data! At 3 km grid spacing, the model runs fine.
In the BC domain, I believe the "magic" point where things were
blowing up was found to be found near 50.13 N and -123.625. It is not a
boundary point. I have tried very small time steps, different vertical
grid structures, microphysics, radiation, PBL physics, land surface, 6th
order diffusion strength, and even divergence damping strength (smdiv in
namelist). Nothing things to prevent this for the WSMR or Whistler areas
I mentioned. I am cc'ing Dr Jimy Dudhia this email, since I think he may
be able to add something regarding this possible model slope issue. I
notice that in my cases where the instabilities occur, model slopes are
pretty high and may be approaching 45 deg. My gut feeling is that slope
may become an issue for some domains at grid spacings about 1 km or
less. Maybe a different terrain smoothing option in geogrid could help??
Where are you running your model?
Bob
-----Original Message-----
From: wrf-users-bounces at ucar.edu [mailto:wrf-users-bounces at ucar.edu] On
Behalf Of Min Zhu
Sent: Thursday, March 04, 2010 3:34 AM
To: wrf-users at ucar.edu
Subject: Re: [Wrf-users] Upper boundary cfl error
Hi,
It seems that the problem is in lower boundary rather than upper
boundary. Also your time step seems to be bigger.
Cheers,
Min Zhu
Meso-scale Wind Modeller
D +44 (0)1923 299 360
RES Group, registered in England and Wales with Company Number 1589961
Registered Office: Beaufort Court, Egg Farm Lane, Kings Langley,
Hertfordshire WD4 8LR
P please consider the environment - do you really need to print this
email?
From: wrf-users-bounces at ucar.edu [mailto:wrf-users-bounces at ucar.edu] On
Behalf Of Andre Pattantyus
Sent: 04 March 2010 00:11
To: wrf-users at ucar.edu
Subject: [Wrf-users] Upper boundary cfl error
Hi all,
I am getting these few errors at my upper boundary. Among other things,
I have tried using the new damping option, diff_opt =2, because I am
using running towards an LES in my inner domain. A solution seems easy
but so far my attempts have not yielded success. below is my namelist.
3 points exceeded cfl=2 in domain d03 at time 2006-03-29_12:00:16 hours
MAX AT i,j,k: 40 80 4 vert_cfl,w,d(eta)= 2.263442993 -80.54151917
0.2999961376E-02
3 points exceeded cfl=2 in domain d03 at time 2006-03-29_12:00:16
hours
MAX AT i,j,k: 40 80 4 vert_cfl,w,d(eta)= 2.485260963 13.09560013
0.2999961376E-02
3 points exceeded cfl=2 in domain d03 at time 2006-03-29_12:00:16
hours
MAX AT i,j,k: 41 80 4 vert_cfl,w,d(eta)= 2.567909241 -117.0119095
0.2999961376E-02
22 points exceeded cfl=2 in domain d03 at time
2006-03-29_12:00:16+08/09 hours
MAX AT i,j,k: 40 80 4 vert_cfl,w,d(eta)= 6.311451435 -170.4623871
0.2999961376E-02
36 points exceeded cfl=2 in domain d03 at time
2006-03-29_12:00:16+08/09 hours
MAX AT i,j,k: 40 80 3 vert_cfl,w,d(eta)= 6.109247208 -223.6106720
0.2799987793E-02
AVOST IN VILKA
~
~
~
&time_control
run_days = 2,
run_hours = 36,
run_minutes = 0,
run_seconds = 0,
start_year = 2006, 2006, 2006,
start_month = 03, 03, 03,
start_day = 29, 29, 29,
start_hour = 12, 12, 12,
start_minute = 00, 00, 00,
start_second = 00, 00, 00,
end_year = 2006, 2006, 2006,
end_month = 03, 03, 03,
end_day = 31, 31, 31,
end_hour = 00, 00, 00,
end_minute = 00, 00, 00,
end_second = 00, 00, 00,
interval_seconds = 10800
input_from_file = .true.,.true.,.true.,
history_interval = 60, 60, 60,
frames_per_outfile = 1000, 1000, 1000,
restart = .false.,
restart_interval = 720,
io_form_history = 2
io_form_restart = 2
io_form_input = 2
io_form_boundary = 2
debug_level = 0
/
&domains
time_step = 8,
time_step_fract_num = 0,
time_step_fract_den = 1,
max_dom = 3,
e_we = 121, 169, 241,
e_sn = 121, 169, 241,
e_vert = 61, 61, 61,
p_top_requested = 5000,
num_metgrid_levels = 40,
num_metgrid_soil_levels = 4,
dx = 4500, 1500, 500,
dy = 4500, 1500, 500,
grid_id = 1, 2, 3,
parent_id = 0, 1, 2,
i_parent_start = 1, 33, 53,
j_parent_start = 1, 33, 53,
parent_grid_ratio = 1, 3, 3,
parent_time_step_ratio = 1, 3, 3,
feedback = 0,
smooth_option = 0,
eta_levels = 1.0000, .9976, .9948, .9920,
.9890,
.9858, .9825, .9790, .9754, .9718, .9679, .9637, .9590, .9538, .9480,
.9415, .9340, .9251, .9144, .9020, .8883, .8736, .8582, .8420, .8253,
.8079, .7900, .7714, .7523, .7326, .7124, .6915, .6699, .6477, .6248,
.6015, .5779, .5540, .5300, .5057, .4812, .4566, .4319, .4070, .3822,
.3576, .3333, .3100, .2881, .2679, .2494, .2316, .2135, .1936, .1707,
.1445, .1159, .0863, .0569, .0282, .0000, /
&physics
mp_physics = 8, 8, 8,
ra_lw_physics = 1, 1, 1,
ra_sw_physics = 2, 2, 2,
radt = 4, 4, 4,
sf_sfclay_physics = 4, 4, 4,
sf_surface_physics = 3, 3, 3,
bl_pbl_physics = 4, 4, 4,
bldt = 0, 0, 0,
cu_physics = 0, 0, 0,
cudt = 0, 0, 0,
isfflx = 1,
ifsnow = 0,
icloud = 1,
surface_input_source = 1,
num_soil_layers = 6,
sf_urban_physics = 0,
maxiens = 1,
maxens = 3,
maxens2 = 3,
maxens3 = 16,
ensdim = 144,
slope_rad = 1, 1, 1,
topo_shading = 1, 1, 1,
shadlen = 25000.,
/
&fdda
/
&dynamics
w_damping = 1,
diff_opt = 2,
km_opt = 4,
diff_6th_opt = 2, 2, 2,
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,
/
&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,
--
Andre Pattantyus, Graduate Student Research Assistant Marine and
Environmental Systems, Florida Institute of Technology 150 W. University
Blvd, Melbourne, FL 32901
Phone: (321) 674-8330 | Fax: (321) 674-7212 | Email:
apattantyus2008 at fit.edu
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