[Wrf-users] Upper boundary cfl error (UNCLASSIFIED)
Mark Stoelinga
mstoelinga at 3tier.com
Thu Mar 4 15:49:44 MST 2010
I can also confirm what Bob and David suggested...I had the same problem for 4/3-km simulations, and solved it the same way ( don't recall if we did 4 or 5 smoothing passes).
What I do recall is that the resultant smoothing of the terrain is not as drastic as one might fear from 5 smoothing passes. The differences are noticeable, but most of the hi-res structure in the terrain is still there. And the WRF crash problem goes away.
Mark
--
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3TIER Inc.
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On Mar 4, 2010, at 1:17 PM, David Ovens wrote:
> All,
>
> Bob's suggestion about using a different smoothing option in geogrid
> is the only way I've been able to consistently run at 4/3-km
> resolution over a region that covers Whistler, BC. We have to do 5
> smoothing passes.
>
> So, in geogrid/GEOGRID.TBL.ARW for all
>
> name = HGT_M
> name = HGT_U
> name = HGT_V
>
> I have
>
> smooth_option = smth-desmth_special; smooth_passes=5
>
> That has worked very well. We had the same problems trying all of the
> other things that Bob mentions.
>
> Note that we run our high resolution run after running ndown.exe, so
> we're able to use smooth_passes=1 for the topography of our coarser
> domains.
>
> David
> --
> David Ovens e-mail: ovens at atmos.washington.edu
> Research Meteorologist phone: (206) 685-8108
> Dept of Atm. Sciences plan: Real-time MM5 forecasting for the
> Box 351640 Pacific Northwest
> University of Washington http://www.atmos.washington.edu/mm5rt
> Seattle, WA 98195 Weather Graphics and Loops
> http://www.atmos.washington.edu/~ovens/loops
>
> On Thu, Mar 04, 2010 at 11:47:40AM -0700, Dumais, Bob (Civ, ARL/CISD) wrote:
>> 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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