[Wrf-users] Experiences with high-resolution WRF-ARW

[David Ovens]

Eric,

I am sure others can state this more precisely, but I would think your
problem is your use of "real terrain".  That sounds like you have not
smoothed the terrain.  You still need to remove 2*dx waves from your
terrain or risk CFL errors.

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 Wed, Feb 27, 2008 at 04:01:49PM -0500, Kemp, Eric M. wrote:
> 
> Dear wrf-users:
> 
> My group is running WRF-ARW at high resolution (dx = 1 km) to simulate turbulence.  
> Recently we tried running at very high vertical resolution (dz ~= 12.5 m in the lowest
> 500 m of the domain), and encountered CFL errors with time steps as
> low as 1/8 of a second.  These runs used the 6th order diffusion
> option from Knievel et al (2007), along with real terrain (area around
> Albuquerque, NM) and physics (MYJ TKE, Noah land surface,
> RRTM/Dudhia radiation, and WSM5 microphysics).
> 
> Has anyone here run WRF at such fine resolution, and if so, what were 
> your experiences with the time step?  The ARW documentation recommends 
> 6 seconds for each kilometer of dx, ignoring the effect of vertical resolution.  
> Are there other settings that should be tuned?
> 
> -Eric
> 
> Eric M. Kemp
> Meteorologist
> Northrop Grumman Information Technology
> Intelligence Group (TASC)
> 4801 Stonecroft Boulevard
> Chantilly, VA 20151
> (703) 633-8300 x7078 (lab)
> (703) 633-8300 x8278 (office)
> (703) 449-3400       (fax)
> eric.kemp at ngc.com
> 

> _______________________________________________
> Wrf-users mailing list
> Wrf-users at ucar.edu
> http://mailman.ucar.edu/mailman/listinfo/wrf-users