[Wrf-users] cfl error in very complex topography

Tue Jun 25 09:37:52 MDT 2013

Thanks for all responses.

epssm solved the problem (0.1, 0.3, 0.6, 0.9 for 27, 9, 3, 1 km of
resolution). But I have one more question:

I am interested in wind speed below 100m, then I am asking me if epssm
parameter has some impact on surface winds results?

Regards

Atentamente
Jorge Arévalo Bórquez
Profesor Auxiliar
Coordinador LMA-UV
Departamento de Meteorología
Universidad de Valparaíso
56-32-2508710

On Sat, Jun 15, 2013 at 8:22 AM, Ólafur Rögnvaldsson <or at belgingur.is>wrote:

> Dear Jorge.
>
> In our experience you may need to set "epssm" to an even greater number
> than what David suggests.
>
> The value we use for our SARWeather system is:
>
> epssm = 0.3, 0.6, 1.2,
>
> where the model resolution is 9, 3, and 1km, respectively.
>
> This setup, using the following 41 full-sigma levels
>
>     eta_levels = 1.000, 0.993, 0.985, 0.969, 0.953, 0.937, 0.921, 0.905,
>                  0.888, 0.870, 0.853, 0.835, 0.816, 0.798, 0.778, 0.759,
>                  0.739, 0.718, 0.696, 0.674, 0.651, 0.628, 0.603, 0.577,
>                  0.550, 0.522, 0.492, 0.461, 0.426, 0.389, 0.348, 0.302,
>                  0.242, 0.212, 0.182, 0.152, 0.121, 0.091, 0.061, 0.030,
>                  0.000,
>
> gives a stable solution over a 24 hour period for a 160x160 points 1km
> domain (nested from 9 and 3 km domains) centered over Mt. Aconcagua:
>
>
> https://www.sarweather.com/forecast/result/20130614-214823-09d847906bb8/static/wind/0
>
> Hope this is of some use and good luck with your simulations.
>
> Best, Ólafur.
>
> Ps. You need to register (https://www.sarweather.com/accounts/register/ -> this is free of charge) if you want to download the wrfout-files from
> the simulation I linked to.
>
> > Jorge,
> >
> > I see you have tried many of the recommended steps.  Have you tried
> > setting epssm to a larger number?  For my 4th domain, 0.2 is
> > sufficient
> > epssm       = 0.1, 0.1, 0.1, 0.2,
> > but you might want as much as 0.4 or even higher.  Change that in the
> > &dynamics section of your namelist.input file, rerun real.exe, and try
> > your run again.
> >
> > 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 Fri, Jun 14, 2013 at 01:36:11PM -0400, Jorge Alejandro Arevalo
> Borquez wrote:
> >> Dears,
> >>
> >> I am trying to run WRF over Central Chile. I am using 4 nested domains,
> the
> >> finner one has 1 km of horizontal resolution with 50 vertical levels.
> >> Domains includes Aconcagua mountain wich is about 6900 masl.
> >>
> >> When I run wrf I get cfl errors at few seconds after start in
> grid-points
> >> near to Aconcagua, but wrf crash in the call to radiation
> parametrization.
> >>
> >> I tried to decrease time-step, use adaptive time-step, edit GEOGRID.TBL
>  to
> >> use 1-2-1 smooth option, change my set of parametrization. Even I tried
> to
> >> edit geog data and apply a simple filter to smooth topography near
> >> aconcagua region. All efforts has concluded with the same cfl errors.
> >>
> >> Any advice is welcome
> >>
> >> Regards
> >>
> >>
> >>
> >> Atentamente
> >> Jorge Ar?valo B?rquez
> >> Profesor Auxiliar
> >> Coordinador LMA-UV
> >> Departamento de Meteorolog?a
> >> Universidad de Valpara?so
> >> 56-32-2508710
> >
> >> _______________________________________________
> >> Wrf-users mailing list
> >> Wrf-users at ucar.edu
> >> http://mailman.ucar.edu/mailman/listinfo/wrf-users
> >
> >
> > _______________________________________________
> > Wrf-users mailing list
> > Wrf-users at ucar.edu
> > http://mailman.ucar.edu/mailman/listinfo/wrf-users
>
> --
> Kveðja/regards,
> Dr. Ólafur Rögnvaldsson
> Belgingur, reiknistofa í veðurfræði
> www.riv.is - www.belgingur.is
>
>
>
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