[Wrf-users] Re: Wrf-users Digest, Vol 33, Issue 6

[Thorsten Beisiegel]

Dear Juan,

More than a help I can tell you that probably I've the same problem. We are simulating the northern South America and the Carribean. We use daily GFS data including skin temperature (TSK) so we don't use SST apart.  With a time step of 240, temperature 
reaches -50 Cº over the Carribean sea after 3 days simulated. We contribute this to XLAND=1 =constant all over the domain. So my question is what values do you get for XLAND in the wrfinput_d01 file and in the wrfout_d0* files? Do they vary? 
We use YSU PBL and RUC. 
In our case the problem seems to be that real.exe changes all water points to land, as if there were sea ice in the carribbean. 

Please let me know when you got some conclusion

thanks 
y suerte!

Thorsten

----- Original Message -----
From: wrf-users-request at ucar.edu
Date: Sunday, May 13, 2007 1:00 pm
Subject: Wrf-users Digest, Vol 33, Issue 6

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> Today's Topics:
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>   1. Cold bias  ( Juan Jos? Ruiz )
> 
> 
> --------------------------------------------------------------------
> --
> 
> Message: 1
> Date: Sat, 12 May 2007 18:42:57 -0300 (ART)
> From: " Juan Jos? Ruiz " <jruiz at cima.fcen.uba.ar>
> Subject: [Wrf-users] Cold bias 
> To: <wrf-users at ucar.edu>
> Message-ID:
> 	<16392.24.232.62.111.1179006177.squirrel at www.cima.fcen.uba.ar>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Dear Wrfhelp, thank you for your answer,
> In the following link
> http://wrf.cima.fcen.uba.ar/tsoil_t2m_mapa.gif you will find an 
> example of
> the cold bias distribution over South America. The shaded fiel is the
> difference between the top layer soil temperature at the beginning 
> of the
> forecast and the 48 hours forecast of the same variable. The contours
> shows the difference (analysis - 48 hour forecast) for the 2 meter
> temperatures. This is the result of averaging 2 months (15 December 
> 2002 -
> 15 February 2003) of 48 hours forecasts over the region. The drop 
> in the
> temperature increases with the forecast time. This is an example of 
> theBIAS for the 850 hPa level comparing with a single RS station 
> locatedwhere the BIAS are larger in the figure (over central 
> Argentina).6 hour forecast: -1�
> 30 hour forecast: -1.68�
> 42 hour forecast: -2.42�
> This BIASES has been computed over a month 01 January - 15 Febrary 
> 2003.The model configuration is 50km horizontal resolution with the 
> followingsigma levels:
> LEVELS = 1.000, 0.993, 0.980, 0.966, 0.950, 0.933,
>               0.913, 0.892, 0.869, 0.844, 0.816, 0.786,
>               0.753, 0.718, 0.680, 0.639, 0.596, 0.550,
>               0.501, 0.451, 0.398, 0.345, 0.290, 0.236,
>               0.188, 0.145, 0.108, 0.075, 0.046, 0.021,
>               0.000,
> 
> PBL= Mellor and Yamada (some improvment is found with YSU but the 
> problemis still present), Grell, Noah LSM and RRTM.
> The initial conditions are taken from the GDAS analysis and the 
> initialsoil temperature and 2m temperature looks very similar to 
> that finded in
> the analysis.
> There is also an improvment using the new version of the model 
> (V2.2.0)the bias is reduced but the spatial distribution remains 
> aproximately the
> same.
> Thanks a lot for your help!
> Best regards.
> Juan.
> 
> > Can you quantify your cold bias? Does the model start with the right
> > low level
> > and surface temperatures (e.g. TSK)? If you use a LSM option, do you
> > have the
> > right soil temp and moisture?
> >
> > wrfhelp
> 
> 
> 
> 
> 
> 
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> End of Wrf-users Digest, Vol 33, Issue 6
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