[Wrf-users] Wrf-users Digest, Vol 56, Issue 1
wrfhelp
wrfhelp at ucar.edu
Fri Apr 3 19:37:57 MDT 2009
When nesting is used, we recommending using the same RADT for all
domains.
wrfhelp
On Apr 1, 2009, at 12:00 PM, wrf-users-request at ucar.edu wrote:
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> Today's Topics:
>
> 1. Setting of RADT with multiple nests (Eric Altshuler)
> 2. Re: Setting of RADT with multiple nests (Satyaban Bishoyi Ratna)
> 3. Running WPS with ECMWF data (Abdullah Kahraman)
> 4. differences in wrf results due to grib2 subsetting
> (Eduardo Penabad Ramos)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 31 Mar 2009 19:13:46 -0400 (EDT)
> From: Eric Altshuler <ela at cola.iges.org>
> Subject: [Wrf-users] Setting of RADT with multiple nests
> To: wrfhelp <wrfhelp at ucar.edu>
> Cc: wrf-users <wrf-users at ucar.edu>
> Message-ID:
> <1780367252.199831238541226244.JavaMail.root at mail.iges.org>
> Content-Type: text/plain; charset=utf-8
>
> Hello,
>
> I have asked this question before, but I have never gotten a clear
> answer. I apologize for asking it again.
>
> I am running WRF-ARW with 3 domains: a coarse grid at 45km
> resolution, an intermediate nest at 15km, and an inner nest at 5km.
> The WRF documentation says two things about RADT:
>
> 1. Set RADT (in minutes) equal to the horizontal resolution (in km),
> e.g. RADT = 10 for DX = 10000
> 2. Set RADT to be the same on all domains
>
> These rules conflict when nesting is used. Obviously, with a 3:1
> nesting ratio, it is impossible to satisfy both rules. My question
> is, which RADT setting should be used here?
>
> a) radt = 45, 45, 45
> b) radt = 15, 15, 15
> c) radt = 5, 5, 5
> d) none of the above?
>
> My intuition is to set radt = 15, 15, 15 but I would appreciate
> feedback on how users deal with the RADT setting when they run WRF
> with nesting.
>
> Thanks in advance for your attention.
>
> Best regards,
>
> Eric L. Altshuler
> Assistant Research Scientist
> Center for Ocean-Land-Atmosphere Studies
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705-3106
> USA
>
> E-mail: ela at cola.iges.org
> Phone: (301) 902-1257
> Fax: (301) 595-9793
>
>
> ------------------------------
>
> Message: 2
> Date: 1 Apr 2009 07:34:04 -0000
> From: "Satyaban Bishoyi Ratna" <satyaban_2001 at rediffmail.com>
> Subject: Re: [Wrf-users] Setting of RADT with multiple nests
> To: "Eric Altshuler" <ela at cola.iges.org>
> Cc: wrfhelp <wrfhelp at ucar.edu>, wrf-users <wrf-users at ucar.edu>
> Message-ID: <20090401073404.9847.qmail at f5mail-236-219.rediffmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Dear Eric,
> With your experimental set up, I will prefare to use
> radt = 45, 45, 45 as we use for our cases.
>
> WRF document says
> 1. recommend 1 min per km of dx
> 2. use the same value for all nests
>
> So first, we can satisfy condition 1 for the parent domain and next
> to follow condition 2 (i.e.) the same 'radt' valuse of outer domain
> to be used in all the nest domains.
>
> Regards
> Satyaban
>
> On Wed, 01 Apr 2009 Eric Altshuler wrote :
>> Hello,
>>
>> I have asked this question before, but I have never gotten a clear
>> answer. I apologize for asking it again.
>>
>> I am running WRF-ARW with 3 domains: a coarse grid at 45km
>> resolution, an intermediate nest at 15km, and an inner nest at 5km.
>> The WRF documentation says two things about RADT:
>>
>> 1. Set RADT (in minutes) equal to the horizontal resolution (in
>> km), e.g. RADT = 10 for DX = 10000
>> 2. Set RADT to be the same on all domains
>>
>> These rules conflict when nesting is used. Obviously, with a 3:1
>> nesting ratio, it is impossible to satisfy both rules. My question
>> is, which RADT setting should be used here?
>>
>> a) radt = 45, 45, 45
>> b) radt = 15, 15, 15
>> c) radt = 5, 5, 5
>> d) none of the above?
>>
>> My intuition is to set radt = 15, 15, 15 but I would appreciate
>> feedback on how users deal with the RADT setting when they run WRF
>> with nesting.
>>
>> Thanks in advance for your attention.
>>
>> Best regards,
>>
>> Eric L. Altshuler
>> Assistant Research Scientist
>> Center for Ocean-Land-Atmosphere Studies
>> 4041 Powder Mill Road, Suite 302
>> Calverton, MD 20705-3106
>> USA
>>
>> E-mail: ela at cola.iges.org
>> Phone: (301) 902-1257
>> Fax: (301) 595-9793
>> _______________________________________________
>> Wrf-users mailing list
>> Wrf-users at ucar.edu
>> http://mailman.ucar.edu/mailman/listinfo/wrf-users
>
>
> -------------------------------------------------------------------------------
> Satyaban Bishoyi Ratna
> Computational Atmospheric Sciences Team
> Scientific & Engineering Computing Group
> Centre for Development of Advanced Computing (C-DAC)
> Pune University Campus, Ganeshkhind
> Pune - 411 007, Maharashtra, India
> E-mail: satyabanb at cdac.in
> Tel (O): +91-020-2570 4226, (Cell): +91-094223 56326
> --------------------------------------------------------------------------------
>
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> ------------------------------
>
> Message: 3
> Date: Wed, 1 Apr 2009 16:17:55 +0300
> From: Abdullah Kahraman <havadurumu at gmail.com>
> Subject: [Wrf-users] Running WPS with ECMWF data
> To: wrf-users at ucar.edu, wrfhelp <wrfhelp at ucar.edu>
> Message-ID:
> <4313f910904010617s33eda2e7je9d5a5cffe846ec4 at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello,
>
> I am trying to run WPS using ECMWF data with 0.25 degrees
> resolution, 3
> hours interval, 10 vertical levels (lv_ISBL1 = 10). Data files
> ERA_GRIB_UPA_BC_3H, ERA_GRIB_SOIL_BC_3H and ERA_GRIB_SFC_BC_3H seems
> OK.
>
> Ungrib seems succesful but I receive error when running metgrid,
> although I
> have tried both Vtable.ECMWF and Vtable.ECMWF_sigma. I changed the
> mod_levs
> in namelist as the following, after looking at the levels of the data.
>
> &mod_levs
> press_pa = 200100 , 100000 ,
> 85000 , 70000 ,
> 50000 , 40000 ,
> 30000 , 25000 ,
> 20000 , 15000 ,
> 10000
>
> The error I receive from metgrid is here:
>
> ERROR: The mandatory field TT was not found in any input data.
>
> I also tried putting 201300 in the mod_levs, then it gave the error
> earlier,
> about not finding the soil data. Ofcourse I would like to use all
> the data.
>
> metgrid.log says that none of the variables could be read from data
> files.
>
> How can I overcome this problem?
>
> Thanks in advance,
> Abdullah Kahraman
> Istanbul Technical University
> Department of Meteorology
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> ------------------------------
>
> Message: 4
> Date: Wed, 1 Apr 2009 15:33:06 +0200
> From: "Eduardo Penabad Ramos" <edu.penabad at meteogalicia.es>
> Subject: [Wrf-users] differences in wrf results due to grib2
> subsetting
> To: <wrf-users at ucar.edu>
> Message-ID: <20090401133305.9072A888076 at xallas.meteogalicia.es>
> Content-Type: text/plain; charset="us-ascii"
>
> Hello!
>
> in our institution, in order to speed up some operational tasks, we
> are
> starting to work with regional subsets of global 0.5-GFS GRIB2 files
> as
> inital/boundary conditions for WRF (we are using "small_grib" option
> of
> wgrib2 to generate our regional subset) as you can observe in the
> attached
> document
>
> We have found some significant differences in WRF results due to use
> of
> those regional files instead of global files (as it can be seen in
> this
> document:
> <http://www.meteogalicia.es/galego/modelos/numerico/edu/dif_grib2.pdf>
> http://www.meteogalicia.es/galego/modelos/numerico/edu/dif_grib2.pdf).
> Differences grow up to 2 degrees in 2m-temperature or 2 m/s in 10m-
> winds at
> the end of the simulation (84/96 hour forecast).
>
> We've contacted with people at NCEP related to grib2 processing, and
> they
> said that this is normal, wgrib2 just "generates" some truncation
> errors,
> and that those differences in WRF results are similar to those
> obtained
> using the same initial conditions in differente machines/compilers.
>
> Even though, it seems that the differences are really important
> (non-negligible)... does anyone has faced with this kind of problem?
> any
> suggestions?
>
> Thanks in advance!
>
> Eduardo Penabad
> MeteoGalicia. NWP Department
>
>
> <http://www.meteogalicia.es/galego/modelos/numerico/edu/dif_grib2.pdf>
>
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> End of Wrf-users Digest, Vol 56, Issue 1
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