[Met_help] [rt.rap.ucar.edu #38969] History for grib file conversion question
RAL HelpDesk {for John Halley Gotway}
met_help at ucar.edu
Fri Jul 2 10:45:51 MDT 2010
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Initial Request
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Hi,
This is a big issue I am having that is indirectly related to MET. Since you guys have been so useful with the past issues I have had with MET itself, I thought I would pass this along and try my luck since I'm at a loss of what to do. I have compiled and am attempting to use the WPP to convert WRF-ARW netcdf to grib1 format. My observations stem from a "truth" wrf simulation at 6km resolution. I wrote a fortran program to coarsen the data to 18km and checked both netcdf files in matlab to make sure that variable names and values seemed reasonable. However, when I use the identical wrf_control.parm file in the run_wrfpost program in WPP, it is not able to read any of the data in the coarsened netcdf file but has no issue with the original 6km resolution file. I have absolutely no idea where to turn to try and resolve this issue or find where it stems from. All of my 18km assimilation runs have converted just fine with the same control file. Any ideas you might have w!
ould really help me out.. or even pointing me to someone who might have a better idea.
Thanks,
Dan
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Complete Ticket History
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Subject: grib file conversion question
From: John Halley Gotway
Time: Wed Jun 30 15:28:02 2010
Dan,
My question would be why are you writing FORTRAN code to coarsen the
model output in the first place? I'd instead suggest processing your
6-km WRF output using wrfpost. Once wrfpost is finished, you can run
copygb on the GRIB output of wrfpost to regrid it to an 18-km domain.
We run copygb to regrid GRIB data all the time.
copygb actually is a executable that's built as part of WPP. You'll
find it in the same directory as wrfpost. The only sticky part of
copygb is figuring out how to specify the domain onto which you'd like
your data regridded. The command line arguments for it are a bit
convoluted. Here's a link to a MET practical session which gives
examples of how to specify the copygb arguments for the different
types of projections:
http://www.dtcenter.org/met/users/support/OnLinePractical/OnLinePractical_210/copygb/index.php
Just click the forward arrow in the bottom-right corner of the page to
advance to the next example.
You can also refer to this file for more info on copygb:
WPPV3/sorc/copygb/copygb.doc
Hope that helps.
John Halley Gotway
met_help at ucar.edu
------------------------------------------------
Subject: grib file conversion question
From: John Halley Gotway
Time: Wed Jun 30 15:28:34 2010
Dan,
My question would be why are you writing FORTRAN code to coarsen the
model output in the first place? I'd instead suggest processing your
6-km WRF output using wrfpost. Once wrfpost is finished, you can run
copygb on the GRIB output of wrfpost to regrid it to an 18-km domain.
We run copygb to regrid GRIB data all the time.
copygb actually is a executable that's built as part of WPP. You'll
find it in the same directory as wrfpost. The only sticky part of
copygb is figuring out how to specify the domain onto which you'd like
your data regridded. The command line arguments for it are a bit
convoluted. Here's a link to a MET practical session which gives
examples of how to specify the copygb arguments for the different
types of projections:
http://www.dtcenter.org/met/users/support/OnLinePractical/OnLinePractical_210/copygb/index.php
Just click the forward arrow in the bottom-right corner of the page to
advance to the next example.
You can also refer to this file for more info on copygb:
WPPV3/sorc/copygb/copygb.doc
Hope that helps.
John Halley Gotway
met_help at ucar.edu
------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #38969] grib file conversion question
From: Dan Hartung
Time: Wed Jun 30 15:31:38 2010
John,
I was coarsening the 6km "truth" run to 18km for analysis / comparison
to 18km assimilation forecast runs.. does copygb use an average of
grid points to regrid data so that the higher resolution of the 6km
run is more preserved? If so, then I will give this a shot.
Thanks,
Dan
On Jun 30, 2010, at 4:28 PM, RAL HelpDesk {for John Halley Gotway}
wrote:
> Dan,
>
> My question would be why are you writing FORTRAN code to coarsen the
model output in the first place? I'd instead suggest processing your
6-km WRF output using wrfpost. Once wrfpost is finished, you can run
copygb on the GRIB output of wrfpost to regrid it to an 18-km domain.
>
> We run copygb to regrid GRIB data all the time.
>
> copygb actually is a executable that's built as part of WPP. You'll
find it in the same directory as wrfpost. The only sticky part of
copygb is figuring out how to specify the domain onto which you'd like
your data regridded. The command line arguments for it are a bit
convoluted. Here's a link to a MET practical session which gives
examples of how to specify the copygb arguments for the different
types of projections:
>
http://www.dtcenter.org/met/users/support/OnLinePractical/OnLinePractical_210/copygb/index.php
>
> Just click the forward arrow in the bottom-right corner of the page
to advance to the next example.
>
> You can also refer to this file for more info on copygb:
> WPPV3/sorc/copygb/copygb.doc
>
> Hope that helps.
>
> John Halley Gotway
> met_help at ucar.edu
------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #38969] grib file conversion question
From: John Halley Gotway
Time: Wed Jun 30 15:38:42 2010
Don,
copygb does provide several interpolation options, but I'd refer you
to that documentation file for details:
WPPV3/sorc/copygb/copygb.doc
Here's an excerpt related to interpolation options:
-i "ip [ipopts]"
Interpolation options. The default is
bilinear
interpolation (ip=0). Other interpolation
options
are bicubic (ip=1), neighbor (ip=2), budget
(ip=3),
and spectral (ip=4). Spectral interpolation
is forced
even if the input and output grids are the
same.
See the documentation for iplib for further
details.
Not sure which you'd want to use in your case.
John
RAL HelpDesk {for Dan Hartung} wrote:
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=38969 >
>
> John,
>
> I was coarsening the 6km "truth" run to 18km for analysis /
comparison to 18km assimilation forecast runs.. does copygb use an
average of grid points to regrid data so that the higher resolution of
the 6km run is more preserved? If so, then I will give this a shot.
>
> Thanks,
> Dan
>
> On Jun 30, 2010, at 4:28 PM, RAL HelpDesk {for John Halley Gotway}
wrote:
>
>> Dan,
>>
>> My question would be why are you writing FORTRAN code to coarsen
the model output in the first place? I'd instead suggest processing
your 6-km WRF output using wrfpost. Once wrfpost is finished, you can
run copygb on the GRIB output of wrfpost to regrid it to an 18-km
domain.
>>
>> We run copygb to regrid GRIB data all the time.
>>
>> copygb actually is a executable that's built as part of WPP.
You'll find it in the same directory as wrfpost. The only sticky part
of copygb is figuring out how to specify the domain onto which you'd
like your data regridded. The command line arguments for it are a bit
convoluted. Here's a link to a MET practical session which gives
examples of how to specify the copygb arguments for the different
types of projections:
>>
http://www.dtcenter.org/met/users/support/OnLinePractical/OnLinePractical_210/copygb/index.php
>>
>> Just click the forward arrow in the bottom-right corner of the page
to advance to the next example.
>>
>> You can also refer to this file for more info on copygb:
>> WPPV3/sorc/copygb/copygb.doc
>>
>> Hope that helps.
>>
>> John Halley Gotway
>> met_help at ucar.edu
>
------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #38969] grib file conversion question
From: Dan Hartung
Time: Fri Jul 02 08:35:46 2010
Thank you very much John.. problem resolved! Feel free to close this
ticket.
-Dan
On Jun 30, 2010, at 4:38 PM, RAL HelpDesk {for John Halley Gotway}
wrote:
> Don,
>
> copygb does provide several interpolation options, but I'd refer you
to that documentation file for details:
> WPPV3/sorc/copygb/copygb.doc
>
> Here's an excerpt related to interpolation options:
> -i "ip [ipopts]"
> Interpolation options. The default is
bilinear
> interpolation (ip=0). Other interpolation
options
> are bicubic (ip=1), neighbor (ip=2), budget
(ip=3),
> and spectral (ip=4). Spectral
interpolation is forced
> even if the input and output grids are the
same.
> See the documentation for iplib for further
details.
>
> Not sure which you'd want to use in your case.
>
> John
>
> RAL HelpDesk {for Dan Hartung} wrote:
>> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=38969 >
>>
>> John,
>>
>> I was coarsening the 6km "truth" run to 18km for analysis /
comparison to 18km assimilation forecast runs.. does copygb use an
average of grid points to regrid data so that the higher resolution of
the 6km run is more preserved? If so, then I will give this a shot.
>>
>> Thanks,
>> Dan
>>
>> On Jun 30, 2010, at 4:28 PM, RAL HelpDesk {for John Halley Gotway}
wrote:
>>
>>> Dan,
>>>
>>> My question would be why are you writing FORTRAN code to coarsen
the model output in the first place? I'd instead suggest processing
your 6-km WRF output using wrfpost. Once wrfpost is finished, you can
run copygb on the GRIB output of wrfpost to regrid it to an 18-km
domain.
>>>
>>> We run copygb to regrid GRIB data all the time.
>>>
>>> copygb actually is a executable that's built as part of WPP.
You'll find it in the same directory as wrfpost. The only sticky part
of copygb is figuring out how to specify the domain onto which you'd
like your data regridded. The command line arguments for it are a bit
convoluted. Here's a link to a MET practical session which gives
examples of how to specify the copygb arguments for the different
types of projections:
>>>
http://www.dtcenter.org/met/users/support/OnLinePractical/OnLinePractical_210/copygb/index.php
>>>
>>> Just click the forward arrow in the bottom-right corner of the
page to advance to the next example.
>>>
>>> You can also refer to this file for more info on copygb:
>>> WPPV3/sorc/copygb/copygb.doc
>>>
>>> Hope that helps.
>>>
>>> John Halley Gotway
>>> met_help at ucar.edu
>>
>
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