[Met_help] [rt.rap.ucar.edu #44843] History for RTMA analysis
RAL HelpDesk {for John Halley Gotway}
met_help at ucar.edu
Thu Mar 10 14:32:21 MST 2011
----------------------------------------------------------------
Initial Request
----------------------------------------------------------------
I am in the process of adding RTMA gridded analysis as a ground truth
source for grid-stat. We appear to be receiving a separate file for
each variable (e.g. grib2 file for 10-m winds, grib2 file for 2-m temp,
etc) that look something like this:
201102221400_TMPKAERR.2m 201102230500_DWPK.2m
201102231900_TMPKAERR.2m
201102221400_UREL.10m 201102230500_DWPKAERR.2m
201102231900_UREL.10m
201102221400_VREL.10m 201102230500_SPED.10m
201102231900_VREL.10m
Each file contains multiple grib records - one for each map projections
(Lambert Conformal, Mercator, and Polar). Can grid-stat handle a grib1
file (I will use cnvgrib to convert to grib1) with multiple projections
or will that be problematic? Also, would it work to use each of the
files separately as a ground truth source or would you advise looking
for some grib utility (if one exists) to combine the separate file into
one that contains all variables?
Thank you for your help,
Jackie
Jackie Miller
Meteorologist
Vaisala Inc.
Phone +1 303 885 3251
Mobile +1 303 885 3251
www.vaisala.com
<https://exchange.ou.edu/owa/redir.aspx?C=b302bd7f7cb24f099b2eb70ba1b9bf
5f&URL=https%3a%2f%2fwebmail.vaisala.com%2fexchweb%2fbin%2fredir.asp%3fU
RL%3dhttp%3a%2f%2fwww.vaisala.com>
This electronic message contains a communication which is strictly
confidential and intended solely for the addressee(s). Any
non-addressee is prohibited from reading, disseminating, distributing,
or copying the communication contained herein. If you are in possession
of the communication in error, please immediately notify the sender via
an electronic response and destroy the original communication. Thank
you.
U.S. Export Restrictions & Disclaimer: Export of any technical
information contained in this email and/or its attachments is subject to
the export control laws and regulations of the U.S. Government and may
require a valid license or written approval prior to export.
----------------------------------------------------------------
Complete Ticket History
----------------------------------------------------------------
Subject: Re: [rt.rap.ucar.edu #44843] RTMA analysis
From: John Halley Gotway
Time: Wed Feb 23 13:42:17 2011
Jackie,
It sounds like you'd like to know how to slice and dice GRIB files.
Everything I say below applies to GRIB1 files and may or may not apply
to GRIB2 files. I haven't had as much experience with
GRIB2, so I'm not certain.
A GRIB1 file consists of one or more GRIB records. A nice feature of
GRIB is that each record is a totally independent thing. Each record
contains all the metadata necessary for understanding it.
That means that you can literally 'cat' together two GRIB files to get
a combined one. And you can use the 'split' command to cut them apart
if you know which byte to cut them at.
However, 'wgrib' provides an easier way to split GRIB records up. For
example, try running the following commands using some sample data
that's distributed with MET:
wgrib METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212
wgrib -d 150 -grib -o single_record.grib
METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212
In the first command you'll see that this GRIB file contains 164
records. The second command extracts a single record (#150) and
writes it out to a GRIB file named "single_record.grib". The wgrib
output of the first command also gives you the byte offset to each
record. You'll notice that the UGRD and VGRD output starts at record
85 with byte offset 1167226. The following split command will
cut the file at that point:
split -b 1167226
METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212
The output of split is named xaa and xab.
Another option is using 'copygb' to select out subset of GRIB records.
For example, this command should pull out all of the relative humidity
(grib code = 52) records from that GRIB file:
copygb -x -k'4*-1 52'
METv3.0/data/sample_fcst/2005080700/wrfprs_ruc13_12.tm00_G212 rh.grib
For more info on copygb, look here:
http://www.dtcenter.org/met/users/support/online_tutorial/METv3.0/copygb/copygb.txt
Since each GRIB record is independent, the grid definition information
is contained within it. Therefore, having a GRIB file with records
that are defined on different grids is not a problem for MET.
However, you need to make sure that:
(1) When you run the grid-to-grid tools in MET (Grid-Stat, Wavelet-
Stat, and MODE), the forecast and observations records must be on the
same grid.
(2) If you need to regrid data using copygb using the -g option, you
can only specify a single output grid. If you have data on multiple
grids in your input and run it through copygb, the output will
all be on the same grid.
Hope that helps.
John Halley Gotway
met_help at ucar.edu
On 02/23/2011 12:57 PM, RAL HelpDesk {for jackie.miller} wrote:
>
> Wed Feb 23 12:57:09 2011: Request 44843 was acted upon.
> Transaction: Ticket created by jackie.miller at vaisala.com
> Queue: met_help
> Subject: RTMA analysis
> Owner: Nobody
> Requestors: jackie.miller at vaisala.com
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=44843 >
>
>
> I am in the process of adding RTMA gridded analysis as a ground
truth
> source for grid-stat. We appear to be receiving a separate file for
> each variable (e.g. grib2 file for 10-m winds, grib2 file for 2-m
temp,
> etc) that look something like this:
>
> 201102221400_TMPKAERR.2m 201102230500_DWPK.2m
> 201102231900_TMPKAERR.2m
>
> 201102221400_UREL.10m 201102230500_DWPKAERR.2m
> 201102231900_UREL.10m
>
> 201102221400_VREL.10m 201102230500_SPED.10m
> 201102231900_VREL.10m
>
> Each file contains multiple grib records - one for each map
projections
> (Lambert Conformal, Mercator, and Polar). Can grid-stat handle a
grib1
> file (I will use cnvgrib to convert to grib1) with multiple
projections
> or will that be problematic? Also, would it work to use each of the
> files separately as a ground truth source or would you advise
looking
> for some grib utility (if one exists) to combine the separate file
into
> one that contains all variables?
>
>
>
> Thank you for your help,
>
> Jackie
>
>
>
> Jackie Miller
> Meteorologist
>
> Vaisala Inc.
>
> Phone +1 303 885 3251
> Mobile +1 303 885 3251
> www.vaisala.com
>
<https://exchange.ou.edu/owa/redir.aspx?C=b302bd7f7cb24f099b2eb70ba1b9bf
>
5f&URL=https%3a%2f%2fwebmail.vaisala.com%2fexchweb%2fbin%2fredir.asp%3fU
> RL%3dhttp%3a%2f%2fwww.vaisala.com>
>
>
>
> This electronic message contains a communication which is strictly
> confidential and intended solely for the addressee(s). Any
> non-addressee is prohibited from reading, disseminating,
distributing,
> or copying the communication contained herein. If you are in
possession
> of the communication in error, please immediately notify the sender
via
> an electronic response and destroy the original communication.
Thank
> you.
>
>
>
> U.S. Export Restrictions & Disclaimer: Export of any technical
> information contained in this email and/or its attachments is
subject to
> the export control laws and regulations of the U.S. Government and
may
> require a valid license or written approval prior to export.
>
>
>
------------------------------------------------
Subject: RTMA analysis
From: John Halley Gotway
Time: Mon Mar 07 13:48:38 2011
Jackie,
Just writing to find out if you have any more questions regarding how
you'd use the RTMA analysis data in MET. If not, I'll go ahead and
resolve this helpdesk ticket. Or did some more questions arise?
Thanks,
John Halley Gotway
------------------------------------------------
Subject: RE: [rt.rap.ucar.edu #44843] RTMA analysis
From: jackie.miller
Time: Thu Mar 10 14:31:32 2011
Not at the moment - thank you for your help! I will let you know if
we
come across any more questions going forward.
Thanks!
Jackie
Jackie Miller
Meteorologist
Vaisala Inc.
Phone +1 303 885 3251
Mobile +1 303 885 3251
www.vaisala.com
This electronic message contains a communication which is strictly
confidential and intended solely for the addressee(s). Any
non-addressee is prohibited from reading, disseminating, distributing,
or copying the communication contained herein. If you are in
possession
of the communication in error, please immediately notify the sender
via
an electronic response and destroy the original communication. Thank
you.
U.S. Export Restrictions & Disclaimer: Export of any technical
information contained in this email and/or its attachments is subject
to
the export control laws and regulations of the U.S. Government and may
require a valid license or written approval prior to export.
-----Original Message-----
From: RAL HelpDesk {for John Halley Gotway} [mailto:met_help at ucar.edu]
Sent: Monday, March 07, 2011 2:49 PM
To: Miller Jackie JCM
Cc: met_help at ucar.edu
Subject: [rt.rap.ucar.edu #44843] RTMA analysis
Jackie,
Just writing to find out if you have any more questions regarding how
you'd use the RTMA analysis data in MET. If not, I'll go ahead and
resolve this helpdesk ticket. Or did some more questions arise?
Thanks,
John Halley Gotway
------------------------------------------------
More information about the Met_help
mailing list