[Met_help] [rt.rap.ucar.edu #79390] History for point_stat

Thu Feb 9 10:14:03 MST 2017

----------------------------------------------------------------
  Initial Request
----------------------------------------------------------------

Hi,

Does anyone have a NETCDF data converted from PREPBUFR by pb2nc, which
contains MEAN SEA LEVEL PRESSURE?

Thanks

Yongzuo

----------------------------------------------------------------
  Complete Ticket History
----------------------------------------------------------------

Subject: point_stat
From: John Halley Gotway
Time: Wed Feb 08 15:51:26 2017

Yongzuo,

I believe that you can use this web GUI to request that the PREPBUFR
data
be run through the PB2NC tool to extract the desired subset of data,
including mean sea level pressure:
   http://rda.ucar.edu/datasets/ds337.0/#!access
<http://rda.ucar.edu/datasets/ds337.0/#%21access>

Earlier today I answered a very similar MET-Help question about
extracting
PRMSL observations from global GDAS files.  I'll cut-and-paste that
message
below in hopes that it applies to your situation as well.

Hope that helps.

Thanks,
John Halley Gotway

I think you're likely running into a problem with the quality marker
used
for surface data in these PREPBUFR files.  Please see the *NOTE* about
surface data at the bottom of this page:
   http://www.dtcenter.org/met/users/downloads/observation_data.php

Surface observations with message type ADPSFC are set to a quality
marker
value of 9.  By default, PB2NC discards any observations whose quality
marker is > 2.  So PB2NC is tossing out all of the ADPSFC observations
of
PRMSL.

I grabbed a recent GDAS PREPBUFR file:
   http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.html

I configured PB2NC to retain the PRMSL observation type by adding it
to the
"obs_grib_code" array.  Then I ran PB2NC twice... once with the
default
quality mark threshold of 2 and a second time with it set to 9:
   quality_mark_thresh = 9;

Then I ran the plot_point_obs command on both output files, plotting
only
PRMSL for the ADPSFC message type:

  /usr/local/met-5.2/bin/plot_point_obs gdas.20170205.t12z_qm2.nc
gdas.20170205.t12z_qm2.ps -gc 2 -msg_typ ADPSFC
  /usr/local/met-5.2/bin/plot_point_obs gdas.20170205.t12z_qm9.nc
gdas.20170205.t12z_qm9.ps -gc 2 -msg_typ ADPSFC

The first one plotted 0 locations while the second one plotted 34462
locations.  The resulting plot quality marker 9 plot is attached.

It's unfortunate that they set the quality maker for the data in this
way.
By setting quality_mark_thresh = 9 in PB2NC, you'll end up with
observations with quality markers ranging from 0 to 9.  However, in
the
Point-Stat config file, you could set the following:
   obs_quality    = [ "0", "1", "2", "9" ];

That would tell Point-Stat to only use observations who's quality flag
is
0, 1, 2, or 9... so we can skip over the 3 - 8 quality marks there.

On Wed, Feb 8, 2017 at 1:09 PM, Yongzuo Li via RT <met_help at ucar.edu>
wrote:

>
> Wed Feb 08 13:09:07 2017: Request 79390 was acted upon.
> Transaction: Ticket created by yongzuoli79 at gmail.com
>        Queue: met_help
>      Subject: point_stat
>        Owner: Nobody
>   Requestors: yongzuoli79 at gmail.com
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=79390 >
>
>
> Hi,
>
> Does anyone have a NETCDF data converted from PREPBUFR by pb2nc,
which
> contains MEAN SEA LEVEL PRESSURE?
>
> Thanks
>
> Yongzuo
>
>

------------------------------------------------
Subject: point_stat
From: Yongzuo Li
Time: Thu Feb 09 09:34:13 2017

John,

PRMSL is retained now
obs_arr =
  0, 11, 1004.3, 9.020992, 297.45,
  0, 52, 1004.3, 9.020992, 98.14411,
  0, 2, 1004.3, 9.020992, 100535.3,
  1, 32, 1004.3, 17.03965, 1.969772,

Thanks

Yongzuo

On Wed, Feb 8, 2017 at 5:51 PM, John Halley Gotway via RT
<met_help at ucar.edu
> wrote:

> Yongzuo,
>
> I believe that you can use this web GUI to request that the PREPBUFR
data
> be run through the PB2NC tool to extract the desired subset of data,
> including mean sea level pressure:
>    http://rda.ucar.edu/datasets/ds337.0/#!access
> <http://rda.ucar.edu/datasets/ds337.0/#%21access>
>
> Earlier today I answered a very similar MET-Help question about
extracting
> PRMSL observations from global GDAS files.  I'll cut-and-paste that
message
> below in hopes that it applies to your situation as well.
>
> Hope that helps.
>
> Thanks,
> John Halley Gotway
>
> I think you're likely running into a problem with the quality marker
used
> for surface data in these PREPBUFR files.  Please see the *NOTE*
about
> surface data at the bottom of this page:
>    http://www.dtcenter.org/met/users/downloads/observation_data.php
>
> Surface observations with message type ADPSFC are set to a quality
marker
> value of 9.  By default, PB2NC discards any observations whose
quality
> marker is > 2.  So PB2NC is tossing out all of the ADPSFC
observations of
> PRMSL.
>
> I grabbed a recent GDAS PREPBUFR file:
>    http://www.nco.ncep.noaa.gov/pmb/docs/on388/table2.html
>
> I configured PB2NC to retain the PRMSL observation type by adding it
to the
> "obs_grib_code" array.  Then I ran PB2NC twice... once with the
default
> quality mark threshold of 2 and a second time with it set to 9:
>    quality_mark_thresh = 9;
>
> Then I ran the plot_point_obs command on both output files, plotting
only
> PRMSL for the ADPSFC message type:
>
>   /usr/local/met-5.2/bin/plot_point_obs gdas.20170205.t12z_qm2.nc
> gdas.20170205.t12z_qm2.ps -gc 2 -msg_typ ADPSFC
>   /usr/local/met-5.2/bin/plot_point_obs gdas.20170205.t12z_qm9.nc
> gdas.20170205.t12z_qm9.ps -gc 2 -msg_typ ADPSFC
>
> The first one plotted 0 locations while the second one plotted 34462
> locations.  The resulting plot quality marker 9 plot is attached.
>
> It's unfortunate that they set the quality maker for the data in
this way.
> By setting quality_mark_thresh = 9 in PB2NC, you'll end up with
> observations with quality markers ranging from 0 to 9.  However, in
the
> Point-Stat config file, you could set the following:
>    obs_quality    = [ "0", "1", "2", "9" ];
>
> That would tell Point-Stat to only use observations who's quality
flag is
> 0, 1, 2, or 9... so we can skip over the 3 - 8 quality marks there.
>
>
> On Wed, Feb 8, 2017 at 1:09 PM, Yongzuo Li via RT
<met_help at ucar.edu>
> wrote:
>
> >
> > Wed Feb 08 13:09:07 2017: Request 79390 was acted upon.
> > Transaction: Ticket created by yongzuoli79 at gmail.com
> >        Queue: met_help
> >      Subject: point_stat
> >        Owner: Nobody
> >   Requestors: yongzuoli79 at gmail.com
> >       Status: new
> >  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=79390 >
> >
> >
> > Hi,
> >
> > Does anyone have a NETCDF data converted from PREPBUFR by pb2nc,
which
> > contains MEAN SEA LEVEL PRESSURE?
> >
> > Thanks
> >
> > Yongzuo
> >
> >
>
>

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