[Met_help] [rt.rap.ucar.edu #80393] History for Verification of visibility in MET
John Halley Gotway via RT
met_help at ucar.edu
Wed May 10 12:05:50 MDT 2017
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Initial Request
----------------------------------------------------------------
Hi, there,
I am trying to figure out how to verify visibility in MET. In the Point
Stat config file, I have this block:
{
name = "VIS";
level = "Z0";
cat_thresh = [ >=800, >=1600, >=8046, >=16090 ];
};
I am guessing the issue comes in the level identifier, as visibility is not
a surface value but a column value. Can you show me what value to use for
level for visibility?
Alternatively the problem may lie in the PB2NC code. I have this line in
the PB2NC config file:
obs_grib_code = [ "SPFH", "TMP", "UGRD", "VGRD", "WIND", "RH", "HGT",
"DPT", "TCDC", "VIS", "PRMSL" ];
I think this is asking for the grib code (even though it is for obs) so I
put in "VIS", the grib code, for visibility, rather than the bufr code for
visibility, which is "HOVI". I want to confirm which is correct for this
code, HOVI or VIS.
Thanks!
Perry
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Complete Ticket History
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Subject: Verification of visibility in MET
From: John Halley Gotway
Time: Tue May 09 09:38:37 2017
Perry,
I see that you have questions about verifying visibility in Point-
Stat.
First, you're wondering how to specify the level value for visibility.
The
answer really just depends on how the GRIB record is encoded. I
usually
use wgrib or wgrib2 along with the plot_data_plane tool to figure
these
sorts of things out. You could either send me a sample data file that
you're using or point me to one online or on theia.
As for PB2NC, currently the PB2NC tools is only pulling observations
of
type P, Q, T, Z, U, V for pressure specific humidity, temperature,
height,
and U/V wind. Additionally, from these variables, it has the ability
to
derive dewpoint (DPT), wind speed (WIND), relative humidity (RH),
mixing
ratio (MIXR), and mean sea level pressure (PRMSL).
Visibility is not one of the variables PB2NC can extract or derive.
For
MET version 6.1, we do have a developer taking a closer look at
BUFRLIB
with the goal of extracting all available observation types. To your
knowledge, should visibility live directly in that PREPBUFR file or
does it
need to be derived from other variables? If you can point me to any
existing code you guys use to extract/derive these additional obs
types, I
can pass them along to our developer.
Thanks,
John
On Tue, May 9, 2017 at 8:45 AM, perry.shafran at noaa.gov via RT <
met_help at ucar.edu> wrote:
>
> Tue May 09 08:45:15 2017: Request 80393 was acted upon.
> Transaction: Ticket created by perry.shafran at noaa.gov
> Queue: met_help
> Subject: Verification of visibility in MET
> Owner: Nobody
> Requestors: perry.shafran at noaa.gov
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=80393 >
>
>
> Hi, there,
>
> I am trying to figure out how to verify visibility in MET. In the
Point
> Stat config file, I have this block:
>
> {
> name = "VIS";
> level = "Z0";
> cat_thresh = [ >=800, >=1600, >=8046, >=16090 ];
> };
>
> I am guessing the issue comes in the level identifier, as visibility
is not
> a surface value but a column value. Can you show me what value to
use for
> level for visibility?
>
> Alternatively the problem may lie in the PB2NC code. I have this
line in
> the PB2NC config file:
>
> obs_grib_code = [ "SPFH", "TMP", "UGRD", "VGRD", "WIND", "RH",
"HGT",
> "DPT", "TCDC", "VIS", "PRMSL" ];
>
> I think this is asking for the grib code (even though it is for obs)
so I
> put in "VIS", the grib code, for visibility, rather than the bufr
code for
> visibility, which is "HOVI". I want to confirm which is correct for
this
> code, HOVI or VIS.
>
> Thanks!
>
> Perry
>
>
------------------------------------------------
Subject: Verification of visibility in MET
From: perry.shafran at noaa.gov
Time: Tue May 09 09:46:20 2017
Hi, John,
Oh! I thought that PB2NC already pulls all the data off the prepbufr
file
except the ones that need to be derived (like CAPE or PBL height).
Visibility is relatively simple to pull off the prepbufr file. It
does not
have to be derived. It is a single-level variable, and you should use
the
same extraction subroutine that is used to pull the other stuff off,
with
the mnemonic being HOVI, and the units of HOVI in the bufr file is
meters.
As for the grib data, I was wrong, visibility is labelled as a
"surface"
dataset, so I guess for data at the surface, the level would be Z0? I
guess I wasn't getting any data because PB2NC isn't reading visibility
at
this time.
I guess that kind of answers my questions for now. I guess we'll have
to
wait until later for the PB2NC development to be able to extract
visibility.
Thanks!
Perry
On Tue, May 9, 2017 at 11:38 AM, John Halley Gotway via RT <
met_help at ucar.edu> wrote:
> Perry,
>
> I see that you have questions about verifying visibility in Point-
Stat.
> First, you're wondering how to specify the level value for
visibility. The
> answer really just depends on how the GRIB record is encoded. I
usually
> use wgrib or wgrib2 along with the plot_data_plane tool to figure
these
> sorts of things out. You could either send me a sample data file
that
> you're using or point me to one online or on theia.
>
> As for PB2NC, currently the PB2NC tools is only pulling observations
of
> type P, Q, T, Z, U, V for pressure specific humidity, temperature,
height,
> and U/V wind. Additionally, from these variables, it has the
ability to
> derive dewpoint (DPT), wind speed (WIND), relative humidity (RH),
mixing
> ratio (MIXR), and mean sea level pressure (PRMSL).
>
> Visibility is not one of the variables PB2NC can extract or derive.
For
> MET version 6.1, we do have a developer taking a closer look at
BUFRLIB
> with the goal of extracting all available observation types. To
your
> knowledge, should visibility live directly in that PREPBUFR file or
does it
> need to be derived from other variables? If you can point me to any
> existing code you guys use to extract/derive these additional obs
types, I
> can pass them along to our developer.
>
> Thanks,
> John
>
>
> On Tue, May 9, 2017 at 8:45 AM, perry.shafran at noaa.gov via RT <
> met_help at ucar.edu> wrote:
>
> >
> > Tue May 09 08:45:15 2017: Request 80393 was acted upon.
> > Transaction: Ticket created by perry.shafran at noaa.gov
> > Queue: met_help
> > Subject: Verification of visibility in MET
> > Owner: Nobody
> > Requestors: perry.shafran at noaa.gov
> > Status: new
> > Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=80393 >
> >
> >
> > Hi, there,
> >
> > I am trying to figure out how to verify visibility in MET. In the
Point
> > Stat config file, I have this block:
> >
> > {
> > name = "VIS";
> > level = "Z0";
> > cat_thresh = [ >=800, >=1600, >=8046, >=16090 ];
> > };
> >
> > I am guessing the issue comes in the level identifier, as
visibility is
> not
> > a surface value but a column value. Can you show me what value to
use
> for
> > level for visibility?
> >
> > Alternatively the problem may lie in the PB2NC code. I have this
line in
> > the PB2NC config file:
> >
> > obs_grib_code = [ "SPFH", "TMP", "UGRD", "VGRD", "WIND", "RH",
"HGT",
> > "DPT", "TCDC", "VIS", "PRMSL" ];
> >
> > I think this is asking for the grib code (even though it is for
obs) so I
> > put in "VIS", the grib code, for visibility, rather than the bufr
code
> for
> > visibility, which is "HOVI". I want to confirm which is correct
for this
> > code, HOVI or VIS.
> >
> > Thanks!
> >
> > Perry
> >
> >
>
>
------------------------------------------------
Subject: Verification of visibility in MET
From: John Halley Gotway
Time: Wed May 10 12:05:38 2017
Perry,
Sounds good. Yes, we're working on extracting/deriving additional
observation data types in PB2NC for the next release. We'll let you
know
what questions come up... having your expertise will help a lot as we
work
to enhance MET to meet the needs at NCEP.
Thanks,
John
On Tue, May 9, 2017 at 9:46 AM, perry.shafran at noaa.gov via RT <
met_help at ucar.edu> wrote:
>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=80393 >
>
> Hi, John,
>
> Oh! I thought that PB2NC already pulls all the data off the
prepbufr file
> except the ones that need to be derived (like CAPE or PBL height).
> Visibility is relatively simple to pull off the prepbufr file. It
does not
> have to be derived. It is a single-level variable, and you should
use the
> same extraction subroutine that is used to pull the other stuff off,
with
> the mnemonic being HOVI, and the units of HOVI in the bufr file is
meters.
>
> As for the grib data, I was wrong, visibility is labelled as a
"surface"
> dataset, so I guess for data at the surface, the level would be Z0?
I
> guess I wasn't getting any data because PB2NC isn't reading
visibility at
> this time.
>
> I guess that kind of answers my questions for now. I guess we'll
have to
> wait until later for the PB2NC development to be able to extract
> visibility.
>
> Thanks!
>
> Perry
>
> On Tue, May 9, 2017 at 11:38 AM, John Halley Gotway via RT <
> met_help at ucar.edu> wrote:
>
> > Perry,
> >
> > I see that you have questions about verifying visibility in Point-
Stat.
> > First, you're wondering how to specify the level value for
visibility.
> The
> > answer really just depends on how the GRIB record is encoded. I
usually
> > use wgrib or wgrib2 along with the plot_data_plane tool to figure
these
> > sorts of things out. You could either send me a sample data file
that
> > you're using or point me to one online or on theia.
> >
> > As for PB2NC, currently the PB2NC tools is only pulling
observations of
> > type P, Q, T, Z, U, V for pressure specific humidity, temperature,
> height,
> > and U/V wind. Additionally, from these variables, it has the
ability to
> > derive dewpoint (DPT), wind speed (WIND), relative humidity (RH),
mixing
> > ratio (MIXR), and mean sea level pressure (PRMSL).
> >
> > Visibility is not one of the variables PB2NC can extract or
derive. For
> > MET version 6.1, we do have a developer taking a closer look at
BUFRLIB
> > with the goal of extracting all available observation types. To
your
> > knowledge, should visibility live directly in that PREPBUFR file
or does
> it
> > need to be derived from other variables? If you can point me to
any
> > existing code you guys use to extract/derive these additional obs
types,
> I
> > can pass them along to our developer.
> >
> > Thanks,
> > John
> >
> >
> > On Tue, May 9, 2017 at 8:45 AM, perry.shafran at noaa.gov via RT <
> > met_help at ucar.edu> wrote:
> >
> > >
> > > Tue May 09 08:45:15 2017: Request 80393 was acted upon.
> > > Transaction: Ticket created by perry.shafran at noaa.gov
> > > Queue: met_help
> > > Subject: Verification of visibility in MET
> > > Owner: Nobody
> > > Requestors: perry.shafran at noaa.gov
> > > Status: new
> > > Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=80393
> >
> > >
> > >
> > > Hi, there,
> > >
> > > I am trying to figure out how to verify visibility in MET. In
the
> Point
> > > Stat config file, I have this block:
> > >
> > > {
> > > name = "VIS";
> > > level = "Z0";
> > > cat_thresh = [ >=800, >=1600, >=8046, >=16090 ];
> > > };
> > >
> > > I am guessing the issue comes in the level identifier, as
visibility is
> > not
> > > a surface value but a column value. Can you show me what value
to use
> > for
> > > level for visibility?
> > >
> > > Alternatively the problem may lie in the PB2NC code. I have
this line
> in
> > > the PB2NC config file:
> > >
> > > obs_grib_code = [ "SPFH", "TMP", "UGRD", "VGRD", "WIND", "RH",
"HGT",
> > > "DPT", "TCDC", "VIS", "PRMSL" ];
> > >
> > > I think this is asking for the grib code (even though it is for
obs)
> so I
> > > put in "VIS", the grib code, for visibility, rather than the
bufr code
> > for
> > > visibility, which is "HOVI". I want to confirm which is correct
for
> this
> > > code, HOVI or VIS.
> > >
> > > Thanks!
> > >
> > > Perry
> > >
> > >
> >
> >
>
>
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