[Met_help] [rt.rap.ucar.edu #86517] History for Wind Speed Derivation Question

John Halley Gotway via RT met_help at ucar.edu
Tue Jul 9 12:07:33 MDT 2019 

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  Initial Request
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Hi,

Does MET grid_stat have the capability to read in gridded U and V wind fields (both in GriB2 format) to verify against a single wind speed field (also in GriB2)?

I've some across a mismatch in available fields and trying to decide the best way to handle it.  If I need to calculate the wind speed field separately, I'll go that route, but I'm hoping MET has logic to handle it.

Thanks,
Matt

Matthew C. Sittel, Meteorologist
University Corporation for Atmospheric Research
Matthew.Sittel.ctr at us.af.mil





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  Complete Ticket History
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Subject: Wind Speed Derivation Question
From: John Halley Gotway
Time: Wed Aug 08 10:53:08 2018

Matt,

Good news, yes, MET does include logic for deriving wind speed on the
fly.
If you request "WIND" (for wind speed), it first checks the file for
that
variable.  If present, it uses it directly.  If not, it searches for
the
corresponding U and V components of wind and uses them to derive it on
the
fly.

But... and this is a big caveat... this logic currently only works for
NCEP's GRIB table usage, where wind speed = "WIND", u-wind = "UGRD",
and
v-wind = "VGRD".  This logic will not work for ECMWF conventions where
wind
speed = "WS", u-wind = "U", and v-wind = "V".

Thanks,
John





On Wed, Aug 8, 2018 at 8:33 AM SITTEL, MATTHEW C CTR USAF AFWA 16
WS/WXN
via RT <met_help at ucar.edu> wrote:

>
> Wed Aug 08 08:33:19 2018: Request 86517 was acted upon.
> Transaction: Ticket created by matthew.sittel.ctr at us.af.mil
>        Queue: met_help
>      Subject: Wind Speed Derivation Question
>        Owner: Nobody
>   Requestors: matthew.sittel.ctr at us.af.mil
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=86517 >
>
>
> Hi,
>
> Does MET grid_stat have the capability to read in gridded U and V
wind
> fields (both in GriB2 format) to verify against a single wind speed
field
> (also in GriB2)?
>
> I've some across a mismatch in available fields and trying to decide
the
> best way to handle it.  If I need to calculate the wind speed field
> separately, I'll go that route, but I'm hoping MET has logic to
handle it.
>
> Thanks,
> Matt
>
> Matthew C. Sittel, Meteorologist
> University Corporation for Atmospheric Research
> Matthew.Sittel.ctr at us.af.mil
>
>
>
>
>

------------------------------------------------
Subject: RE: [Non-DoD Source] Re: [rt.rap.ucar.edu #86517] Wind Speed Derivation Question
From: SITTEL, MATTHEW C CTR USAF AFWA 16 WS/WXN
Time: Wed Aug 08 10:59:37 2018

Hey John,

I'd be using it for GFS and NAVGEM ensemble members.  Both have UGRD
and VGRD listed so it should work.  They will be compared against
"WIND" in a GALWEM 0.25-degree global analysis file.

So I'd put in "WIND,P850" for the variable and it will search for
"UGRD,P850" and "VGRD,P850" in the same file?  That would work great.

Our system is down now, but when it comes back up I'll give it a try.

Thanks!
Matt

-----Original Message-----
From: John Halley Gotway via RT [mailto:met_help at ucar.edu]
Sent: Wednesday, August 8, 2018 11:53 AM
To: SITTEL, MATTHEW C CTR USAF AFMC AFLCMC/HBAW-OL
<matthew.sittel.ctr at us.af.mil>
Subject: [Non-DoD Source] Re: [rt.rap.ucar.edu #86517] Wind Speed
Derivation Question

Matt,

Good news, yes, MET does include logic for deriving wind speed on the
fly.
If you request "WIND" (for wind speed), it first checks the file for
that variable.  If present, it uses it directly.  If not, it searches
for the corresponding U and V components of wind and uses them to
derive it on the fly.

But... and this is a big caveat... this logic currently only works for
NCEP's GRIB table usage, where wind speed = "WIND", u-wind = "UGRD",
and v-wind = "VGRD".  This logic will not work for ECMWF conventions
where wind speed = "WS", u-wind = "U", and v-wind = "V".

Thanks,
John





On Wed, Aug 8, 2018 at 8:33 AM SITTEL, MATTHEW C CTR USAF AFWA 16
WS/WXN via RT <met_help at ucar.edu> wrote:

>
> Wed Aug 08 08:33:19 2018: Request 86517 was acted upon.
> Transaction: Ticket created by matthew.sittel.ctr at us.af.mil
>        Queue: met_help
>      Subject: Wind Speed Derivation Question
>        Owner: Nobody
>   Requestors: matthew.sittel.ctr at us.af.mil
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=86517
> >
>
>
> Hi,
>
> Does MET grid_stat have the capability to read in gridded U and V
wind
> fields (both in GriB2 format) to verify against a single wind speed
> field (also in GriB2)?
>
> I've some across a mismatch in available fields and trying to decide
> the best way to handle it.  If I need to calculate the wind speed
> field separately, I'll go that route, but I'm hoping MET has logic
to handle it.
>
> Thanks,
> Matt
>
> Matthew C. Sittel, Meteorologist
> University Corporation for Atmospheric Research
> Matthew.Sittel.ctr at us.af.mil
>
>
>
>
>



------------------------------------------------
Subject: Wind Speed Derivation Question
From: John Halley Gotway
Time: Wed Aug 08 11:23:14 2018

Matt,

Yes, that's correct.  For starters, I'd suggest running the
plot_data_plane
tool to test this out:

   plot_data_plane in.grb2 plot_wind.ps 'name="WIND"; level="P850";'
-v 3

Running at -v 3 logging level will print log messages telling you that
it's
deriving wind speed from U and V.

John

On Wed, Aug 8, 2018 at 11:00 AM SITTEL, MATTHEW C CTR USAF AFWA 16
WS/WXN
via RT <met_help at ucar.edu> wrote:

>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=86517 >
>
> Hey John,
>
> I'd be using it for GFS and NAVGEM ensemble members.  Both have UGRD
and
> VGRD listed so it should work.  They will be compared against "WIND"
in a
> GALWEM 0.25-degree global analysis file.
>
> So I'd put in "WIND,P850" for the variable and it will search for
> "UGRD,P850" and "VGRD,P850" in the same file?  That would work
great.
>
> Our system is down now, but when it comes back up I'll give it a
try.
>
> Thanks!
> Matt
>
> -----Original Message-----
> From: John Halley Gotway via RT [mailto:met_help at ucar.edu]
> Sent: Wednesday, August 8, 2018 11:53 AM
> To: SITTEL, MATTHEW C CTR USAF AFMC AFLCMC/HBAW-OL <
> matthew.sittel.ctr at us.af.mil>
> Subject: [Non-DoD Source] Re: [rt.rap.ucar.edu #86517] Wind Speed
> Derivation Question
>
> Matt,
>
> Good news, yes, MET does include logic for deriving wind speed on
the fly.
> If you request "WIND" (for wind speed), it first checks the file for
that
> variable.  If present, it uses it directly.  If not, it searches for
the
> corresponding U and V components of wind and uses them to derive it
on the
> fly.
>
> But... and this is a big caveat... this logic currently only works
for
> NCEP's GRIB table usage, where wind speed = "WIND", u-wind = "UGRD",
and
> v-wind = "VGRD".  This logic will not work for ECMWF conventions
where wind
> speed = "WS", u-wind = "U", and v-wind = "V".
>
> Thanks,
> John
>
>
>
>
>
> On Wed, Aug 8, 2018 at 8:33 AM SITTEL, MATTHEW C CTR USAF AFWA 16
WS/WXN
> via RT <met_help at ucar.edu> wrote:
>
> >
> > Wed Aug 08 08:33:19 2018: Request 86517 was acted upon.
> > Transaction: Ticket created by matthew.sittel.ctr at us.af.mil
> >        Queue: met_help
> >      Subject: Wind Speed Derivation Question
> >        Owner: Nobody
> >   Requestors: matthew.sittel.ctr at us.af.mil
> >       Status: new
> >  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=86517
> > >
> >
> >
> > Hi,
> >
> > Does MET grid_stat have the capability to read in gridded U and V
wind
> > fields (both in GriB2 format) to verify against a single wind
speed
> > field (also in GriB2)?
> >
> > I've some across a mismatch in available fields and trying to
decide
> > the best way to handle it.  If I need to calculate the wind speed
> > field separately, I'll go that route, but I'm hoping MET has logic
to
> handle it.
> >
> > Thanks,
> > Matt
> >
> > Matthew C. Sittel, Meteorologist
> > University Corporation for Atmospheric Research
> > Matthew.Sittel.ctr at us.af.mil
> >
> >
> >
> >
> >
>
>
>
>

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