[Met_help] [rt.rap.ucar.edu #41643] History for Verifying Wind Direction with Point Stat
RAL HelpDesk {for John Halley Gotway}
met_help at ucar.edu
Fri Oct 22 11:45:21 MDT 2010
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Initial Request
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In the process of verifying 5-min average winds using point observations (tower data) I would like to use UGRD/VGRD along with WIND and WDIR. I have all four quantities available in both the GRIB-format WRF output and the obs data. When I specify these fields in the PointStatConfig file I get the error message...
-> the wind direction field may not be verified using point_stat.
I see in the documentation that wind direction is done in Stat-Anal as long as the vector partial sums (VL1L2) for UGRD and VGRD are computed in the previous step (Point-Stat in my case). Based on earlier exchanges with met-help (John) regarding these 5-min winds, it was suggested that I have Point-Stat write out matched pair (MPR) line types and compute statistics using Stat-Anal. If I do that I assume I have to eliminate WDIR (and maybe WIND too??) from my PointStatConfig file, but how can I then get Stat-Anal to verify the wind direction if I haven't already generated the vector partial sums?
Many thanks,
Scott
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Complete Ticket History
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Subject: Re: [rt.rap.ucar.edu #41643] Verifying Wind Direction with Point Stat
From: John Halley Gotway
Time: Thu Oct 21 11:38:24 2010
Scott,
Yes, good question. Verifying wind direction is tricky, and we're not
completely satisfied with the support we've provided in MET. But to
answer your questions...
You can verify UGRD, VGRD, and WIND (wind speed) in exactly the way we
discussed. All three are just scalar fields, and MET will treat them
the same way.
You're right (I forgot about this wrinkle), you won't be able to look
at wind direction errors in STAT-Analysis unless you dump out the
VL1L2 lines in Point-Stat. In the output_flag column, turn on
the output of the VL1L2 line. You'll have some pretty basic VL1L2
lines for each run consisting of a single point! But then you will be
able to run STAT-Analysis jobs on them the aggregate them
through time and compute errors in wind direction.
Let me know if any more questions arise.
Thanks,
John
On 10/20/2010 12:22 PM, RAL HelpDesk {for Dembek, Scott
Robert[Universities Space Research Association]} wrote:
>
> Wed Oct 20 12:22:00 2010: Request 41643 was acted upon.
> Transaction: Ticket created by scott.r.dembek at nasa.gov
> Queue: met_help
> Subject: Verifying Wind Direction with Point Stat
> Owner: Nobody
> Requestors: scott.r.dembek at nasa.gov
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=41643 >
>
>
> In the process of verifying 5-min average winds using point
observations (tower data) I would like to use UGRD/VGRD along with
WIND and WDIR. I have all four quantities available in both the GRIB-
format WRF output and the obs data. When I specify these fields in
the PointStatConfig file I get the error message...
>
> -> the wind direction field may not be verified using point_stat.
>
> I see in the documentation that wind direction is done in Stat-Anal
as long as the vector partial sums (VL1L2) for UGRD and VGRD are
computed in the previous step (Point-Stat in my case). Based on
earlier exchanges with met-help (John) regarding these 5-min winds, it
was suggested that I have Point-Stat write out matched pair (MPR) line
types and compute statistics using Stat-Anal. If I do that I assume I
have to eliminate WDIR (and maybe WIND too??) from my PointStatConfig
file, but how can I then get Stat-Anal to verify the wind direction if
I haven't already generated the vector partial sums?
>
> Many thanks,
> Scott
>
------------------------------------------------
Subject: Verifying Wind Direction with Point Stat
From: Dembek, Scott Robert[Universities Space Research Association]
Time: Fri Oct 22 09:43:33 2010
John, thanks for the explanation. I'll give that a try and email met-
help again if I have additional questions.
Regards,
Scott
________________________________
From: RAL HelpDesk {for John Halley Gotway} [met_help at ucar.edu]
Sent: Thursday, October 21, 2010 1:38 PM
To: Dembek, Scott Robert (MSFC-VP61)[Universities Space Research
Association (USRA)]
Subject: Re: [rt.rap.ucar.edu #41643] Verifying Wind Direction with
Point Stat
Scott,
Yes, good question. Verifying wind direction is tricky, and we're not
completely satisfied with the support we've provided in MET. But to
answer your questions...
You can verify UGRD, VGRD, and WIND (wind speed) in exactly the way we
discussed. All three are just scalar fields, and MET will treat them
the same way.
You're right (I forgot about this wrinkle), you won't be able to look
at wind direction errors in STAT-Analysis unless you dump out the
VL1L2 lines in Point-Stat. In the output_flag column, turn on
the output of the VL1L2 line. You'll have some pretty basic VL1L2
lines for each run consisting of a single point! But then you will be
able to run STAT-Analysis jobs on them the aggregate them
through time and compute errors in wind direction.
Let me know if any more questions arise.
Thanks,
John
On 10/20/2010 12:22 PM, RAL HelpDesk {for Dembek, Scott
Robert[Universities Space Research Association]} wrote:
>
> Wed Oct 20 12:22:00 2010: Request 41643 was acted upon.
> Transaction: Ticket created by scott.r.dembek at nasa.gov
> Queue: met_help
> Subject: Verifying Wind Direction with Point Stat
> Owner: Nobody
> Requestors: scott.r.dembek at nasa.gov
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=41643 >
>
>
> In the process of verifying 5-min average winds using point
observations (tower data) I would like to use UGRD/VGRD along with
WIND and WDIR. I have all four quantities available in both the GRIB-
format WRF output and the obs data. When I specify these fields in
the PointStatConfig file I get the error message...
>
> -> the wind direction field may not be verified using point_stat.
>
> I see in the documentation that wind direction is done in Stat-Anal
as long as the vector partial sums (VL1L2) for UGRD and VGRD are
computed in the previous step (Point-Stat in my case). Based on
earlier exchanges with met-help (John) regarding these 5-min winds, it
was suggested that I have Point-Stat write out matched pair (MPR) line
types and compute statistics using Stat-Anal. If I do that I assume I
have to eliminate WDIR (and maybe WIND too??) from my PointStatConfig
file, but how can I then get Stat-Anal to verify the wind direction if
I haven't already generated the vector partial sums?
>
> Many thanks,
> Scott
>
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