[Met_help] [rt.rap.ucar.edu #78314] History for the use of the fcst_thresh and obs_thresh for CTC from met_gridstat

Tue Oct 18 14:05:09 MDT 2016

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  Initial Request
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Dear Mr. or Mrs.,

IN the output from the gridstat for CTC,
there are two parameters fcst_thresh ( field 17) and obs_thresh (field 18)..
How are they used?   Are those thresh used as the top or bottom levels?
Namely, should the selected sample be larger or smaller than the thresh
values?
Can I choose either one of them?

Your clarification is appreciated.
Best Regards,
Ting

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  Complete Ticket History
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Subject: the use of the fcst_thresh and obs_thresh for CTC from met_gridstat
From: Julie Prestopnik
Time: Tue Oct 18 13:27:44 2016

Hi Ting.

The "fcst_thresh" and "obs_thresh" settings are used to define
contingency
tables from which contingency table statistics are derived.  These
settings
are applied only when computing categorical statistics and not
continuous
ones.

One thing to note is that when you're specifying thresholds for these,
the
threshold-types must be consistent.  For example, the following
thresholds would work because they partition the forecast space:
   fcst_thresh[] = [ "gt0.0 gt5.0 gt10.0" ];

However, the following would produce an error because the thresholds
overlap:
   fcst_thresh[] = [ "gt0.0 gt5.0 le10.0" ];

I hope that helps.

Please let us know if you have further questions.

Thanks,
Julie

On Tue, Oct 18, 2016 at 11:07 AM, Ting Lei - NOAA Affiliate via RT <
met_help at ucar.edu> wrote:
>
>
> Tue Oct 18 11:07:47 2016: Request 78314 was acted upon.
> Transaction: Ticket created by ting.lei at noaa.gov
>        Queue: met_help
>      Subject: the use of the fcst_thresh and obs_thresh for CTC from
met_gridstat
>        Owner: Nobody
>   Requestors: ting.lei at noaa.gov
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78314 >
>
>
> Dear Mr. or Mrs.,
>
> IN the output from the gridstat for CTC,
> there are two parameters fcst_thresh ( field 17) and obs_thresh
(field
18)..
> How are they used?   Are those thresh used as the top or bottom
levels?
> Namely, should the selected sample be larger or smaller than the
thresh
> values?
> Can I choose either one of them?
>
> Your clarification is appreciated.
> Best Regards,
> Ting
>

--
Julie Prestopnik
National Center for Atmospheric Research
Research Applications Laboratory
Phone: 303.497.8399
Email: jpresto at ucar.edu

------------------------------------------------
Subject: the use of the fcst_thresh and obs_thresh for CTC from met_gridstat
From: Ting Lei - NOAA Affiliate
Time: Tue Oct 18 13:38:21 2016

Julie,
Thank you so much for your perfect explanation.
That totally resolved my problem.

Ting

On Tue, Oct 18, 2016 at 3:27 PM, Julie Prestopnik via RT
<met_help at ucar.edu>
wrote:

> Hi Ting.
>
> The "fcst_thresh" and "obs_thresh" settings are used to define
contingency
> tables from which contingency table statistics are derived.  These
settings
> are applied only when computing categorical statistics and not
continuous
> ones.
>
> One thing to note is that when you're specifying thresholds for
these, the
> threshold-types must be consistent.  For example, the following
> thresholds would work because they partition the forecast space:
>    fcst_thresh[] = [ "gt0.0 gt5.0 gt10.0" ];
>
> However, the following would produce an error because the thresholds
> overlap:
>    fcst_thresh[] = [ "gt0.0 gt5.0 le10.0" ];
>
> I hope that helps.
>
> Please let us know if you have further questions.
>
> Thanks,
> Julie
>
> On Tue, Oct 18, 2016 at 11:07 AM, Ting Lei - NOAA Affiliate via RT <
> met_help at ucar.edu> wrote:
> >
> >
> > Tue Oct 18 11:07:47 2016: Request 78314 was acted upon.
> > Transaction: Ticket created by ting.lei at noaa.gov
> >        Queue: met_help
> >      Subject: the use of the fcst_thresh and obs_thresh for CTC
from
> met_gridstat
> >        Owner: Nobody
> >   Requestors: ting.lei at noaa.gov
> >       Status: new
> >  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78314 >
> >
> >
> > Dear Mr. or Mrs.,
> >
> > IN the output from the gridstat for CTC,
> > there are two parameters fcst_thresh ( field 17) and obs_thresh
(field
> 18)..
> > How are they used?   Are those thresh used as the top or bottom
levels?
> > Namely, should the selected sample be larger or smaller than the
thresh
> > values?
> > Can I choose either one of them?
> >
> > Your clarification is appreciated.
> > Best Regards,
> > Ting
> >
>
>
>
> --
> Julie Prestopnik
> National Center for Atmospheric Research
> Research Applications Laboratory
> Phone: 303.497.8399
> Email: jpresto at ucar.edu
>
>

------------------------------------------------
Subject: the use of the fcst_thresh and obs_thresh for CTC from met_gridstat
From: Julie Prestopnik
Time: Tue Oct 18 13:47:49 2016

Great!  Thank you for letting us know.

Julie

On Tue, Oct 18, 2016 at 1:38 PM, Ting Lei - NOAA Affiliate via RT <
met_help at ucar.edu> wrote:

>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78314 >
>
> Julie,
> Thank you so much for your perfect explanation.
> That totally resolved my problem.
>
> Ting
>
> On Tue, Oct 18, 2016 at 3:27 PM, Julie Prestopnik via RT <
> met_help at ucar.edu>
> wrote:
>
> > Hi Ting.
> >
> > The "fcst_thresh" and "obs_thresh" settings are used to define
> contingency
> > tables from which contingency table statistics are derived.  These
> settings
> > are applied only when computing categorical statistics and not
continuous
> > ones.
> >
> > One thing to note is that when you're specifying thresholds for
these,
> the
> > threshold-types must be consistent.  For example, the following
> > thresholds would work because they partition the forecast space:
> >    fcst_thresh[] = [ "gt0.0 gt5.0 gt10.0" ];
> >
> > However, the following would produce an error because the
thresholds
> > overlap:
> >    fcst_thresh[] = [ "gt0.0 gt5.0 le10.0" ];
> >
> > I hope that helps.
> >
> > Please let us know if you have further questions.
> >
> > Thanks,
> > Julie
> >
> > On Tue, Oct 18, 2016 at 11:07 AM, Ting Lei - NOAA Affiliate via RT
<
> > met_help at ucar.edu> wrote:
> > >
> > >
> > > Tue Oct 18 11:07:47 2016: Request 78314 was acted upon.
> > > Transaction: Ticket created by ting.lei at noaa.gov
> > >        Queue: met_help
> > >      Subject: the use of the fcst_thresh and obs_thresh for CTC
from
> > met_gridstat
> > >        Owner: Nobody
> > >   Requestors: ting.lei at noaa.gov
> > >       Status: new
> > >  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78314
> >
> > >
> > >
> > > Dear Mr. or Mrs.,
> > >
> > > IN the output from the gridstat for CTC,
> > > there are two parameters fcst_thresh ( field 17) and obs_thresh
(field
> > 18)..
> > > How are they used?   Are those thresh used as the top or bottom
levels?
> > > Namely, should the selected sample be larger or smaller than the
thresh
> > > values?
> > > Can I choose either one of them?
> > >
> > > Your clarification is appreciated.
> > > Best Regards,
> > > Ting
> > >
> >
> >
> >
> > --
> > Julie Prestopnik
> > National Center for Atmospheric Research
> > Research Applications Laboratory
> > Phone: 303.497.8399
> > Email: jpresto at ucar.edu
> >
> >
>
>

--
Julie Prestopnik
National Center for Atmospheric Research
Research Applications Laboratory
Phone: 303.497.8399
Email: jpresto at ucar.edu

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