[Met_help] [rt.rap.ucar.edu #78579] History for Point-Stat question
John Halley Gotway via RT
met_help at ucar.edu
Fri Nov 4 09:57:48 MDT 2016
----------------------------------------------------------------
Initial Request
----------------------------------------------------------------
My config file specifies the following in the "Forecast and observation fields to be verified" section:
field = [
{
name = "TMP";
level = [ "P100-225" ];
cat_thresh = [ >273.0 ];
},
The model output GRIB file (valid at 1200 UTC) contains output at the pressure levels 100, 150, and 200 mb all of which contain TMP FCST output.
The Point-Stat MPR file shows that there are 10 TMP observations in the layer P100-225.
The Point-Stat CNT file shows that TMP error statistics for the layer P100-225 were calculated using 10 matched pairs (TOTAL).
What model pressure level(s) was used to provide the FCST values used in the error statistics?
Another related question:
In cases where I have specified a layer (in pressure) P625-775 for verification, followed by another layer (P775-875) for verification, the model output contains the pressure level of 775mb. Which layer will the model output be used?
Thanks.
R/
John
----------------------------------------------------------------
Complete Ticket History
----------------------------------------------------------------
Subject: Point-Stat question
From: John Halley Gotway
Time: Thu Nov 03 16:28:24 2016
John,
I see that you have a question about how Point-Stat does
interpolation/matching in the vertical coordinate. The answer is
pretty
simple and you have some control over it based on how you set up the
config
file.
First, there's a brief description in section 7.2.1 of the MET User's
Guide
(http://www.dtcenter.org/met/users/docs/users_guide/MET_Users_Guide_v5.2.pdf)
but let's work through your first example:
(1) You have model output at 100, 150, and 200 mb.
(2) You're verifying the level "P100-225" in *both* the forecast and
observation field setting.
Since you've defined the forecast level as a range, it'll step through
all
the forecast levels and read all 3 levels falling within that range
into
memory (100, 150, and 200). Then it'll read through all the
observations
and only keep those that fall within the observation level range
(which is
also 100-225).
- For an observation at 200mb, it sees that exactly matches a forecast
level. So it'll do horizontal interpolation at 200mb and no vertical
interpolation.
- For an observation at 115mb, it'll do horizontal interpolation for
the
level above (100) and below (200). Then it interpolates those values
above/below to 115mb linear in the log of pressure.
- For an observation at 225mb, it finds a level above it (200) but
none
below. So it'll do horizontal interpolation at 200mb and use that
value
as-is, with no vertical interpolation.
I want to emphasize that the forecast and observation level settings
do not
need to be the same. Here are two examples...
(1) Set fcst -> level = [ "P100-250" ]; and obs -> level = [ "P100-
225" ];
Assuming 250mb is another forecast level, this will give more forecast
data
to Point-Stat to use in vertical interpolation. An observation at
225mb
will be interpolated between the 200 and 250 forecast levels. But
only
observations in the range 100-225 will be used. You need to pass
Point-Stat all the forecast levels that you'd like it to use for
vertical
interpolation.
(2) Set fcst -> level = [ "P100", "P200", "P300" ]; and obs -> level =
[
"P75-125", "P175-225", "P275-325" ];
This will perform 3 different verification tasks. For each, only one
forecast level is used (100, 200, or 300), but the observation level
is
defined as a range. For example, all observations between 75 and 125
will
be compared to the forecast values at 100mb. And so on.
So tweaking the level settings in the config file impacts how the
forecast
and observation data is matched up in the vertical.
Hope that helps.
Thanks,
John
On Thu, Nov 3, 2016 at 9:57 AM, Raby, John W USA CIV via RT <
met_help at ucar.edu> wrote:
>
> Thu Nov 03 09:57:10 2016: Request 78579 was acted upon.
> Transaction: Ticket created by john.w.raby2.civ at mail.mil
> Queue: met_help
> Subject: Point-Stat question
> Owner: Nobody
> Requestors: john.w.raby2.civ at mail.mil
> Status: new
> Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78579 >
>
>
> My config file specifies the following in the "Forecast and
observation
> fields to be verified" section:
>
> field = [
> {
> name = "TMP";
> level = [ "P100-225" ];
> cat_thresh = [ >273.0 ];
> },
>
> The model output GRIB file (valid at 1200 UTC) contains output at
the
> pressure levels 100, 150, and 200 mb all of which contain TMP FCST
output.
>
> The Point-Stat MPR file shows that there are 10 TMP observations in
the
> layer P100-225.
>
> The Point-Stat CNT file shows that TMP error statistics for the
layer
> P100-225 were calculated using 10 matched pairs (TOTAL).
>
> What model pressure level(s) was used to provide the FCST values
used in
> the error statistics?
>
> Another related question:
>
> In cases where I have specified a layer (in pressure) P625-775 for
> verification, followed by another layer (P775-875) for verification,
the
> model output contains the pressure level of 775mb. Which layer will
the
> model output be used?
>
> Thanks.
>
> R/
> John
>
>
>
>
------------------------------------------------
Subject: Point-Stat question
From: Raby, John W USA CIV
Time: Thu Nov 03 16:56:10 2016
CLASSIFICATION: UNCLASSIFIED
John -
Thanks for providing more detailed info on this. I need to think about
what I
would do given the info you provided on how to be more specific about
the
config file settings. My take on the way my current setting is working
is that
the error stats for the layer P100-225 are evaluating the model output
for
potentially all 3 model pressure levels depending on the levels of the
observations. I'm leaving for the day, shortly, so I don't have time
for
follow-up. I won't be back in the office until 08 NOV. I think you've
provided
all I needed to know.
R/
John
-----Original Message-----
From: John Halley Gotway via RT [mailto:met_help at ucar.edu]
Sent: Thursday, November 03, 2016 4:28 PM
To: Raby, John W CIV USARMY RDECOM ARL (US)
<john.w.raby2.civ at mail.mil>
Subject: [Non-DoD Source] Re: [rt.rap.ucar.edu #78579] Point-Stat
question
All active links contained in this email were disabled. Please verify
the
identity of the sender, and confirm the authenticity of all links
contained
within the message prior to copying and pasting the address to a Web
browser.
----
John,
I see that you have a question about how Point-Stat does
interpolation/matching in the vertical coordinate. The answer is
pretty
simple and you have some control over it based on how you set up the
config
file.
First, there's a brief description in section 7.2.1 of the MET User's
Guide
(Caution-
http://www.dtcenter.org/met/users/docs/users_guide/MET_Users_Guide_v5.2.pdf)
but let's work through your first example:
(1) You have model output at 100, 150, and 200 mb.
(2) You're verifying the level "P100-225" in *both* the forecast and
observation field setting.
Since you've defined the forecast level as a range, it'll step through
all the
forecast levels and read all 3 levels falling within that range into
memory
(100, 150, and 200). Then it'll read through all the observations and
only
keep those that fall within the observation level range (which is also
100-225).
- For an observation at 200mb, it sees that exactly matches a forecast
level.
So it'll do horizontal interpolation at 200mb and no vertical
interpolation.
- For an observation at 115mb, it'll do horizontal interpolation for
the level
above (100) and below (200). Then it interpolates those values
above/below to
115mb linear in the log of pressure.
- For an observation at 225mb, it finds a level above it (200) but
none below.
So it'll do horizontal interpolation at 200mb and use that value as-
is, with
no vertical interpolation.
I want to emphasize that the forecast and observation level settings
do not
need to be the same. Here are two examples...
(1) Set fcst -> level = [ "P100-250" ]; and obs -> level = [ "P100-
225" ];
Assuming 250mb is another forecast level, this will give more forecast
data to
Point-Stat to use in vertical interpolation. An observation at 225mb
will be
interpolated between the 200 and 250 forecast levels. But only
observations
in the range 100-225 will be used. You need to pass Point-Stat all
the
forecast levels that you'd like it to use for vertical interpolation.
(2) Set fcst -> level = [ "P100", "P200", "P300" ]; and obs -> level =
[
"P75-125", "P175-225", "P275-325" ]; This will perform 3 different
verification tasks. For each, only one forecast level is used (100,
200, or
300), but the observation level is defined as a range. For example,
all
observations between 75 and 125 will be compared to the forecast
values at
100mb. And so on.
So tweaking the level settings in the config file impacts how the
forecast and
observation data is matched up in the vertical.
Hope that helps.
Thanks,
John
On Thu, Nov 3, 2016 at 9:57 AM, Raby, John W USA CIV via RT <
met_help at ucar.edu> wrote:
>
> Thu Nov 03 09:57:10 2016: Request 78579 was acted upon.
> Transaction: Ticket created by john.w.raby2.civ at mail.mil
> Queue: met_help
> Subject: Point-Stat question
> Owner: Nobody
> Requestors: john.w.raby2.civ at mail.mil
> Status: new
> Ticket <Caution-url:
> Caution-https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78579 >
>
>
> My config file specifies the following in the "Forecast and
> observation fields to be verified" section:
>
> field = [
> {
> name = "TMP";
> level = [ "P100-225" ];
> cat_thresh = [ >273.0 ];
> },
>
> The model output GRIB file (valid at 1200 UTC) contains output at
the
> pressure levels 100, 150, and 200 mb all of which contain TMP FCST
output.
>
> The Point-Stat MPR file shows that there are 10 TMP observations in
> the layer P100-225.
>
> The Point-Stat CNT file shows that TMP error statistics for the
layer
> P100-225 were calculated using 10 matched pairs (TOTAL).
>
> What model pressure level(s) was used to provide the FCST values
used
> in the error statistics?
>
> Another related question:
>
> In cases where I have specified a layer (in pressure) P625-775 for
> verification, followed by another layer (P775-875) for verification,
> the model output contains the pressure level of 775mb. Which layer
> will the model output be used?
>
> Thanks.
>
> R/
> John
>
>
>
>
CLASSIFICATION: UNCLASSIFIED
------------------------------------------------
Subject: Point-Stat question
From: John Halley Gotway
Time: Fri Nov 04 09:56:46 2016
John,
Sounds good. I'll go ahead and resolve this ticket now. If more
questions
come up when you get back to this, feel free to write.
Thanks,
John
On Thu, Nov 3, 2016 at 4:56 PM, Raby, John W USA CIV via RT <
met_help at ucar.edu> wrote:
>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78579 >
>
> CLASSIFICATION: UNCLASSIFIED
>
> John -
>
> Thanks for providing more detailed info on this. I need to think
about
> what I
> would do given the info you provided on how to be more specific
about the
> config file settings. My take on the way my current setting is
working is
> that
> the error stats for the layer P100-225 are evaluating the model
output for
> potentially all 3 model pressure levels depending on the levels of
the
> observations. I'm leaving for the day, shortly, so I don't have time
for
> follow-up. I won't be back in the office until 08 NOV. I think
you've
> provided
> all I needed to know.
>
> R/
> John
>
>
> -----Original Message-----
> From: John Halley Gotway via RT [mailto:met_help at ucar.edu]
> Sent: Thursday, November 03, 2016 4:28 PM
> To: Raby, John W CIV USARMY RDECOM ARL (US)
<john.w.raby2.civ at mail.mil>
> Subject: [Non-DoD Source] Re: [rt.rap.ucar.edu #78579] Point-Stat
question
>
> All active links contained in this email were disabled. Please
verify the
> identity of the sender, and confirm the authenticity of all links
contained
> within the message prior to copying and pasting the address to a Web
> browser.
>
>
>
>
> ----
>
> John,
>
> I see that you have a question about how Point-Stat does
> interpolation/matching in the vertical coordinate. The answer is
pretty
> simple and you have some control over it based on how you set up the
config
> file.
>
> First, there's a brief description in section 7.2.1 of the MET
User's Guide
> (Caution-http://www.dtcenter.org/met/users/docs/users_
> guide/MET_Users_Guide_v5.2.pdf)
> but let's work through your first example:
>
> (1) You have model output at 100, 150, and 200 mb.
> (2) You're verifying the level "P100-225" in *both* the forecast and
> observation field setting.
>
> Since you've defined the forecast level as a range, it'll step
through all
> the
> forecast levels and read all 3 levels falling within that range into
memory
> (100, 150, and 200). Then it'll read through all the observations
and only
> keep those that fall within the observation level range (which is
also
> 100-225).
>
> - For an observation at 200mb, it sees that exactly matches a
forecast
> level.
> So it'll do horizontal interpolation at 200mb and no vertical
> interpolation.
>
> - For an observation at 115mb, it'll do horizontal interpolation for
the
> level
> above (100) and below (200). Then it interpolates those values
> above/below to
> 115mb linear in the log of pressure.
>
> - For an observation at 225mb, it finds a level above it (200) but
none
> below.
> So it'll do horizontal interpolation at 200mb and use that value as-
is,
> with
> no vertical interpolation.
>
> I want to emphasize that the forecast and observation level settings
do not
> need to be the same. Here are two examples...
>
> (1) Set fcst -> level = [ "P100-250" ]; and obs -> level = [ "P100-
225" ];
>
> Assuming 250mb is another forecast level, this will give more
forecast
> data to
> Point-Stat to use in vertical interpolation. An observation at
225mb will
> be
> interpolated between the 200 and 250 forecast levels. But only
> observations
> in the range 100-225 will be used. You need to pass Point-Stat all
the
> forecast levels that you'd like it to use for vertical
interpolation.
>
> (2) Set fcst -> level = [ "P100", "P200", "P300" ]; and obs -> level
= [
> "P75-125", "P175-225", "P275-325" ]; This will perform 3 different
> verification tasks. For each, only one forecast level is used (100,
200,
> or
> 300), but the observation level is defined as a range. For
example, all
> observations between 75 and 125 will be compared to the forecast
values at
> 100mb. And so on.
>
> So tweaking the level settings in the config file impacts how the
forecast
> and
> observation data is matched up in the vertical.
>
> Hope that helps.
>
> Thanks,
> John
>
>
>
>
>
> On Thu, Nov 3, 2016 at 9:57 AM, Raby, John W USA CIV via RT <
> met_help at ucar.edu> wrote:
>
> >
> > Thu Nov 03 09:57:10 2016: Request 78579 was acted upon.
> > Transaction: Ticket created by john.w.raby2.civ at mail.mil
> > Queue: met_help
> > Subject: Point-Stat question
> > Owner: Nobody
> > Requestors: john.w.raby2.civ at mail.mil
> > Status: new
> > Ticket <Caution-url:
> > Caution-https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=78579 >
> >
> >
> > My config file specifies the following in the "Forecast and
> > observation fields to be verified" section:
> >
> > field = [
> > {
> > name = "TMP";
> > level = [ "P100-225" ];
> > cat_thresh = [ >273.0 ];
> > },
> >
> > The model output GRIB file (valid at 1200 UTC) contains output at
the
> > pressure levels 100, 150, and 200 mb all of which contain TMP FCST
> output.
> >
> > The Point-Stat MPR file shows that there are 10 TMP observations
in
> > the layer P100-225.
> >
> > The Point-Stat CNT file shows that TMP error statistics for the
layer
> > P100-225 were calculated using 10 matched pairs (TOTAL).
> >
> > What model pressure level(s) was used to provide the FCST values
used
> > in the error statistics?
> >
> > Another related question:
> >
> > In cases where I have specified a layer (in pressure) P625-775 for
> > verification, followed by another layer (P775-875) for
verification,
> > the model output contains the pressure level of 775mb. Which layer
> > will the model output be used?
> >
> > Thanks.
> >
> > R/
> > John
> >
> >
> >
> >
>
>
> CLASSIFICATION: UNCLASSIFIED
>
>
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