[Met_help] [rt.rap.ucar.edu #74283] History for Question about MODE (UNCLASSIFIED)

Tue Jan 26 12:12:16 MST 2016

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  Initial Request
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CLASSIFICATION: UNCLASSIFIED

I'm running MODE with METV4.1 and I am trying to define objects in the 2m AGL UGRD and VGRD fields using a negative conv_thresh value so as to work with objects whose values are negative.

For UGRD, I set the value of raw_thresh to <=0.0 to set all positive values to bad data since I'm only interested in defining objects from the field of negative values. I set conv_thresh to <=-3.0 to define objects with negative values greater than -3.0. (ie. -3.5, -4.0, -4.5, etc). I know that the observation field contains a significant number of values meeting this criterion.

When I run MODE, it finds no objects forecast or observed.

I then tried changing the conv_thresh value to a positive number, conv_thresh<=3.0  (leaving raw_thresh the same) to see if MODE isn't reading the - sign. In this case it defines the entire domain as a single object. 

This leads me to conclude that the functionality of raw_thresh is not what I'm expecting. I thought that it would throw out all positive values of UGRD from consideration when defining objects. If this were the case why would the entire domain containing positive and negative values be considered a single object?

I then tried a test by setting raw_thresh<=0.0 and conv_thresh>=3.0 and MODE found no objects forecast or observed which makes sense and seems to indicate that perhaps the functionality of raw_thresh is what I thought it was.

Could you offer an explanation about the above observations and why I can't seem to define objects in fields of negative values? If you need me to send data, I can use our Secure Access File Exchange, but I will need a specific email address to send the download link.

Thanks.

R/
John Raby
US Army Research Laboratory

CLASSIFICATION: UNCLASSIFIED

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  Complete Ticket History
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Subject: Question about MODE (UNCLASSIFIED)
From: John Halley Gotway
Time: Thu Dec 03 14:31:18 2015

Hi John,

For defining objects using values < 0, I think you'll need to use a
newer
version of MET.  The release notes for MET version 5.0 list a bugfix
for
MODE when trying to create objects using values < 0:

http://www.dtcenter.org/met/users/support/release_notes/METv5.0_release_notes.php

And you should generally not use the raw_thresh option unless you have
a
good reason to do so.  It should only be used when the range of
forecast
and observation values differ.  For example, suppose you have a
forecast
predicting reflectivity, but only for values >= 35 dbz.  However, your
observations contain a full range of dbz values... both above and
below
35.  In that case, you'd set "raw_thresh = >=35" to toss out any
observation values less than 35.  That way you'd define forecast and
observation objects in MODE using the same range of raw data values.

I'd suggest installing and using MET version 5.1 to run MODE on this
type
of data.

Thanks,
John

On Thu, Dec 3, 2015 at 2:02 PM, Raby, John W USA CIV via RT <
met_help at ucar.edu> wrote:

>
> Thu Dec 03 14:02:04 2015: Request 74283 was acted upon.
> Transaction: Ticket created by john.w.raby2.civ at mail.mil
>        Queue: met_help
>      Subject: Question about MODE (UNCLASSIFIED)
>        Owner: Nobody
>   Requestors: john.w.raby2.civ at mail.mil
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=74283 >
>
>
> CLASSIFICATION: UNCLASSIFIED
>
> I'm running MODE with METV4.1 and I am trying to define objects in
the 2m
> AGL UGRD and VGRD fields using a negative conv_thresh value so as to
work
> with objects whose values are negative.
>
> For UGRD, I set the value of raw_thresh to <=0.0 to set all positive
> values to bad data since I'm only interested in defining objects
from the
> field of negative values. I set conv_thresh to <=-3.0 to define
objects
> with negative values greater than -3.0. (ie. -3.5, -4.0, -4.5, etc).
I know
> that the observation field contains a significant number of values
meeting
> this criterion.
>
> When I run MODE, it finds no objects forecast or observed.
>
> I then tried changing the conv_thresh value to a positive number,
> conv_thresh<=3.0  (leaving raw_thresh the same) to see if MODE isn't
> reading the - sign. In this case it defines the entire domain as a
single
> object.
>
> This leads me to conclude that the functionality of raw_thresh is
not what
> I'm expecting. I thought that it would throw out all positive values
of
> UGRD from consideration when defining objects. If this were the case
why
> would the entire domain containing positive and negative values be
> considered a single object?
>
> I then tried a test by setting raw_thresh<=0.0 and conv_thresh>=3.0
and
> MODE found no objects forecast or observed which makes sense and
seems to
> indicate that perhaps the functionality of raw_thresh is what I
thought it
> was.
>
> Could you offer an explanation about the above observations and why
I
> can't seem to define objects in fields of negative values? If you
need me
> to send data, I can use our Secure Access File Exchange, but I will
need a
> specific email address to send the download link.
>
> Thanks.
>
> R/
> John Raby
> US Army Research Laboratory
>
>
>
>
> CLASSIFICATION: UNCLASSIFIED
>
>
>

------------------------------------------------
Subject: RE: [Non-DoD Source] Re: [rt.rap.ucar.edu #74283] Question about MODE (UNCLASSIFIED)
From: Raby, John W USA CIV
Time: Thu Dec 03 14:58:05 2015

CLASSIFICATION: UNCLASSIFIED

John -

Thanks for pointing that out. I am starting the process of upgrading
to V5.1. That will be one among a few other benefits to gain by
upgrading. I'll restore the raw_thresh back to 0.0 since the forecast
data I use do not use thresholds.

R/
John

-----Original Message-----
From: John Halley Gotway via RT [mailto:met_help at ucar.edu]
Sent: Thursday, December 03, 2015 2:31 PM
To: Raby, John W CIV USARMY RDECOM ARL (US)
Subject: [Non-DoD Source] Re: [rt.rap.ucar.edu #74283] Question about
MODE (UNCLASSIFIED)

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.

----

Hi John,

For defining objects using values < 0, I think you'll need to use a
newer version of MET.  The release notes for MET version 5.0 list a
bugfix for MODE when trying to create objects using values < 0:

Caution-
http://www.dtcenter.org/met/users/support/release_notes/METv5.0_release_notes.php

And you should generally not use the raw_thresh option unless you have
a good reason to do so.  It should only be used when the range of
forecast and observation values differ.  For example, suppose you have
a forecast predicting reflectivity, but only for values >= 35 dbz.
However, your observations contain a full range of dbz values... both
above and below 35.  In that case, you'd set "raw_thresh = >=35" to
toss out any observation values less than 35.  That way you'd define
forecast and observation objects in MODE using the same range of raw
data values.

I'd suggest installing and using MET version 5.1 to run MODE on this
type of data.

Thanks,
John

On Thu, Dec 3, 2015 at 2:02 PM, Raby, John W USA CIV via RT <
met_help at ucar.edu> wrote:

>
> Thu Dec 03 14:02:04 2015: Request 74283 was acted upon.
> Transaction: Ticket created by john.w.raby2.civ at mail.mil
>        Queue: met_help
>      Subject: Question about MODE (UNCLASSIFIED)
>        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=74283 >
>
>
> CLASSIFICATION: UNCLASSIFIED
>
> I'm running MODE with METV4.1 and I am trying to define objects in
the
> 2m AGL UGRD and VGRD fields using a negative conv_thresh value so as
> to work with objects whose values are negative.
>
> For UGRD, I set the value of raw_thresh to <=0.0 to set all positive
> values to bad data since I'm only interested in defining objects
from
> the field of negative values. I set conv_thresh to <=-3.0 to define
> objects with negative values greater than -3.0. (ie. -3.5, -4.0,
-4.5,
> etc). I know that the observation field contains a significant
number
> of values meeting this criterion.
>
> When I run MODE, it finds no objects forecast or observed.
>
> I then tried changing the conv_thresh value to a positive number,
> conv_thresh<=3.0  (leaving raw_thresh the same) to see if MODE isn't
> reading the - sign. In this case it defines the entire domain as a
> single object.
>
> This leads me to conclude that the functionality of raw_thresh is
not
> what I'm expecting. I thought that it would throw out all positive
> values of UGRD from consideration when defining objects. If this
were
> the case why would the entire domain containing positive and
negative
> values be considered a single object?
>
> I then tried a test by setting raw_thresh<=0.0 and conv_thresh>=3.0
> and MODE found no objects forecast or observed which makes sense and
> seems to indicate that perhaps the functionality of raw_thresh is
what
> I thought it was.
>
> Could you offer an explanation about the above observations and why
I
> can't seem to define objects in fields of negative values? If you
need
> me to send data, I can use our Secure Access File Exchange, but I
will
> need a specific email address to send the download link.
>
> Thanks.
>
> R/
> John Raby
> US Army Research Laboratory
>
>
>
>
> CLASSIFICATION: UNCLASSIFIED
>
>
>

CLASSIFICATION: UNCLASSIFIED

------------------------------------------------
Subject: Question about MODE (UNCLASSIFIED)
From: John Halley Gotway
Time: Thu Dec 03 15:18:50 2015

John,

OK, and you'll notice in MET version 5.1 that the default value for
raw_thresh is NA, meaning do not apply it:
   raw_thresh = NA;

Just let us know what additional questions or issues arise.

Thanks,
John

On Thu, Dec 3, 2015 at 2:58 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=74283 >
>
> CLASSIFICATION: UNCLASSIFIED
>
> John -
>
> Thanks for pointing that out. I am starting the process of upgrading
to
> V5.1. That will be one among a few other benefits to gain by
upgrading.
> I'll restore the raw_thresh back to 0.0 since the forecast data I
use do
> not use thresholds.
>
> R/
> John
>
> -----Original Message-----
> From: John Halley Gotway via RT [mailto:met_help at ucar.edu]
> Sent: Thursday, December 03, 2015 2:31 PM
> To: Raby, John W CIV USARMY RDECOM ARL (US)
> Subject: [Non-DoD Source] Re: [rt.rap.ucar.edu #74283] Question
about
> MODE (UNCLASSIFIED)
>
> 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.
>
>
>
>
> ----
>
> Hi John,
>
> For defining objects using values < 0, I think you'll need to use a
newer
> version of MET.  The release notes for MET version 5.0 list a bugfix
for
> MODE when trying to create objects using values < 0:
>
> Caution-
>
http://www.dtcenter.org/met/users/support/release_notes/METv5.0_release_notes.php
>
> And you should generally not use the raw_thresh option unless you
have a
> good reason to do so.  It should only be used when the range of
forecast
> and observation values differ.  For example, suppose you have a
forecast
> predicting reflectivity, but only for values >= 35 dbz.  However,
your
> observations contain a full range of dbz values... both above and
below
> 35.  In that case, you'd set "raw_thresh = >=35" to toss out any
> observation values less than 35.  That way you'd define forecast and
> observation objects in MODE using the same range of raw data values.
>
> I'd suggest installing and using MET version 5.1 to run MODE on this
type
> of data.
>
> Thanks,
> John
>
> On Thu, Dec 3, 2015 at 2:02 PM, Raby, John W USA CIV via RT <
> met_help at ucar.edu> wrote:
>
> >
> > Thu Dec 03 14:02:04 2015: Request 74283 was acted upon.
> > Transaction: Ticket created by john.w.raby2.civ at mail.mil
> >        Queue: met_help
> >      Subject: Question about MODE (UNCLASSIFIED)
> >        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=74283 >
> >
> >
> > CLASSIFICATION: UNCLASSIFIED
> >
> > I'm running MODE with METV4.1 and I am trying to define objects in
the
> > 2m AGL UGRD and VGRD fields using a negative conv_thresh value so
as
> > to work with objects whose values are negative.
> >
> > For UGRD, I set the value of raw_thresh to <=0.0 to set all
positive
> > values to bad data since I'm only interested in defining objects
from
> > the field of negative values. I set conv_thresh to <=-3.0 to
define
> > objects with negative values greater than -3.0. (ie. -3.5, -4.0,
-4.5,
> > etc). I know that the observation field contains a significant
number
> > of values meeting this criterion.
> >
> > When I run MODE, it finds no objects forecast or observed.
> >
> > I then tried changing the conv_thresh value to a positive number,
> > conv_thresh<=3.0  (leaving raw_thresh the same) to see if MODE
isn't
> > reading the - sign. In this case it defines the entire domain as a
> > single object.
> >
> > This leads me to conclude that the functionality of raw_thresh is
not
> > what I'm expecting. I thought that it would throw out all positive
> > values of UGRD from consideration when defining objects. If this
were
> > the case why would the entire domain containing positive and
negative
> > values be considered a single object?
> >
> > I then tried a test by setting raw_thresh<=0.0 and
conv_thresh>=3.0
> > and MODE found no objects forecast or observed which makes sense
and
> > seems to indicate that perhaps the functionality of raw_thresh is
what
> > I thought it was.
> >
> > Could you offer an explanation about the above observations and
why I
> > can't seem to define objects in fields of negative values? If you
need
> > me to send data, I can use our Secure Access File Exchange, but I
will
> > need a specific email address to send the download link.
> >
> > Thanks.
> >
> > R/
> > John Raby
> > US Army Research Laboratory
> >
> >
> >
> >
> > CLASSIFICATION: UNCLASSIFIED
> >
> >
> >
>
>
> CLASSIFICATION: UNCLASSIFIED
>
>
>

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