[Met_help] [rt.rap.ucar.edu #99964] History for obs_thresh

John Halley Gotway via RT met_help at ucar.edu
Mon May 24 14:35:31 MDT 2021


----------------------------------------------------------------
  Initial Request
----------------------------------------------------------------

Hello,

I have a very basic question that may sounds naive:

To filter/remove obs. value less than 0.5, which of the expression below is
correct:
obs_thersh = [0.5]

 or obs_thresh = [<0.5];

 or obs_thresh = [>0.5];

Is the 3rd the right answer?
Thank you.
Binyu


----------------------------------------------------------------
  Complete Ticket History
----------------------------------------------------------------

Subject: obs_thresh
From: John Halley Gotway
Time: Mon May 24 09:24:59 2021

Binyu,

Yes, that's correct. You should set: obs_thresh = [ >=0.5 ];

The obs_thresh setting is a threshold that defines the points you want
to
KEEP, not the ones that you want to throw out.

Looking at the description below from the user's guide, I see that we
don't
explicitly state that. I'll add another sentence there to clarify.

Thanks,
John

*obs_thresh*

The “obs_thresh” entry is an array of thresholds for filtering
observation
values prior to applying ensemble verification logic. The default
setting
of NA means that no observations should be filtered out. Verification
output will be computed separately for each threshold specified. This
option may be set separately for each obs.field entry.

On Sun, May 23, 2021 at 2:10 PM binyu.wang at noaa.gov via RT <
met_help at ucar.edu> wrote:

>
> Sun May 23 14:08:58 2021: Request 99964 was acted upon.
> Transaction: Ticket created by binyu.wang at noaa.gov
>        Queue: met_help
>      Subject: obs_thresh
>        Owner: Nobody
>   Requestors: binyu.wang at noaa.gov
>       Status: new
>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964 >
>
>
> Hello,
>
> I have a very basic question that may sounds naive:
>
> To filter/remove obs. value less than 0.5, which of the expression
below is
> correct:
> obs_thersh = [0.5]
>
>  or obs_thresh = [<0.5];
>
>  or obs_thresh = [>0.5];
>
> Is the 3rd the right answer?
> Thank you.
> Binyu
>
>

------------------------------------------------
Subject: obs_thresh
From: John Halley Gotway
Time: Mon May 24 09:30:56 2021

Binyu,

Do you find this description to be more clear?

The "obs_thresh" entry is an array of thresholds for filtering
observation

values prior to applying ensemble verification logic. They specify the
values

to be included in the verification, not excluded. The default setting
of NA,

which always evaluates to true, means that all observations should be
used.

Verification output will be computed separately for each threshold
specified.

This option may be set separately for each obs.field entry.


Thanks,

John

On Mon, May 24, 2021 at 9:24 AM John Halley Gotway <johnhg at ucar.edu>
wrote:

> Binyu,
>
> Yes, that's correct. You should set: obs_thresh = [ >=0.5 ];
>
> The obs_thresh setting is a threshold that defines the points you
want to
> KEEP, not the ones that you want to throw out.
>
> Looking at the description below from the user's guide, I see that
we
> don't explicitly state that. I'll add another sentence there to
clarify.
>
> Thanks,
> John
>
> *obs_thresh*
>
> The “obs_thresh” entry is an array of thresholds for filtering
observation
> values prior to applying ensemble verification logic. The default
setting
> of NA means that no observations should be filtered out.
Verification
> output will be computed separately for each threshold specified.
This
> option may be set separately for each obs.field entry.
>
> On Sun, May 23, 2021 at 2:10 PM binyu.wang at noaa.gov via RT <
> met_help at ucar.edu> wrote:
>
>>
>> Sun May 23 14:08:58 2021: Request 99964 was acted upon.
>> Transaction: Ticket created by binyu.wang at noaa.gov
>>        Queue: met_help
>>      Subject: obs_thresh
>>        Owner: Nobody
>>   Requestors: binyu.wang at noaa.gov
>>       Status: new
>>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964 >
>>
>>
>> Hello,
>>
>> I have a very basic question that may sounds naive:
>>
>> To filter/remove obs. value less than 0.5, which of the expression
below
>> is
>> correct:
>> obs_thersh = [0.5]
>>
>>  or obs_thresh = [<0.5];
>>
>>  or obs_thresh = [>0.5];
>>
>> Is the 3rd the right answer?
>> Thank you.
>> Binyu
>>
>>

------------------------------------------------
Subject: obs_thresh
From: binyu.wang at noaa.gov
Time: Mon May 24 10:23:38 2021

Yes, the new document is much clearer. I get confused because for
censor_thresh, it is OPPOSITE:  several months ago, you showed me how
to
filter values less than 0.5 from ensemble forecast as:

 censor_thresh=[<0.5];

 censor_val=[-9999]; desc="GE0.5";

Am I correct here? Or I made a mistake again?

I have another question for "obs_window". Just curious why does this
only
apply for Point-Stat and Ensemble-Stat? NOT grid_stat? Is there a
specific reason for this?

obs_window

// Point observation time window


Thank you,

Binyu

On Mon, May 24, 2021 at 11:31 AM John Halley Gotway via RT <
met_help at ucar.edu> wrote:

> Binyu,
>
> Do you find this description to be more clear?
>
> The "obs_thresh" entry is an array of thresholds for filtering
observation
>
> values prior to applying ensemble verification logic. They specify
the
> values
>
> to be included in the verification, not excluded. The default
setting of
> NA,
>
> which always evaluates to true, means that all observations should
be used.
>
> Verification output will be computed separately for each threshold
> specified.
>
> This option may be set separately for each obs.field entry.
>
>
> Thanks,
>
> John
>
> On Mon, May 24, 2021 at 9:24 AM John Halley Gotway <johnhg at ucar.edu>
> wrote:
>
> > Binyu,
> >
> > Yes, that's correct. You should set: obs_thresh = [ >=0.5 ];
> >
> > The obs_thresh setting is a threshold that defines the points you
want to
> > KEEP, not the ones that you want to throw out.
> >
> > Looking at the description below from the user's guide, I see that
we
> > don't explicitly state that. I'll add another sentence there to
clarify.
> >
> > Thanks,
> > John
> >
> > *obs_thresh*
> >
> > The “obs_thresh” entry is an array of thresholds for filtering
> observation
> > values prior to applying ensemble verification logic. The default
setting
> > of NA means that no observations should be filtered out.
Verification
> > output will be computed separately for each threshold specified.
This
> > option may be set separately for each obs.field entry.
> >
> > On Sun, May 23, 2021 at 2:10 PM binyu.wang at noaa.gov via RT <
> > met_help at ucar.edu> wrote:
> >
> >>
> >> Sun May 23 14:08:58 2021: Request 99964 was acted upon.
> >> Transaction: Ticket created by binyu.wang at noaa.gov
> >>        Queue: met_help
> >>      Subject: obs_thresh
> >>        Owner: Nobody
> >>   Requestors: binyu.wang at noaa.gov
> >>       Status: new
> >>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964 >
> >>
> >>
> >> Hello,
> >>
> >> I have a very basic question that may sounds naive:
> >>
> >> To filter/remove obs. value less than 0.5, which of the
expression below
> >> is
> >> correct:
> >> obs_thersh = [0.5]
> >>
> >>  or obs_thresh = [<0.5];
> >>
> >>  or obs_thresh = [>0.5];
> >>
> >> Is the 3rd the right answer?
> >> Thank you.
> >> Binyu
> >>
> >>
>
>

------------------------------------------------
Subject: obs_thresh
From: John Halley Gotway
Time: Mon May 24 12:40:07 2021

Binyu,

Yes, that's correct.

With censor_thresh you specify some set of values (e.g. values less
than
0.5 would be censor_thresh = [ <=0.5 ];) followed by some replacement
value
(e.g. censor_value = [ -9999 ];). So any values meeting that threshold
criteria are replaced by the replacement value.

The obs_window does apply to the point_stat and ensemble_stat tools
when
processing point observations. It does not apply to grid_stat because
that
tool processes gridded observations. So it does NOT need to do any
filtering by time. It just compares whatever 2 fields are passed as
input
to it on the command line. If the valid times of those 2 input fields
differ, it'll print a warning message. But it still proceeds with the
comparison and computes output stats.

That being said, the METplus python wrappers DO include time window
logic
that does apply when calling grid_stat. For example, you could setup
the
wrappers to find the forecast and observation files closest to the top
of
the hour and then pass them to grid_stat to be processed.

John

On Mon, May 24, 2021 at 10:24 AM binyu.wang at noaa.gov via RT <
met_help at ucar.edu> wrote:

>
> <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964 >
>
> Yes, the new document is much clearer. I get confused because for
> censor_thresh, it is OPPOSITE:  several months ago, you showed me
how to
> filter values less than 0.5 from ensemble forecast as:
>
>  censor_thresh=[<0.5];
>
>  censor_val=[-9999]; desc="GE0.5";
>
> Am I correct here? Or I made a mistake again?
>
> I have another question for "obs_window". Just curious why does this
only
> apply for Point-Stat and Ensemble-Stat? NOT grid_stat? Is there a
> specific reason for this?
>
> obs_window
>
> // Point observation time window
>
>
> Thank you,
>
> Binyu
>
> On Mon, May 24, 2021 at 11:31 AM John Halley Gotway via RT <
> met_help at ucar.edu> wrote:
>
> > Binyu,
> >
> > Do you find this description to be more clear?
> >
> > The "obs_thresh" entry is an array of thresholds for filtering
> observation
> >
> > values prior to applying ensemble verification logic. They specify
the
> > values
> >
> > to be included in the verification, not excluded. The default
setting of
> > NA,
> >
> > which always evaluates to true, means that all observations should
be
> used.
> >
> > Verification output will be computed separately for each threshold
> > specified.
> >
> > This option may be set separately for each obs.field entry.
> >
> >
> > Thanks,
> >
> > John
> >
> > On Mon, May 24, 2021 at 9:24 AM John Halley Gotway
<johnhg at ucar.edu>
> > wrote:
> >
> > > Binyu,
> > >
> > > Yes, that's correct. You should set: obs_thresh = [ >=0.5 ];
> > >
> > > The obs_thresh setting is a threshold that defines the points
you want
> to
> > > KEEP, not the ones that you want to throw out.
> > >
> > > Looking at the description below from the user's guide, I see
that we
> > > don't explicitly state that. I'll add another sentence there to
> clarify.
> > >
> > > Thanks,
> > > John
> > >
> > > *obs_thresh*
> > >
> > > The “obs_thresh” entry is an array of thresholds for filtering
> > observation
> > > values prior to applying ensemble verification logic. The
default
> setting
> > > of NA means that no observations should be filtered out.
Verification
> > > output will be computed separately for each threshold specified.
This
> > > option may be set separately for each obs.field entry.
> > >
> > > On Sun, May 23, 2021 at 2:10 PM binyu.wang at noaa.gov via RT <
> > > met_help at ucar.edu> wrote:
> > >
> > >>
> > >> Sun May 23 14:08:58 2021: Request 99964 was acted upon.
> > >> Transaction: Ticket created by binyu.wang at noaa.gov
> > >>        Queue: met_help
> > >>      Subject: obs_thresh
> > >>        Owner: Nobody
> > >>   Requestors: binyu.wang at noaa.gov
> > >>       Status: new
> > >>  Ticket <URL:
https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964
> >
> > >>
> > >>
> > >> Hello,
> > >>
> > >> I have a very basic question that may sounds naive:
> > >>
> > >> To filter/remove obs. value less than 0.5, which of the
expression
> below
> > >> is
> > >> correct:
> > >> obs_thersh = [0.5]
> > >>
> > >>  or obs_thresh = [<0.5];
> > >>
> > >>  or obs_thresh = [>0.5];
> > >>
> > >> Is the 3rd the right answer?
> > >> Thank you.
> > >> Binyu
> > >>
> > >>
> >
> >
>
>

------------------------------------------------
Subject: obs_thresh
From: binyu.wang at noaa.gov
Time: Mon May 24 13:30:14 2021

Hello John,

Thank you for the explanation.
------------------------------------------
The obs_window does apply to the point_stat and ensemble_stat tools
when
processing point observations. It does not apply to grid_stat because
that
tool processes gridded observations. So it does NOT need to do any
filtering by time.
---Why gridded observations don't need filtering by time? Sorry I am
still confused. Do you mean
there is time filtering in grid_stat, but it is not needed most time?

Binyu


On Mon, May 24, 2021 at 2:40 PM John Halley Gotway via RT
<met_help at ucar.edu>
wrote:

> Binyu,
>
> Yes, that's correct.
>
> With censor_thresh you specify some set of values (e.g. values less
than
> 0.5 would be censor_thresh = [ <=0.5 ];) followed by some
replacement value
> (e.g. censor_value = [ -9999 ];). So any values meeting that
threshold
> criteria are replaced by the replacement value.
>
> The obs_window does apply to the point_stat and ensemble_stat tools
when
> processing point observations. It does not apply to grid_stat
because that
> tool processes gridded observations. So it does NOT need to do any
> filtering by time. It just compares whatever 2 fields are passed as
input
> to it on the command line. If the valid times of those 2 input
fields
> differ, it'll print a warning message. But it still proceeds with
the
> comparison and computes output stats.
>
> That being said, the METplus python wrappers DO include time window
logic
> that does apply when calling grid_stat. For example, you could setup
the
> wrappers to find the forecast and observation files closest to the
top of
> the hour and then pass them to grid_stat to be processed.
>
> John
>
> On Mon, May 24, 2021 at 10:24 AM binyu.wang at noaa.gov via RT <
> met_help at ucar.edu> wrote:
>
> >
> > <URL: https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964 >
> >
> > Yes, the new document is much clearer. I get confused because for
> > censor_thresh, it is OPPOSITE:  several months ago, you showed me
how to
> > filter values less than 0.5 from ensemble forecast as:
> >
> >  censor_thresh=[<0.5];
> >
> >  censor_val=[-9999]; desc="GE0.5";
> >
> > Am I correct here? Or I made a mistake again?
> >
> > I have another question for "obs_window". Just curious why does
this only
> > apply for Point-Stat and Ensemble-Stat? NOT grid_stat? Is there a
> > specific reason for this?
> >
> > obs_window
> >
> > // Point observation time window
> >
> >
> > Thank you,
> >
> > Binyu
> >
> > On Mon, May 24, 2021 at 11:31 AM John Halley Gotway via RT <
> > met_help at ucar.edu> wrote:
> >
> > > Binyu,
> > >
> > > Do you find this description to be more clear?
> > >
> > > The "obs_thresh" entry is an array of thresholds for filtering
> > observation
> > >
> > > values prior to applying ensemble verification logic. They
specify the
> > > values
> > >
> > > to be included in the verification, not excluded. The default
setting
> of
> > > NA,
> > >
> > > which always evaluates to true, means that all observations
should be
> > used.
> > >
> > > Verification output will be computed separately for each
threshold
> > > specified.
> > >
> > > This option may be set separately for each obs.field entry.
> > >
> > >
> > > Thanks,
> > >
> > > John
> > >
> > > On Mon, May 24, 2021 at 9:24 AM John Halley Gotway
<johnhg at ucar.edu>
> > > wrote:
> > >
> > > > Binyu,
> > > >
> > > > Yes, that's correct. You should set: obs_thresh = [ >=0.5 ];
> > > >
> > > > The obs_thresh setting is a threshold that defines the points
you
> want
> > to
> > > > KEEP, not the ones that you want to throw out.
> > > >
> > > > Looking at the description below from the user's guide, I see
that we
> > > > don't explicitly state that. I'll add another sentence there
to
> > clarify.
> > > >
> > > > Thanks,
> > > > John
> > > >
> > > > *obs_thresh*
> > > >
> > > > The “obs_thresh” entry is an array of thresholds for filtering
> > > observation
> > > > values prior to applying ensemble verification logic. The
default
> > setting
> > > > of NA means that no observations should be filtered out.
Verification
> > > > output will be computed separately for each threshold
specified. This
> > > > option may be set separately for each obs.field entry.
> > > >
> > > > On Sun, May 23, 2021 at 2:10 PM binyu.wang at noaa.gov via RT <
> > > > met_help at ucar.edu> wrote:
> > > >
> > > >>
> > > >> Sun May 23 14:08:58 2021: Request 99964 was acted upon.
> > > >> Transaction: Ticket created by binyu.wang at noaa.gov
> > > >>        Queue: met_help
> > > >>      Subject: obs_thresh
> > > >>        Owner: Nobody
> > > >>   Requestors: binyu.wang at noaa.gov
> > > >>       Status: new
> > > >>  Ticket <URL:
> https://rt.rap.ucar.edu/rt/Ticket/Display.html?id=99964
> > >
> > > >>
> > > >>
> > > >> Hello,
> > > >>
> > > >> I have a very basic question that may sounds naive:
> > > >>
> > > >> To filter/remove obs. value less than 0.5, which of the
expression
> > below
> > > >> is
> > > >> correct:
> > > >> obs_thersh = [0.5]
> > > >>
> > > >>  or obs_thresh = [<0.5];
> > > >>
> > > >>  or obs_thresh = [>0.5];
> > > >>
> > > >> Is the 3rd the right answer?
> > > >> Thank you.
> > > >> Binyu
> > > >>
> > > >>
> > >
> > >
> >
> >
>
>

------------------------------------------------


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