[gradsusr] Incompatible Grids in 20th Century Reanalysis (Version 2) Data

Don Hooper hoop at Colorado.EDU
Wed Feb 23 17:09:25 EST 2011


All,

I am not the webmaster, but I was the person quoted.  It was limited
to a handful of files in the data set, but I've no excuse as to how
it slipped past me.  I've fixed the files, and the corrected versions
should be available on our outer servers in about three hours or so.

-Hoop

On 02/23/11 10:07, gradsusr-request at gradsusr.org wrote:
> 
> Today's Topics:
> 
>    4. Incompatible Grids in 20th Century Reanalysis (Version	2)
>       Data (Stephen McMillan)
>    5. Re: Incompatible Grids in 20th Century Reanalysis (Version 2)
>       Data (Semyon Grodsky)
>    6. Re: Incompatible Grids in 20th Century Reanalysis (Version 2)
>       Data (Stephen McMillan)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 4 Date: Wed, 23 Feb 2011 15:14:49 -0500 From: Stephen McMillan <smcmillan at planalytics.com> Subject: [gradsusr] Incompatible Grids in 20th Century Reanalysis (Version 2) Data To: GrADS Users Forum <gradsusr at gradsusr.org> Message-ID: <AANLkTi=OKCKDinnxKqP_xfjSq_G+0TZssz_jAukQOEf7 at mail.gmail.com> Content-Type: text/plain; charset="iso-8859-1" Recently I wrote the Webmaster for the 20th Century Reanalysis V2 data plotting pages, regarding grid incompatibility between the following two data files: Monthly means: ftp://ftp.cdc.noaa.gov/Datasets/20thC_ReanV2/Monthlies/monolevel/air.sig995.mon.mean.nc Monthly longterm means: ftp://ftp.cdc.noaa.gov/Datasets/20thC_ReanV2/Derived/Monthlies/monolevel/air.sig995.mon.ltm.nc I can plot the "air" variable from each without a problem, but when I subtract the longterm mean from the mean to create an anomaly, I get a grid incompatibility error. The means file was sdfopened first, the longterm means file second. For example, doing Aug
1969: ga-> d air(time=aug1969)-air.2(t=8) Operation error: Incompatable grids Dimension ranges aren't equivalent Dimension = 0 1st grid range = 1 181 2nd = 1 181 Error ocurred at column 29 DISPLAY error: Invalid expression Expression = air(time=aug1969)-air.2(t=8) My workaround is to first regrid the longterm mean to a 2-deg linear grid, but it would be preferable to do a simple difference as in example above. The Webmaster suggests it's a GrADS bug. His response: "The grids are identical. This appears to be a GrADS bug. No such problem obtains in NCL. GrADS appears to insist that the longitudes in the LTM file don't wrap, even when they are manually set to do so. We have run every test we can think of, including dumping the longitudes from both files and comparing them. They are the same." I have tried this with OpenGrADS versions 2.0.a7.oga.3 and 2.0.a9.oga.3 with equal results, but have not tried with the COLA version of either. Can one of the developers or other user shed
 some light on this? I am using GrADS on a Windows XP. Stephen McMillan *************************************************** The information contained in this e-mail message is intended only for the use of the recipient(s) named above and may contain information that is privileged, confidential, and/or proprietary. If you are not the intended recipient, you may not review, copy or distribute this message. If you have received this communication in error, please notify the sender immediately by e-mail, and delete the original message. *************************************************** -------------- next part -------------- An HTML attachment was scrubbed... URL: http://gradsusr.org/pipermail/gradsusr/attachments/20110223/0beeeaba/attachment-0001.html ------------------------------ Message: 5 Date: Wed, 23 Feb 2011 16:03:54 -0500 (EST) From: Semyon Grodsky <senya at atmos.umd.edu> Subject: Re: [gradsusr] Incompatible Grids in 20th Century Reanalysis (Version 2) Data To: GrADS Use
rs Forum <gradsusr at gradsusr.org> Message-ID: <Pine.LNX.4.64.1102231559210.18624 at mail.meto.umd.edu> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Stephen, lon from LTM file is corrupted. It has two 164 values, one of which is supposed to be 166. That is why lon from LTM is set to levels instead of linear when opening by sdfopen. The easiest way to avoid this problem is to write the CTL for LTM data. --Senya On Wed, 23 Feb 2011, Stephen McMillan wrote:
>> > Recently I wrote the Webmaster for the 20th Century Reanalysis V2 data
>> > plotting pages, regarding grid incompatibility between the following two
>> > data files:
>> >
>> > Monthly means:
>> >
>> > ftp://ftp.cdc.noaa.gov/Datasets/20thC_ReanV2/Monthlies/monolevel/air.sig995.mon.mean.nc
>> > Monthly longterm means:
>> >
>> > ftp://ftp.cdc.noaa.gov/Datasets/20thC_ReanV2/Derived/Monthlies/monolevel/air.sig995.mon.ltm.nc
>> >
>> > I can plot the "air" variable from each without a problem, but when I
>> > subtract the longterm mean from the mean to create an anomaly, I get a grid
>> > incompatibility error.  The means file was sdfopened first, the longterm
>> > means file second.  For example, doing Aug1969:
>> >
>> > ga-> d air(time=aug1969)-air.2(t=8)
>> > Operation error:  Incompatable grids
>> >  Dimension ranges aren't equivalent
>> >  Dimension = 0
>> >  1st grid range = 1 181   2nd = 1 181
>> >  Error ocurred at column 29
>> > DISPLAY error:  Invalid expression
>> >  Expression = air(time=aug1969)-air.2(t=8)
>> >
>> > My workaround is to first regrid the longterm mean to a 2-deg linear grid,
>> > but it would be preferable to do a simple difference as in example above.
>> > The Webmaster suggests it's a GrADS bug.  His response:
>> >
>> > "The grids are identical.  This appears to be a GrADS bug.  No such
>> > problem obtains in NCL.  GrADS appears to insist that the longitudes
>> > in the LTM file don't wrap, even when they are manually set to do so.
>> > We have run every test we can think of, including dumping the longitudes
>> > from both files and comparing them.  They are the same."
>> >
>> > I have tried this with OpenGrADS versions 2.0.a7.oga.3 and 2.0.a9.oga.3 with
>> > equal results, but have not tried with the COLA version of either.  Can one
>> > of the developers or other user shed some light on this?
>> >
>> > I am using GrADS on a Windows XP.
>> >
>> > Stephen McMillan
>> >
>> > ***************************************************
>> > The information contained in this e-mail message
>> > is intended only for the use of the recipient(s)
>> > named above and may contain information that is
>> > privileged, confidential, and/or proprietary.
>> > If you are not the intended recipient, you may not
>> > review, copy or distribute this message. If you have
>> > received this communication in error, please notify
>> > the sender immediately by e-mail, and delete the original message.
>> > ***************************************************
>> >
> -----------------------------------------------------------
> Semyon Grodsky
> Computer and Space Science Building (Bldg. #224), Room 2409
> Department of Atmospheric and Oceanic Science
> University of Maryland
> College Park, MD 20742
> 
> Phone:  301-405-5330
> Fax:    301-314-9482
> E-mail: senya at atmos.umd.edu
> 
> 
> ------------------------------
> 
> Message: 6
> Date: Wed, 23 Feb 2011 16:18:07 -0500
> From: Stephen McMillan <smcmillan at planalytics.com>
> Subject: Re: [gradsusr] Incompatible Grids in 20th Century Reanalysis
> 	(Version 2) Data
> To: GrADS Users Forum <gradsusr at gradsusr.org>
> Message-ID:
> 	<AANLkTikYnCOQ2XOw0EiS69kw8R9t4uhLoiTxZUtRm=Hw at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
> 
> Senya,
> I had not noticed the duplicate 164 values before, but I now see it when I
> 'q ctlinfo' on the LTM file.  Thanks for pointing that out, and for the CTL
> file suggestion.
> Stephen
> 
> On Wed, Feb 23, 2011 at 4:03 PM, Semyon Grodsky <senya at atmos.umd.edu> wrote:
> 
>> > Stephen,
>> > lon from LTM file is corrupted. It has two 164 values, one of which is
>> > supposed to be 166. That is why lon from LTM is set to levels instead of
>> > linear when opening by sdfopen.
>> > The easiest way to avoid this problem is to write the CTL for LTM data.
>> > --Senya
>> >
>> >
>> >  On Wed, 23 Feb 2011, Stephen McMillan
>> > wrote:
>> >
>>> > > Recently I wrote the Webmaster for the 20th Century Reanalysis V2 data
>>> > > plotting pages, regarding grid incompatibility between the following two
>>> > > data files:
>>> > >
>>> > > Monthly means:
>>> > >
>> > ftp://ftp.cdc.noaa.gov/Datasets/20thC_ReanV2/Monthlies/monolevel/air.sig995.mon.mean.nc
>>> > > Monthly longterm means:
>>> > >
>>> > >
>> > ftp://ftp.cdc.noaa.gov/Datasets/20thC_ReanV2/Derived/Monthlies/monolevel/air.sig995.mon.ltm.nc
>>> > >
>>> > > I can plot the "air" variable from each without a problem, but when I
>>> > > subtract the longterm mean from the mean to create an anomaly, I get a
>> > grid
>>> > > incompatibility error.  The means file was sdfopened first, the longterm
>>> > > means file second.  For example, doing Aug1969:
>>> > >
>>> > > ga-> d air(time=aug1969)-air.2(t=8)
>>> > > Operation error:  Incompatable grids
>>> > >  Dimension ranges aren't equivalent
>>> > >  Dimension = 0
>>> > >  1st grid range = 1 181   2nd = 1 181
>>> > >  Error ocurred at column 29
>>> > > DISPLAY error:  Invalid expression
>>> > >  Expression = air(time=aug1969)-air.2(t=8)
>>> > >
>>> > > My workaround is to first regrid the longterm mean to a 2-deg linear
>> > grid,
>>> > > but it would be preferable to do a simple difference as in example above.
>>> > > The Webmaster suggests it's a GrADS bug.  His response:
>>> > >
>>> > > "The grids are identical.  This appears to be a GrADS bug.  No such
>>> > > problem obtains in NCL.  GrADS appears to insist that the longitudes
>>> > > in the LTM file don't wrap, even when they are manually set to do so.
>>> > > We have run every test we can think of, including dumping the longitudes
>>> > > from both files and comparing them.  They are the same."
>>> > >
>>> > > I have tried this with OpenGrADS versions 2.0.a7.oga.3 and 2.0.a9.oga.3
>> > with
>>> > > equal results, but have not tried with the COLA version of either.  Can
>> > one
>>> > > of the developers or other user shed some light on this?
>>> > >
>>> > > I am using GrADS on a Windows XP.
>>> > >
>>> > > Stephen McMillan
>>> > >
>>> > > ***************************************************
>>> > > The information contained in this e-mail message
>>> > > is intended only for the use of the recipient(s)
>>> > > named above and may contain information that is
>>> > > privileged, confidential, and/or proprietary.
>>> > > If you are not the intended recipient, you may not
>>> > > review, copy or distribute this message. If you have
>>> > > received this communication in error, please notify
>>> > > the sender immediately by e-mail, and delete the original message.
>>> > > ***************************************************
>> > -----------------------------------------------------------
>> > Semyon Grodsky
>> > Computer and Space Science Building (Bldg. #224), Room 2409
>> > Department of Atmospheric and Oceanic Science
>> > University of Maryland
>> > College Park, MD 20742
>> > Phone:  301-405-5330
>> > Fax:    301-314-9482
>> > E-mail: senya at atmos.umd.edu
>> > _______________________________________________
>> > gradsusr mailing list
>> > gradsusr at gradsusr.org
>> > http://gradsusr.org/mailman/listinfo/gradsusr
> ***************************************************
> The information contained in this e-mail message 
> is intended only for the use of the recipient(s) 
> named above and may contain information that is 
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> If you are not the intended recipient, you may not
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> received this communication in error, please notify 
> the sender immediately by e-mail, and delete the original message.
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