Hello,
I also support the the flexibility given by the conventions.
All the best,
David
---- Original message from David Charles Hassell (08AM 30 Apr 15)
> Date: Thu, 30 Apr 2015 08:13:42 +0000
> From: David Charles Hassell <d.c.hassell at reading.ac.uk>
> To: "Little, Chris" <chris.little at metoffice.gov.uk>,
> "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] Is there ambiguity in labelling climatological
> time. Was: CF-metadata Digest, Vol 144, Issue 25
>
> Hello Chris, Charlie, Karl, ....
>
> Personally, I prefer to use the first (or last) year, as this is unambiguous. Ambiguities about how to define the mid-year could arise depending on whether number of years in the climatology is odd or even. The mid-year could, of course, be carefully defined, but the definition would be arbitrary, I think.
>
> (I used "year" here, but the same argument applies to "day")
>
> All the best,
>
> David
> ________________________________________
> From: CF-metadata [cf-metadata-bounces at cgd.ucar.edu] on behalf of Little, Chris [chris.little at metoffice.gov.uk]
> Sent: 30 April 2015 08:58
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] Is there ambiguity in labelling climatological time. Was: CF-metadata Digest, Vol 144, Issue 25
>
> Dear Charlie, Karl, and other CF'ers,
>
> If you can all agree on a preferred convention for whether the first, last, mid, or some other date is used to label a climatology, or a way of unambiguously labelling which has been used, it would make lots of people happier.
>
> Does anyone know of any WMO Climate Commission, or Commission for Basic Systems, guidance?
>
> Best wishes, Chris
>
> -----Original Message-----
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of cf-metadata-request at cgd.ucar.edu
> Sent: Thursday, April 30, 2015 7:44 AM
> To: cf-metadata at cgd.ucar.edu
> Subject: CF-metadata Digest, Vol 144, Issue 25
>
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> Today's Topics:
>
> 1. Is there ambiguity in labeling climatological time
> coordinates? (Charlie Zender)
> 2. Re: Is there ambiguity in labeling climatological time
> coordinates? (Karl Taylor)
> 3. Ancillary variables in coordinate variables (latitude,
> longitude, ...) (Kristian Sebasti?n)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 29 Apr 2015 17:11:07 -0700
> From: Charlie Zender <zender at uci.edu>
> To: CF Metadata Mail List <cf-metadata at cgd.ucar.edu>
> Subject: [CF-metadata] Is there ambiguity in labeling climatological
> time coordinates?
> Message-ID: <5541731B.50800 at uci.edu>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Dear CF'ers,
>
> The draft 1.7 conventions example Example 7.8. Climatological seasons has the following for the time coordinate:
>
> time="1960-4-16", "1960-7-16", "1960-10-16", "1961-1-16" ;
>
> All else being equal, are the values
>
> time="1975-4-16", "1975-7-16", "1975-10-16", "1976-1-16" ;
>
> also be acceptable for this same example?
>
> The underlying question is whether there is permissible ambiguity in the time coordinate values, or if for some reason the beginning year (1960) must be used as in this example. An alternative choice that seems reasonable to me is the use of the midpoint year (1975). I'm unsure whether 1960 was chosen arbitrarily or because one is expected to apply the minimum operation discussed in this example (seasonal minimum temperature) to the values of the time coordinate as well.
>
> Thanks,
> Charlie
> --
> Charlie Zender, Earth System Sci. & Computer Sci.
> University of California, Irvine 949-891-2429 )'(
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 29 Apr 2015 18:22:45 -0700
> From: Karl Taylor <taylor13 at llnl.gov>
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] Is there ambiguity in labeling
> climatological time coordinates?
> Message-ID: <554183E5.1080104 at llnl.gov>
> Content-Type: text/plain; charset="windows-1252"; Format="flowed"
>
> Hi Charlie,
>
> I think the only guidance CF provides is:
>
> "The time coordinates should be values that are representative of the
> climatological time intervals, such that an application which does not
> recognise climatological time will nonetheless be able to make a
> reasonable interpretation"
>
> I think for your case any consecutive dates within the climatological
> period would do, but like you I'd probably choose the middle year (or
> perhaps the first year, as in the example).
>
> Hope others will correct me if I'm wrong.
>
> Karl
>
> On 4/29/15 5:11 PM, Charlie Zender wrote:
> > Dear CF'ers,
> >
> > The draft 1.7 conventions example Example 7.8. Climatological seasons
> > has the following for the time coordinate:
> >
> > time="1960-4-16", "1960-7-16", "1960-10-16", "1961-1-16" ;
> >
> > All else being equal, are the values
> >
> > time="1975-4-16", "1975-7-16", "1975-10-16", "1976-1-16" ;
> >
> > also be acceptable for this same example?
> >
> > The underlying question is whether there is permissible ambiguity
> > in the time coordinate values, or if for some reason the
> > beginning year (1960) must be used as in this example. An alternative
> > choice that seems reasonable to me is the use of the midpoint year
> > (1975). I'm unsure whether 1960 was chosen arbitrarily or because one
> > is expected to apply the minimum operation discussed in this example
> > (seasonal minimum temperature) to the values of the time coordinate
> > as well.
> >
> > Thanks,
> > Charlie
>
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> ------------------------------
>
> Message: 3
> Date: Thu, 30 Apr 2015 08:43:54 +0200
> From: Kristian Sebasti?n <ksebastian at socib.es>
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] Ancillary variables in coordinate variables
> (latitude, longitude, ...)
> Message-ID:
> <CAGfa=MDW7dpnpZj=EOJgGrK2eQ9o1Nvtz_dcUx-EeMH4MyBWXw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Dear CF community,
>
> We have some dataset with quality controls applied to the coordinate
> variables, such as latitude and longitude coordinate. The result are
> quality control variables that we associate as ancillary variables of the
> coordinate variables with the ancillary_variables attribute. For example,
> the LAT coordinate variable has the ancillary variable QC_LAT. The dataset
> http://thredds.socib.es/thredds/dodsC/drifter/surface_drifter/drifter_svp052-ime_svp017/L1/2014/dep0001_drifter-svp052_ime-svp017_L1_2014-05-25.nc
>
> The cf-conventions clarifies the use of the ancillary_variables attribute
> for data variables but not for coordinate variables. My question is, Is the
> ancillary_variables attribute in coordinates variables compliant with the
> cf-conventions?
>
> Best regards,
>
> Kristian
>
> --
>
> Kristian Sebastian Blalid
> SOS Division: Data Center Technical
> Tel: 971439860 - Fax: 971439979
> E-mail: kristian.sebastian at socib.es
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--
David Hassell
National Centre for Atmospheric Science (NCAS)
Department of Meteorology, University of Reading,
Earley Gate, PO Box 243,
Reading RG6 6BB, U.K.
Tel : +44 118 3785613
E-mail: d.c.hassell at reading.ac.uk
Received on Wed May 06 2015 - 06:16:59 BST
