Good point! Thanks for pointing that out.
--Seth
On Mon, 18 Mar 2013 11:14:22 +0000
"Hattersley, Richard" <richard.hattersley at metoffice.gov.uk> wrote:
>Hi Andreas,
>
>With regards to point (2): including the text " (interval: 1 month)" implies
>that the *original* data from which the monthly aggregate was calculated had a
>monthly frequency. (See section 7.3.2 of the conventions.) This is probably
>not what you intend to say.
>
>NB. Specifying the time resolution of the original data is optional - so it
>would be entirely valid to just use "time: mean" for the cell_methods
>attribute.
>
>
>Richard Hattersley
>Benevolent Dictator of Iris - a CF library for Python:
>www.scitools.org.uk/iris
>Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom
>Tel: +44 (0)1392 885702
>Email: richard.hattersley at metoffice.gov.uk Web: www.metoffice.gov.uk
>
>
>-----Original Message-----
>From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Seth
>McGinnis
>Sent: 15 March 2013 22:01
>To: Andreas Hilboll; CF-metadata at cgd.ucar.edu
>Subject: Re: [CF-metadata] how to specify time dimension for monthly averages
>
>1) Set the time values to the midpoint of the time interval.*
>
>2) Set a "cell_methods" attribute on the data variable with a value of "time:
>mean (interval: 1 month)".
>
>3) Create a time_bounds variable with dimensions (time,2) whose values are the
>start and end points of each time interval.
>
>4) Set a "bounds" attribute on the time coordinate variable equal to the name
>of your time_bounds variable.
>
>*CF allows you to put the time coordinate anywhere in the interval, but in my
>experience at the midpoint is the best option, as it is the most intuitively
>obvious and least likely to cause problems if you ever create aggregations
>over longer periods.
>
>Cheers,
>
>--Seth
>
>On Fri, 15 Mar 2013 22:45:39 +0100
> Andreas Hilboll <lists at hilboll.de> wrote:
>>Hi,
>>
>>I want to store monthly averages of gridded satellite measurements of
>>atmospheric trace gas columns. I'm wondering how I should specify the
>>time axis, i.e. set the time for each monthly aggregate to the first,
>>or the central, or the last day of the month. How should I specify that
>>the values are actually monthly averages?
>>
>>Thanks for your ideas!
>>Cheers, Andreas.
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>
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Received on Mon Mar 18 2013 - 11:38:49 GMT
