Good point! Thanks for pointing that out. --Seth
On Mon, 18 Mar 2013 11:14:22 +0000 "Hattersley, Richard" <[email protected]> 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: [email protected] Web: www.metoffice.gov.uk > > >-----Original Message----- >From: CF-metadata [mailto:[email protected]] On Behalf Of Seth >McGinnis >Sent: 15 March 2013 22:01 >To: Andreas Hilboll; [email protected] >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 <[email protected]> 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. >>_______________________________________________ >>CF-metadata mailing list >>[email protected] >>http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > >_______________________________________________ >CF-metadata mailing list >[email protected] >http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
