Hi all, Having encountered some subtle and insidious errors arising from coordinate values aligned with the end of the interval, I would argue that it's good practice to always place the time centers somewhere near the middle of the interval. It's a better match for your default mental model, and is much less likely to result in you accidentally using a single edge value as the average for an entire period when aggregating to longer timescales...
Cheers, --Seth On Mon, 08 Aug 2011 15:16:34 -0700 Karl Taylor <[email protected]> wrote: >Dear Jim, > >CF allows you considerable flexibility. The coordinate value should lie in the >open interval from the beginning to the end of the month, but otherwise is >unconstrained. Many folks put it at the mid-point of the month (half-way >between the bounds), but if your coordinate variable is an integer and the >units are "days since ...", then you can't do this, of course. > >For climatologies, see section 7.4: >http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.5/cf-conventions.html#climatological-statistics > >regards, >Karl > > >On 8/8/11 2:43 PM, Jim Biard wrote: >> Hi. >> >> I have a time series of monthly averaged values. I have an >> integer-valued time coordinate variable and an associated time_bounds >> variable. Is it correct to use the 15th of February and the 16th of all >> the other months for my time centers, or should I use the 16th of every >> month? >> >> Also, should I do anything differently if my data are climatological >> monthly averages (say, over 30 years of data)? And, in this case, >> should the time coordinate values be day numbers from the beginning of >> the 30-year time interval, the end of the time interval, or something >> else entirely? >> >> Grace and peace, >> >> Jim Biard >> _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
