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[CF-metadata] Is there a convention defining day offsets to use for monthly average time series?

From: Karl Taylor <taylor13>
Date: Mon, 08 Aug 2011 15:16:34 -0700

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
>
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