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 <taylor13 at llnl.gov> 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
>>
Received on Mon Aug 08 2011 - 16:37:17 BST
