[CF-metadata] CDM calendar date handling

From: Jonathan Gregory <j.m.gregory>
Date: Mon, 22 Aug 2011 13:37:53 +0100

Dear Chris

> Perhaps there could be an attribute we could set that says whether we have accounted for leap seconds? With the absence of such an attribute to be presumed as meaning leap seconds have been ignored.

Perhaps the real-world calendars with and without leap seconds should be
regarded as two different calendars, since they have different encodings
(meaning decoding/encoding as YMD HMS <-> time-interval since reference-time).
The "true" real-world calendar is the one with leap seconds.

CF has a calendar
proleptic_gregorian

    A Gregorian calendar extended to dates before 1582-10-15. That is, a year is a leap year if either (i) it is divisible by 4 but not by 100 or (ii) it is divisible by 400.

What if we clarified this calendar as not having leap seconds? Then it could
be used for real-world applications for recent dates meaning that it was just
like the real world except that it doesn't have leap seconds.

Model calendars, which are already idealised wrt length of year, don't have
leap seconds anyway, I am sure.

Best wishes

Jonathan
Received on Mon Aug 22 2011 - 06:37:53 BST