Re: [CF-metadata] CDM calendar date handling

2011-08-19 Thread Lynnes, Christopher S. (GSFC-6102)
On Aug 18, 2011, at 6:23 PM, John Caron ca...@unidata.ucar.edu wrote: In order to do calculations with times, which are often necessary, we need to be able to convert them into a form which has a fixed-length unit since a reference time (like udunits), even though that isn't the most

Re: [CF-metadata] CDM calendar date handling

2011-08-19 Thread John Caron
On 8/19/2011 7:48 AM, Lynnes, Christopher S. (GSFC-6102) wrote: On Aug 19, 2011, at 7:54 AM, Jon Blower wrote: Hi Chris, Does the calendar system usually define whether leap-seconds are taken into account or not? Generally speaking, I don't believe so, if only because calendar systems

Re: [CF-metadata] CDM calendar date handling

2011-08-19 Thread John Caron
Regarding paleoclimate, a point I forgot is that some modellers may wish to have years which are very large negative numbers (many more than four digits) if they set up the model with the true date for the run. Although for geological timescales you might say that this isn't necessary and you

Re: [CF-metadata] CDM calendar date handling

2011-08-19 Thread Lynnes, Christopher S. (GSFC-6102)
On Aug 19, 2011, at 4:12 PM, Karl Taylor wrote: Hi all, My understanding is that leap-seconds are inserted so that the calendar remains (almost) perfectly synchronized with the seasons. If, under the CF convention, leap seconds are ignored and time is recorded as, say, days since