Hi John,
You might have a look at the ESMF time handling utilies for some ideas
about what a library that supports modelling (i.e., non-standard calendars)
contains.
http://www.earthsystemmodeling.org/esmf_releases/public/last/ESMF_refdoc/
Brian
On Fri, Apr 01, 2011 at 05:04:42AM -0600, John Caron wrote:
> Hi Martin and all:
>
> Im wondering what essential methods a calendar library needs to have
> to support, eg 360 day calendars? The only one that comes to mind is
> to calculate the difference between two dates in, say, seconds? What
> else?
>
> John
>
> On 4/1/2011 12:55 AM, Schultz, Martin wrote:
> >Hi Chris et al.,
> >
> > indeed it seems like some clarification is necessary about the use of different calendars in modelling. Your suggestion to "map" the 360 day calendar onto the Gregorian calendar in output files won't work: there would be no need for a 360 day calendar if it would. The idea behind fixed-length-year calendars is precisely the opposite: preserve seasonality without having to deal with leap years etc. Of course you need to adjust the solar cycle accordingly, that means your model will have a solar year that is precisely 360 days long (and not 365.25 as in reality). If you were to map these dates onto the gregorian calendar, you would have to interpolate the time axis so that days 1 to 360 fit into the range 1 to 365 or 366, respectively. Yes - a converter 360-days (or 365-days) to gregorian (and reverse) could be written, but you would redce the number of your friends if you insist that this is the only valid way to represent time of the model output ;-)
> >
> > You are right that a date such as 1960-01-31 is invalid in a 360-day calendar, and indeed a smart tool should flag this as an error.
> >
> >Hope this helps,
> >
> >Martin
> >
> >
> >
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Received on Fri Apr 01 2011 - 09:50:03 BST
