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 > > > > > > > >------------------------------------------------------------------------------------------------ > >------------------------------------------------------------------------------------------------ > >Forschungszentrum Juelich GmbH > >52425 Juelich > >Sitz der Gesellschaft: Juelich > >Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 > >Vorsitzender des Aufsichtsrats: MinDirig Dr. Karl Eugen Huthmacher > >Geschaeftsfuehrung: Prof. Dr. Achim Bachem (Vorsitzender), > >Dr. Ulrich Krafft (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt, > >Prof. Dr. Sebastian M. Schmidt > >------------------------------------------------------------------------------------------------ > >------------------------------------------------------------------------------------------------ > > > >Besuchen Sie uns auf unserem neuen Webauftritt unter www.fz-juelich.de > >_______________________________________________ > >CF-metadata mailing list > >CF-metadata@cgd.ucar.edu > >http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
