Dear Tobias @d70-t Thanks for raising this issue. I agree with your idea of clarifying the current convention as a separate issue from adding a convention for leap seconds. As you have no doubt seen, that other discussion https://github.com/cf-convention/cf-conventions/issues/148 was very long and has stalled, because we didn't seem able to understand one another or reach a consensus. But perhaps we can return to it. If you have a definite requirement and use-case that will help.
You've labelled this ticket as a defect, and I agree that it arguably is simply an ambiguity or mistake, but in view of the history I don't think we should treat this as a defect issue. That would mean it would get accepted if no-one objected, whereas I think we should make sure there's some positive support, as required for an enhancement. Therefore I'll change the label. I hope that's OK with you. You suggest that this issue applies to all existing calendars but actually I think it only affects the default/`standard`/`gregorian` calendar. The others are used only in models and definitely have no leap seconds. Do you think that's right? It seems to me that the clearest way to describe this is as an issue affecting the computation of the interval of time between two instants of time each identified by components of date-time (year month day hour minute second). When this calculation is done, it is assumed in CF calendars that 00:00 on any calendar day is 60 seconds after 23:59 on the previous calendar day. As you say, we could simply state that this is the case. It raises questions which logically I feel we should also make clear. However, in view of the previous discussion, I think they might be contentious. * Date-times between the end of the 60th second of the last minute of one day and the first second of the next day cannot be encoded as time coordinates. That's what you mean by "measurements which happen exactly on the leap second can not be represented", isn't it. * A date-time in that excluded range is not a correct decoding of a time coordinate in CF. For instance, 60 seconds after 23:59 should always be decoded as 00:00 on the next day. * A date-time in the excluded range should not be used as a reference time in a time unit e.g. we shouldn't allow "seconds since 2016-12-31 23:59:60" as `units`. Best wishes Jonathan -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/cf-convention/cf-conventions/issues/313#issuecomment-788275980 This list forwards relevant notifications from Github. It is distinct from cf-metad...@cgd.ucar.edu, although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to cf-metadata-unsubscribe-requ...@listserv.llnl.gov.
