Hello @JimBiardCics , thanks again for a detailed response. I support the aim of allowing users to place either a UTC or TAI time stamp in the units statement (so that they can do whatever fits with their existing processes) and making it possible for them to declare which they are using. The suggestion of using the calendar attribute for this makes sense.
I think we are agreed now that there is a unique and well defined mapping between these time stamps, and there is a unique and well defined way of calculating an elapsed time (in the SI sense) between any two such time stamps. I don't see how the layers of complexity need to come into this. The TAI time stamp counts up with 86400 seconds per TAI day, while the UTC has a known selection of days with an extra second in the final minute. All we can do is define these things clearly, we can't force users to adopt best practice. As you say, some people don't have accurate clocks, just as some record temperature without accurate thermometers. I would disagree with you on one point: a non-monotonic data array is no problem, but a non-monotonic coordinate array is a problem. As Chris commented, people who need to know about this sort of problem are likely to have sorted it out before they get around to writing NetCDF files. -- You are receiving this because you commented. Reply to this email directly or view it on GitHub: https://github.com/cf-convention/cf-conventions/issues/148#issuecomment-434771654
