Dear Ken Yes, the `standard_error` modifier is not in `cell_methods` because it doesn't relate to a particular dimension. But considering (as I said above) that the statistical standard error of a quantity is 1/sqrt(N) times the standard deviation over an imaginary `realization` dimension which indexes the observations of the quantity, I think it's very similar to a cell method.
My suggestion above is to define `standard_error` as a new cell method, and introduce a special keyword of `uncertainty` which would go in place of the dimension, indicating a statistic calculated over a set of realisations, thus making `cell_methods="uncertainty: standard_error"`. There would be no need to use the `standard_error` modifier. I think some of the comments in the previous email discussion, as well as yours and @larsbarring's, may be partly addressed by keeping in mind that the `standard_name` is __not__ the entire description of the quantity. The `cell_methods` is often a very important qualifier. For example, `standard_name="air_temperature"` with `cell_methods="time: mean longitude: maximum"` means the zonal maximum of the time-mean air temperature. I appreciate the point that a standard deviation "feels" a bit different from a mean, and a variance even more so because of its different units, but I can't see a clear justification for treating these two differently from mean, median, mode or other cell methods - they are all statistics which characterise variation of a single quantity over its dimensions. I agree that what I sketched above is insufficient to deal with your more complex description of uncertainty computations. I didn't write any more because I'd already written quite a lot! I agree that some further attributes may be needed to provide information about how the uncertainty is derived. 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://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/320*issuecomment-904586884__;Iw!!G2kpM7uM-TzIFchu!lkbolIGlrdEUhW5OXk8GjSjelAX1SdKy30TjHAE8y84X6fMAq2W1YJIYeVqi3hdxKt546DvJPng$ This list forwards relevant notifications from Github. It is distinct from [email protected], 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 [email protected].
