Dear @kenkehoe You write
> Requiring the data producer to explain the full process in a `cell_methods` > attribute that the data user will only glance at is an excessive requirement > on the data producer, if even possible and I agree that that. I didn't suggest such a requirement myself. In https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/issues/320*issuecomment-904586884__;Iw!!G2kpM7uM-TzIFchu!lkfdJNIu6LL1jWZiX6DukQNDR9SRz_kRTP6Msq1-SXTbqXxbTsq7PsWOAzZ9GuOzYxVMtcXVaXo$ I wrote, > I agree that what I sketched above is insufficient to deal with your more > complex description of uncertainty computations. ... I agree that some > further attributes may be needed to provide information about how the > uncertainty is derived. The detailed description which you give in these two examples is probably too cumbersome for `cell_methods`, as you say, and maybe `comment` is where it should go, as you have shown. Omitting the `comment` and `missing_value` and using shorter variable names for brevity, my suggestion for these examples would be ``` float random(time); random:standard_name = "something"; random:long_name = "Random uncertainty in calibration_e_LH"; random:units = "1"; random:cell_methods = "uncertainty: standard_error (statistical)"; float systematic(time); systematic:standard_name = "something"; systematic:long_name = "Systematic uncertainty in calibration_e_LH"; systematic:units = "1"; systematic:cell_methods = "uncertainty: standard_error (subjective)"; ``` I don't know what quantity this is so I can't suggest the standard name! But it doesn't need a modifier in this suggestion. > If we are making the process of determining if a variable is an uncertainty > more difficult than just searching a `comment` attribute for the word > _uncertainty_, we are making things too complicated. The proposal is that to determine whether a variable contains an uncertainty you would search the `cell_methods` attribute for the word `uncertainty:`. That's just the same level of complexity as you advocate. The next word in the attribute states the kind of statistic which is used to measure the uncertainty (`standard_error` in this case). The next word (the comment in `()`) indicates whether it is random or systematic (which I called `statistical` and `subjective` following the GUM, which you cited). As I said before, the assumption elsewhere in CF (standard names in particular) is that the absence of a qualification implies the "whole thing". Following this, if the `cell_methods` `uncertainty` entry contains neither `statistical` nor `subjective`, we assume it is the "total" error. 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-920050512__;Iw!!G2kpM7uM-TzIFchu!lkfdJNIu6LL1jWZiX6DukQNDR9SRz_kRTP6Msq1-SXTbqXxbTsq7PsWOAzZ9GuOzYxVMPB_EuNc$ 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.
