Hello, In the proposed text we have:
_The parameter `sigma(k)` is defined only for the `nsigma` layers nearest the ocean surface, while `zlev(k)` is defined for the deeper layers. If the layers are numbered top-down i.e. with `k = 1` nearest the surface and increasing numbers for greater depth, then `sigma(k)` is defined for `1 \<= k \<= nsigma`. If the layers are numbered bottom-up i.e. with `k = 1` nearest the sea floor, then `sigma(k)` is defined for `nlayer - nsigma \<= k \<= nlayer`, where `nlayer` is the number of layers. It is recommended that `sigma(k)` and `zlev(k)` should contain missing data at layers for which they are not defined._ I'm still not sure how the user can know if the layers are numbered top-own or bottom-up. @johnwilkin [commented](https://urldefense.us/v3/__https://github.com/cf-convention/cf-conventions/pull/317*issuecomment-810527573__;Iw!!G2kpM7uM-TzIFchu!hmpRAPE5pg6OPeqihSMSYvgwnAIkLum1RGUagped50qJGmTSCSvoTFSZrtNQ3VfAuAg0dEWk0IA$ ): _Regardless of how the modeler orders the k index it is a universal convention that sigma, or s, increases upward from -1 at the bottom (or of c_depth) to 0 at the sea surface._ Does that mean we should work it out from inspection of the sigma values - decreasing sigma values indicate top-down, and vice versa? If so, it would be good to state that... Thanks, David -- 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/314*issuecomment-822681038__;Iw!!G2kpM7uM-TzIFchu!hmpRAPE5pg6OPeqihSMSYvgwnAIkLum1RGUagped50qJGmTSCSvoTFSZrtNQ3VfAuAg0twaM750$ 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].
