Dear Richard I've just looked through the definitions again while thinking about Rich's ticket 93, and I agree with you (again) that this needs clarification. In some cases it could be made clearer which is the quantity that you would expect to be used as a vertical coordinate, with the standard name that is given in the relevant definition of Appendix D.
Hybrid height is a peculiar case. It says, "There is no dimensionless hybrid height coordinate. The hybrid height is best approximated as a(k) if a level-dependent constant is needed." There are two unusual things about this. * It seems inevitable that the vertical coordinate is indeed one of the terms, as you said. There must be a 1D monotonic vertical coordinate variable, and I can't see what it could be other than a(k), the height part of the hybrid coordinate. Perhaps it is this quantity, therefore, which has the standard_name of atmosphere_hybrid_height_coordinate, even though it is not itself really a hybrid. What do you think? * It's not dimensionless. Although Appendix D was introduced for coordinates which are dimensionless, I don't think that's a necessary restriction, because formula terms can have a more general function of computing a multidimensional vertical coordinate from various 1D terms, which might be either dimensional or dimensionless, one of which could be the 1D monotonic vertical coordinate variable. So I'm disagreeing with what I said before. The vertical coord var might have to be one of the terms. If you agree and have time to draft a defect ticket, or a ticket to modify the convention if it seems more substantial, that would be interesting and useful. Best wishes and thanks Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
