Dear Martin I like your idea of identifying the chemical compound in an extra tag in the standard_name table. Coincidentally this is very similar to what I proposed a couple of days ago in ticket https://cf-pcmdi.llnl.gov/trac/ticket/79 about vector components. There, I suggested that the standard_name table could identify the components in a separate tag e.g. eastward in eastward_wind. The reason is the same: it's difficult for a program to parse standard names.
In fact, I think this is generally a good way to address a long-standing issue. Standard names are not really intended to be parsed. Although we try to construct them systematically and consistently, they are not necessarily capable of being analysed into semantic elements. This is true particularly because we deliberately use words and phrases from natural language to make the standard_name more self-explanatory. For instance, we use "wind" rather than "air velocity", although the latter would be analogous to "sea water velocity" and "sea ice velocity". To get round this, we can record semantic markers in the standard_name table. That means the table will become a dictionary, providing some explanation of what the names mean (for use by programs - humans should be able to understand them anyway), not just a list. For consistency, I think the semantic markers should correspond to the largely systematic ways in which we have constructed the names, e.g. the phrasetypes in my lexicon http://www.met.reading.ac.uk/~jonathan/CF_metadata/14.1/#lexicon. As usual, I would not advocate doing this comprehensively, just for the cases we need, when we need them. Getting back to your particular case, I have a couple of comments: * What if there is more than one compound involved in a standard name? This could be the case with the existing construction using expressed_as, and you can probably imagine better than me other situations where standard_names might want to name more than one species. * Is it specifically only compounds that you want to identify, that is, excluding elements, lumped groups of components, ions or other chemical species? In my draft lexicon, I have a category "species". This includes all chemical species, but also biological species and some other things such as aerosol and grapel. That's because they appear in similarly patterened standard_names. Do we need to draw a semantic distinction? That would increase the number of standard_name patterns. Best wishes Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
