Hello Jonathan,
This opens up the issue of basing Standard Names on some sort of semantic model. It's not just number of names - which is greater than Philip imagines because we are supporting multiple concentration parameters (v/v, moles/v etc.) - but issues like spelling errors creeping in (I have always found organic nomenclature to be much more error prone than other text) and the need to link to chemistry domain standards as recently raised by Christiane.
One possibility would be to link consideration of this issue to the CF controlled vocabulary proposal that Frank recently put forward leading to the development of ontological support for CF. If people think this is a good way to go then I'll try and find some time to take it forward with Frank (get a Trac proposal going) when we're both around in early August.
Cheers, Roy.
>>> Jonathan Gregory <j.m.gregory at reading.ac.uk> 07/16/07 11:07 PM >>>
Dear Philip
> First, the list of CF standard names will ultimately become very long
> (with concentrations, tendencies, emissions, depositions, and many other
> quantities for each species)
I agree that if we carry on as we are presently working, we could add hundreds
of names to the standard name table for chemistry. I don't think that is in
itself a problem, though, so long as it is easy to search the table, and it's
available in machine-readable form for programs.
> Second, unless proposers are very diligent, or there is some mechanism to
> avoid it, there will end up being a lot of 'holes' in the convention.
> For example, long lists of wet_deposition_of_X, and emission_of_Y, could
> be added, but with X and Y being different sets which only partially
> overlap.
Yes, but that also doesn't necessarily matter, does it? We already have plenty
of holes like that in other areas, because we have not added names until some-
one has needed them. One way in which holes may be a problem is that when you
find one you need to be filled, you have to request a new name. But if it is
an obvious interpolation, there should be no problem with including it.
> Would it make more sense to represent chemical quantities under CF by
> splitting the standard name into two pieces, e.g. 'Quantity_of_X' and
> 'X_is_species_name' ?
We could do something like that. For consistency with other similar cases,
we would make one of them a coordinate variable with string values. I expect
that in some chemistry models there are data variables which have a dimension
in chemical species, and this approach would represent that kind of
organisation. We have started to do this with land-surface types. However,
I do not actually think we need to do it for chemical species, because they
are generally well-defined and discrete, even though numerous. Land-surface
types are rather more model-dependent and so far we have not standardised them;
it is convenient to put the non-standardised part of the quantity in a
coordinate variable.
Best wishes
Jonathan
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Received on Tue Jul 17 2007 - 08:37:17 BST
