[CF-metadata] standard name proposal for CCMVal

Martin Juckes m.n.juckes at rl.ac.uk
Tue Mar 4 03:19:36 MST 2008


> Date: Sun, 24 Feb 2008 16:24:06 +0000
> From: Jonathan Gregory <j.m.gregory at reading.ac.uk>
> Subject: [CF-metadata]  standard name proposal for CCMVal
> To: cf-metadata at cgd.ucar.edu
> Message-ID: <20080224162406.GB21005 at met.reading.ac.uk>
> Content-Type: text/plain; charset=us-ascii
> 
> Dear Martin
> 
> > Do people think that the use of the "_content" syntax should be 
depricated?
> 
> I admit responsibility for the choice of "content" to mean "mass per unit 
area"
> and "energy_content" for "energy per unit area" in the original set of 
standard
> names (back in 2001!). I agree, that is a similar case. It is terminology 
that
> was already in use in some connections e.g. soil moisture content, but it is
> not self-explanatory. Perhaps that was the wrong decision and we should have
> had soil_moisture_mass_per_unit_area etc. instead, although no-one's thought 
it
> obscure enough to propose changing it, so I assume it's not too bad. We 
*could*
> change it, using aliases, but there are 117 existing standard names that use
> "content" in that way now, so it's pretty well entrenched.
> 
> As I said before, I think our choice of standard names is some compromise
> between convenient terminology for brevity, and definition to make them more
> self-explanatory. There are other phrases apart from "content" which we use
> with standardised meanings that may need explanation, such as "tendency" to
> mean time-derivative. But whereas "mass per unit area" is more cumbersome
> than "content", and "derivative with respect to time" is more cumbersome 
than
> "tendency", "moles" is not more cumbersome than "mole burden", so that is a
> difference between these cases.

But "moles" is not self-explanatory!  mole_burden is less cumbersome than 
moles_in_whole_atmosphere. 

In addition, the use of burden would make the data discoverable by people 
looking for data which is referred to in the literature as burden.

> 
> Another reservation about "mole burden" that has occurred to me is that it 
is
> a term that naturally refers to a minor consituent, which is carried out by
> the bulk of the air. But you might wish to refer to the number of moles of
> nitrogen in the atmosphere, or the number of moles of air. I wouldn't find 
it
> natural to call these a "burden" too.

So the names have to be `natural' too? When did that creep in as a 
requirement?

> 
> > If the usage in the IPCC reports are not significant, what kind of 
evidence
> > of previous usage would be considered meaningful?
> 
> I don't think that the terminology used in the IPCC reports was generally
> designed to be self-explanatory, unlike CF metadata. In the parts I was
> connected with, we were concerned to be consistent in our terminology, and
> to make sure it was defined correctly in the glossary, but the terminology
> which we used (and standardised within the report as far as possible) was 
that
> used in the literature being assessed i.e. specialist terminology. I think 
the
> the issue of self-explanatory terminology is more important for metadata 
than
> it is in text document, where you have the context to help you understand 
it,
> and that serves to clarify the terminology in a way that isn't possible for
> standard names.
> 

I think that your constant referal to the IPCC reports as specialist is 
blocking constructive discussion here. 

cheers,
Martin



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