[CF-metadata] standard name proposal for CCMVal

From: Jonathan Gregory <j.m.gregory>
Date: Sun, 24 Feb 2008 16:24:06 +0000

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.

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.

> 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.

Best wishes

Jonathan
Received on Sun Feb 24 2008 - 09:24:06 GMT