Dear Martin and Jonathan,

Thank you both for your comments. Regarding the provision of additional 
metadata about the particular processes included within a variable I think we 
should not change the syntax of the standard name itself for two reasons: (1) 
We would have to propose a modification to the CF conventions under a trac 
ticket which would then have to be discussed and agreed - this would delay the 
introduction of the names into the table 
(the current conventions say "A standard name contains no whitespace and is 
case sensitive" with the only exception being for the use of a standard name 
modifier); (2) I think it would be very difficult to standardize what the 
additional text should be - this is why I suggested using a comment attribute 
that allows free text to be included. There is nothing to stop co-workers 
within a project agreeing a further standardisation of the contents of the 
comment attribute to further aid data exchange but that need not be part of the 
CF conventions themselves.

In the definitions of the group chemical names such as "alkanes" we suggest use 
of the comment attribute to list the species that are included in a particular 
model. That is why I suggested the same approach for the emissions names. The 
other alternative would be to include the information using the long_name 
attribute whose values are also not standardized. Would that be more 
appropriate? Whichever attribute we choose to use, I think the standard name 
definition should include some guidance to that effect so that we at least 
encourage some standardization of which attributes to inspect for the 
information.

If we can agree on this last point I will prepare definitions for the twelve 
emissions categories based on Martin's wording and suggesting either comment or 
long_name as the place to put the additional metadata.

Best wishes,
Alison

------
Alison Pamment                          Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre    Email: [email protected]
STFC Rutherford Appleton Laboratory     
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.


> -----Original Message-----
> From: CF-metadata [mailto:[email protected]] On Behalf
> Of Jonathan Gregory
> Sent: 06 July 2012 12:19
> To: [email protected]
> Subject: Re: [CF-metadata] Warming up old stuff - 4 (emissions)
> 
> Dear Alison
> 
> Thank you for your careful and thoughtful commentary on Martin's
> proposal. I
> agree that we should accept them as they are. It may not be the last
> word, but
> that is always the case with CF! If we decide subsequently that we need
> a
> quite different approach, we will have to introduce aliases to support
> these
> names which we are adding now.
> 
> I think it is OK to recommend including further information where
> helpful,
> but I would not say in the definition that it "should" be included.
> That
> appears to mandate a standard use of a non-standardised attribute
> (comment),
> without proposing how it should be done, as Martin says. I would
> recommend
> saying something like, "If clarification is useful or necessary, it
> could be
> given in the comment attribute." In fact this may not really be
> necessary to
> say, because it's always true that one could use the comment attribute,
> or
> others such as long_name and references, to record extra information.
> 
> Best wishes
> 
> Jonathan
> _______________________________________________
> CF-metadata mailing list
> [email protected]
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
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