Dear Philip, Roy and Jonathan,
Thank you all for your input. I know that Christiane is also preparing
something for the list and I would like to wait for her comments before
coming to any final conclusions on the chemistry names.
Roy wrote:
>
> Hi Alison,
>
> I totally agree with Philip. We have to strike a balance between
> discussing/defining absolute best practice and the requirements of the
CF
> user community to be able to get on with their work. The semantic
model
> is a case in point - something we can aspire to, but in no way should
it
> be become a blocker to standard name allocation. The essential thing
as
> Jonatahn says is to ensure that the definitions of the terms are as
> accurate and as complete as we can make them.
>
> Cheers, Roy.
>
>
> >>> "Philip J. Cameron-smith" <cameronsmith1 at llnl.gov> 11/6/2007 7:14
pm
> >>>
>>
>> Hi Alison,
>>
>> I wouldn't worry about isomers at this point. You are absolutely
correct
>> that xylene has three structural isomers, and they are a bit
different
>> chemically. However, there are different sorts of isomer, including
>> isotopic isomers, that will apply to many or all of these species.
>>
>> The good news is that it is generally assumed that if nothing is
specified
>> then a chemical name includes all of the isomers. Of course, it
would be
>> good to state that in a comment somewhere so that there can be no
doubt.
I too agree that we need to balance allowing people to get on with their
work against developments to CF as a standard. This is precisely the
reason that I am suggesting we go ahead and include most of the
currently proposed chemistry names at the next update. At the same
time, however, I don't want to paint CF into a corner that will make
things more difficult as future developments come along. That is why I
was being cautious about including 'group' names in the very short term
and, as I explained, I am not necessarily the best person to spot which
are the group species! For the species proposed so far, if there are no
strenuous objections, I would favour putting in all the mole_fraction
names.
Philip wrote:
> I can live with that. I'm sure that a short bit of text could be
crafted
> to state the distinctions being ignored, if it hasn't been written by
> someone already.
>
>>On Tue, 6 Nov 2007, Jonathan Gregory wrote:
>>
>> Dear Philip
>>
>>> On the issue of ozone GROSS production and loss which I raised in
>>> (http://www.cgd.ucar.edu/pipermail/cf-metadata/2007/001788.html) I
am
>>> conflicted. This is a useful and commonly reported variable, but
the
>>> definition is not universally agreed upon. In practice, experts
>>> generally use definitions that are within the same ball-park as each
>>> other, but an outside user could be led astray, and judicious care
>>> needs to be used when comparing figures from different models.
>>> Whether this is enough to stop it being accepted by CF, I don't
know.
>>
>> I don't know the details of this case, of course, but I don't think
>> that's a reason not to include a name for ozone gross production. If
>> it is useful to compare quantities from different datasets for
certain
>> purposes, even though they may have somewhat different definitions,
>> then it will be useful to assign them a common name to indicate they
>> are comparable. That is the main purpose of standard names. To avoid
>> misunderstanding, the definition could state what distinctions are
>> being ignored. For more exacting applications in which the
differences
>> of definition are material, alternative more precisely phrased
>> standard names could be devised.
>>
I agree that provided we can define exactly what we mean by a name,
there is no reason not to include it. I would be grateful if someone
could come up with the bit of text needed to clarify this particular
name. Would similar considerations also apply to the other
chemical_gross_production|destruction names?
Philip wrote:
>
> I also spotted a trivial typo: there was a space instead of an
underscore
> in
>
"tendency_of_atmosphere_mole_concentration_of_methane_due_to_chemical_gr
o
> ss destruction"
>
Thanks! I'll correct that.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Fax: +44 1235 446314
Rutherford Appleton Laboratory Email: J.A.Pamment at rl.ac.uk
Chilton, Didcot, OX11 0QX, U.K.
Received on Wed Nov 07 2007 - 05:31:29 GMT
