[CF-metadata] CF: new names for atmospheric chemistry and aerosols

From: Philip J. Cameronsmith1 <cameronsmith1>
Date: Thu, 25 Sep 2008 12:36:46 -0700 (PDT)

Hi Martin, Jonathan, et al.

It looks like we are pretty much in alignment on both (i) using templates
with X [which I think is an excellent idea], and (ii) the value of lumping
species.

I just want to clarify 'lumped' vs 'total'. I think we are pretty much in
agreement, but I want to make sure.

To me, when lumping species there is a sliding scale from (i) groups which
contain a small and well agreed upon set of species, to (ii) an amorphous
catch-all of many species which can differ greatly between different
models and observations. All are useful.

I would naturally use 'total' for (i), and 'lumped' for (ii). BUT, there
is no clear dividing line, as Martin illustrated.

Hence, I think it would be better for CF to stick with just one out of
'total' and 'lumped'. My vote would be for 'total' since it is already in
the list, and will be clear to both specialists and non-specialists
('lumped' might make someone think of particle clusters).

On the separate issue of naming NMHC groups/lumps, I still think that
including the minimum number of carbons in the group will go a long way
towards addressing the problems.

Best wishes,

      Philip

On Thu, 25 Sep 2008, Schultz, Martin wrote:

> Dear Jonathan,
>
> great! Sounds like we are on a good path then.
>
> Concerning the "lumped" NOx and HOx you raise a valid point -- probably
> mostly a matter of sloppiness in the jargon. It's a somewhat fuzzy divide:
> NOx is probably rather clearly defined in most applications as NO+NO2, and
> HOx is OH+HO2 (sometimes people add atomic oxygen as well if looking at the
> upper atmosphere). Then we have NOy, which was defined originally based on a
> specific measurement technology "everything that can be detected as NO after
> passage through a heated gold converter" and practically means all oxidized
> nitrogen componds with oxidation state of at least 1 (i.e. no N2O). Also you
> have RO2 which is the organic counterpart of HO2, i.e. all kinds of organic
> peroxy radicals. And here the mess fully unravels ;-) Although one would
> probably agree to the naming of "total" for these groups. For the "lumped"
> NMVOCs the situation is clearly less well defined and ultimately depends on
> the investigator who put in a couple fo hours at some point to reduce a
> mechanism of >10000 reactions to something managable in a CTM. Perhaps a
> handful of people have performed pioneering work in this area and thus we
> have a handful of fundamentally different lumping schemes.
>
> Best regards,
>
> Martin
>
>
> -----Original Message-----
> From: Jonathan Gregory [mailto:jonathan at met.reading.ac.uk] On Behalf Of
> Jonathan Gregory
> Sent: Thursday, September 25, 2008 4:53 PM
> To: Schultz, Martin
> Cc: cf-metadata at cgd.ucar.edu; Martin.Suttie at ecmwf.int
> Subject: Re: [CF-metadata] CF: new names for atmospheric chemistry and
> aerosols
>
> Dear Martin
>
> Thanks for your email. I am glad of this initiative to achieve a mapping
> between GRIB2 and CF in this area.
>
> I think the list of new species is not too large. You are right that we
> don't generally try to look ahead too far, and we add things when they are
> required.
> However, it seems appropriate to me to include things which are very likely
> to be needed in the near future, when they fit into an obvious framework.
>
> I believe I understand the scientific difference between "lumped" and
> "total".
> The need to be vague for model comparison is also fine within the standard
> name table; we give the same name to things that are intended to be
> comparable. We already have "nox" in a standard name, for instance. What I
> am not clear about is whether the word "lumped" would appear in a standard
> name, if the "lumped"
> group has a name anyway, such as hox and nox.
>
> I think that the "template" names with X in should be included in the guide-
> lines for constructions of standard names. This is similar idea to the
> section in the guidelines on "Transformations". There are other non-chemical
> templates of this kind which should likewise be shown in the guidelines. I
> had an earlier exchange on this email list with Martina about the templates;
> I think she and I agreed on some modifications to what she had originally
> proposed, but no outstanding difficulties.
>
> Best wishes
>
> Jonathan
>

------------------------------------------------------------------------
Dr Philip Cameron-Smith Atmospheric, Earth, and Energy Division
pjc at llnl.gov Lawrence Livermore National Laboratory
+1 925 4236634 7000 East Avenue, Livermore, CA94550, USA
------------------------------------------------------------------------
Received on Thu Sep 25 2008 - 13:36:46 BST