Hi Alison, et al.
On the burden issue I would say that I am pretty much on-the-fence. I see
the merits of both arguments. I would also say that both options are
good, so I don't think there is a wrong choice.
The question of 'passive' can also be discussed on the flip-side by
discussing opposite: 'interactive'. Chemicals can be interactive with
other chemicals, aerosols, clouds, radiation, wet & dry deposition, and
vegetation, among other things. Thus a tracer can be passive to any
combination of such interactions. Handling all the possibilities through
the standard names probably wouldn't be feasible.
Would there be a way of listing the 'interactions' or 'non-interactions'
somewhere else in the metadata?
Alternatively, most of the combinations of interactions will never be
used in practice. Would it be possible to have standard names for
passive1, passive2, passive3, etc, with the combination of interactions
defined for each case as needed?
On the issue of the definitions for Cly, NOx, NMVOC, and other chemical
families, it is true that different models can include different species
in a family. However, the family is typically useful because the total has
a meaning independent of the exact split between its component
parts, so that output of families from different models will be somewhat
comparable.
This issue is similar to the challenge of defining 'ozone production'.
In that case, I believe CF decided that the merits of including the
quantity outweighed the ambiguity in the definition. I believe the same
should be true here too.
Best wishes,
Philip
On Thu, 6 Mar 2008, Jonathan Gregory wrote:
> Dear Martin
>
>> Concerning the passivity of passive ozone, I believe that it is absolute. I.e.
>> it has no feedbacks on the model evolution. If we start listing the feedbacks
>> which it doesn't have we need to anticipate all feedbacks for true ozone that
>> might be incorporated into the models in the future. Isn't it simpler to say
>> that there are none?
>
>> Chemically_passive would be wrong, as it is also radiatively passive.
>
> Ah. Obviously that didn't occur to me or Alison, and my feeling is that
> indicates "passive" to be an uninformative term. In what respect is it "ozone"?
>
> Cheers
>
> Jonathan
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
------------------------------------------------------------------------
Dr Philip Cameron-Smith Energy & Environment Directorate
pjc at llnl.gov Lawrence Livermore National Laboratory
+1 925 4236634 7000 East Avenue, Livermore, CA94550, USA
------------------------------------------------------------------------
Received on Thu Mar 06 2008 - 16:52:08 GMT
