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[CF-metadata] "positive" attribute

From: Forrest Hoffman <forrest>
Date: Thu, 28 Jun 2007 10:07:38 -0400

Bryan:

That's what made sense to me as well, but it appears that directionality
is included in many standard_names already whenever that sign convention
is not implied by a process-based description in the standard_name.

It would be helpful if a consensus were reached on this issue before I
start proposing lots of new standard_names.

Forrest

Bryan Lawrence wrote:
> Your original email started me worrying about a number of things. I'm aware
> that we're busy building standard names with embedded sign conventions, and
> I'm not entirely comfortable about that.
>
> What happens if I build (or have) a model which happens to have a different
> sign convention than the one chosen thus far? Do I have to reprocess all my
> data, or introduce a duplicate set of standard names with the opposite
> convention embedded. The latter doesn't seem right!
>
> I would rather we expanded the use of the positive attribute in a sensible
> manner in conjunction with new groupings of standard names.
>
> Bryan
>
>
>
>
> On Thursday 28 June 2007 14:45:11 Forrest Hoffman wrote:
>
>> Bryan:
>>
>> Jonathan Gregory has been offering suggestions and help off list for a
>> suite of new standard_names I would like to propose. Jonathan pointed
>> out that the sign convention is specified in the standard_name, so use
>> of the "positive" attribute is not needed.
>>
>> Thanks!
>>
>> Forrest
>>
>> Bryan Lawrence wrote:
>>
>>> Hi Forrest
>>>
>>> Are some of these going to be implicit in the standard name? (I imagine
>>> no always, so I can see the sense of the argument). Personally I don't
>>> have a problem with introducing an extended controlled vocabulary into
>>> the positive argument.
>>>
>>> Cheers
>>> Bryan
>>>
>>> On Tuesday 26 June 2007 15:03:31 Forrest Hoffman wrote:
>>>
>>>> Much of the CF-1.0 convention seems to be atmospherically biased. I
>>>> know that's because it is the atmospheric scientists that pioneered all
>>>> these developments. In attempting to adopt this methodology for other
>>>> components of Earth System Models, I'm concluding it may be necessary to
>>>> extend the convention to adequately support the needs of these
>>>> components.
>>>>
>>>> For example, it appears to me that the "positive" attribute for CF-1.0
>>>> variables is really used to describe vertical directionality. This
>>>> attribute is often traditionally associated with atmospheric radiation
>>>> variables. In CMOR, the only valid attribute values are "up" and
>>>> "down."
>>>>
>>>> In terrestrial biogeochemistry various sign conventions exist, and I had
>>>> hoped to use the "positive" attribute to describe the desired convention
>>>> where vertical directionality is not important or known. The values I
>>>> had initially hoped to use for the "positive" attribute for some
>>>> biogeochemistry variables were "into biosphere" and "out of biosphere"
>>>> and "into pool" and "out of pool."
>>>>
>>>> It would seem that "vertical-directionality" would be a more appropriate
>>>> attribute where the "positive" attribute has been traditionally
>>>> applied. I'm sure nobody wants to change this now, but I'm looking for
>>>> suggestions for attributes that might describe sign conventions where
>>>> directionality is either not vertical or is more conceptually abstract.
>>>> We could establish a "negative" attribute, but users might expect some
>>>> kind of correspondence with the "positive" attribute. A
>>>> "sign-convention" attribute might work, but it might have many possible
>>>> values. Any other suggestions?
>>>>
>>>> Forrest
>>>>
>
>

-- 
Forrest Hoffman                       mailto:forrest at climatemodeling.org
Oak Ridge National Laboratory         mailto:forrest at computer.org
Climate & Carbon Research Institute   http://www.climatemodeling.org/~forrest
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Building 5600, Room C221, MS 6016     (865) 576-5491 fax
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"The ability to speak doesn't                  Check out ORNL's
 make you intelligent."               Climate & Carbon Research Institute
              -- Qui-Gon Jinn           at http://www.ccs.ornl.gov/CCR/
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