[CF-metadata] "positive" attribute

[Forrest Hoffman]

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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