[CF-metadata] CMIP5 ocean biogeochemistry standard names

From: John.Dunne at noaa.gov <John.Dunne>
Date: Fri, 26 Mar 2010 13:45:00 -0400

Hi Alison,

Here are the responses you requested...

> > (1) I don't understand what the definition of picophytoplankton
> (carbon
> > concentration from the picophytoplankton (<2 um; < 5um) component
> > alone) means Does it mean cells between 2 and 5 um in size, in
> which> case it should be expressed as 2-5um, or does it mean
> something else?
> >
>
> I agree that this definition doesn't make sense as it stands - I'll
> check with John Dunne.

The wishy-washiness of this definition was intended to account for the
fact that some groups make their distinction of smallest phytoplankton
class at the <2um size, while others do it at the <5um size. I agree
that it would be better to have a single cut off for clarity. Perhaps
we should use the '2um' designation to be consistent with the
traditional definition of 'picoplankton' (where nanoplankton is the 2-5
umclass), and leave the individual participants to determine whether
they think their definition is consistent with this designation.

> > (3) 'mole_concenration_of_dissolved_iron_in_sea_water'. Besides the
> > typo (concentration), does this refer to iron in all oxidation
> states> (Fe2+/Fe3+) and chemical environments. If so, calling it
> 'total iron'
> > might be better.
>
> Thanks for pointing out the typo - I'll correct it. I think whenever
> the word "total" has come up in standard names proposals in the past
> that we have tried to avoid using it. Indeed, there are no standard
> names that use the term. I think "iron" essentially should be
> understood to mean "total iron" and if we want more specific names for
> Fe2+, etc, we should introduce terms such as "divalent iron" in the
> waythat we have done for elemental and divalent mercury in the
> atmosphere.Having said all that, I think it would be helpful if
> John could clarify
> the definition.

In the geochemical literature, 'total' iron refers to the sum of iron
associated with the particulate organic, particulate inorganic,
dissolved organic and dissolved inorganic components (both Fe2+ and
Fe3+). As we treat phytoplankton iron and particulate detrital iron
separately from dissolved, 'total' does not equal 'dissolved'. As most,
if not all, of the models do not distinguish between Fe2+ and Fe3+, I
think we could simply add a note in the definition to the effect that
'dissolved' is intended to represent both Fe2+ and Fe3+.

Cheers, John
Received on Fri Mar 26 2010 - 11:45:00 GMT