Hi Roy,
The indication I had received from other sources (when I asked them why CF didn't seem to have any production per unit volume names that I could find) was that this parameter was generally measured only at the ocean surface, via satellites -- hence per unit area was the common unit. Your explanation adds a lot to my understanding -- and maybe should be reflected in the descriptions!
Thanks!
John
On Nov 4, 2013, at 14:18, "Lowry, Roy K." <rkl at bodc.ac.uk> wrote:
> Hi John,
>
> Production per unit volume is the usual parameter measured in the oceans. What is usually done is to measure this at maybe half a dozen depths at a given position between the surface and 100m and then there is an integration procedure that can be done on this dataset to produce a single value of production per unit area for that position - I guess with the objective of making oceanographic data compatible with terrestrial for global aggregates.
>
> The tow oceanographic parameters have different dimensionality and therefore need to be described by different standard names.
>
> Cheers, Roy.
>
> ________________________________________
> From: CF-metadata [cf-metadata-bounces at cgd.ucar.edu] On Behalf Of John Graybeal [john.graybeal at marinexplore.com]
> Sent: 04 November 2013 15:55
> To: alison.pamment at stfc.ac.uk
> Cc: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] new standard name for primary production of carbon per unit volume
>
> Hi Alison,
>
> First change is fine by me.
>
> Second change is fine for _my_ request. I note that most terms to date (and all terrestrial terms?) consider productivity per unit area; mine is the first, or one of the first, that is per unit volume. (The difference is reflected in the units.) The definition of "net primary production" needs to either be written generically (e.g., "per unit area or volume according to the units"), or we'll need two different concepts. (I vaguely recall a notion that productivity could be by unit area and production by unit volume, but have no personal expertise.)
>
> John
>
>
> On Nov 4, 2013, at 01:33, alison.pamment at stfc.ac.uk wrote:
>
>> Dear John G.,
>>
>> Some time ago you proposed a standard name net_primary_production_of_carbon_per_unit_volume_in_sea_water with canonical units of kg m-3 s-1.
>>
>> The proposal is certainly consistent with the syntax of existing productivity_of_carbon names. However, there ensued some discussion as to whether production|productivity_of_carbon means the same as production|productivity_of_biomass_expressed_as_carbon. I think the answer to this question is actually 'yes'. The definitions even say ' "Production of carbon" refers to the production of biomass expressed as the mass of carbon which it contains.' I think we need to be careful to retain the terms "productivity" or "production" of carbon as part of the names because these are the terms widely used and understood by the land surface modellers and ocean biogeochemists. However, in the interests of making standard names as standard as possible, I suggest that we should in fact insert "expressed_as". For example, net_primary_mole_productivity_of_carbon_by_diatoms would become net_primary_mole_productivity_of_biomass_expressed_as_carbon_by_diatoms and your proposed name would be
> co
>> me net_primary_production_of_biomass_expressed_as_carbon_per_unit_volume_in_sea_water. The change would affect eleven existing names. Would that be acceptable? Does anyone else object to the change?
>>
>> Regarding the definition of the proposed name, I see that you have tried to make it consistent with existing net_primary_productivity names. Looking through the standard name table I have found that we have two versions of the wording that have been tailored to land based or ocean based photosynthesis, respectively. See, for example, the definition of net_primary_mole_productivity_of_carbon_by_diatoms versus that of net_primary_productivity_of_carbon_accumulated_in_leaves. I think it would be better to settle on a single wording for all net_primary_production/productivity names, regardless of where the process is taking place, so I suggest the following:
>> " "Production of carbon" refers to the production of biomass expressed as the mass of carbon which it contains. Net primary production is the excess of gross primary production (rate of synthesis of biomass per unit volume from inorganic precursors) by autotrophs ("producers"), for example, photosynthesis in plants or phytoplankton, over the rate at which the autotrophs themselves respire some of this biomass. "
>>
>> Is this OK? If so, I will amend the definitions of the existing names to all have consistent wording.
>>
>> Thanks for your patience,
>> Alison
>>
>> ------
>> Alison Pamment Tel: +44 1235 778065
>> NCAS/British Atmospheric Data Centre Email: alison.pamment at stfc.ac.uk
>> STFC Rutherford Appleton Laboratory
>> R25, 2.22
>> Harwell Oxford, Didcot, OX11 0QX, U.K.
>>
>>
>>> -----Original Message-----
>>> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf
>>> Of John Graybeal
>>> Sent: 02 July 2013 22:56
>>> To: CF Metadata List
>>> Subject: Re: [CF-metadata] new standard name for primary production of
>>> carbon per unit volume
>>>
>>> As of June 5 this revised name was requested to go with the previously
>>> submitted definition:
>>>
>>> On Jun 5, 2013, at 11:38, John Graybeal <graybeal at marinexplore.com>
>>> wrote:
>>>> So I think we have the replacement name of
>>>> net_primary_production_of_carbon_per_unit_volume_in_sea_water
>>>> pending further thoughts and responses.
>>>
>>> There has been some discussion (thank you), but to my knowledge, no
>>> outstanding requests for changes since that posting.
>>>
>>> In the definition below, I've modified bits of that definition to match the
>>> new term (production). Is this request approvable at this point?
>>>
>>> Name: net_primary_production_of_carbon_per_unit_volume_in_sea_water
>>> Units: kg m-3 s-1
>>> Definition: Net primary production is the excess of gross primary production
>>> (rate of synthesis of biomass per unit volume from inorganic precursors by
>>> autotrophs, or "producers", especially by photosynthesising plants using
>>> sunlight for energy) over the rate at which they themselves respire some of
>>> this biomass (plant_respiration, assuming all producers to be plants).
>>> "Production of carbon" refers to the production of biomass expressed as the
>>> mass of carbon which it contains.
>>>
>>> John
>>>
>>> ------------------------------------
>>> John Graybeal
>>> Senior Data Manager, Metadata and Semantics
>>>
>>> Marinexplore
>>> 920 Stewart Drive
>>> Sunnyvale, CA
>>>
>>>
>>>
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>> --
Received on Mon Nov 04 2013 - 15:54:27 GMT
