Hi John,
I must admit that I haven't systematically gone through the oceanographic Standard Names definitions looking for quality or consistency. Your e-mail caught my eye and so got comments!
hydrated silica (opal) is the most 'natural' description to me based on my time as a hands-on oceanographic data manager (1988-2001) - I don't think I've ever described SiO2 as silicon dioxide.
Now BATS was on my watch - I chaired the JGOFS DMTT through the 90s and it now looks like what you're describing is a million miles from my initial guess. The standard JGOFS protocol for sediment trappers was to measure the mass of particles trapped in a known time by a trap of known area. This gave the mass flux. A split sample was then acidified (usually fumed by conc HCl) and stuck into an elemental analyser like a Carlo Erba which gave the proportion of elemental nitrogen and elemental carbon per unit mass of trapped sediment. Multiplying these by the mass flux then gave parameters that were generally referred to as 'PON flux' and 'POC flux': the 'organic' credentials come from a (fairly safe) assumption that all nitrogen in suspended particulate material is organic and the removal of inorganic carbon by the acidification step.
I'm now getting the feeling that 'moles_of_nitrogen_per_unit_mass_in_sea_water' is an attempt to describe the organic nitrogen concentration in a suspended particulate material sample: i.e. the values multiplied with mass flux to give PON flux. Am I right? If I am then you should be looking at something like 'moles_of_nitrogen_per_unit_mass_of_suspended_particulate_matter'. Note that per unit mass of SPM is VERY different to per unit mass of sea water and 'per_unit_mass_in_sea_water' is a statement of the latter.
The other two BATS parameters you quote are:
Nitrate+Nitrite - this is inorganic nitrogen dissolved in sea water in two different oxidation states which is expressed (in the BOFS era) as the number of moles of nitrogen in a given volume of sea water. These days the preference is to give the number of moles per unit mass of sea water.
PON - this is the amount of particulate nitrogen in a given volume or mass of sea water. It is computed by measuring the amount of nitrogen per unit mass of particulate material and multiplying the result by the mass of particulate material (SPM) per unit volume or mass of sea water.
As to my organic carbon suggestion, it was simply a reaction prompted when I read your text to improve things by injecting some of my oceanographic domain expertise. I don't know the extent of the CF list readership, but I suspect I'm one of very few who have done any hands-on biogeographical measurement or data management (which to me involves gaining the same level of understanding of the measurement made as the scientist who made them).
Cheers, Roy.
________________________________________
From: John Graybeal [john.graybeal at marinexplore.com]
Sent: 28 September 2013 02:00
To: Lowry, Roy K.; CF Metadata List
Subject: Re: [CF-metadata] request #1 for names: mole concentrations and mass fractions, similar to current names
Hi Roy, all,
Thank you for your input. My comments are in line -- the one general question is how to deal with inconsistencies found vs existing definitions in the table.
As generally people haven't risen up in protest, I will prepare another request shortly. Any presentation suggestions are welcome.
On Sep 12, 2013, at 23:54, "Lowry, Roy K." <rkl at bodc.ac.uk> wrote:
> Biogenic silica isn't simply silicon dioxide - it's the hydrated amorphous form commonly known as opal. How about replacing 'silicon dioxide' by 'hydrated silicon dioxide (opal)'?
That's good by me. I wondered if silicate or silica was a better term, as well, but was influenced by another standard name I think.
> I find 'moles_of_nitrogen_per_unit_mass_in_sea_water' ambiguous. Do you mean dissolved, particulate or particulate+dissolved and organic, inorganic or total (organic+inorganic). I'm guessing you're aiming at dissolved NO3+NO2+NH4, in which case 'dissolved_total_inorganic_nitrogen' might suit.
This is a BATS measurement, reference
http://bats.bios.edu/bats_measurements.html, and
http://bats.bios.edu/methods/chapter20.pdf:. "Total nigrogen mass flux is defined as the amount of sinking particular organic nitrogen passing through a depth level." Later: "Particular flux is then calculated by multiple the %N by the mass flux." (BATS also presents Nitrate+Nitrite and Particulate Organic Nitrogen separately.)
My domain expertise (!) doesn't tell me whether that means the answer to your question is yes, no, or don't know.
> Possible replace 'Chlorophyll is the green pigment ' by 'Chlorophylls are the green pigments'. There's also at least six of them if the divinyl forms are taken into account - maybe replacing 'five' by 'several' is the way to go.
Merely went for consistency with existing definitions here. Happy to change if that's the consensus, but then the other ones should change too. (mass_concentration_of_chlorophyll_a_in_sea_water, mass_concentration_of_chlorophyll_in_sea_water).
> I'm not totally comfortable with the organic carbon definition - it doesn't really tell me anything. How about 'Organic carbon is the carbon remaining in a sample after carbonates and bicarbonates have been removed by acidification'
I agree with the criticism, but again there's a consistency issue. There are a number of definitions that are rather abstract tutorials on the various components of the standard name, but you can't tell from them what the parameter actually is. In this case, can we speak with authority about whether the organic carbon is always derived in a certain way or consists exactly of that matter? The other organic carbon definitions were much less authoritative.
John
>
> Cheers, Roy.
>
>
>
> ________________________________________
> From: CF-metadata [cf-metadata-bounces at cgd.ucar.edu] On Behalf Of John Graybeal [john.graybeal at marinexplore.com]
> Sent: 13 September 2013 00:05
> To: CF Metadata List
> Subject: [CF-metadata] request #1 for names: mole concentrations and mass fractions, similar to current names
>
> Hi,
>
> This is the first in a series of standard name requests. I've tried to group the requests meaningfully, and I apologize in advance if I need a fair bit of CF wisdom going forward through this process.
>
> In this set of requests, there is a reasonable similarity to other existing names, and I've given an example or two for comparison under the "Analogs" section for each.
>
> -- Name: mole_concentration_of_particulate_matter_expressed_as_biogenic_silicon_per_unit_mass_in_sea_water
> -- Units: mol kg -1
> -- Definition: Concentration in sea water of silicon dioxide particles produced by living organisms, presented as moles per unit mass. Mole fraction is used in the construction mole_fraction_of_X_in_Y, where X is a material constituent of Y.
> -- Analogs: mole_concentration_of_particulate_matter_expressed_as_silicon_in_sea_water
> -- Notes: A more narrow form of the analog, and is per unit mass instead of volume
>
> -- Name: mole_concentration_of_particulate_matter_expressed_as_lithogenic_silicon_per_unit_mass_in_sea_water
> -- Units: mol kg -1
> -- Definition: Concentration in sea water of silicon dioxide particles produced from terrestrial rocks and soil, presented as moles per unit mass. The concept moles_of_X_per_unit_mass_in_Y is also called "molality" of X in Y, where X is a material constituent of Y.
> -- Analogs: mole_concentration_of_particulate_matter_expressed_as_silicon_in_sea_water
> -- Notes: A more narrow form of the analog, and is per unit mass instead of volume
>
> -- Name: moles_of_nitrogen_per_unit_mass_in_sea_water
> -- Units: mol kg-1
> -- Definition: Concentration of nitrogen in sea water, presented as number of moles per unit mass. The concept moles_of_X_per_unit_mass_in_Y is also called "molality" of X in Y, where X is a material constituent of Y.
> -- Analogs: moles_of_nitrate_per_unit_mass_in_sea_water
> -- Notes: Is this better as "mole_concentration_of_nitrogen_per_unit_mass_in_sea_water", to match a more prevalent pattern?
>
> -- Name: mole_concentration_of_dissolved_phosphorus_per_unit_mass_in_sea_water
> -- Units: mol kg-1
> -- Definition: Concentration of dissolved phosphorus in sea water, presented as number of moles per unit mass. The concept moles_of_X_per_unit_mass_in_Y is also called "molality" of X in Y, where X is a material constituent of Y.
> -- Analogs: mole_concentration_of_particulate_organic_carbon_in_sea_water
>
> -- Name: mass_fraction_of_chlorophyll_a_in_sea_water
> -- Units: 1
> -- Definition: Proportion of the chlorophyll a pigment in sea water. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of X to the mass of Y (including X). A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. Chlorophyll is the green pigment found in most plants, algae and cyanobacteria; it's presence is essential for photosynthesis to take place. There are five different forms of chlorophyll that occur naturally; all contain a chlorin ring which gives the green pigment and a side chain whose structure varies. Chlorophyll-a is the most commonly occurring form of natural chlorophyll.
> -- Analogs: mass_concentration_of_chlorophyll_a_in_sea_water
>
> -- Name: mass_fraction_of_particulate_organic_carbon_in_sea_water
> -- Units: 1
> -- Definition: Proportion of carbon particles from organic sources in sea water. Mass fraction is used in the construction mass_fraction_of_X_in_Y, where X is a material constituent of Y. It means the ratio of the mass of X to the mass of Y (including X). A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. Organic carbon describes a family of chemical species and is the term used in standard names for all species belonging to the family that are represented within a given model. The list of individual species that are included in a quantity having a group chemical standard name can vary between models. Where possible, the data variable should be accompanied by a complete description of the species represented, for example, by using a comment attribute. Particulate organic carbon is in the form of particles too big to pass through a filter.
> -- Analogs: mole_concentration_of_particulate_organic_matter_expressed_as_nitrogen_in_sea_water, mass_fraction_of_primary_particulate_organic_matter_dry_aerosol_in_air
> -- Notes: Is this better as "mass_fraction_of_particulate_organic_matter_expressed_as_carbon_in_sea_water"? I don't understand the purpose of the indirection "particulate_organic_matter_expressed_as_X", as opposed to just "particulate_organic_X", but it appears to be a pattern.
>
> Thank you for your consideration of these requests.
>
> John
>
> ------------------------------------
> John Graybeal
> Senior Data Manager, Metadata and Semantics
>
> T +1 (408) 675-5545
> F +1 (408) 616-1626
> skype: graybealski
>
> Marinexplore
> 920 Stewart Drive
> Sunnyvale, CA
>
>
>
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------------------------------------
John Graybeal
Senior Data Manager, Metadata and Semantics
T +1 (408) 675-5545
F +1 (408) 616-1626
skype: graybealski
Marinexplore
920 Stewart Drive
Sunnyvale, CA
This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system.
Received on Sat Sep 28 2013 - 10:04:00 BST
