Philip, For me the question is whether "productivity_of_carbon" is in fact trying to "express the mass of chemicals by the amount of just one element". On the face of it, I don't see any evidence for that -- rather it looks like someone is strictly interested in carbon, and the other chemicals can go hang (so to speak).
Whereas I assume all the _expressed_as_ cases are trying to do just that, expressing a mass via one element. Others may be able to speak more authoritatively to this question. Your example of two wildly different names that may mean the same thing was intriguing. I'm glad it's above my pay grade! John On Jun 5, 2013, at 16:59, "Cameron-smith, Philip" <[email protected]> wrote: > Hi John, et al., > > It seems that the concept of expressing the mass of chemicals by the amount > of just one element has been codified into CF twice, and handled differently. > And ocean productivity quantities also seem to follow two different patterns. > > For the record, > > _productivity_of_carbon appears in 12 std_names. > > _expressed_as_carbon appears in 13 std_names related to primary > production (eg > tendency_of_mole_concentration_of_particulate_organic_matter_expressed_as_carbon_in_sea_water_due_to_net_primary_production) > > _expressed_as_carbon appears in over 20 std_names related to > concentration of biomass (eg, > mole_concentration_of_diatoms_expressed_as_carbon_in_sea_water) > > _expressed_as_carbon appears in 3 std_names related to sinking of > biomass (eg, > sinking_mole_flux_of_particulate_organic_matter_expressed_as_carbon_in_sea_water) > > _expressed_as_carbon appears in 20 std_names related to atmospheric > chemicals. > > _expressed_as_ appears in over 100 other atmospheric > chemistry std_names. > > I also note for the record that the following two std_names appear to be > similar quantities with the same units [mol m-2 s-1]: > > net_primary_mole_PRODUCTIVITY_OF_CARBON_by_calcareous_phytoplankton > > tendency_of_ocean_mole_content_of_calcite_EXPRESSED_AS_CARBON_due_to_biological_production > (Note: there are 21 tendency_of_ocean_mole_content_ std_names) > > > Is there a distinction I am missing? > > Is it worth trying to create aliases to harmonize these std_names at this > point? > > What about new std_names going forward, such as the one being proposed? > > Best wishes, > > Philip > > ----------------------------------------------------------------------- > Dr Philip Cameron-Smith, [email protected], Lawrence Livermore National Lab. > ----------------------------------------------------------------------- > > > > > -----Original Message----- > > From: CF-metadata [mailto:[email protected]] On Behalf Of > > Lowry, Roy K. > > Sent: Wednesday, June 05, 2013 12:32 PM > > To: John Graybeal; CF Metadata List > > Subject: Re: [CF-metadata] new standard name for primary productivity of > > carbon per unit volume > > > > Hi John, > > > > Defining 'production' as 'production per unit volume' or maybe 'mass created > > per unit volume per unit time' would seem consistent to me. I'll leave to > > Jonathan to pick it up if I've got it wrong. > > > > I've never seen a terrestrial production profile and understand that > > terrestrial > > measurement protocols tend to give direct measurements per unit area, > > whereas in the oceans we measure per unit volume to generate profiles that > > are > > then integrated to give values per unit area. Hence my comment, but as > > you're > > happy to be marine-specific then no problem. > > > > I don't agree with Philip - if you look at all existing productivity codes > > (mostly > > mole productivities) then you seem to be following a well-established > > trend.. > > > > I also failed to understand Jonathan's comment concerning an alias - spot > > measurements and depth-integrated measurements are very different > > quantities. > > > > Cheers, Roy. > > > > ________________________________________ > > From: CF-metadata [[email protected]] On Behalf Of John > > Graybeal [[email protected]] > > Sent: 05 June 2013 19:38 > > To: CF Metadata List > > Subject: Re: [CF-metadata] new standard name for primary productivity of > > carbon per unit volume > > > > Roy, I'm happy to use production instead of productivity, if that's the > > rule. > > Should the definition say '"Production" means production per unit volume."? > > > > Jonathan and Roy, adding a reference to sea_water is fine. I could imagine > > the > > same metric in a terrestrial experiment, but this item is marine, so if > > that's the > > preference I'll go with it. The "mass_concentration" and > > "moles_per_unit_mass" terms use the expression 'in_sea_water', which seems > > the right phrase fit to me. > > > > Philip, adding expressed_as_carbon is present in some patterns, but was not > > present in the names of the two examples I was working from > > (net/gross_primary_productivity_of_carbon). To this lay person, it > > indicates the > > carbon is being ussed as a proxy, at least in part. ("The productivity was > > actually > > of 4 substances, but we are measuring the carbon expression only.") Since > > in this > > case, the data seemed to be representing actual carbon productivity, and the > > provider initially chose net_primary_productivity_of_carbon as the > > appropriate > > term, I want with that. Of course, I Am Not An Expert, may not understand > > the > > nuances, and can not explain why the existing explanation includes this > > phrasing. > > > > Jonathan, I think it is not an alias (as I understand aliases) of the terms > > that are > > per unit area, because the units are different. Do I understand aliases > > correctly? > > > > 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. > > > > John > > > > > > > > > From: Jonathan Gregory <[email protected]> > > > Subject: [CF-metadata] new standard name for primary productivity of > > > carbon per unit volume > > > Date: June 5, 2013 7:53:25 AM PDT > > > To: <[email protected]> > > > > > > Dear John > > > > > > I should think it would be helpful to add per unit volume of *what*? > > > to make this clearer. > > > > > > The existing name could be made an alias of one _per_unit_area if that > > > is generally thought to be a good idea. > > > > > > Besy wishes > > > > > > Jonathan > > > > > > > From: "Cameron-smith, Philip" <[email protected]> > > > Subject: Re: [CF-metadata] new standard name for primary productivity of > > carbon per unit volume > > > Date: June 5, 2013 8:11:53 AM PDT > > > To: "'[email protected]'" > > > <[email protected]>, "'[email protected]'" > > > <[email protected]> > > > > > > Hi John, > > > > > > Would it be appropriate to add _expressed_as_carbon, as indicated in the > > description (which follows an existing CF pattern)? > > > > > > Best wishes, > > > > > > Philip > > > > > > On Jun 5, 2013, at 07:54, "Lowry, Roy K." <[email protected]> wrote: > > > > > Hi John, > > > > > > I think if you look at the various molar primary productivity standard > > > names you'll see that the decision has been made in the past to define > > > 'productivity' as 'production per unit area'. It might be less > > > confusing if you used > > > > > > net_primary_production_of_carbon_per_unit_volume > > > > > > It might also be helpful to constrain this new standard name to the marine > > environment as production per unit volume doesn't fit the terrestrial > > domain as > > well as production per unit area - say something like: > > > > > > net_primary_production_of_carbon_per_unit_volume_of_sea_water > > > > > > Cheers, Roy. > > > > > > Please note that I now work part-time from Tuesday to Thursday. E-mail > > response on other days is possible but not guaranteed! > > > > > > -----Original Message----- > > > From: CF-metadata [mailto:[email protected]] On Behalf > > > Of John Graybeal > > > Sent: 05 June 2013 03:07 > > > To: CF Metadata List > > > Subject: [CF-metadata] new standard name for primary productivity of > > > carbon per unit volume > > > > > > I would like to request a CF standard name. > > > > > > Name: net_primary_productivity_of_carbon_per_unit_volume > > > Units: kg m-3 s-1 > > > Definition: Net primary productivity is the excess of > > > gross_primary_producivity > > (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). "Productivity of > > carbon" > > refers to the production of biomass expressed as the mass of carbon which it > > contains. > > > > > > There is an existing net_primary_productivity_of_carbon, expressed per > > > unit > > area. As we are making a data set available which is integrated over a > > vertical > > extent, producing values with units to match (i.e., kg m-3 s-1), a new > > standard > > name is needed. > > > > > > Note: It appears the definition of net primary productivity may assume the > > value will be measured as per unit area. This probably needs to be > > corrected. > > > > > > 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 > > > > > > > > > > > > _______________________________________________ > > > CF-metadata mailing list > > > [email protected] > > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > > > > 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. > > > > ------------------------------------ > > 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 > > > > > > > > _______________________________________________ > > CF-metadata mailing list > > [email protected] > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > > 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. > > _______________________________________________ > > CF-metadata mailing list > > [email protected] > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ------------------------------------ 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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