Hello Jonathan, One change I would recommend is to change composition terms such as 'composition_ratio_of_silicon_30_to_silicon_28_in_sinking_flux' to 'composition_ratio_of_silicon_30_to_silicon_28_in_suspended_matter'. The reason for this is that the particles in the water can be collected in several different ways - sediment trapping, stand-alone pumps, filtration of water samples and continuous centrifugation are the ones that instantly spring to mind. The description 'sinking_flux' is only strictly true for the first of these, whereas 'suspended_matter' applies equally to all of them.
Also, is it OK for the fact that the suspended matter is in sea water to be implicit? The term could be confused with atmospheric aerosols or particulates. If not, we need 'in_suspended_matter_in_sea_water'. Cheers, Roy. ________________________________________ From: CF-metadata [[email protected]] On Behalf Of Jonathan Gregory [[email protected]] Sent: 13 October 2013 09:33 To: [email protected] Subject: Re: [CF-metadata] standard names for sediment trap data Dear Matthias et al. Thanks for the proposals. I don't know much about this subject. From a CF point of view, I'd like to follow up various comments that have been made. As Roy says, CF doesn't decide what quantities should be used; its role is to agree names for quantities that are used in practice. Thus, we need names for both mole_flux and mass_flux in this case (quantities with different canonical units always have distinct standard names), and for biogenic, lithogenic or unspecified, according to what is needed. Like Tom, I think "total" does not need to be included. The problem with "total" is that it's a word whose meaning depends on the comparison with "partial" quantities i.e. it's a relative term, rather than an absolute one. Potential users might have different ideas about what's included in "total" so it's best not to use that word, or if necessary to spell out explicitly what is included. If isotopic composition needs to be specified, I would prefer phrases like the one Philip suggested (composition_ratio_of_silicon_30_to_silicon_28_in_sinking_flux). The three downward_mass_flux names in the standard name table are for carbon dioxide in air. The idea in mind is that CO2 is a passive tracer, advected as a constituent of air. The seven sinking names are for particles in sea water - I'm guessing that the calcite and aragonite refer to solid matter i.e. shells - is that right? I guess the idea is that sinking is a process. These are passive constituents too, but their weight is responsible for their downward motion; this gets near to the point that Philip made, about the reference frame. The distinction is natural, but I'm not convinced that we would like to maintain it, and I think downward would be preferable to sinking. For instance, what would you choose for the flux of dissolved constituents, such as oxygen or salt? It wouldn't be natural to call those "sinking". If it is important to convey the idea of sinking, I suggest it would be better to say downward_mass/mole_flux_of_X_in_sea_water_due_to_sinking, but I'm sure others have better informed opinions on this. Best wishes Jonathan _______________________________________________ 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
