A couple of questions... 1) Regarding the request to add Chlorophyll_a fluorescence, the proposed unit is kg/m3, but shouldn't fluorescence have radiation units (i.e. Watts/m2)? I was not aware that any of the proposed CMIP models treated fluorescence explicitly, but if that were the case, it would seem like converting to chlorophyll_a volumetric mass units would seem to me redundant with the existing chlorophyll_a metric.
2) Regarding the request to add a variable for alkalinity in mass units to augment the current one volumetric units, this would seem redundant for models using the Boussinesq Assumption and thus a single reference density. For non-Boussinesq models, one should be able to approximate this with sea_water_potential_density (rhopoto), but I acknowledge that this would make the global integral not exact... Are non-Boussinesq models being planned? If so, adding alkalinity as a mass-based variable would also then beg the question as to which tracers should be posted in both units (e.g. DIC) - how much is the request expected to be expanded? Cheers, John On Mon, Dec 5, 2016 at 3:38 AM, Elodie Fernandez < elodie.fernan...@mercator-ocean.fr> wrote: > Dear all, > > We would like to suggest the addition of two new standard_names for ocean > biogeochemistry: > > - *mass_concentration_of_chlorophyll_a_fluorescence_in_sea_water* > unit: kg m-3 > definition: > Mass concentration means mass per unit volume and is used in the > construction mass_concentration_of_X_in_Y, where X is a material > constituent of Y. 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'. Chloropyll fluorescence is a proxy for > Chlorophyll concentration measuring re-emitted light from light absorption. > Chlorophylls are the green pigments found in most plants, algae and > cyanobacteria; their presence is essential for photosynthesis to take > place. There are several different forms of chlorophyll that occur > naturally. All contain a chlorin ring (chemical formula C20H16N4) which > gives the green pigment and a side chain whose structure varies. The > naturally occurring forms of chlorophyll contain between 35 and 55 carbon > atoms.Chlorophyll fluorescence is mainly emitted from the Chlorophyll a > pigment. > > I believe there are no standard_names yet for fluorescence. The definition > was built from the mass_concentration_of_chlorophyll_a_in_sea_water > definition. > > - *sea_water_alkalinity_per_unit_mass* > unit: mol kg-1 > definition: > sea_water_alkalinity_per_unit_mass is the total alkalinity (including > carbonate, nitrogen, silicate, and borate components). > > A standard name already exists for alkalinity expressed as mol/m3, > sea_water_alkalinity_expressed_as_mole_equivalent, but none exist for > mol/kg. > > Best regards, > Elodie > > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > >
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