[CF-metadata] Proposed Standard Names

Jonathan Gregory j.m.gregory at reading.ac.uk
Wed Jul 27 17:19:27 MDT 2005


Dear Michael et al.

Thanks for the proposal and discussion. I've got some further questions and
comments:

partial_pressure_of_carbon_dioxide_in_air:Pa
(OK)

partial_pressure_of_carbon_dioxide_in_sea_water:Pa
(unit OK? You had 1 for this one too. I believe this is the pressure of carbon
dioxide gas which would be in equilibrium with the dissolved carbon dioxide.)

speed_of_sound_in_sea_water:m s-1
(OK)

height_above_sea_floor:m
(The standard name of "altitude" is reserved to mean "height above geoid".)

molality_of_oxygen_in_sea_water:mol kg-1
molality_of_nitrate_in_sea_water:mol kg-1
molality_of_phosphate_in_sea_water:mol kg-1
molality_of_silicate_in_sea_water:mol kg-1
(OK. However, I don't really like the word "molality" since it's so close to
"molarity". So far, there are no "molarity" standard names, and the PRISM CF
guidelines propose mole_concentration for mol m-3 rather than "molarity". Are
there any alternative terms to "molality"? Something with "specific" in it for
instance? I haven't been able find any. If "molality" is always used, then we
should use it too of course.)

omnidirectional_photosynthetic_spherical_irradiance_in_sea_water:W m-2
omnidirectional_spectral_spherical_irradiance_in_sea_water:W m-3
("Omnidirectional spherical irradiance" is my proposal for 4-pi spherical or
"scalar" irradiance. What do you think? The 2-pi spherical irradiances have
"upwelling" and "downwelling" to distinguish them. Note the first of these is
W m-2, not W m-3, because it's not spectral.)

volume_absorption_coefficient_of_radiation_in_sea_water:m-1
volume_attenuation_coefficient_of_radiation_in_sea_water:m-1
volume_transmissivity_of_radiation_in_sea_water:m-1
volume_scattering_coefficient_of_radiation_in_sea_water:m-1
volume_scattering_function_of_radiation_in_sea_water:m-1 sr-1
(These all refer to fractional change (or lack of change) of radiance per unit
path length. "Volume attentuation/extinction coefficient" is the term in the
AMS glossary. "Volume" distinguishes them from "specific" coefficients in
m2 kg-1, which are also in use; specific coefficients have to be multiplied
by density. I have put just "scattering" rather than "back-scattering"; is
"back" important? I don't understand your comments about being "relative to
air or pure water". If these are in m-1, surely they aren't relative to any
other material?)

The various types of direction discussed - platform heading, true heading and
course - are they all by intention the *same* quantity, ascertained by
different means? If so, they probably should have the same standard name.

platform_pitch:degree	
platform_roll:degree	
platform_speed:m s-1	
(These seem clear enough, although they aren't properties of the "observed
world", like most CF names; they are for describing the observation.)

sea_water_bioluminescence:s-1	
(I didn't really understand why this one is related to flow rate. What does
that mean? Also, if it's from unit volume should it not also be m-3?)

sea_water_dissolved_oxygen_saturation:1	
(Is this the concentration as a fraction of the saturated concentration?)

sea_water_dissolved_oxygen_volume_fraction:1	
(What does this mean? Perhaps the ratio of the volume of oxygen gas to the
volume of sea water?)

sea_water_fluorescence:1
(Given your discussion with Roy, I wonder if there is any point in this as a
standard name. It's reminiscent of the discussion we had about acoustic
intensity. Without any kind of calibration, such numbers can't be compared
between datasets, and that's the main purpose of standard names.)

You have withdrawn the "particulate" radiation attenuation quantities; if you
want them later, I think the best way to name them would be with a suffix
due_to_particulates or something like that.

surface_carbon_dioxide_partial_pressure_anomaly
(What does "anomaly" indicate?)

water_volume_transport:m3 s-1
(This would be the correct name for "water flow rate" following the guidelines.
I wonder what you use this quantity for?)

Best wishes

Jonathan



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