[CF-metadata] Proposed Standard Names

From: Godin, Michael <Godin>
Date: Mon, 19 Sep 2005 09:48:12 -0700

Here is my long-delayed response to Jonathan's questions:

I believe we continue to agree on these:

 * partial_pressure_of_carbon_dioxide_in_air:Pa
 * partial_pressure_of_carbon_dioxide_in_sea_water:Pa
 * speed_of_sound_in_sea_water:m s-1
 * height_above_sea_floor:m
 * volume_absorption_coefficient_of_radiation_in_sea_water:m-1
 * volume_attenuation_coefficient_of_radiation_in_sea_water:m-1
 * volume_scattering_function_of_radiation_in_sea_water:m-1 sr-1

I would like to propose that absorption, attenuation, AND scattering should be integrals over all wavelengths, unless there is a coordinate variable specifying range(s) of wavelengths.

I agree to your suggestions regarding the terms:

 * omnidirectional_photosynthetic_spherical_irradiance_in_sea_water:W m-2
 * omnidirectional_spectral_spherical_irradiance_in_sea_water:W m-3 I
 * moles_of_oxygen_per_unit_mass_in_sea_water:mol kg-1
 * moles_of_nitrate_per_unit_mass_in_sea_water:mol kg-1
 * moles_of_phosphate_per_unit_mass_in_sea_water:mol kg-1
 * moles_of_silicate_per_unit_mass_in_sea_water:mol kg-1

I would also like to propose:
 * moles_of_nitrite_per_unit_mass_in_sea_water:mol kg-1
(those darn new sensors keep popping up!)

And the probably more controversial:
 * moles_of_nitrate_and_nitrite_per_unit_mass_in_sea_water:mol kg-1
(some sensors apparently can't differentiate between the two)

On the topic of scattering, I had argued that in addition to a general "scattering" variable, there ought to be a variable called "backscattering". Your reply was that backscattering is just a special case of scattering, and that a coordinate variable should be used to differentiate the two. Well, I agree that the coordinate variable is important, because there certainly are many angles around which scattering is measured. However, I would like to propose once again that "back" be retained as a special case of "scattering" in much the same way that "upwelling" and "downwelling" are used modify "radiation", conveying concepts that can be expressed concisely with a coordinate variable, but which are conveyed more clearly with a choice of name.

So how about:
 * volume_backwards_scattering_coefficient_of_radiation_in_sea_water:m-1

You suggested that we need a convention for the angle in the scattering function, assuming it to be the opening angle between the incident beam and the scattered beam (pi for backward scattering). That is the convention that optical oceanographers use (zero to pi). The solid angle width of the beam is also very important, particularly around zero and pi where the scattering function is the most nonlinear.

You suggested:
 * bioluminescent_photon_rate_in_sea_water:s-1 m-3
 * fractional_saturation_of_oxygen_in_sea_water:1
 * volume_mixing_ratio_of_oxygen_at_stp_in_sea_water:1
And I agree.

You had quite reluctantly suggested:
 * carbon_dioxide_partial_pressure_difference_between_sea_water_and_air:Pa
And I would like to offer (with the subtraction order corrected)
 * carbon_dioxide_partial_pressure_difference_between_air_and_sea_water:Pa
And I agree that it is a very awkward variable name. However, it is commonly directly measured (don't ask me how), and even more commonly calculated from two separate measurements to give an idea of the rate of CO2 absorption by the oceans.

I had used the term "surface" in some of my original proposed variable names... It is probably redundant in the cases I had suggested, since there will often be a coordinate variable that indicates depth or altitude = 0.

Finally, for sea water flow, you had suggested
 * sea_water_volume_transport:m3 s-1
But had wondered about the application. I imagine the application is rather controversial, as it applies to instruments that have internal measurement elements and require a pump to ensure flow through the measurement elements. Commonly, the flow rate through these measurement elements is also measured, usually as a quality control check.

Thank you for prodding me to keep this discussion going,
Mike
Received on Mon Sep 19 2005 - 10:48:12 BST