[CF-metadata] New standard names for OMIP biogeochemistry and chemistry

From: Jonathan Gregory <j.m.gregory>
Date: Thu, 20 Oct 2016 17:55:29 +0100

Dear Alison

I agree with you and Roy about the below. I think that it would be much better
to specify the depth of measurement, unless they really have the same
unavoidable vagueness of SST and SSS. In the case of those quantities, we
followed the existing universally used terminology rather than defining our
own, as we often do for clarity - perhaps that was a mistake!

Best wishes

Jonathan

> d. Surface concentration names
> There are a lot of these: 42 surface_mole_concentration names (units of mol m-3), 6 surface_mass_concentration names (kg m-3) and I'm also including 2 surface_sea_water_alkalinity (mol m-3) names and 3 surface_sea_water_ph names in this section.
>
> My concern about these proposals is that the names and units are not consistent. In CF standard names, "surface" means the lower boundary of the atmosphere. It has no depth, so it is not meaningful to regard it as having a mass or a volume. For this reason we can't assign units of kg m-3 or mol m-3 to a 'surface' name. I assume that all these quantities are in fact "near surface" values, i.e. representative of the top model layer, in which case there are two possible ways to deal with this.
>
> The first solution is simply to remove 'surface' from all these names and instead use a vertical coordinate or scalar coordinate and coordinate bounds to indicate the location and thickness of the layer. This has the advantage that many of the required names actually already exist, without the need to introduce separate surface names. E.g, instead of adding a new name surface_mole_concentration_of_dissolved_inorganic_carbon_in_sea_water, you could use the existing name mole_concentration_of_dissolved_inorganic_carbon_in_sea_water accompanied by suitable coordinate information to describe your quantity.
>
> The second solution, if you do feel that it is necessary to have distinct standard names for all these near-surface quantities, would be to follow the approach used in some existing sea_surface names such as sea_surface_temperature and sea_surface_salinity. The names would then be 'sea_surface' names and there would be an accompanying sentence in the definition to explain what that means, i.e. that it refers to water close to the surface. You would still also need to include the coordinate information and coordinate bounds to fully describe your data. With this approach the proposed name surface_mole_concentration_of_dissolved_inorganic_carbon_in_sea_water would become sea_surface_mole_concentration_of_dissolved_inorganic_carbon.
Received on Thu Oct 20 2016 - 10:55:29 BST