Dear Jim
Thanks for your explanations and your patience. We're discussing names with
these forms:
mole_concentration_of_dissolved_inorganic_carbon_in_sea_water_due_to_X_component
sea_water_alkalinity_expressed_as_mole_equivalent_due_to_X_component
sea_water_ph_reported_on_total_scale_due_to_X_component
surface_downward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_X_component
surface_mole_concentration_of_dissolved_inorganic_carbon_in_sea_water_due_to_X_component
surface_sea_water_alkalinity_expressed_as_mole_equivalent_due_to_X_component
surface_sea_water_ph_reported_on_total_scale_due_to_X_component
surface_mole_concentration_of_carbonate_expressed_as_carbon_in_sea_water_due_to_X_component
surface_partial_pressure_of_carbon_dioxide_in_sea_water_due_to_X_component
surface_carbon_dioxide_partial_pressure_difference_between_sea_water_and_air_due_to_X_component
where X is natural or abiotic, except there are no abiotic alkalinity names.
What you've said suggests to me that natural and abiotic are two different
kinds of qualification. The abiotic part is actually another tracer, you say,
while natural refers to a condition of the experiment. These are different
"dimensions" in namespace. (By the way, does it mean you might have an abiotic
anthropogenic component?)
Since abiotic carbon is a tracer, one possibility would be to replace carbon
with abiotic_carbon in the relevant names, rather than using due_to e.g.
mole_concentration_of_dissolved_inorganic_abiotic_carbon_in_sea_water
This would be a bit shorter. What do you think?
It doesn't work for pH though, because carbon isn't in the name and I guess
"abiotic pH" wouldn't make sense. Now I understand it, I agree that
due_to_abiotic_component is a good description, which works for pH as well.
The ones called due_to_natural_component are, if I understand correctly, that
quantity in the natural experiment e.g.
surface_partial_pressure_of_carbon_dioxide_in_sea_water_due_to_natural_component
means surface_partial_pressure_of_carbon_dioxide_in_sea_water in the natural
experiment. This isn't a really a different geophysical quantity from
surface_partial_pressure_of_carbon_dioxide_in_sea_water in the total experiment
or in any other experiment, so I'm not clear why it needs a standard name. It's
the same model diagnostic in the natural and total experiment, so shouldn't it
have the same name? We don't have distinct standard names for air_temperature
in piControl, air_temperature in abrupt4xCO2, and so on. The quantities can
be distinguished according to which experiment they come from and which file
they are in.
You define the anthropogenic component as the difference between the total
and the natural experiments. These quantities are *not* model diagnostics and
you might need standard names for them when you calculate them offline. For
example, they might be called
anthropogenic_biogeochemical_perturbation_to_Y
where Y is any of the standard names concerned, because the difference between
total and natural is that the biogeochemistry is perturbed by the changing
atmospheric CO2 in total, but not in natural, while both of them have the
anthropogenic climate change imposed.
Best wishes
Jonathan
> You are right that this may be confusing. In ocean biogemchemical
> modeling, anthropogenic CO2 (or anthropogenic dissolved inorganic
> carbon in the ocean) is always defined as due only to the increase
> in atmospheric CO2 since the onset of the industrial era. Natural
> CO2 is everything else, i.e., referring to the idealized unperturbed
> natural state AND its changes due to changes climate. So for ocean
> biogeochemical community there is less room for ambiguity. These
> terms are also defined in the OMIP-BGC protocols paper (in the CMIP6
> special issue):
>
> http://www.geosci-model-dev-discuss.net/gmd-2016-155/
>
> For others, what would you have in mind? One possibility would be
> to change part of the name "*_due_to_natural_component"
> "*_for_the_natural_component_and_its_changes_due_to_changing_climate"
> but that makes for some awfully long names.
>
> >>For the biogeochemistry in OMIP, we've agreed on using the terms
> >>'abiotic' and 'natural', neither synonyms nor antonyms for our
> >>purposes. The OMIP-BGC simulations will be run with 2 parallel
> >>simulations (or parallel tracers in the same simulation):
> >>
> >>* 'natural' means it will be maintained at same the CMIP6
> >>preindustrial CO2 level throughout the simulation, while the
> >>
> >>* 'total' simulation will have varying atmospheric CO2, but the same
> >>climate (e.g., forced in the OMIP ocean only run).
> >>
> >>The difference between the total and natural carbon tracers in the
> >>two will give us the anthropogenic carbon. The ocean's natural
> >>carbon cycle is considered in OMIP to change with climate change
> >>even though its simulated atmospheric CO2 is held constant.
> >>
> >>Regarding 'abiotic', the natural and the total simulation include
> >>both abiotic and biotic processes. To distinguish the two we also
> >>include an abiotic carbon tracer. Furthermore, we use a simplified
> >>abiotic approach to model C-14 in the ocean, e.g., to provide
> >>deep-ocean ventilation ages.
----- End forwarded message -----
Received on Thu Oct 06 2016 - 12:29:32 BST
