Dear Jonathan,
those are good points. I've copied Michaela into the discussion as she knows more about the intended use of this variable.
The generic quantity that AerChemMIP is interested in, Phytotoxic ozone dose, can be used with a non-zero threshold -- so there may be a requirement for this in the future, but for CMIP6 we only need the case of threshold=0. As you point out, we can simplify the CF metadata if we restrict ourselves to this case. I'd be happy with that approach.
Looking at other CF names, I notice that we should be referring to the "_mole_flux_of_ozone_" rather than just the "ozone_flux" (to distinguish it from mass flux).
I'm not sure about the phrase "flux_into_stomata": the stomata are the holes in the leaves, what we really mean is into the plant through the stomata. I'm not sure if "integration_wrt_time_of_mole_flux_of_ozone_into_vegetation" would be specific enough; "integration_wrt_time_of_mole_flux_of_ozone_into_vegetation_through_stomata" looks a bit long, but may be justified for a specialised quantity like this,
regards,
Martin
________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Jonathan Gregory <j.m.gregory at reading.ac.uk>
Sent: 18 April 2018 17:41
To: cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] Four standard names for the AerChemMIP data request
Dear Martin
> Proposed name: integral_wrt_time_of_stomatal_ozone_flux_excess
I appreciate that not all fluxes have their sign convention mentioned in the
name, but in the case of precipitation, for example, I think it's obvious -
that's not quite so with ozone_flux, I would say - on reflection, I guess
that plants don't ever produce ozone, so the flux should be into the stomata,
but although it can be clarified in the definition, as you say, I feel it would
be even better to choose a word in the standard name which indicates which way
the flux is going e.g. flux_into_stomata.
There are existing names containing mole_flux_of_SPECIES. This is one of those
so it might be good to follow that pattern too.
I see that pod0 has a threshold of zero. You're proposing something more
general, which could support any threshold, but is the threshold ever going
to be non-zero? If zero is the only possibility, it doesn't need to be
described as an excess.
> (3b) stomatal_ozone_flux_threshold [mol m-2 s-1]
>
> A standard name to be used on variable specifying a threshold value of stomatal ozone flux.
This quantity would be more generally useful if "threshold" was omitted. I'm
aware there is an air_temperature_threshold in the table, but I see no reason
why a quantity used as a threshold must have "threshold" in its name.
Best wishes and thanks
Jonathan
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Received on Thu Apr 19 2018 - 02:21:58 BST
