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[CF-metadata] standard names for FAFMIP passive tracers

From: alison.pamment at stfc.ac.uk <alison.pamment>
Date: Tue, 20 Mar 2018 11:08:19 +0000

Dear Jonathan,

Thank you for proposing these FAFMIP names and for providing such clear definitions. I recall our previous discussion of OMIP names in which we established the necessity of using Celsius rather than Kelvin for certain ocean model temperature quantities, so the canonical units of these are fine. The names themselves are also fine - I think it is clear that these are not the usual model prognostic variables and they are unlikely to be mistaken as such. I'm happy with these names as they currently stand - unless we receive any objections in the next seven days they will be accepted for inclusion in the standard name table and published in the April update.

Best wishes,
Alison

------
Alison Pamment Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.

-----Original Message-----
From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Jonathan Gregory
Sent: 19 March 2018 18:32
To: cf-metadata at cgd.ucar.edu
Subject: [CF-metadata] standard names for FAFMIP passive tracers

Dear all

Martin and Alison have pointed out that four standard names needed for FAFMIP haven't yet been proposed. That was my oversight. I would now like to propose:

sea_water_added_conservative_temperature, degC A passive tracer in an ocean model whose surface flux does not come from the atmosphere but is imposed externally upon the simulated climate system. The surface flux is expressed as a heat flux and converted to a passive tracer increment as if it were a heat flux being added to conservative temperature.
The passive tracer is transported within the ocean as if it were conservative temperature. The passive tracer is zero in the control climate of the model.
The passive tracer records added heat, as described for the CMIP6 FAFMIP experiment (doi:10.5194/gmd-9-3993-2016), following earlier ideas.
** Then repeat the definition of sea_water_conservative_temperature.

sea_water_added_potential_temperature, degC A passive tracer in an ocean model whose surface flux does not come from the atmosphere but is imposed externally upon the simulated climate system. The surface flux is expressed as a heat flux and converted to a passive tracer increment as if it were a heat flux being added to potential temperature. The passive tracer is transported within the ocean as if it were potential temperature. The passive tracer is zero in the control climate of the model.
The passive tracer records added heat, as described for the CMIP6 FAFMIP experiment (doi:10.5194/gmd-9-3993-2016), following earlier ideas.
Potential temperature of sea water is the temperature a parcel of sea water would have if moved adiabatically to sea level pressure.

sea_water_redistributed_conservative_temperature, degC A passive tracer in an ocean model which is subject to an externally imposed perturbative surface heat flux. The passive tracer is initialised to the conservative temperature in the control climate before the perturbation is imposed. Its surface flux is the heat flux from the atmosphere, not including the imposed perturbation, and is converted to a passive tracer increment as if it were being added to conservative temperature. The passivetracer is transported within the ocean as if it were conservative temperature. The passive tracer records redistributed heat, as described for the CMIP6 FAFMIP experiment (doi:10.5194/gmd-9-3993-2016), following earlier ideas.
** Then repeat the definition of sea_water_conservative_temperature.

sea_water_redistributed_potential_temperature, degC A passive tracer in an ocean model which is subject to an externally imposed perturbative surface heat flux. The passive tracer is initialised to the potential temperature in the control climate before the perturbation is imposed. Its surface flux is the heat flux from the atmosphere, not including the imposed perturbation, and is converted to a passive tracer increment as if it were being added to potential temperature. The passive tracer is transported within the ocean as if it were potential temperature. The passive tracer records redistributed heat, as described for the CMIP6 FAFMIP experiment (doi:10.5194/gmd-9-3993-2016), following earlier ideas.
Potential temperature of sea water is the temperature a parcel of sea water would have if moved adiabatically to sea level pressure.

I note that in Table 3 of the paper cited we said "additional" temperature for the standard names, but throughout the rest of the paper we referred to "added"
heat (not "additional"), following earlier literature, and in the existing CF-netCDF data produced for FAFMIP we have used "added" in the standard names.
Hence I think this must have been a change of mind and should be regarded as a mistake in the paper. We will make a note of it on the FAFMIP website once this proposal has been decided upon.

Cheers

Jonathan
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Received on Tue Mar 20 2018 - 05:08:19 GMT

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