[CF-metadata] New standard names for NEMO ocean model output

Kevin Marsh kevin.marsh at ecmwf.int
Fri Apr 21 04:25:24 MDT 2017


Indeed, many thanks for the summary Alison!

re: Jonathan's second point could we use the 'non-expert' names and have the 'expert' name as an alias?

Thanks,
Kevin

----- Original Message -----
From: "j m gregory" <j.m.gregory at reading.ac.uk>
To: cf-metadata at cgd.ucar.edu
Sent: Friday, 21 April, 2017 10:25:30
Subject: Re: [CF-metadata] New standard names for NEMO ocean model output

Dear Alison and Sebastien

Thanks for your summary, Alison. I agree with Sebastien that we do not need
above_SURFACE in the sea-level change names, because they are changes, so the
reference level cancels out. Picking up Sebastien's other point, I agree that
instead of [thermo/halo]steric, we could say
due_to_change_in_sea_water_temperature/salinity/density.
If I was not an "expert" in this area, indeed I might argue against using the
usual words, for the sake of easy understanding by others! These quantities
are pretty much always called [thermo/halo]steric, and we already use "steric"
in a couple of standard names. However, it would be fine to rename these ones
as well if we prefer to avoid more opaque terminology.

Best wishes

Jonathan

----- Forwarded message from Sebastien Villaume <sebastien.villaume at ecmwf.int> -----

> Date: Tue, 18 Apr 2017 08:20:21 +0000
> From: Sebastien Villaume <sebastien.villaume at ecmwf.int>
> To: alison pamment <alison.pamment at stfc.ac.uk>
> CC: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] New standard names for NEMO ocean model output
> X-Mailer: Zimbra 8.6.0_GA_1200 (ZimbraWebClient - FF50 (Linux)/8.6.0_GA_1200)
> 
> Dear Alison,
> 
> The new standard names you are suggesting for (3), (4) and (5) are interesting. 
> 
> I have few comments:
> 
> when I searched "sea_surface_height" in the latest standard name table, I noticed standard names with "sea_surface_height_amplitude_due_to", "sea_surface_height_bias_due_to", and "sea_surface_height_correction_due_to". would it make sense to use "sea_surface_height_change_due_to" or "due_to" is only reserved for certain cases (like external physical processes)?
> 
> I am also wondering if the reference "above_X" for the height is needed: the change in height will be the same whatever the origin chosen (sea floor, geoid, etc.) because it is the difference between 2 heights sharing the same reference. In that sense it feels that "steric_change_in_sea_surface_height", "halosteric_change_in_sea_surface_height" and "thermosteric_change_in_sea_surface_height" are enough.
> 
> Best wishes,
> /Sébastien
> 
> ----- Original Message -----
> From: "alison pamment" <alison.pamment at stfc.ac.uk>
> To: "sebastien villaume" <sebastien.villaume at ecmwf.int>, cf-metadata at cgd.ucar.edu
> Sent: Thursday, 13 April, 2017 17:41:38
> Subject: RE: New standard names for NEMO ocean model output
> 
> Dear Jonathan and Sebastien,
> 
> Thank you both for your comments. I think we are now agreed on the following names (with definitions as given in my previous email http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2017/059392.html):
> 
> 1. sea_water_mass_per_unit_area_expressed_as_thickness (m)
> 2. ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity_threshold (m)
> 2a. The existing name ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity will become an alias of ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity_deficit (m).
> 6. ratio_of_sea_water_potential_temperature_anomaly_to_relaxation_timescale (K s-1)
> 7. ratio_of_sea_water_practical_salinity_anomaly_to_relaxation_timescale (s-1)
> 8. integral_of_sea_water_practical_salinity_wrt_depth (m)
> 
> These names are accepted for publication in the standard name table and will be added at the next update, scheduled for 24th April.
> 
> I think we have also agreed to drop proposal (9) integral_of_sea_water_practical_salinity_wrt_total_depth (m) because it is the same quantity as (8).
> 
> For the 'steric' names, Jonathan feels these should indicate that the term relates to a change in local sea level, rather than simply water column thickness, and Sebastien is keen that we adopt a common approach for all three names. We have a number of "sea_surface_height_above_X" names where X is variously "geoid", "reference_ellipsoid", etc. Based on this syntax I would then suggest the following names:
> 
> 3. steric_change_in_sea_surface_height_above_sea_floor (m)
> ' "Sea surface height" is a time-varying quantity. The steric change in sea surface height is the change in height a water column of standard temperature T=0°C and practical salinity S=35.0 would undergo when its temperature and salinity are changed to the observed values. The sum of the quantities with standard names thermosteric_change_in_sea_surface_height_above_sea_floor and halosteric_change_in_sea_surface_height_above_sea_floor is the total steric change in the water column height, which has the standard name of steric_change_in_sea_surface_height_above_sea_floor. The sum of the quantities with standard names sea_water_mass_per_unit_area_expressed_as_thickness and steric_change_in_sea_surface_height_above_sea_floor is the total thickness of the sea water column.'
> 
> 4. halosteric_change_in_sea_surface_height_above_sea_floor (m)
> ' "Sea surface height" is a time-varying quantity. The halosteric change in sea surface height is the change in height a water column of standard practical salinity S=35.0 would undergo when its salinity is changed to the observed value. The sum of the quantities with standard names thermosteric_change_in_sea_surface_height_above_sea_floor and halosteric_change_in_sea_surface_height_above_sea_floor is the total steric change in the water column height, which has the standard name of steric_change_in_sea_surface_height_above_sea_floor.'
> 
> 5. thermosteric_change_in_sea_surface_height_above_sea_floor (m)
> ' "Sea surface height" is a time-varying quantity. The thermosteric change in sea surface height is the change in height a water column of standard temperature T=0°C would undergo when its temperature is changed to the observed value. The sum of the quantities with standard names thermosteric_change_in_sea_surface_height_above_sea_floor and halosteric_change_in_sea_surface_height_above_sea_floor is the total steric change in the water column height, which has the standard name of steric_change_in_sea_surface_height_above_sea_floor.'
> 
> Are these better?
> 
> Best wishes,
> Alison
> 
> ------
> Alison Pamment                                                       Tel: +44 1235 778065
> Centre for Environmental Data Analysis         Email: alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory     
> R25, 2.22
> Harwell Campus, Didcot, OX11 0QX, U.K.
> 
> 
> 
> > -----Original Message-----
> > From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of
> > Sebastien Villaume
> > Sent: 05 April 2017 11:51
> > To: cf-metadata at cgd.ucar.edu
> > Subject: Re: [CF-metadata] New standard names for NEMO ocean model output
> > 
> > 
> > Dear Alison et al,
> > 
> > we are happy with your suggestions/modifications.
> > 
> > I also understand from your comments to
> > integral_of_sea_water_practical_salinity_wrt_depth that my proposal to
> > rename
> > integral_of_sea_water_potential_temperature_wrt_depth_expressed_as_heat_
> > content for consistency is no longer required.
> > 
> > 
> > Regarding Jonathan comments, I think we (Eric, Kevin, myself) are fine with
> > "thickness", "thickness_change", "height" or "height_change" for the steric,
> > halosteric and thermosteric contributions as long as it is consistent for the
> > three standard names and other related names.
> > 
> > In the future, we may want to produce the steric, halosteric and thermosteric
> > contributions of each water cell of the column, not only for the whole water
> > column. The definitions of the present standard names and the possibility to
> > derive new standard names for this future situation need to be taken into
> > account.
> > 
> > one more question: what is the standard name corresponding to
> > sea_water_mass_per_unit_area_expressed_as_thickness (at 0degC, 35psu) +
> > ocean_steric_thickness? i.e the total thickness of the water column? it is not
> > clear to me if it exists or if we should use
> > sea_water_mass_per_unit_area_expressed_as_thickness and point to an
> > auxiliary variable sea_water_density at XdegC and Ypsu...
> > 
> > thanks,
> > Sebastien
> > 
> > ____________________________________
> > 
> > Dr. Sébastien Villaume
> > Analyst
> > ECMWF Shinfield Park,
> > Reading RG2 9AX, UK
> > +44 7825 521592
> > sebastien.villaume at ecmwf.int
> > ____________________________________
> > 
> > ----- Original Message -----
> > From: "Jonathan Gregory" <j.m.gregory at reading.ac.uk>
> > To: cf-metadata at cgd.ucar.edu
> > Sent: Tuesday, 4 April, 2017 21:13:08
> > Subject: Re: [CF-metadata] New standard names for NEMO ocean model output
> > 
> > Dear Alison
> > 
> > Thank you for your careful and sensible analysis, as always. I agree with all
> > your proposals except that I'm sorry to say I'm not happy about the steric
> > height yet. I don't seek to insist on what I suggested before, but I don't
> > think the proposal so far matches scientific terminology as far as I'm aware.
> > 
> > > 3. ocean_steric_thickness (m)
> > > 4. ocean_halosteric_thickness (m)
> > > 5. ocean_thermosteric_thickness (m)
> > 
> > I understand these to mean the *change* in the thickness of the water column
> > caused by change to sea water density, due to change in T and S. That's what
> > your definitions indicate. If it's a change in thickness, it's confusing to
> > call it a thickness, I would say. People often refer to quantities of "steric/
> > halosteric/thermosteric sea level change", which I think are the same as what
> > we're talking about here. The change in thickness of the water column (the
> > vertical distance from the sea floor to the sea surface) is of course the same
> > thing as local sea level change.
> > 
> > Best wishes
> > 
> > Jonathan
> > _______________________________________________
> > CF-metadata mailing list
> > CF-metadata at cgd.ucar.edu
> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
> > _______________________________________________
> > CF-metadata mailing list
> > CF-metadata at cgd.ucar.edu
> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata

----- End forwarded message -----
_______________________________________________
CF-metadata mailing list
CF-metadata at cgd.ucar.edu
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata



More information about the CF-metadata mailing list