Dear Eric OK. In that case, I would suggest we rename the existing standard_name ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity which refers to the level at which the diffusivity differs from its surface value by a certain amount, as ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity_deficit using an alias, and we introduce a new standard name for your definition of ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity_threshold which refers to the level at which the diffusivity falls below a threshold value (not referred to the surface). Woudl that be OK?
Best wishes Jonathan On Wed, Jan 11, 2017 at 11:30:19AM +0000, Eric Boisseson wrote: > Date: Wed, 11 Jan 2017 11:30:19 +0000 > From: Eric Boisseson <eric.boisse...@ecmwf.int> > To: j.m.greg...@reading.ac.uk, cf-metadata@cgd.ucar.edu > CC: Sebastien Villaume <sebastien.villa...@ecmwf.int>, Kevin Marsh > <kevin.ma...@ecmwf.int> > Subject: Re: [CF-metadata] Re: New standard names for NEMO ocean model > output > X-Mailer: Zimbra 8.6.0_GA_1200 (ZimbraWebClient - FF45 > (Linux)/8.6.0_GA_1200) > > Dear Johnatan, > > Sorry for the delayed answer. > > >> If we could clarify the "defined by" part, would you be content to > >> describe the turbocline as a mixed layer (with appropriate definition)? > > Yes, I'll be fine with that. > > Best regards, > > Eric > > ----- Forwarded Message ----- > From: "Jonathan Gregory" <j.m.greg...@reading.ac.uk> > To: cf-metadata@cgd.ucar.edu > Sent: Tuesday, 13 December, 2016 17:46:50 > Subject: [CF-metadata] Fwd: Re: New standard names for NEMO ocean model output > > Dear Eric > > Yes, I see what you mean. If we could clarify the "defined by" part, would you > be content to describe the turbocline as a mixed layer (with appropriate > definition)? > > Best wishes > > Jonathan > > > - ocean_turbocline_thickness in m > > The turbocline thickness is similar to the mixed layer thickness but is > > estimated in models as the thickness at which the vertical eddy diffusivity > > coefficient (resulting from the vertical physics alone) falls below a given > > value defined locally. > > > > You mentioned that this is the same as > > ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity. > > > > But the definition for this one in the CF table is > > > > "The ocean mixed layer is the upper part of the ocean, regarded as being > > well-mixed. The base of the mixed layer defined by temperature, sigma, > > sigma_theta, or vertical diffusivity is the level at which the quantity > > indicated differs from its surface value by a certain amount. The amount by > > which the quantity differs can be specified by a scalar coordinate > > variable." > > > > Unlike with temperature or density criteria, the turbocline thickness is > > not estimated based on the difference with respect to the vertical > > diffusivity at the surface. As written in the definition we gave you, when > > the vertical diffusivity falls below a given value defined locally then we > > are at the turbocline depth. > > > > ############################# > > > > I hope this helps. > > > > Best regards, > > > > Eric > > > > > > > > > > ----- Original Message ----- > > From: "Kevin Marsh" <kevin.ma...@ecmwf.int> > > To: "Eric Boisseson" <eric.boisse...@ecmwf.int> > > Sent: Tuesday, 13 December, 2016 14:35:48 > > Subject: Fwd: [CF-metadata] New standard names for NEMO ocean model output > > > > Hi Eric, > > some feedback on your feedback...feel free to send any responses directly > > to the list, or to me if you prefer and i will send the comments to the > > list. > > I think that he's happy with 1, so only need input for 2. and 3., > > Thanks, > > Kevin > > > > ----- Forwarded Message ----- > > From: "j m gregory" <j.m.greg...@reading.ac.uk> > > To: cf-metadata@cgd.ucar.edu > > Sent: Tuesday, 13 December, 2016 13:56:41 > > Subject: [CF-metadata] New standard names for NEMO ocean model output > > > > Dear Kevin > > > > > 1. bottom_pressure_equivalent_height (m) > > > 3. ocean_steric_height (m) > > > > > > The steric height is estimated as the vertical integral of the density > > > (relative to a reference density where T=0K and S=35psu). The bottom > > > pressure is the mass of the water column at a given location. > > > > Ah, I see. > > > > For > > > 3. ocean_steric_height_above_sea_level (m) > > I would suggest > > > The ocean steric height above sea level measures the change in thickness > > > of a column of water when its temperature and salinity are changed from > > > standard values of 0°C and 0.035 to the actual values > > > > > The bottom pressure equivalent height is estimated indirectly as the > > > difference between the steric height and the sea level. > > > > I don't follow that, which sounds like the definition of ocean steric height > > again. However your alternative statement of its being the mass of the > > column > > makes sense to me. Going with the latter definition, I would suggest > > > > sea_water_mass_per_unit_area_expressed_as_thickness > > > > and presumably you have to state a standard density to be used in this > > conversion - what is that? NB sea_water_mass_per_unit_area (kg m-2) is > > already > > a standard name. > > > > > 2. Instead of "ocean_turbocline_depth (m)" we suggest: > > > ocean_turbocline_thickness (m) > > > 'The turbocline thickness is similar to the mixed layer thickness but is > > > estimated in models as the thickness at which the vertical eddy > > > diffusivity coefficient (resulting from the vertical physics alone) falls > > > below a given value defined locally.' > > > > Is there a difference between that and the existing > > ocean_mixed_layer_thickness_defined_by_vertical_tracer_diffusivity > > ? > > > > > ratio_of_sea_water_potential_temperature_anomaly_to_relaxation_timescale > > > (K s-1) > > > > > > 'This term is estimated as the deviation of the local sea water potential > > > temperature from an ocean model wrt an observation-based climatology (eg > > > World Ocean Database) weighted by a user-specified relaxation coefficient > > > in s-1 (1/(relaxation timescale)). The relaxation coefficient depends on > > > the timescale on which the correction is applied.' > > > > It seems to me that the last sentence is probably not necessary, since the > > previous sentence says the same. > > > > Best wishes and thanks > > > > Jonathan > > _______________________________________________ > > CF-metadata mailing list > > CF-metadata@cgd.ucar.edu > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > ----- End forwarded message ----- > _______________________________________________ > CF-metadata mailing list > CF-metadata@cgd.ucar.edu > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
