Dear Jonathan and Roy, thank you for your suggestions.
I am happy to go with a set of general standard names if it is fine with everyone. I find it actually useful to make the standard names reusable by not hard-coding one of the reference. It is pretty clear from the mixed layer definition that it is a difference with respect to the sea surface. I am also happy to prefix sigma_theta and sigma_t with sea_water: sea_water_temperature_difference (K) sea_water_sigma_theta_difference (kg/m3) sea_water_sigma_t_difference (kg/m3) I will draft some definitions for tomorrow. thanks! /Sébastien ----- Original Message ----- > From: "Lowry, Roy K." <r...@bodc.ac.uk> > To: cf-metadata@cgd.ucar.edu, "Jonathan Gregory" <j.m.greg...@reading.ac.uk> > Sent: Thursday, 5 April, 2018 18:34:48 > Subject: Re: [CF-metadata] how to use > ocean_mixed_layer_thickness_defined_by_* > Dear Jonathan and Sebastien, > > > > > I was initially thinking of not including ' _defining_mixed_layer' in my > suggestion and am certainly happy with leaving it out. However, I still think > sigma_t and sigma_theta should be prefixed with 'sea_water'. This would give: > > > > > > sea_water_temperature_difference > sea_water_sigma_theta_difference > sea_water_sigma_t_difference > > Cheers, Roy. > > > > > > > > > Please note that I partially retired on 01/11/2015. I am now only working 7.5 > hours a week and can only guarantee e-mail response on Wednesdays, my day in > the office. All vocabulary queries should be sent to enquir...@bodc.ac.uk. > Please also use this e-mail if your requirement is urgent. > > > > From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu> on behalf of Jonathan > Gregory <j.m.greg...@reading.ac.uk> > Sent: 05 April 2018 18:28 > To: cf-metadata@cgd.ucar.edu > Subject: Re: [CF-metadata] how to use ocean_mixed_layer_thickness_defined_by_* > Dear Sebastien > > It's interesting that this question hasn't been raised before. Thanks for > doing > so now. I agree that new standard names would be appropriate. There are > already > some standard names containing "difference" in various ways. I would suggest > that for your purpose the names don't have to be so specific. You could use > sea_water_temperature_difference > sigma_theta_difference > sigma_t_difference > because in the context of your use of them it is obvious what difference you > mean. That would make these names perhaps useful for other purposes too. This > is like the rather generic name > air_temperature_threshold > which doesn't indicate what the threshold can be used for. I would also > suggest > that the definitions of the three kinds of mixed layer depth should have a > sentence added to say that the threshold should be stored in a coordinate var, > e.g. like the sentence for > number_of_days_with_air_temperature_above_threshold. > > Best wishes > > Jonathan > > ----- Forwarded message from Sebastien Villaume <sebastien.villa...@ecmwf.int> > ----- > >> Date: Thu, 5 Apr 2018 13:55:50 +0000 >> From: Sebastien Villaume <sebastien.villa...@ecmwf.int> >> To: CF Metadata <cf-metadata@cgd.ucar.edu> >> Subject: Re: [CF-metadata] how to use >> ocean_mixed_layer_thickness_defined_by_* >> X-Mailer: Zimbra 8.6.0_GA_1200 (ZimbraWebClient - FF52 (Linux)/8.6.0_GA_1200) >> >> Hi all, >> >> It seems that my question did not attract much response. :( >> >> Is it because no one knows how to use these standard names and properly >> encode >> the "quantity that differs from its surface value by a certain amount"? >> >> Giving it more thoughts I feel that I need new standard names to describe >> this >> properly. >> >> Would it make sense to describe it this way: >> >> float swtd ; >> swtd:standard_name = "sea_water_temperature_difference_wrt_sea_surface" ; >> swtd:units = "degC" ; >> swtd:axis = "Z" ; >> swtd:positive = "down" ; >> swtd:long_name = "temperature difference wrt its surface value" >> >> float omlt(t, j, i) ; >> omlt:standard_name = "ocean_mixed_layer_thickness_defined_by_temperature" ; >> omlt:units = "m" ; >> omlt:coordinates = "time swtd1 latitude longitude" ; >> omlt:long_name = "ocean mixed layer defined by difference of temperature from >> surface" >> >> and the scalar value swtd can be 0.5 degC, 1.0 degC, etc. >> >> In this case, I need standard names working with temperature, sigma_theta and >> sigma_t: >> >> sea_water_temperature_difference_wrt_sea_surface >> sigma_theta_difference_wrt_sea_surface >> sigma_t_difference_wrt_sea_surface >> >> >> any quick suggestions are very welcome! >> >> thanks >> /Sébastien >> >> ----- Original Message ----- >> > From: "Sebastien Villaume" <sebastien.villa...@ecmwf.int> >> > To: "CF Metadata" <cf-metadata@cgd.ucar.edu> >> > Sent: Wednesday, 4 April, 2018 14:04:42 >> > Subject: [CF-metadata] how to use ocean_mixed_layer_thickness_defined_by_* >> >> > Dear list, >> > >> > I have a question regarding the use of the standard names of the form >> > ocean_mixed_layer_thickness_defined_by_* >> > >> > the definition from the official standard name 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 or >> > sigma_theta is the level at which the quantity indicated differs from its >> > surface value by a certain amount." >> > >> > From what I understand, in the case of >> > ocean_mixed_layer_thickness_defined_by_temperature, I should specify some >> > quantity as a scalar (Z axis), but it is actually a temperature difference >> > that >> > I need to encode, not a plain temperature : temp_surf - temp_base_level = >> > temp_delta_defining_mixed_layer_thickness >> > >> > if it was simply a temperature I would maybe use: >> > >> > float swpt ; >> > swpt:standard_name = "sea_water_potential_temperature" ; >> > swpt:units = "degC" ; >> > swpt:axis = "Z" ; >> > swpt:positive = "down" ; >> > >> > but what I really want to encode is a temperature difference. How can I >> > specify >> > that? Is "sea_water_potential_temperature" the correct standard name to >> > use? >> > >> > >> > same question for ocean_mixed_layer_thickness_defined_by_sigma_theta, how >> > do I >> > encode a "difference" in sigma_theta? >> > >> > thanks, >> > >> > ____________________________________ >> > >> > Dr. Sébastien Villaume >> > >> > M.A.R.S. Analyst >> > ECMWF Data Governance facilitator >> > >> > ECMWF >> > Shinfield Park, >> > Reading RG2 9AX, UK >> > +44 (0)118 949 9301 >> > +44 (0)7825 521592 >> > sebastien.villa...@ecmwf.int >> > ____________________________________ >> > _______________________________________________ >> > CF-metadata mailing list >> > CF-metadata@cgd.ucar.edu >> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > > CF-metadata Info Page - mailman.cgd.ucar.edu > mailman.cgd.ucar.edu > This is an unmoderated list for discussions about interpretation, > clarification, > and proposals for extensions or change to the CF conventions. > > >> _______________________________________________ >> 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 > > This message (and any attachments) is for the recipient only. 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