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 [email protected]. Please also use this e-mail if your requirement is urgent. ________________________________ From: CF-metadata <[email protected]> on behalf of Jonathan Gregory <[email protected]> Sent: 05 April 2018 18:28 To: [email protected] 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 <[email protected]> ----- > Date: Thu, 5 Apr 2018 13:55:50 +0000 > From: Sebastien Villaume <[email protected]> > To: CF Metadata <[email protected]> > 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" <[email protected]> > > To: "CF Metadata" <[email protected]> > > 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 > > [email protected] > > ____________________________________ > > _______________________________________________ > > CF-metadata mailing list > > [email protected] > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata CF-metadata Info Page - mailman.cgd.ucar.edu<http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata> 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 > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ________________________________ This message (and any attachments) is for the recipient only. 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