Dear Martin I would favour minus_one_times_tendency. This is clumsy but it is very clear, I think, and as you say it's already in use for other such awkward situations. I feel that if we replace the word tendency (as in 2) or use a different idea altogether (as in 3) there will not be such an obvious relationship between the names of opposite sign i.e. tendency_of_X and minus_one_times_tendency_of_X and this is a strong advantage, I feel.
I wonder whether we could reduce the clumsiness by saying e.g. minus_tendency, negated_tendency or negative_tendency, but I'm not sure these are as clear as minus_one_times_tendency. I think they might all give rise to questions. Of those, I think minus_tendency would be best. Other more exotic alternatives could be to invent a new word e.g. antitendency, or to allow a - sign in the standard name: -tendency_of_X! Best wishes Jonathan ----- Forwarded message from Martin Juckes - UKRI STFC <[email protected]> ----- > Date: Wed, 16 May 2018 11:58:05 +0000 > From: Martin Juckes - UKRI STFC <[email protected]> > To: "[email protected]" <[email protected]>, Michael Schulz > <[email protected]>, Taylor Karl <[email protected]> > Subject: [CF-metadata] Dry and wet deposition rates > > There are 20 variables in the CMIP6 data request for a variety of dry and wet > deposition rates. Many of these variables have been used in CMIP5 and earlier > with standard names of the form: > tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_dry_deposition. > > > However, there is a conflict in the intended sign convention. The deposition > rates should be positive when material is leaving the atmosphere, but the > standard names that have been used should be positive when the atmospheric > content is increasing. To resolve this we need a set of new standard names. > The existing tendency names are: > > tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_ammonia_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_ammonium_dry_aerosol_particles_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_particles_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_sulfur_dioxide_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_particles_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_nitrogen_compounds_expressed_as_nitrogen_due_to_deposition > tendency_of_atmosphere_mass_content_of_dust_dry_aerosol_particles_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_ammonia_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_ammonium_dry_aerosol_particles_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_noy_expressed_as_nitrogen_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_sulfur_dioxide_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_particles_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_particles_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_ozone_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_seasalt_dry_aerosol_particles_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_elemental_carbon_dry_aerosol_particles_due_to_wet_deposition > tendency_of_atmosphere_mass_content_of_seasalt_dry_aerosol_particles_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_noy_expressed_as_nitrogen_due_to_dry_deposition > tendency_of_atmosphere_mass_content_of_elemental_carbon_dry_aerosol_particles_due_to_dry_deposition > > Three options have been raised in the preliminary discussions: > (1) Prefix each name with "minus_one_times_": this construction is already > used for 3 names. > > (2) Replace "tendency_of_" with "depletion_rate_of_": this is a new > construction, but is structurally close to what we have and makes the > relation between variables very clear; > > (3) Replace "tendency_of_atmosphere_mass_content_of_" with > "surface_downward_mass_flux_of_": this uses an existing construction already > used in 8 standard names. > > What do others on the list think? > > regards, > Martin > > > > > ________________________________ > From: Juckes, Martin (STFC,RAL,RALSP) > Sent: 16 May 2018 08:14 > To: Michael Schulz; Taylor Karl > Cc: [email protected]; [email protected]; Bodas-Salcedo, > Alejandro; Pamment, Alison (STFC,RAL,RALSP) > Subject: Re: Conflicting sign conventions in deposition rates > > > Hello Michael, Karl, > > > OK, it sounds as though we should keep the variables as they are, i.e. > positive for deposition from the atmosphere, and fix the standard names. > > > I don't think a positive attribute will solve this problem. It may be useful > to add "positive=down", but it still leaves an inconsistency with the > standard names which definitely should be used with positive "up". Standard > names for variables with an opposite sign convention would not be synonyms: > there are many examples of pairs of names which differ only in the sign > convention, e.g. > > surface_upwelling_shortwave_flux_in_air -- > minus_one_times_surface_upwelling_shortwave_flux_in_air (+ 2 other pairs > like this); > > surface_downward_heat_flux_in_air -- surface_upward_heat_flux_in_air (+ 5 > other pairs like this). > > > We can construct standard names for minus the tendency of quantities in > several ways, but it may be better to have that discussion on the CF > discussions email list .. so I'll make a proposal there, also raising Karl's > suggestion (depletion_rate_of_ ....), > > > regards, > > Martin > > > > > > > ________________________________ > From: Michael Schulz <[email protected]> > Sent: 15 May 2018 19:46 > To: Juckes, Martin (STFC,RAL,RALSP) > Cc: Taylor Karl; [email protected]; [email protected]; > Bodas-Salcedo, Alejandro; Pamment, Alison (STFC,RAL,RALSP) > Subject: Re: Conflicting sign conventions in deposition rates > > Hi, > > true - tendencies have not carefully chosen with a sign in mind. > > There is very long tradition that these variables are “positive". So that > should not be changed. > > The standard names are also used since quite some time. > > Adding a positive attribute would be my preferred solution. > > Otherwise “surface_downward_mass_flux_of_” is fine for me as well. But that > would introduce a synonym in the system, right? > > best wishes > Michael > > > > > > > On 15 May 2018, at 20:13, Martin Juckes - UKRI STFC > > <[email protected]> wrote: > > > > Hello All, > > > > > > Larry has pointed out a conflict between variable long names and standard > > names for a set of deposition rate variables, many of which were in the > > CMIP5 aero table, e.g. wetso4, "Wet Deposition Rate of SO4" with standard > > name > > tendency_of_atmosphere_mass_content_of_sulfate_expressed_as_sulfur_dry_aerosol_due_to_wet_deposition > > > > > > A deposition rate would normally be positive when material is leaving the > > atmosphere, making the tendency of atmosphere mass content negative. > > > > > > I will try to check the sign convention adopted by people submitting data > > for CMIP5, but I suspect that we should follow the sign convention implied > > by the long name .. but this would require new standard names for these > > variables. A full list of the variables is here: > > https://github.com/cmip6dr/CMIP6_DataRequest_VariableDefinitions/issues/328 > > > > > > For new standard names, we could either use the "minus_one_times_" > > construction, or replace "tendency_of_atmosphere_mass_content_of_" with > > "surface_downward_mass_flux_of_". > > > > > > What do others think? > > > > > > > > regards, > > > > Martin > > > > > > _______________________________________________ > 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
