Dear Alison I agree with all this and support Martin's suggestions that you have enacted. I agree that omega is like w and it's normal to write wT.
Best wishes and thanks Jonathan ----- Forwarded message from Alison Pamment - UKRI STFC <alison.pamm...@stfc.ac.uk> ----- > Date: Thu, 30 May 2019 13:12:10 +0000 > From: Alison Pamment - UKRI STFC <alison.pamm...@stfc.ac.uk> > To: "cf-metadata@cgd.ucar.edu" <cf-metadata@cgd.ucar.edu> > Subject: Re: [CF-metadata] order of product in standard name > > Dear Jonathan and Martin, > > I would like to make sure that we have fully resolved this issue as it > affects names that are currently under discussion in two threads: > covariance_over_longitude_of_northward_wind_and_air_temperature (latest > comment: http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2019/020922.html); > also: > * product_of_eastward_wind_and_lagrangian_tendency_of_air_pressure > * product_of_northward_wind_and_lagrangian_tendency_of_air_pressure > * product_of_lagrangian_tendency_of_air_pressure_and_specific_humidity > * product_of_lagrangian_tendency_of_air_pressure_and_air_temperature > * product_of_lagrangian_tendency_of_air_pressure_and_geopotential_height > (latest comment > http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2019/020927.html). > > I agree with Jonathan that for covariance and correlation names it is better > to have covariance_over_Z_of_X_and_Y, (rather than putting over_Z at the end > as stated in the current guidelines). This is consistent with the way we now > write integrals as integral_wrt_X_of_Y. > > The current guidelines for correlation and covariance say simply that X and Y > should be ordered alphabetically, whereas for product we have additional > guidance: 'If X and Y are both scalars or both components of vectors, they > are put in alphabetical order. If one of them is the component of a vector, > it is put first i.e. the vector component is X, the scalar is Y.' > > I think we are agreed that the same guidelines should apply to the ordering > of X and Y in standard names for all commutative properties such as product, > covariance, correlation, etc. > > The rule about putting vector components first means that the covariance name > as written above is in the correct order. > > Regarding the lagrangian tendency names, I agree with Martin's argument that > lagrangian_tendency_of_air_pressure should be regarded as a vertical > component of the air velocity vector, rather than a scalar. Therefore it is > correct to write the specific_humidity, air_temperature and > geopotential_height names as above (this is the opposite way round to what > was originally proposed). > > I also agree with Martin's suggestion of ordering vector components as > X=horizontal and Y=vertical when horizontal and vertical components are the > operands. This is a useful general convention and gets around the problem of > having product_of_eastward_wind_and_lagrangian_tendency_of_air_pressure and > product_of_lagrangian_tendency_of_air_pressure_and_northward_wind which would > arise from the alphabetical rule. (Of course if we are combining two > horizontal or two vertical vector components we would still need to fall back > on the alphabetical rule). > > It is on my 'To Do' list in the next couple of months to conduct a thorough > review of the standard names Guidelines document and the sections of the > Conventions document covering standard names and units. They are all somewhat > out of date. If we can agree these changes they can be included as part of > that process. > > Best wishes, > Alison > > ----------------------------------------------------------------------------------------------------------- > Alison Pamment Tel: > +44 1235 778065 > NCAS/Centre for Environmental Data Analysis Email: > alison.pamm...@stfc.ac.uk > STFC Rutherford Appleton Laboratory > R25, 2.22 > Harwell Oxford, Didcot, OX11 0QX, U.K. > > > -----Original Message----- > From: CF-metadata <cf-metadata-boun...@cgd.ucar.edu> On Behalf Of Jonathan > Gregory > Sent: 10 May 2019 15:08 > To: cf-metadata@cgd.ucar.edu > Subject: [CF-metadata] order of product in standard name > > Dear all > > I should have noticed that we already have a guideline about > product_of_X_and_Y, which should also apply to covariance, correlation, and > any other commutative function of X and Y: > > If X and Y are both scalars or both components of vectors, they are put in > alphabetical order. If one of them is the component of a vector, it is put > first i.e. the vector component is X, the scalar is Y. > > Cheers > > Jonathan > _______________________________________________ > 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 ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
