Dear Alison et al. I still find myself tripping over rainfall_mass. Why not rainfall_amount, rainfall_flux or rainfall_rate? They would all be the same number, since it's a *fraction*. Another possibility would be a reordering to mass_fraction_of_rainfall_falling_onto_surface_snow (1) mass_fraction_of_solid_precipitation_falling_onto_surface_snow (1) We have many mass_fraction names, and consistency could be good.
Best wishes Jonathan ----- Forwarded message from Alison Pamment - UKRI STFC <[email protected]> ----- > Date: Thu, 21 Jun 2018 11:34:45 +0000 > From: Alison Pamment - UKRI STFC <[email protected]> > To: 'Karl Taylor' <[email protected]>, Martin Juckes - UKRI STFC > <[email protected]>, "CF-metadata ([email protected])" > <[email protected]> > Subject: Re: [CF-metadata] Precipitation fractions for LS3MIP > > Dear Martin, Jonathan, Karl, > > I have had another look at these two names and amended the definitions in the > light of the discussion. > > fraction_of_rainfall_mass_falling_onto_surface_snow (1) > 'The quantity with standard name > fraction_of_rainfall_mass_falling_onto_surface_snow is the mass of rainfall > falling onto snow as a fraction of the mass of rainfall falling within the > area of interest. The horizontal domain over which the quantity is calculated > is described by the associated coordinate variables and coordinate bounds or > by a coordinate variable or scalar coordinate variable with the standard name > of "region" supplied according to section 6.1.1 of the CF conventions. The > phrase "surface_snow" means snow lying on the surface.' > > fraction_of_solid_precipitation_mass_falling_onto_surface_snow (1) > 'Solid precipitation refers to the precipitation of water in the solid phase. > Water in the atmosphere exists in one of three phases: solid, liquid or > vapor. The solid phase can exist as snow, hail, graupel, cloud ice, or as a > component of aerosol. The quantity with standard name > fraction_of_solid_precipitation_mass_falling_onto_surface_snow is the mass of > solid precipitation falling onto snow as a fraction of the mass of solid > precipitation falling within the area of interest. The horizontal domain over > which the quantity is calculated is described by the associated coordinate > variables and coordinate bounds or by a coordinate variable or scalar > coordinate variable with the standard name of "region" supplied according to > section 6.1.1 of the CF conventions. The phrase "surface_snow" means snow > lying on the surface.' > > Are these okay? If so I think they can be accepted. > > Best wishes, > Alison > > ------ > Alison Pamment Tel: +44 1235 778065 > NCAS/Centre for Environmental Data Archival Email: > [email protected] > STFC Rutherford Appleton Laboratory > R25, 2.22 > Harwell Oxford, Didcot, OX11 0QX, U.K. > > -----Original Message----- > From: CF-metadata <[email protected]> On Behalf Of Alison > Pamment - UKRI STFC > Sent: 11 June 2018 11:33 > To: 'Karl Taylor' <[email protected]>; Juckes, Martin (STFC,RAL,RALSP) > <[email protected]>; CF-metadata ([email protected]) > <[email protected]> > Subject: Re: [CF-metadata] Precipitation fractions for LS3MIP > > Dear Martin, Karl and Steve, > > Thank you for the proposing these two names and the comments received so far. > > fraction_of_rainfall_mass_falling_onto_surface_snow (1) 'The phrase > "surface_snow" means snow lying on the surface.' > > fraction_of_solid_precipitation_mass_falling_onto_surface_snow (1) 'The > phrase "surface_snow" means snow lying on the surface. Solid precipitation > refers to the precipitation of water in the solid phase. Water in the > atmosphere exists in one of three phases: solid, liquid or vapor. The solid > phase can exist as snow, hail, graupel, cloud ice, or as a component of > aerosol.' > > The names and units look fine. > > Are these variables calculated over quite large areas? If so, would it be > appropriate to add the following sentence to their definitions: > 'The horizontal domain over which the quantity is calculated is described by > the associated coordinate variables and coordinate bounds or by a coordinate > variable or scalar coordinate variable with the standard name of "region" > supplied according to section 6.1.1 of the CF conventions'? > > This is what we do with names like land_ice_mass where the quantity might > represent the mass of a whole ice sheet, rather than something calculated in > a small lat-long grid box. > > Best wishes, > Alison > > ------ > Alison Pamment Tel: +44 1235 778065 > NCAS/Centre for Environmental Data Archival Email: > [email protected] > STFC Rutherford Appleton Laboratory > R25, 2.22 > Harwell Oxford, Didcot, OX11 0QX, U.K. > > From: CF-metadata <[email protected]> On Behalf Of Karl Taylor > Sent: 05 June 2018 17:03 > To: Steven Emmerson <[email protected]>; Juckes, Martin (STFC,RAL,RALSP) > <[email protected]> > Cc: [email protected] > Subject: Re: [CF-metadata] Precipitation fractions for LS3MIP > > Hi all, > > I think in common usage "mass fraction" is the ratio of the mass of a > particular species to the total mass of all species combined (e.g., the mass > fraction of oxygen molecules in air). For the variable considered here, the > fraction refers to the ratio of the mass of as particular "species" (e.g., > rain) that falls on a particular surface (e.g., surface snow). This is enough > different from the standard usage that I think it would be wise to avoid > "mass fraction" in the standard name; thus, the suggestion: > > fraction_of_rainfall_mass_falling_onto_surface_snow > > Using "mass_fraction" here might lead some to wrongly jump to an > interpretation that this had something to do with the fraction of > precipitation that was falling as rain. > > best regards, > Karl > On 6/5/18 7:55 AM, Steven Emmerson wrote: > Greetings, > > On Tue, Jun 5, 2018 at 3:31 AM, Martin Juckes - UKRI STFC > <mailto:[email protected]> wrote: > We don't want the mass per unit area on snow divided by the mass per unit > area on the whole grid cell, but rather, as Jonathan has spelled out, the > mass on snow divided by the mass on the whole grid cell. Hence, I support > Karl's suggestion of using "mass" in the name, rather than "amount". > > I believe that's called a "mass fraction". See Table 12 of > <https://www.nist.gov/pml/nist-guide-si-chapter-8-comments-some-quantities-and-their-units>. > > > Regards, > Steve Emmerson > > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > > _______________________________________________ > 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
