Dear Pierre, Philip and Robert, I think Philip's last email pretty much sums up the position as I understand it. There are two standard names involved, one describing carbon release from all anthropogenic emissions and another describing carbon release from fossil fuels alone. The only question is whether these two quantities should most appropriately be named as surface fluxes or atmospheric tendencies. The other carbon cycle emissions names are unaffected by this discussion as they are clearly surface quantities.
Pierre has explained that the anthropogenic/fossil fuel quantities do both include emissions from airborne sources such as aircraft and chimneys. The former are certainly not surface emissions; we could debate the latter. I think it would be misleading to label the emissions purely as surface fluxes and we should instead call them atmospheric tendencies. This way we are not tying the emissions to any particular vertical location. In fact, the definition of 'emission' in CF standard names is as follows: ' "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. earth's surface),' so it explicitly copes with the case of emissions aloft. Also, to answer Pierre's point regarding the meaning of tendency, in standard names it is defined as follows: ' "tendency_of_X" means derivative of X with respect to time.' I agree with Philip's point that it would be worth expanding the definitions where appropriate to explain more fully the relationship between surface upward fluxes and emissions into the atmosphere as a whole. I suppose that a surface downward flux would be considered equivalent to the contributions from various deposition processes. I think this has been a useful discussion as it has helped to clarify the definitions of the names as well as arriving at the most appropriate terminology. I think we should stick with the names as originally accepted: tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carbo n_due_to_anthropogenic_emission; kg m-2 s-1 tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carbo n_due_to_emission_from_fossil_fuel_combustion; kg m-2 s-1. Robert contacted me by email with some comments regarding the consistency of the carbon cycle names: > Carbon_content > 1. leaf_carbon_content; kg m-2 > 2. wood_carbon_content; kg m-2 > 3. root_carbon_content; kg m-2 > 4. carbon_content_of_miscellaneous_living_matter; kg m-2 > 5. wood_debris_carbon_content; kg m-2 > > 1, 2. 3 and 5 have the structure "X_carbon_content", while 4 has the structure "carbon_content_of_X". Is there any particular reason for not giving > 4 the name: > 4. miscellaneous_living_matter_carbon_content, > which would conform to the pattern? I think it was Jonathan who suggested carbon_content_of_miscellaneous_living_matter as an improvement on my original proposal of miscellaneous_living_compartments_carbon_content. However, I think that Robert is correct that we could take Jonathan's wording and change the order without loss of clarity. Does anyone object to using miscellaneous_living_matter_carbon_content? > Fluxes of carbon > 1. surface_upward_flux_of_carbon_dioxide_expressed_as_carbon > [_due_to_emission_from_fires_excluding_land_use_change]; kg m-2 s-1 2. > surface_upward_mass_flux_of_carbon > [_due_to_natural_emission]; kg m-2 3. > surface_upward_carbon_flux > [_due_to_plant_respiration_for_biomass_growth]; kg m-2 s-1 (I have bracketted [...] the part of the name which is not relevant to my > question.) > > Is there any difference in meaning between these three syntactic forms > for carbon flux? It's not my field, but on the face of it they appear > to be alternative way of expressing the same quantity. > > I presume that there is a principle that, where possible, names should be constructed according to a consistent pattern (especially in the light of > Jonathan's work on rules for formulating names), so my guess is that there are some reasons for the above differences but I am not sure > what they are. As you've probably guessed, my interest in this relates > to my own work on developing a grammar for standard names, and it is clearly desirable to reduce the number of grammar rules to a minimum. I agree that wherever possible we should stick to using a small set of grammar rules. However, there are occasions where being too rigid about the syntax can result in immensely long and unwieldy (and therefore difficult to understand) names. Often it is just a question of readability. I think we could call the second quantity surface_upward_mass_flux_of_carbon[_due_to_emission_from_natural_sources ] to make it more consistent with the first without any loss of readability. Does anyone object to this change? Looking at the third name and trying to squeeze it into the same pattern would give something like: surface_upward_carbon_mass_flux_due_to_emission_from_plant_respiration_f or_biomass_growth which I think is less readable, so I prefer the syntax without the 'emission'. Do others agree? (Incidentally, this would also affect another related name: surface_upward_carbon_mass_flux_due_to_plant_respiration_for_biomass_mai ntenance). Robert's email has caused me to re-read the names more carefully and I realise that I have neglected to make clear that many of the carbon fluxes are in fact mass fluxes (as opposed to mole fluxes, for example). I would like to slightly revise some of the names already accepted to include the word 'mass': surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_em ission_from_fires_excluding_land_use_change; kg m-2 s-1 surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_em ission_from_grazing; kg m-2 s-1 surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_em ission_from_crop_harvesting; kg m-2 s-1 surface_net_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_t o_emission_from_anthropogenic_land_use_change; kg m-2 s-1 surface_net_downward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due _to_photosynthesis_and_respiration_and_fires_including_land_use_change; kg m-2 s-1 carbon_mass_flux_into_soil_from_litter; kg m-2 s-1 carbon_mass_flux_into_soil_from_vegetation_excluding_litter; kg m-2 s-1 surface_upward_carbon_mass_flux_due_to_plant_respiration_for_biomass_gro wth; kg m-2 s-1 surface_upward_carbon_mass_flux_due_to_plant_respiration_for_biomass_mai ntenance; kg m-2 s-1 surface_net_downward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due _to_photosynthesis_and_respiration_and_fires_excluding_land_use_change; kg m-2 s-1. Best wishes, Alison ------ Alison Pamment Tel: +44 1235 778065 NCAS/British Atmospheric Data Centre Fax: +44 1235 446314 Rutherford Appleton Laboratory Email: alison.pamm...@stfc.ac.uk Chilton, Didcot, OX11 0QX, U.K. > -----Original Message----- > From: Cameron-smith, Philip [mailto:cameronsmi...@llnl.gov] > Sent: 23 September 2010 19:48 > To: Pierre Friedlingstein; Pamment, Alison (STFC,RAL,SSTD) > Cc: cf-metadata@cgd.ucar.edu > Subject: RE: [CF-metadata] CMIP5 carbon cycle standard names > > Hi Pierre, > > Sorry for causing confusion. > > I understood that the question was whether to introduce the following > two standard names (for your purpose) > > tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carb > on_due_to_anthropogenic_emission; kg m-2 s-1 > tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carb > on_due_to_emission_from_fossil_fuel_combustion; kg m-2 s-1 > > Or these two, > > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_a > nthropogenic_emission; kg m-2 s-1 > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_e > mission_from_fossil_fuel_combustion; kg m-2 s-1. > > Alison had originally proposed the former (tendency_), and you (Pierre) > argued for the latter (surface_). > > What I liked was Alison's description of why these tendency_ and > surface_ quantities are physically different because the tendency_ > quantity also includes non-surface emissions. > > My first point was that your application included aircraft emissions so > that the tendency_ quantity is the correct physical quantity for your > application (even if your data may put the aircraft emissions in the > wrong box). Hence, I recommended we add the tendency_ names to the > standard name list, rather than the surface_ names (following CF > tradition of not adding names unless needed). > > My second point was that we already have both tendency_ and surface_ > names in the list, and many users could easily miss the physical > distinction. Hence, I suggested that we expand the descriptions of > these names in the list (when they occur) to highlight the distinction > (because, as you say, many people are likely to look for the surface_ > names). > > My third point was just to note that the one example of a standard name > similar to the surface_ names proposed above actually specifies the > _downward_ direction. > > I am somewhat sensitive to this issue because I am currently trying to > use various emission estimates and it is often hard to tell what is and > isn't included, and hence whether or not I am double counting. > > Best wishes :-), > > Philip > > ----------------------------------------------------------------------- > Dr Philip Cameron-Smith, p...@llnl.gov, Lawrence Livermore National Lab. > ----------------------------------------------------------------------- > > > > -----Original Message----- > > From: Pierre Friedlingstein [mailto:p.friedlingst...@exeter.ac.uk] > > Sent: Thursday, September 23, 2010 10:50 AM > > To: Cameron-smith, Philip; alison.pamm...@stfc.ac.uk > > Cc: cf-metadata@cgd.ucar.edu > > Subject: Re: [CF-metadata] CMIP5 carbon cycle standard names > > > > Hi all, > > I'm getting confused now. > > I understood Alison last proposal as keeping only one name : > > > > > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_a > > nthropogenic_emission; kg m-2 s-1 > > > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_e > > mission_from_fossil_fuel_combustion; kg m-2 s-1. > > > > Philip's mail, seemed to imply that both names could be used as he > > liked Alison's distinction... > > > > Could you clarify what the final decision? > > > > For info, yes the data do include aircraft, chimneys,... emissions as > > these data are derived from country based reporting of fossil fuel > > trades. > > Hence the aircraft emissions from US carriers are in the US numbers > and > > hence assigned on the US territory. This might be OK for US as most > of > > the flight are domestic, but I'm sure this is 99.9 % wrong for > Belgium > > ;-). > > Saying emissions are a vertical integral here would imply that planes > > are only flying up and down ! > > > > Anyway, I will leave with either or definition (you'll just have to > > explain what the "tendency" one mean to non-chemists...) > > > > Best > > Pierre > > > > > > > > On 22/09/2010 17:28, Cameron-smith, Philip wrote: > > > Hi All, > > > > > > Even if the dataset doesn't have vertical information, if it > includes > > > aircraft emissions then the physical quantity it is quantifying is > > the > > > vertical integral rather than the surface emission. In which case > I > > > would favour tendency_of_atmosphere_mass_content_ > > > > > > If there are no aircraft in the data, then do smoke stacks produce > > 'surface emissions'? An interesting question that could be debated. > > Hence, another advantage of tendency_of_atmosphere_mass_content_ is > > that it makes the question moot. > > > > > > BTW, FWIW, I note that the closest related standard name already in > > the table specifies the downward direction > > (surface_downward_mass_flux_of_carbon_dioxide_expressed_as_carbon). > > > > > > On a different note, I like Alison's distinction between > > > > > > > > > tendency_of_atmosphere_mass_content_of_..._due_to_anthropogenic_emissi > > > on > > > > > > and > > > > > > surface_upward_mass_flux_of_..._due_to_anthropogenic_emission > > > > > > Perhaps we should cross-reference such standard names in their > > descriptions to help future users? > > > > > > Best wishes, > > > > > > Philip > > > > > > ------------------------------------------------------------------- > -- > > - > > > -- Dr Philip Cameron-Smith, p...@llnl.gov, Lawrence Livermore Nat. > > > Lab. > > > ------------------------------------------------------------------- > -- > > - > > > -- > > > > > > > > > > > >> -----Original Message----- > > >> From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata- > > >> boun...@cgd.ucar.edu] On Behalf Of Pierre Friedlingstein > > >> Sent: Wednesday, September 22, 2010 6:01 AM > > >> To: alison.pamm...@stfc.ac.uk > > >> Cc: cf-metadata@cgd.ucar.edu > > >> Subject: Re: [CF-metadata] CMIP5 carbon cycle standard names > > >> > > >> Alison, > > >> I see your point. > > >> As far as I know the anthropogenic emissions data will be surface > > >> fluxes. Data are based on country level consumption of fossil > fuel, > > >> they don't have the info on where in the air it is released... > > >> Pierre > > >> > > >> On 22/09/2010 13:04, alison.pamm...@stfc.ac.uk wrote: > > >> > > >>> Hi Pierre, > > >>> > > >>> My thinking here was that 'anthropegenic emissions' (which > > >>> presumably include fossil fuel emissions) and 'fossil fuel' > > >>> emissions themselves do not necessarily always occur at the > earth's > > >>> surface. For example, emissions from tall chimneys and aircraft > > may > > >>> occur at many levels in the atmosphere. It was not clear to me > > that > > >>> these particular quantities in the CMIP5 tables are intended only > > to > > >>> account for > > >>> > > >> surface emissions. > > >> > > >>> If that is the case, then we certainly need to make it clear and > I > > >>> agree with your suggestion to label them as surface fluxes. So > > >>> > > >> instead > > >> > > >>> of introducing > > >>> > > >>> > > >>> > > >> > > tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_ca > > >> r > > >> > > >>> bo n_due_to_anthropogenic_emission; kg m-2 s-1 > > >>> > > >>> > > >> > > tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_ca > > >> r > > >> > > >>> bo n_due_to_emission_from_fossil_fuel_combustion; kg m-2 s-1 > > >>> > > >>> I will add > > >>> > > >>> > > >> > > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to > > >> _ > > >> > > >>> an > > >>> thropogenic_emission; kg m-2 s-1 > > >>> > > >>> > > >> > > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to > > >> _ > > >> > > >>> em ission_from_fossil_fuel_combustion; kg m-2 s-1. > > >>> > > >>> OK? > > >>> > > >>> Best wishes, > > >>> Alison > > >>> > > >>> ------ > > >>> Alison Pamment Tel: +44 1235 778065 > > >>> NCAS/British Atmospheric Data Centre Fax: +44 1235 446314 > > >>> Rutherford Appleton Laboratory Email: > > >>> > > >> alison.pamm...@stfc.ac.uk > > >> > > >>> Chilton, Didcot, OX11 0QX, U.K. > > >>> > > >>> > > >>> > > >>> > > >>>> -----Original Message----- > > >>>> From: Pierre Friedlingstein > [mailto:p.friedlingst...@exeter.ac.uk] > > >>>> Sent: 21 September 2010 16:41 > > >>>> To: Pamment, Alison (STFC,RAL,SSTD) > > >>>> Cc: j.m.greg...@reading.ac.uk; cf-metadata@cgd.ucar.edu > > >>>> Subject: Re: [CF-metadata] CMIP5 carbon cycle standard names > > >>>> > > >>>> Hi Alison, > > >>>> Just wondering, why are the first two variables below named as > > >>>> "tendency_of_atmosphere_mass_content_of..." > > >>>> while all others are named as "surface_upward_mass_flux_of_ > ..." > > >>>> Any reason ? > > >>>> I know the "tendency..." is used for other chemical species... > But > > >>>> > > >>>> > > >>> here > > >>> > > >>> > > >>>> for CO2 variables, I think intra-consistency should be favoured. > > No > > >>>> > > >> ? > > >> > > >>>> Best > > >>>> Pierre > > >>>> > > >>>> On 21/09/2010 13:40, alison.pamm...@stfc.ac.uk wrote: > > >>>> > > >>>> > > >>>>> Dear Jonathan and Pierre, > > >>>>> > > >>>>> Thank you both for your comments on the CMIP5 carbon cycle > names. > > >>>>> Looking back through this thread I think we have resolved all > the > > >>>>> outstanding issues and so the following names are now accepted > > for > > >>>>> inclusion in the standard name table: > > >>>>> > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_ca > > >> > > >>>> r > > >>>> > > >>>> > > >>>>> bo n_due_to_anthropogenic_emission; kg m-2 s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_ca > > >> > > >>>> r > > >>>> > > >>>> > > >>>>> bo n_due_to_emission_from_fossil_fuel_combustion; kg m-2 s-1 > > >>>>> surface_upward_mass_flux_of_carbon_due_to_natural_emission; > kg m- > > >>>>> > > >>>>> > > >>>> 2 > > >>>> > > >>>> > > >>>>> s-1 > > >>>>> atmosphere_mass_of_carbon_dioxide; kg > > >>>>> carbon_content_of_products_of_land_use_change; kg m-2 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_upward_flux_of_carbon_dioxide_expressed_as_carbon_due_to_emis > > >> > > >>>> s > > >>>> > > >>>> > > >>>>> io n_from_fires_excluding_land_use_change; kg m-2 s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_upward_flux_of_carbon_dioxide_expressed_as_carbon_due_to_emis > > >> > > >>>> s > > >>>> > > >>>> > > >>>>> io > > >>>>> n_from_grazing; kg m-2 s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_upward_flux_of_carbon_dioxide_expressed_as_carbon_due_to_emis > > >> > > >>>> s > > >>>> > > >>>> > > >>>>> io > > >>>>> n_from_crop_harvesting; kg m-2 s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_net_upward_flux_of_carbon_dioxide_expressed_as_carbon_due_to_ > > >> > > >>>> e > > >>>> > > >>>> > > >>>>> mi ssion_from_anthropogenic_land_use_change; kg m-2 s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_net_downward_flux_of_carbon_dioxide_expressed_as_carbon_due_t > > >> > > >>>> o > > >>>> > > >>>> > > >>>>> _p > > >>>>> > > >>>>> > > >>> > hotosynthesis_and_respiration_and_fires_including_land_use_change; > > >>> > > >>> > > >>>>> kg > > >>>>> m-2 s-1 > > >>>>> carbon_flux_into_soil_from_litter; kg m-2 s-1 > > >>>>> carbon_flux_into_soil_from_vegetation_excluding_litter; kg m-2 > s- > > 1 > > >>>>> leaf_carbon_content; kg m-2 wood_carbon_content; kg m-2 > > >>>>> root_carbon_content; kg m-2 > > >>>>> carbon_content_of_miscellaneous_living_matter; kg m-2 (N.B. > > >>>>> 'miscellaneous' means carbon content of living matter apart > from > > >>>>> > > >>>>> > > >>>> those > > >>>> > > >>>> > > >>>>> individually named in the preceding three items) > > >>>>> wood_debris_carbon_content; kg m-2 > surface_litter_carbon_content; > > >>>>> > > >> kg > > >> > > >>>>> m-2 subsurface_litter_carbon_content; kg m-2 > > >>>>> fast_soil_pool_carbon_content; kg m-2 > > >>>>> > > >>>>> > > >>>> medium_soil_pool_carbon_content; > > >>>> > > >>>> > > >>>>> kg m-2 slow_soil_pool_carbon_content; kg m-2 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_upward_carbon_flux_due_to_plant_respiration_for_biomass_growt > > >> > > >>>> h > > >>>> > > >>>> > > >>>>> ; > > >>>>> kg m-2 s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_upward_carbon_flux_due_to_plant_respiration_for_biomass_maint > > >> > > >>>> e > > >>>> > > >>>> > > >>>>> na > > >>>>> nce; kg m-2 s-1 > > >>>>> net_primary_productivity_of_carbon_accumulated_in_leaves; kg m- > 2 > > >>>>> s- > > >>>>> > > >> 1 > > >> > > >>>>> net_primary_productivity_of_carbon_accumulated_in_wood; kg m-2 > s- > > 1 > > >>>>> net_primary_productivity_of_carbon_accumulated_in_roots; kg m-2 > > >>>>> s-1 > > >>>>> > > >>>>> > > >>>>> > > >>>> > > >> > > surface_net_downward_flux_of_carbon_dioxide_expressed_as_carbon_due_t > > >> > > >>>> o > > >>>> > > >>>> > > >>>>> _p > > >>>>> > > >>>>> > > >>> > hotosynthesis_and_respiration_and_fires_excluding_land_use_change; > > >>> > > >>> > > >>>>> kg > > >>>>> m-2 s-1. > > >>>>> > > >>>>> To cope with the various fractional vegetation coverage > > quantities > > >>>>> > > >>>>> > > >>> we > > >>> > > >>> > > >>>>> will use the existing standard name area_fraction and introduce > > >>>>> new entries of primary_evergreen_trees, > > secondary_deciduous_trees, > > >>>>> secondary_evergreen_trees, C3_plant_functional_types, > > >>>>> C4_plant_functional_types into the area_type table. > > >>>>> > > >>>>> Best wishes, > > >>>>> Alison > > >>>>> > > >>>>> ------ > > >>>>> Alison Pamment Tel: +44 1235 778065 > > >>>>> NCAS/British Atmospheric Data Centre Fax: +44 1235 446314 > > >>>>> Rutherford Appleton Laboratory Email: > > >>>>> > > >>>>> > > >>>> alison.pamm...@stfc.ac.uk > > >>>> > > >>>> > > >>>>> Chilton, Didcot, OX11 0QX, U.K. > > >>>>> > > >>>>> > > >>>>> > > >>>>> > > >>> > > > -- Scanned by iCritical. _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
