Hi Alison, My responses are below, but they mostly consist of "yes, I agree."
On Thu, Dec 1, 2016 at 4:00 PM, <[email protected]> wrote: > Dear Dave and Jonathan, > > Thank you for the discussion of the product names and I see that we have > now settled on wood_and_agricultural_products, which I agree is easier to > understand for the non-expert. This same terminology will also need to be > adopted for C4MIP so that we have a consistent approach for all the names. > > Following on from our earlier discussion (http://mailman.cgd.ucar.edu/ > pipermail/cf-metadata/2016/059101.html) I have updated all the LUMIP > names and definitions as detailed below. The majority of LUMIP names are > now either agreed or very close to agreement. Dave, please could you check > through the list once more and let me know if anything else needs changing > for proposals 1 - 6. I do still have some outstanding questions regarding > proposals 7 and 8. > > > > 1. moisture_content_of_soil_layer (canonical units: kg m-2) > > > 'Moisture in top 10 cm of soil column of land use tile.' > > > > > > soil_moisture_content (canonical units: kg m-2) > > > 'Total soil moisture'. > > > > > > Jonathan is correct that these two names already exist. However, the > reason I suggested raising them on the mailing list is that I think we > should improve the wording of > > > the existing names by changing them to mass_content_of_water_in_soil_layer > and soil_mass_content_of_water respectively. This would make the syntax of > the soil > > > names more consistent with other existing names such as > atmosphere_mass_content_of_water and > mass_content_of_water_vapor_in_atmosphere_layer, > for example. > > > There are also existing soil names that refer to "frozen_water" and > "condensed_water" rather than "moisture" so I think it would be sensible to > standardize the > > > terminology used across all the names. The soil names could continue > to use their existing definitions as follows: > > > > > > mass_content_of_water_in_soil_layer (kg m-2) > > > ' "Water" means water in all phases. "Content" indicates a quantity > per unit area. "Layer" means any layer with upper and lower boundaries that > have constant values in > > > some vertical coordinate. There must be a vertical coordinate variable > indicating the extent of the layer(s). If the layers are model layers, the > vertical coordinate can be > > > model_level_number, but it is recommended to specify a physical > coordinate (in a scalar or auxiliary coordinate variable) as well. > Quantities defined for a soil layer must > > > have a vertical coordinate variable with boundaries indicating the > extent of the layer(s).' > > > > > > soil_mass_content_of_water (kg m-2) > > > ' "Water" means water in all phases. "Content" indicates a quantity > per unit area. The "soil content" of a quantity refers to the vertical > integral from the surface down to > > > the bottom of the soil model. For the content between specified levels > in the soil, standard names including content_of_soil_layer are used.' > > > > > > Is this OK? If so, I think these names can be accepted for inclusion > in the standard name table (the older versions of the names would be > retained as aliases). > > > > > This is fine with me. Presumably this will affect not only LUMIP > variable request but that of other MIPs like LS3MIP. But, main thing is > getting a consistent naming > > convention and this seems good. > > Following discussion with Jonathan it was agreed to change the order of > the words in the second name as follows: > mass_content_of_water_in_soil (kg m-2) > ' "Water" means water in all phases. "Content" indicates a quantity per > unit area. The mass content of water in soil refers to the vertical > integral from the surface down to the bottom of the soil model. For the > content between specified levels in the soil, standard names including > "content_of_soil_layer" are used.' > > Any changes to these names will affect all CF users. I will make sure that > the LS3MIP team are aware of the change. The old versions of the names will > be retained in the standard name table as aliases which means that any data > already written with those names will not be invalidated. However, data > written in the future should use the most up to date version of the names. > > These changes are accepted for publication in the standard name table and > will be added at the next update, scheduled for December 13th. > > > > 2. surface_downward_mass_flux_of_water_due_to_crop_irrigation > (canonical_units: kg m-2) > > > 'cropland irrigation flux' > > > > > > I think the name and units are fine. We need to expand the definition > and based on text used for existing names I would suggest: > > > ' "Downward" indicates a vector component which is positive when > directed downward (negative upward). The surface called "surface" means the > lower boundary of the > > > atmosphere. In accordance with common usage in geophysical > disciplines, "flux" implies per unit area, called "flux density" in > physics. The specification of a physical > > > process by the phrase "due_to_" process means that the quantity named > is a single term in a sum of terms which together compose the general > quantity named by > > > omitting the phrase.' > > > > > > Is this OK? I am wondering if this name refers to any particular > definition of 'crop', for example, arable crops, fruit trees, trees grown > for timber, or perhaps all of the > > > above? It would be useful to add that into the text too. > > > > > I would suggest changing to (note the unit change as well as name > change), removing the term crop to be more general. > > > > surface_downward_mass_flux_of_water_due_to_irrigation (canonical_units: > kg m-2 s-1 or kg s-1) > > The description would then be: Irrigation flux including any irrigation > for crops, trees, pasture, or urban lawns. > > As with other flux variables, is the per unit area implied since this is > a flux term? > > Yes, flux always does imply per unit area in standard names so the units > should be kg m-2 s-1 as you say. The name looks fine. So then we would have: > surface_downward_mass_flux_of_water_due_to_irrigation (canonical_units: > kg m-2 s-1) > ' "Downward" indicates a vector component which is positive when directed > downward (negative upward). The surface called "surface" means the lower > boundary of the > atmosphere. In accordance with common usage in geophysical disciplines, > "flux" implies per unit area, called "flux density" in physics. The > specification of a physical > process by the phrase "due_to_" process means that the quantity named is a > single term in a sum of terms which together compose the general quantity > named by omitting > the phrase. "Irrigation" includes water used to sustain crops, trees, > pastures and urban lawns.' > > OK? > Yes, this is ok. The only issue is that I get confused about whether or not m-2 should be in the units or not. For other variables (e.g. the carbon mass flux variables listed below), you remove the m-2 because it is implied by the term flux, but you have included it here for this variable. > > > > 3. > > > surface_upward_sensible_heat_flux_due_to_anthropogenic_energy_consumption > (canonical units: W m-2) > > > ' anthropogenic heat flux' > > > > > > I note that after discussion with Jonathan, Dave has agreed that the > name should be more general, i.e., it is not only a sensible heat flux and > the proposal is now > > > surface_upward_heat_flux_due_to_anthropogenic_energy_consumption > (Wm-2). > > > > > > That name and the units are fine, so now we need a definition. Based > on the definitions of existing names we would have the following: > > > 'The surface called "surface" means the lower boundary of the > atmosphere. "Upward" indicates a vector component which is positive when > directed upward (negative > > > downward). The vertical heat flux in air is the sum of all heat fluxes > i.e. radiative, latent and sensible. In accordance with common usage in > geophysical disciplines, "flux" > > > implies per unit area, called "flux density" in physics. The > specification of a physical process by the phrase "due_to_" process means > that the quantity named is a single > > > term in a sum of terms which together compose the general quantity > named by omitting the phrase. "Anthropogenic" means influenced, caused, or > created by human > > > activity.' > > > > > > Does 'anthropogenic_energy_consumption' mean all anthropogenic > processes, e.g., domestic, industrial, transport, agriculture, and so on? > It would make the definition > > > (and hence the name) more useful if we can say something about which > processes are included or excluded. > > > > > Anthropogenic heat flux generated from non-renewable human primary > energy consumption, including energy use by vehicles, commercial and > residential buildings, > > industry, and power plants. Primary energy refers to energy in natural > resources, fossil and nonfossil, before conversion into other forms, such > as electricity. > > Thank you for supplying the definition. So, in full, we have: > surface_upward_heat_flux_due_to_anthropogenic_energy_consumption > (canonical units: W m-2) > 'The surface called "surface" means the lower boundary of the atmosphere. > "Upward" indicates a vector component which is positive when directed > upward (negative downward). The vertical heat flux in air is the sum of all > heat fluxes i.e. radiative, latent and sensible. In accordance with common > usage in geophysical disciplines, "flux" implies per unit area, called > "flux density" in physics. The specification of a physical process by the > phrase "due_to_" process means that the quantity named is a single term in > a sum of terms which together compose the general quantity named by > omitting the phrase. "Anthropogenic" means influenced, caused, or created > by human activity. The heat flux due to anthropogenic energy consumption > results from non-renewable human primary energy consumption, including > energy use by vehicles, commercial and residential buildings, industry, and > power plants. Primary energy refers to energy in natural resources, fossil > and non-fossil, before conversion into other forms, such as electricity.' > > OK? > Yes. > > > > 4. tendency_of_atmosphere_mass_content_of_carbon_due_to_ > emission_from_anthropogenic_product_pool (canonical units: kg s-1) > > > ' flux from anthropogenic pools on land use tile into atmosphere' > > Following the discussion on product names, this proposal has now become: > tendency_of_atmosphere_mass_content_of_carbon_dioxide_ > expressed_as_carbon_due_to_emission_from_wood_and_agricultural_products > (canonical units: kg s-1) > ' "tendency_of_X" means derivative of X with respect to time. The phrase > "expressed_as" is used in the construction A_expressed_as_B, where B is a > chemical constituent of A. It means that the quantity indicated by the > standard name is calculated solely with respect to the B contained in A, > neglecting all other chemical constituents of A. The chemical formula for > carbon dioxide is CO2. "Content" indicates a quantity per unit area. The > "atmosphere content" of a quantity refers to the vertical integral from the > surface to the top of the atmosphere. For the content between specified > levels in the atmosphere, standard names including > "content_of_atmosphere_layer" are used. The specification of a physical > process by the phrase "due_to_" process means that the quantity named is a > single term in a sum of terms which together compose the general quantity > named by omitting the phrase. "Emission" means emission from a primary > source located anywhere within the atmosphere, including at the lower > boundary (i.e. the surface of the earth). "Emission" is a process entirely > distinct from "re-emission" which is used in some standard names. Examples > of "wood and agricultural products" are paper, cardboard, furniture, timber > for construction, biofuels and food for both humans and livestock. Models > that simulate land use changes have one or more pools of carbon that > represent these products in order to conserve carbon and allow its eventual > release into the atmosphere, for example, when the products decompose in > landfill sites. > > OK? > Yes. > > For consistency with this discussion, the existing standard name > carbon_content_of_products_of_anthropogenic_land_use_change will be made > into an alias. The new version of the name will then be: > carbon_content_of_wood_and_agricultural_products (kg m-2) > ' "Content" indicates a quantity per unit area. Examples of "wood and > agricultural products" are paper, cardboard, furniture, timber for > construction, biofuels and food for both humans and livestock. Models that > simulate land use changes have one or more pools of carbon that represent > these products in order to conserve carbon and allow its eventual release > into the atmosphere, for example, when the products decompose in landfill > sites.' > > OK? > > Yes. > > > 5. carbon_mass_flux_into_anthropogenic_product_pools_ > due_to_land_use_land_cover_change (canonical units: kg s-1) > > > 'carbon harvested due to land-use or land-cover change process that > enters anthropogenic product pools on tile' > > Following the discussion on product names, and the discussion about > anthropogenic land use or land cover change (see proposal 7 below), this > proposal has now become: > mass_flux_of_carbon_into_wood_and_agricultural_products_due_ > to_anthropogenic_land_use_or_land_cover_change (canonical units: kg s-1) > 'In accordance with common usage in geophysical disciplines, "flux" > implies per unit area, called "flux density" in physics. The specification > of a physical process by the phrase "due_to_" process means that the > quantity named is a single term in a sum of terms which together compose > the general quantity named by omitting the phrase. "Anthropogenic" means > influenced, caused, or created by human activity. Examples of "wood and > agricultural products" are paper, cardboard, furniture, timber for > construction, biofuels and food for both humans and livestock. Models that > simulate land use changes have one or more pools of carbon that represent > these products in order to conserve carbon and allow its eventual release > into the atmosphere, for example, when the products decompose in landfill > sites.' > > OK? > > Yes. > > > 6. > > > carbon_mass_flux_into_soil_or_litter_pools_due_to_land_use_land_cover_change > (canonical_units: kg s-1) > > > 'carbon transferred to soil or litter pools due to land-use or > land-cover change processes on tile' > > > > > > As with the previous proposal, is it correct to refer simply to > 'carbon' rather than carbon_dioxide_expressed_as_carbon? Dave and > Jonathan agreed that we should refer to > > > 'land_use_or_land_cover_change. Perhaps the name should say > soil_and_litter, rather than soil_or_litter because presumably the carbon > is going into both pools? Also, > > > existing names refer simply to 'soil' and/or 'litter' without using > the word 'pool', so I think we should leave that word out for consistency. > > > > > > So then the name would be: > > > carbon_mass_flux_into_soil_and_litter_due_to_land_use_or_land_cover_change > (kg s-1) > > > 'In accordance with common usage in geophysical disciplines, "flux" > implies per unit area, called "flux density" in physics. "Litter" is dead > plant material in or above the > > > soil. The specification of a physical process by the phrase "due_to_" > process means that the quantity named is a single term in a sum of terms > which together compose > > > the general quantity named by omitting the phrase.' > > > > > > OK? > > > > > It is more appropriate to refer to 'carbon' rather than > 'carbon_dioxide_expressed_as_carbon'. Leaving out the word pool is > fine. Changing to soil and litter is fine. > > Thanks for clarifying. Following the discussion about anthropogenic land > use or land cover change (see proposal 7 below) I have added > 'anthropogenic' into this name, so we now have: > carbon_mass_flux_into_soil_and_litter_due_to_anthropogenic_land_use_or_land_cover_change > (kg s-1) > 'In accordance with common usage in geophysical disciplines, "flux" > implies per unit area, called "flux density" in physics. "Litter" is dead > plant material in or above the soil. The specification of a physical > process by the phrase "due_to_" process means that the quantity named is a > single term in a sum of terms which together compose > the general quantity named by omitting the phrase. "Anthropogenic" means > influenced, caused, or created by human activity.' > > OK? > Yes. > > > > 7. > > > carbon_mass_flux_direct_to_atmosphere_due_to_land_use_land_cover_change > (canonical units: kg s1) > > > 'carbon transferred directly to atmosphere due to any land-use or > land-cover change activities including deforestation or agricultural fire' > > > > > > Jonathan suggested that this name would be better expressed as > > > surface_upward_mass_flux_of_carbon_dioxide_expressed_as_ > carbon_due_to_land_use_or_land_cover_change for consistency with other > surface flux names and Dave > > > agreed with this change. For the definition, I note that agricultural > fires are included but what about natural ones? Do all these > 'land_use_or_land_cover_change' names > > > really refer to anthropogenic changes rather than natural ones? If so, > we should really say 'anthropogenic_land_use_or_land_cover_change' in all > of them. > > > > > Natural fire or natural land cover change due to shifts in vegetation > biogeography should not be included. Generally, the term land-use and > land-cover change implies > > anthropogenic, but to be more explicit, it would be appropriate to add > 'anthropogenic' in front of land-use and land-cover change. > > Thanks for clarifying. I think it is useful to be explicit about which > processes are natural and which are anthropogenic. Looking back through the > standard name table, I now see that we have some existing names that refer > to anthropogenic_land_use_change which I think were proposed for CMIP5. The > definitions of these names all say '"Anthropogenic land use change" means > human changes to land, excluding forest regrowth. It includes fires ignited > by humans for the purpose of land use change and the processes of eventual > disposal and decomposition of wood products such as paper, cardboard, > furniture and timber for construction.' Does all of that apply to this name? > > Yes. > > > 8. change_over_time_in_area_fraction (canonical units: 1) > > > 'annual gross fraction of land use tile that was transferred into > other land use tiles' > > > > > > Jonathan suggested that this quantity could be described as > tendency_of_area_fraction (canonical unit: s-1) and that units of yr-1 > could be used in the data files. Dave > > > agreed that this would be an acceptable approach. > > > > > > Thus the name, units and definition would be: > > > tendency_of_area_fraction (s-1) > > > ' "tendency_of_X" means derivative of X with respect to time. > "X_area_fraction" means the fraction of horizontal area occupied by X. > Annual gross fraction of land use tile > > that was transferred into other > land use tiles.' > > > > > > OK? If so, I think this one can be accepted for inclusion in the > standard name table. > > Note that we want to track two variables separately, which we originally > labeled something like: > > tendency_of_area_fraction_transitioned_out_of_land_use_tile (s-1) > > annual gross fraction that was transferred out of this tile to other > land use tiles > > > > tendency_of_area_fraction_transitioned_into_land_use_tile (s-1) > > annual gross fraction that was transferred into this tile from other > land use tiles > > The goal here is to be able to track the gross transitions. In > principle, for example, in a grid cell you could have 50% > primary_and_secondary_land and 50% cropland and > > then transfer all of the primary_and_secondary_land to cropland and all > of the cropland to primary_and_secondary_land giving a net change of zero > but a gross change of > > 50% in either direction. We want to be able to track the gross change > so we need to know both what is being transferred out and transferred in > for each land use tile. > > Thank you for explaining more about your use case - I hadn't understood it > properly before. I think, on balance, the best way to handle this is to go > back to your original idea of using two standard names to make the meaning > as clear as possible. I think Jonathan's suggestion of having canonical > units of s-1 is still a good one, because you can then use year-1 in your > data files. For gross changes I think we need to be clear about the sign > convention in the name itself, hence the following suggestions. > > gross_rate_of_increase_in_area_fraction (s-1) > The "rate of increase in area fraction" is the fraction of a grid cell > that transitions to a given area type per unit time, for example, as a > result of land use changes. The quantity described by this standard name is > a gross increase because it includes only land where the use transitions to > the given area type and excludes land that transitions away from that area > type during the same period. The area type should be specified using a > coordinate or scalar coordinate variable with standard name area_type. > There is also a standard name for gross_rate_of_decrease_in_area_fraction. > > gross_rate_of_decrease_in_area_fraction (s-1) > The "gross rate of decrease in area fraction" is the fraction of a grid > cell that transitions from a given area type per unit time, for example, as > a result of land use changes. The quantity described by this standard name > is a gross decrease because it includes only land where the use transitions > away from the given area type and excludes land that transitions to that > area type during the same period. The area type should be specified using a > coordinate of scalar coordinate variable with standard name area_type. > There is also a standard name for gross_rate_of_increase_in_area_fraction. > > Does that sound better? > Yes. I like this suggestion. > > Best wishes, > Alison > > ------ > Alison Pamment Tel: +44 > 1235 778065 > Centre for Environmental Data Analysis Email: > [email protected] > STFC Rutherford Appleton Laboratory > R25, 2.22 > Harwell Campus, Didcot, OX11 0QX, U.K. > >
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