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?
> > 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?
> > 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 surfa
ce 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?
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?
> > 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?
?
> > 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?
> > 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?
> > 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?
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
Centre for Environmental Data Analysis Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Campus, Didcot, OX11 0QX, U.K.
Received on Thu Dec 01 2016 - 14:00:42 GMT
