DR v1.2.2 land misc. issue 13

[taylor13]

land misc. issue 13

How do Emon.fAnthDisturb and Amon.fco2antt differ, other than fAnthDisturb being reported only over land?

Please clarify:
Further information should be provided by the description explaining how the two variables differ? Alternatively and preferably, can we eliminate Amon.fAnthDisturb? What sources of emissions are considered over the ocean?

[bethdingley]

At least one of these variables are in your variable groups @tomaslovato, @ckoven,

[chrisdane]

I agree that they suppose to represent the same thing, having identical standard_name, and very similar long_name:

git diff --word-diff=porcelain --no-index fco2antt.md fAnthDisturb.md
--- a/fco2antt.md
+++ b/fAnthDisturb.md
             "standard_name": "tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_emission", 
~
             "units": "kg m-2 s-1", 
~
             "cell_methods": "area: 
+mean where land
  time: mean", 
~
             "cell_measures": "area: areacella", 
~
             "long_name": "Carbon Mass Flux 
+from Vegetation, Litter or Soil Pools
  into 
+the
  Atmosphere Due to 
-All Anthropogenic Emissions of CO2
+any Human Activity
  [kgC m-2 s-1]", 
~
             "comment": 
-"This is requested only for
+"Anthropogenic flux of carbon as carbon dioxide into
  the 
-emission-driven coupled
+atmosphere. That is, emissions influenced, caused, or created by human activity. Anthropogenic emission of
  carbon 
-climate model runs.  Does not include natural fire sources but,
+dioxide
  includes
-all anthropogenic sources, including
  fossil fuel use, cement production, agricultural 
-burning,
+burning
  and sources associated with anthropogenic land use 
-change excluding
+change, except
  forest regrowth.", 
~
             "dimensions": "longitude latitude time",

For fco2antt it's explicitly mentioned to be requested for emissions-driven simulations only. But again, if they represent the same thing, that would apply to both, too. If that is the case, I also agree that fAnthDisturb can be dropped.

Regarding (CO2) emissions over the ocean, CEDS (Hoesly et al. 2025) provides aircraft (and ship; but not for CO2 as far as I understand?) emissions in their *em-AIR-anthro_input4MIPs_emissions_CMIP_CEDS* files that could (should?) be included in the CMIP7 forcing (https://zenodo.org/records/15127477), see here a snapshot of the vertical sum of those:

In addition,

        "fCLandToOcean": {
            "modeling_realm": "land", 
            "standard_name": "mass_flux_of_carbon_into_sea_water_from_rivers", 
            "units": "kg m-2 s-1", 
            "cell_methods": "area: mean where land time: mean", 
            "cell_measures": "area: areacellr", 
            "long_name": "Lateral Transfer of Carbon out of Grid Cell That Eventually Goes into Ocean", 
            "comment": "leached carbon etc that goes into run off or river routing and finds its way into ocean should be reported here.", 
            "dimensions": "longitude latitude time", 

could be considered as a carbon source to the ocean if enabled in an ESM?

[ckoven]

Noting some overlap here with issue #92

[ChrisJones-MOHC]

We need to keep fAnthDisturb. It is part of the C4MIP request and required to close the carbon budget of the models. It represents the carbon flux to the atmosphere from human disturbance of the land (i.e. land-use/land-use change).

It is very different from fossil fuel emissions. These are not modelled, but provided as inputs for the emissions-driven runs.

[gangtang-au]

fAnthDisturb: carbon flux to the atmosphere from human disturbance of the land (i.e. land-use/land-use change). It is a model output. It should never include fossil fuel emissions (the current definition is thus problematic), which is an input for the emission-driven experiments.

I just had a look at the fco2antt. It is part of the atmosphere carbon cycle (see figure below). The description says it includes the fossil fuel emission but maybe it should not. Assuming it is just anthropogenic emission from land and ocean, the co2mass change = -fco2nat (land and ocean sinks) + fco2foss (fossil emission) + fco2antt (anthropogenic emission from land and ocean excluding fossil fuel), which makes sense to me. This way, the distinction between fAnthDisturb and fco2antt is that the fco2antt = fAnthDisturb + anthropogenic fire + emission from ocean? Not sure if this is the original intention from the proposal.

Also from my recent communications with ESM teams, most ESMs cannot seperate anthropogenic and natural fire emissions. So the atmosphere carbon cycle with fco2nat and fco2antt, which requires separated fire emissions, may need to consider the feasibility.

[taylor13]

In light of the above, the current current "title" of Emon.fAnthDisturb appears to be correct: "Carbon Mass Flux from Vegetation, Litter or Soil Pools into the Atmosphere Due to any Human Activity [kgC m-2 s-1]". But its "description" and the CF description of its standard_name must be incorrect because they include emission of carbon dioxide due to fossil fuel use:

Anthropogenic flux of carbon as carbon dioxide into the atmosphere. That is, emissions influenced, caused, or created by human activity. Anthropogenic emission of carbon dioxide includes fossil fuel use, cement production, agricultural burning and sources associated with anthropogenic land use change, except forest regrowth.

Thus, we need a different standard name for this variable. Can we adopt/adapt one of the following two existing names?

surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_land_use_or_land_cover_change (kg m-2 s-1)  This is described as:

"Anthropogenic" means influenced, caused, or created by human activity. "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. This is described as:

surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_land_use_or_land_cover_change_excluding_forestry_and_agricultural_products. (kg m-2 s-1)

This quantity ... excludes the carbon dioxide flux into the atmosphere due to the processes of eventual disposal and decomposition of wood products such as paper, cardboard, furniture and timber for construction. The standard name for the quantity that includes product decomposition is surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_land_use_or_land_cover_change.

@chrisdane @ChrisJones-MOHC @gangtang-au : Can you vote on one of the above 2 names or devise a new name if those are incorrect? Thanks!

[taylor13]

Regarding #100 (comment) whom should we contact to find out whether or not whether or not fco2antt should include fossil fuel emissions? Thanks @gangtang-au for suggesting this possibility.

[ChrisJones-MOHC]

thanks Karl - yes, the fAnthDisturb definition is very wrong. no idea how fossil fuel got a mention.

i would vote for the second one: surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_land_use_or_land_cover_change_excluding_forestry_and_agricultural_products. (kg m-2 s-1)

fAnthDisturb explcitily excludes carbon going into/out of product pools. That is covered by fProductDecomp

Is it useful to also point to the GMD paper (Jones 2016) in the satndard names? I get the feel a lot of issues have come from people not reading the documentation.

[znichollscr]

@ChrisJones-MOHC what do you think of dropping fco2antt? Reading @gangtang-au's comment, my impression is that it can't really be calculated by ESMs anyway because you need a split between anthropogenic and natural fire, which is kind of impossible to do.

[gangtang-au]

I also think the second one is better.

[ChrisJones-MOHC]

happy to drop fco2antt from a C4MIP perspective. it's not part of our diagnostic set

[taylor13]

In the data request the wrong standard name was assigned to fAnthDisturb. The correct name already is already available from CF and is surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_land_use_or_land_cover_change_excluding_forestry_and_agricultural_products, which should replace tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_emission.

Do we need to indicate in the description something about whether fires are included, following the input above:

Also from my recent communications with ESM teams, most ESMs cannot seperate anthropogenic and natural fire emissions. So the atmosphere carbon cycle with fco2nat and fco2antt, which requires separated fire emissions, may need to consider the feasibility.

Also, anyone object to removing fco2antt?

[bethdingley]

In the data request the wrong standard name was assigned to fAnthDisturb. The correct name already is already available from CF and is surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_land_use_or_land_cover_change_excluding_forestry_and_agricultural_products, which should replace tendency_of_atmosphere_mass_content_of_carbon_dioxide_expressed_as_carbon_due_to_anthropogenic_emission.

I have implemented this change.

Do we need to indicate in the description something about whether fires are included, following the input above:

If anyone requires a description update, please let me know. Otherwise I have left it as is for now

Also, anyone object to removing fco2antt?

This is requested by people outside this thread (including CFMIP's CFsubhr.fco2antt), who we don't have time to consult with at this point. While is seems modelling centres will struggle to produce, I think we should leave in for now and requesters might need to accept it won't be produced.