The two terms: surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_plant_respiration_for_biomass_growth
surface_upward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_plant_respiration_for_biomass_maintenance carry the same description which makes no reference to "growth" or "maintenance": The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for carbon dioxide is CO2. 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 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. Plant respiration is the sum of respiration by parts of plants both above and below the soil. It is assumed that all the respired carbon dioxide is emitted to the atmosphere. The term "plants" refers to the kingdom of plants in the modern classification which excludes fungi. Plants are autotrophs i.e. "producers" of biomass using carbon obtained from carbon dioxide. Other relevant concepts are "mortality" (loss of biomass due to death of the whole plant, not only the leaves, "senescence" (loss of living biomass excluding plant death, e.g. leaf drop and other seasonal effects), "gross primary productivity" (flux from atmosphere into the plant) and "net primary productivity" (gross minus the amount that is respired back into the atmosphere). We should add some explanation. The terms appear to relate to different metabolism pathways associated with the mechanisms for growth and maintenance (adjusting to the surroundings) in a plant. Here are some possible definitions: * Maintenance respiration is defined as the carbon cost to support the metabolic activity of existing live tissue. * Growth respiration is defined as the additional carbon cost for the synthesis of new growth. Taken from https://escomp.github.io/ctsm-docs/doc/build/html/tech_note/Plant_Respiration/CLM50_Tech_Note_Plant_Respiration.html It would be good to hear the views of someone who knows about these processes, regards, Martin _______________________________________________ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
