Dear Jim Thanks for explaining. So "natural" is the opposite of "anthropogenic", in a restricted sense. It includes the effect of anthropogenic climate change, but not the anthropogenic emissions of CO2. Is that right? I think this is potentially confusing in the context of CF, which has to cover a wide range of applications. It is not hard to imagine people wanting to use natural in the sense of *completely* unaffected by anthropogenic influence. (Obviously I'm not commenting on the terminology used in OMIP - I'm sure that's clear in that context.) I wonder if for CF we could think of something more explicit.
Actually I'm unclear quite what is meant by due_to_natural_component (in several names). Component of what? Could you explain a bit more? Also, what does sea_water_ph_reported_on_total_scale_due_to_X mean? Is it perhaps a *change* in pH? Best wishes Jonathan > For the biogeochemistry in OMIP, we've agreed on using the terms > 'abiotic' and 'natural', neither synonyms nor antonyms for our > purposes. The OMIP-BGC simulations will be run with 2 parallel > simulations (or parallel tracers in the same simulation): > > * 'natural' means it will be maintained at same the CMIP6 > preindustrial CO2 level throughout the simulation, while the > > * 'total' simulation will have varying atmospheric CO2, but the same > climate (e.g., forced in the OMIP ocean only run). > > The difference between the total and natural carbon tracers in the > two will give us the anthropogenic carbon. The ocean's natural > carbon cycle is considered in OMIP to change with climate change > even though its simulated atmospheric CO2 is held constant. > > Regarding 'abiotic', the natural and the total simulation include > both abiotic and biotic processes. To distinguish the two we also > include an abiotic carbon tracer. Furthermore, we use a simplified > abiotic approach to model C-14 in the ocean, e.g., to provide > deep-ocean ventilation ages. _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
