On Thu, 29 Sep 2016, Jonathan Gregory wrote:
> Dear Paul
>
> Thank you for this list. It looks like they conform well to existing patterns
> and it must have been a lot of work to compile them!
>
> I have a couple of comments:
>
> * Several pairs of names contrast "abiotic" and "natural", apparently. Am I
> right to understand that these are opposites? That's not obvious to me. Not
> everything which is "natural" in the Earth system is biotic. In other contexts,
> "natural" and "anthropogenic" are opposites. Would it be correct to say
> "biotic" instead of "natural" here?
Hi 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.
Jim
--
LSCE/IPSL, Laboratoire des Sciences du Climat et de l'Environnement
CEA-CNRS-UVSQ
LSCE/IPSL, CEA Saclay http://www.ipsl.jussieu.fr/~jomce
Bat. 712 - Orme mailto: James.Orr at lsce.ipsl.fr
Point courrier 132
F-91191 Gif-sur-Yvette Cedex Phone: (33) (0)1 69 08 39 73
FRANCE Fax: (33) (0)1 69 08 30 73
Received on Thu Sep 29 2016 - 08:43:10 BST
