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This is just one comment; the whole article is good on this subject.
http://www.realclimate.org/index.php/
99
Jeff Pierce says:
29 Aug 2011 at 2:02 PM
#95, Pete Dunkelberg: The “climate models need to be substantially revised” comment. I don’t think this comment has anything to do with their cosmic ray results (and I’ve found it interesting that the media has used it as a statement about the cosmic rays), and I’ll explain why in a moment…
But first regarding the IPCC climate models, I think Gavin explains it well. Right now the IPCC climate models don’t take into account any aspect of aerosol number or size (just the total mass). Thus, they do not take nucleation into account. If changes in nucleation with time end up being important for climate change, we will need to incorporate these physics into the IPCC models. The comment really is directed at people like me (and about 10-20 other groups around the world) who use detailed global (or regional) aerosol microphysics models.
However, the comment is really stating that the CLOUD experiments could not reproduce atmospheric nucleation rates from sulfuric acid + ammonia + cosmic rays + water vapor, “The nucleation observed in the chamber occurs at only one‐tenth to one‐thousandth of the rate observed in the lower atmosphere.”. Therefore, some other component (e.g. organic vapors) needs to be included in order for the CLOUD experiments match atmospheric nucleation in their chamber. These are going to be the results from the next set of CLOUD experiments (which occurred earlier this summer), and they are foreshadowing these results. They do not actually bring up cosmic rays in that paragraph at all, but they make it clear in the paper that even with cosmic rays cranked up in the chamber that they still cannot reproduce atmospheric nucleation rates.
Since detailed aerosol models (like the one I use) do not include organics (or these other missing species) in the nucleation calculations, THESE missing components are what needs to be revised in our models, not the dependence of cosmic rays. Recent modeling by my group and those out of Fangqun Yu’s group at SUNY Albany does use a nucleation scheme that has a dependence on cosmic rays that is very similar to the CLOUD results. Thus, our models don’t need to be revised based on the cosmic ray results, but they do for the additional missing components (e.g. organics).
http://www.realclimate.org/index.php/
99
Jeff Pierce says:
29 Aug 2011 at 2:02 PM
#95, Pete Dunkelberg: The “climate models need to be substantially revised” comment. I don’t think this comment has anything to do with their cosmic ray results (and I’ve found it interesting that the media has used it as a statement about the cosmic rays), and I’ll explain why in a moment…
But first regarding the IPCC climate models, I think Gavin explains it well. Right now the IPCC climate models don’t take into account any aspect of aerosol number or size (just the total mass). Thus, they do not take nucleation into account. If changes in nucleation with time end up being important for climate change, we will need to incorporate these physics into the IPCC models. The comment really is directed at people like me (and about 10-20 other groups around the world) who use detailed global (or regional) aerosol microphysics models.
However, the comment is really stating that the CLOUD experiments could not reproduce atmospheric nucleation rates from sulfuric acid + ammonia + cosmic rays + water vapor, “The nucleation observed in the chamber occurs at only one‐tenth to one‐thousandth of the rate observed in the lower atmosphere.”. Therefore, some other component (e.g. organic vapors) needs to be included in order for the CLOUD experiments match atmospheric nucleation in their chamber. These are going to be the results from the next set of CLOUD experiments (which occurred earlier this summer), and they are foreshadowing these results. They do not actually bring up cosmic rays in that paragraph at all, but they make it clear in the paper that even with cosmic rays cranked up in the chamber that they still cannot reproduce atmospheric nucleation rates.
Since detailed aerosol models (like the one I use) do not include organics (or these other missing species) in the nucleation calculations, THESE missing components are what needs to be revised in our models, not the dependence of cosmic rays. Recent modeling by my group and those out of Fangqun Yu’s group at SUNY Albany does use a nucleation scheme that has a dependence on cosmic rays that is very similar to the CLOUD results. Thus, our models don’t need to be revised based on the cosmic ray results, but they do for the additional missing components (e.g. organics).
