Stealth paper: Association of parameter, software, and hardware variation with large-scale behavior across 57,000 climate models

OK, so I missed it, not that I was looking for it. Why did everyone else miss it? Because cp.net is obsolete? Since I don't have a subs to PNAS I can't read it except the abstract.

Here is the abstract so you don't have to follow the link and I show up on google:

In complex spatial models, as used to predict the climate response to greenhouse gas emissions, parameter variation within plausible bounds has major effects on model behavior of interest. Here, we present an unprecedentedly large ensemble of >57,000 climate model runs in which 10 parameters, initial conditions, hardware, and software used to run the model all have been varied. We relate information about the model runs to large-scale model behavior (equilibrium sensitivity of global mean temperature to a doubling of carbon dioxide). We demonstrate that effects of parameter, hardware, and software variation are detectable, complex, and interacting. However, we find most of the effects of parameter variation are caused by a small subset of parameters. Notably, the entrainment coefficient in clouds is associated with 30% of the variation seen in climate sensitivity, although both low and high values can give high climate sensitivity. We demonstrate that the effect of hardware and software is small relative to the effect of parameter variation and, over the wide range of systems tested, may be treated as equivalent to that caused by changes in initial conditions. We discuss the significance of these results in relation to the design and interpretation of climate modeling experiments and large-scale modeling more generally.

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You can also read the "Supporting Information" (that's some of the figures and some of the tables) free, linked from the Abstract page. Pretty pictures .... hope someone finds the text elsewhere eventually.

http://www.pnas.org/cgi/content/full/0608144104/DC1

By Hank Roberts (not verified) on 02 Nov 2007 #permalink

I linked to Dr. Knight's home page; look down that page Publications for this paper and click "preprint"-- as you look, it's most interesting to see how many different areas the author's published in.

By Hank Roberts (not verified) on 03 Nov 2007 #permalink

No idea why I see only a blank page but google has a cached version.

Hmm that difference between the middlewares tested is rather large.