Thursday, January 06, 2011

Fourier and the greenhouse.

Ray Pierrehumbert has pointed Eli to a new book that he and David Archer have put together, The Warming Papers, a collection of foundational climate science papers with commentary. Unfortunately the price is high enough that bunnies gotta think this was put together as a text, or supplementary text for a course. Talk to Ray and David about that.

You can read sections at Amazon, and Eli points the bunnies at the first chapter, a discussion of Fourier's Mémoire sur les Températures du Globe Terrestre et des Espaces Planétaires

In thinking about the effect of the atmosphere on the Earth’s energy balance, Fourier drew on the behavior of a simple device invented by the Swiss Alpinist Horace-Bénédict de Saussure (1740–99). This device, called a heliothermometer, consisted of a wooden box insulated with cork and wool, with a lid consisting of one or more panes of transparent glass (Fig. 1). The interior walls were painted black so as to absorb nearly all the sunlight entering the box, and a thermometer was placed in the box so that its temperature could be determined. de Saussure devised this instrument as a means of measuring the intensity of sunlight, so that he could test the hypothesis that it is colder atop mountains because the sunlight is weaker there.
which pretty well describes the box that Roy Spencer built to demonstrate the existence of back radiation. In Ray's words: "Ok, well you might say that the heliothermometer is a kind of at tiny RABBIT-SIZED greenhouse :)"
One thing Fourier did not do was coin the term “greenhouse effect,” though his use of de Saussure’s heliothermometer as an analogue could be considered similar to a greenhouse analogue. de Saussure’s box is indeed a kind of miniature greenhouse. In any event, Fourier showed a clear awareness of the imperfection of the analogy, stating explicitly that the temperature in the hot box was influenced by turbulent heat transfers that have no proper counterpart in the planetary temperature problem.
Further, Fourier did not compute the temperature of the Earth in the absence of an atmosphere and concluded that it was colder than the observed temperature. In fact, he never actually computed the Earth’s temperature based on a balance between incoming sunlight and outgoing infrared, though he could have attempted this using the Dulong–Petit radiation law. It is not clear why Fourier thought the atmosphere had to have a warming role. Rather than this being demanded by too cold temperatures in the absence of an atmosphere, Fourier seems to be inferring that the atmosphere ought to act like a pane of glass in being transparent to sunlight but opaque to infrared; he shows awareness of the downward infrared radiated by the atmosphere, but it is not clear what the basis of Fourier’s leap of intuition about the atmosphere was. In any event, he was right, and his work stimulated a great deal of further research on the effect of the atmosphere on infrared, and ultimately Tyndall’s definitive experiments to be discussed next.
But Ray agrees with Eli that
And I applaud your defense of the term "Greenhouse Effect." People who quibble with it simply do not understand what an analogy is. Fourier doesn't use the term himself, but in his discussion of the De Saussure hot box (a kind of mini-greenhouse) he is quite clear and coherent about the nature of the analogy.
and makes a pitch
(See my translation of Fourier on my web page, or better, buy "The Warming Papers," recently out by me and Archer).
And, oh yes, with their winnings, Ray and David can buy a copy of the original
In: Annales de Chimie et de Physique, pp. 136-167, Tome XXVII, Octobre 1824. Paris: Crochard, 1824. Octavo, original printed wrappers, uncut. custom cloth box. Minor edgewear and foxing to wrappers, early stamp of the Académie d’Aix on first page of text (not affecting Fourier article); text exceptionally clean. Extremely rare in original wrappers. $3300.
Which brings us to the point that analogies are good, but never perfect. Like models, analogies are never complete but some are useful.


Anonymous said...

Ray P Comments

I appreciated your discussion of Fourier, which should help publicize the nature of his accomplishment. Anders A. may have been the first to systematically measure back-radiation, but it is clear from Fourier's remarks that he had detected it with his mirror. But not quantified it in any sense.

The reason The Warming Papers is so expensive is that the journals charged us HUGE fees for the rights to reprint the stuff that was still under copyright. That doesn't apply to Fourier or Tyndall, but it does to most of the rest. Not something that was under our control.

Finally, Knut Ängtrom (son of the Angstrom Unit angstrom) is the original perpetrator of the saturation fallacy. He thought that Arrhenius was full of it because (according to Knut) CO2 absorption is saturated. Of course he was wrong. See the RealClimate piece, "What Ängström didn't know."

Lionel A said...

I eagerly await the arrival of my copy of 'The Warming Papers', I have been notified that it has dispatched.

raypierre said...

Eli -- the diacritics on Ångström's name in the comment you posted for me got messed up in the email transmission somehow. I wouldn't want my Swedish friends to think my spelling was that incompetent. --raypierre

(Safari seems to allow me to post here, though I continue to have trouble with Firefox)