söndag 19 augusti 2012

Is Robert G. Brown a denier?

Recently I became aware of a blog post on WUWT written by Robert G. Brown at Duke University dating back to january this year, so I apologize for not having noticed it earlier. The aim of text is to disprove the long lasting conjecture that an isolated column of air maintains a nonzero temperature gradient solely by the influence of a graviational field. I will not comment on the details of the refutation here since there is already plenty of material out there that does, instead I would like to focus on a sentence in the concluding part of the text:

In nature, the dry adiabatic lapse rate of air in the atmosphere is maintained because the system is differentially heated from below causing parcels of air to constantly move up and down.

If it hasn't already become clear to the reader I would like to once again point out the obvious fact that this is not in accordance with the greenhouse gas hypothesis. Hence, that would make Robert G. Brown a denier in the eyes of Fred Singer, wouldn't it. To clarify things a bit further, at present there appears to be three explanations for the lapse rate advocated by various people:

1. The gravity theory

This theory (which dates back at least 150 years) claims that gravity alone induces a lapse rate even in a state of equilibrium. The theory is thus essentially an equilibrium theory.

Keynote: Gravity destabilises the atmosphere

2. The differential heating theory

This theory claims that it is the differential heating of the surface and the atmosphere that causes the lapse rate. The same argument could be used to explain why it s hotter 1cm away from a lit candle than it is 1m away. The lapse rate is however reduced in magnitude by convection, but the convection itself is limited by pressure induced bouyancy. This is essentially a non-equilibrium theory.

Keynote: Sunlight destabilises the atmosphere

3. The greenhouse gas hypothesis

The radiative transfer of greenhouse gases in the atmosphere creates a temperature gradient (see the two previous posts) which is limited in magnitude by convection is the same way as expressed above. This doesn't fall into any of the categories Equilibrium/Non-equilibrium.

Keynote: Greenhouse gases destabilise the atmosphere



To my knowledge, the only person in the world that openly defends the greenhouse gas hypothesis is Roy Spencer, and the only one in the world that points out that he is indeed defending the greenhouse gas hypothesis as it is presented in the literature is myself. The reason for this state of affairs puzzles me a bit. Recently if have become more and more interested in Theory nr 2, simply because it seems to put the pieces together in a more satisfactory way than Theory nr 1, though I welcome all well argued developements of either theory. In any case, the main point of this post is:

Theory nr 2 is not identical to Theory nr 3 

I will elaborate on this in detail in an upcoming post. This is just a preemptive step to make sure that the lukewarmers not yet again take the opportunity to obfuscate things so as to make people believe that the greenhouse gas theory is simply Theory nr 2 (or just any theory that is not Theory nr 1). 

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