Thursday, May 3, 2012
Atmospheric Warming and the Tropospheric Temperature Lapse Rate
I have posted the following at the Tallbloke site, where the tropospheric temperature gradient is being discussed: The fact that the Venus/Earth temperature ratio, at points of equal pressure over the range of Earth tropospheric pressures (excepting only at points inside the Venus cloud layer), is a constant that is precisely and entirely due only to the ratio of the two planets' distances from the Sun, IS the definitive empirical evidence--of two detailed atmospheres, and thus the largest, and clearest, experimental test--revealing the fundamental physical mechanism of warming of planetary atmospheres by direct absorption of radiative (infrared) energy from the Sun. My Venus/Earth comparison establishes: 1) The tropospheres of both Venus and Earth must directly absorb, and be fundamentally warmed only by, the same physical fraction of the incident solar energy, whose intensity varies with solar distance r as one over r-squared (in which case, as I have shown at the above link, the temperature ratio is necessarily what it is observed to be); 2) The tropospheres, especially Earth's, are not fundamentally warmed from the surface at all, as most scientists currently believe, as any such warming would cause the Venus/Earth temperature ratio to be other than what it is, due only to the solar distances of the two planets; 3) The Standard Atmosphere properly represents the stable equilibrium state of Earth's troposphere, while Venus's atmosphere is always in its equilibrium state (this means the Earth is not subject to "runaway" global warming OR cooling--meaning no "ice ages" due only to undirected physical processes, and no need for auxiliarly theories, like the physically suspect Milankovitch correlation-model theory, to "explain" them); 4) There is no "greenhouse effect", of increased global mean surface temperature, with an atmospheric increase in carbon dioxide or any other so-called "greenhouse gas"; 5) There is no albedo effect, either from the planetary surface or from cloud tops, upon the equilibrium atmospheric temperature, since the great differences in these variables for Venus and Earth have no effect upon the Venus/Earth temperature ratio (and this is also the obvious physical consequence of atmospheric warming solely by direct absorption of solar IR); and 6) the proper handling of the Stefan-Boltzmann formula in analyzing the problem of atmospheric warming (it applies only in the case of warming only by incident radiation, assumes that all absorbed radiation is transformed into heat energy, and it cannot be applied anywhere within a system in which other forms of heat transfer--conduction and convection--are occurring). My Venus/Earth comparison also shows that the temperature lapse rate structure of the troposphere predominates over all other atmospheric conditions, including night and day, that it fundamentally and strictly governs atmospheric temperatures, and that the lapse rate structure does NOT depend upon gross vertical convection, especially from the surface, since each layer of the atmosphere is directly warmed by the Sun. The term "adiabatic lapse rate" should be replaced by "hydrostatic lapse rate" (as I have consistently emphasized) to be consistent with the fundamental physics--of real gases in a gravitational field--behind it.