tag:blogger.com,1999:blog-4828122657384873884.post2348868315374800040..comments2023-10-17T08:02:47.368-04:00Comments on DENIS RANCOURT ON CLIMATE: Radiation physics constraints on global warming – RevisedDenis Rancourthttp://www.blogger.com/profile/16743375141824505606noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-4828122657384873884.post-16576488999145723712013-11-28T16:42:00.708-05:002013-11-28T16:42:00.708-05:00Still trying to figure how to calculate the temper...Still trying to figure how to calculate the temperature of spheres in the sun in space.<br /><br />Pekka says absorptivity does not equal emissivity at radiative thermal equilibrium. I thought Kirchoff's law said they were equal.<br /><br />Discussion here<br />http://scienceofdoom.com/2013/11/23/ghosts-of-climates-past-part-seven-gcm-i/#comment-34452<br /><br />I think simple physics experiments can easily settle the science of this, but nobody is game.<br /><br />So if we can use a solar cooker at night to simulate radiative cooling, we can get some real measurements and estimate thermal equilibrium temperature of spheres of different absorptivity/emissivityblouis79https://www.blogger.com/profile/13769400459008203001noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-21172957956753868092013-11-24T08:37:36.641-05:002013-11-24T08:37:36.641-05:00Have been trying to figure the difference in temp...Have been trying to figure the difference in temperature of a polished metal sphere (very low emissivity/absorptivity) versus a black sphere (high emissivity/absorptivity) in sunlight in space at similar distance from sun as earth.<br /><br />Found this site on spacecraft where emissivity factor is included for emission.<br />http://www.columbiassacrifice.com/$D_temperature.htm<br /><br />If SB equations for both absorption and emission of such a body include emissivity facotors, then the emissivity factors cancel and we find radiarive thermal equilibrium temperature is independent of emissivity.<br /><br />A simple experiment can easily demonstrate the truth - two different emissivity spheres in space in sunlight and some simple temperature measurements.<br /><br />Tallblokes calculation assumes emissivity of 1.<br />http://tallbloke.wordpress.com/2011/06/06/what-temperature-would-earths-surface-be-without-greenhouse-gases/<br /><br />My workings in comments on this blog.<br />http://climateofsophistry.com/2012/11/06/on-the-absence-of-a-measurable-greenhouse-effect-part-1-the-failure-of-ipcc-energy-budgets/#comment-4207<br />blouis79https://www.blogger.com/profile/13769400459008203001noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-2667905163032657892012-11-28T21:30:46.273-05:002012-11-28T21:30:46.273-05:00High altitude gas temperature or space (radiation)...High altitude gas temperature or space (radiation) temperature. Two different things.<br />A theoretical gas cloud in space with no absorption will drop to -273C regardless how far from the Sun it is.<br />What heats up any planets surface is the lapse rate. You know, high pressure zones are hot sinking air from the icy heights. How you theorists avoid this so simple fact is totally beyond me to the point I'm beginning to think: Venus' poles are as hot as the equator. Titan was found to have a more dense atmosphere and +7C warmer to boot. The light barely reaches the surface of Venus so the heating occurs high up... Yet... At 55Km high it is one bar pressure and 26C.<br /><br />Time to face reality before you lose credibility.Andyjhttps://www.blogger.com/profile/11910687437796998340noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-33887851969305190272011-05-20T17:45:29.474-04:002011-05-20T17:45:29.474-04:00Regarding Rancourt's comments on page 8/17 (on...Regarding Rancourt's comments on page 8/17 (on Gerlich and Tscheuschner), their argument is that eqn (3) on page 4/17 is incorrect for starters. They demonstrate a different integration procedure (cf. their eqns (82) and (83), their page 64) that basically has to do with taking the fourth root of T <i>before</i> you integrate rather than after. Then they show that the number obtained this way is even lower, namely -129C, but this, they then argue, is to be expected in view of Hoelder's inequality. If I understand their argument correctly (Sections 3.7.5 and 3.7.6), they attribute the difference between -18C and +15C to Hoelder's inequality as well, thus discarding the need for greenhouse effect. They also quote McKitrick and Andresen, who argued that the very notion of an average global temperature for a planet is not physically meaningful.Gustavhttps://www.blogger.com/profile/04812624716905319048noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-18838533848651873412011-05-18T23:07:32.140-04:002011-05-18T23:07:32.140-04:00According to a textbook on remote sensing (p210 eq...According to a textbook on remote sensing (p210 eqn 6.2) http://www.iki.rssi.ru/asp/pub_sha1/Sharch06.pdf, blackbody emission into a gas is (refractive index)^2 times greater than emission into a vacuum. <br /><br />So what happens to blackbody emission into a cloud???blouis79https://www.blogger.com/profile/13769400459008203001noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-20069073696992563772011-05-18T21:43:47.055-04:002011-05-18T21:43:47.055-04:00It does not make a lot of sense to me to confine K...It does not make a lot of sense to me to confine Kirchoff's Law only to specific frequencies, since the more general form of the law appears to apply to the "integrated power over all wavelengths and angles" (Wikipedia:Kirchhoff's law of thermal radiation). For a true blackbody, there should be no dispute, since all wavelengths and angles are equivalent for absorption and emission.<br /><br />What I would like to know is if the real gap between absorption and emission is the difference between the theoretical 0.7 (1-albedo) and measured 0.62 emissivity, how close does thermal pollution energy liberated on earth account for the gap?<br /><br />(See Nordell on thermal pollution http://tinyurl.com/3calxm2.)blouis79https://www.blogger.com/profile/13769400459008203001noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-33737230871504001812011-05-18T19:16:28.310-04:002011-05-18T19:16:28.310-04:00"One can measure the longwave scattering tran...<i>"One can measure the longwave scattering transmittance (or cross section) of a greenhouse effect gas (e.g., CO2, H2O) in the laboratory. "</i><br /><br />I presume this would be easy. I thought it would be common knowledge in physics. Any ideas where one might find the data?<br /><br />Presumably the data are explained by known theoretical physics. Any clues as to where to look would be welcome.<br /><br />I am bothered by the use of emissivity, since for the earth from space we seem happy to use an albedo of 0.3 or therabouts. Surely the emissivity of earth as a planet seen from space should be taken from a similar perspective. Therefore the emissivity of the ground surface should not be used at all, it should the net emissivity of earth with atmosphere including clouds - a greybody rather than a blackbody.blouis79https://www.blogger.com/profile/13769400459008203001noreply@blogger.comtag:blogger.com,1999:blog-4828122657384873884.post-63029346065855830852011-05-18T15:58:11.964-04:002011-05-18T15:58:11.964-04:00Clearly there are differences of opinion amongst p...Clearly there are differences of opinion amongst physicists. Calling people names is not the way of science.<br /><br />If one takes a historical perspective and the original radiative "greenhouse" effect was debunked a century ago, then there would be no "atmospheric greenhouse" theory. The null hypothesis would have been that the earth's temperature is explained by current knowledge of planets in radiative energy balance with the sun. The burden of proof would be on "greenhouse" proponents to explain and demonstrate the error of the prevailing belief (there is no greenhouse), and describe and verify a physical mechanism for the "greenhouse".<br /><br />There are a lot of "big" assumptions in the Rancourt description, which need further elucidation.<br /><br />Clearly, the pancake earth is never true. The fact that the poles are always colder than the equator means that there will always be convection from the warmer equator and this will be replaced by cooler air from the poles. The effect of this on surface temperatures cannot be ignored. <br /><br />It may still be that the despite variations in temperature at various points on earth, the essentials of radiative thermal equilibrium must hold according to the laws of thermodynamics.<br /><br />Only time and good science will reveal which assumptions are correct and which are flawed.blouis79https://www.blogger.com/profile/13769400459008203001noreply@blogger.com