tag:blogger.com,1999:blog-16612221.post4963434145934390841..comments2024-03-19T03:14:04.172-04:00Comments on Rabett Run: EliRabetthttp://www.blogger.com/profile/07957002964638398767noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-16612221.post-22119746780182608642008-02-27T16:38:00.000-05:002008-02-27T16:38:00.000-05:00I'm ready to call this one. Emissivity has 5 sylla...I'm ready to call this one. Emissivity has 5 syllables, which is 2 more than a denialist is trained to handle. Furthermore, epsilon is a Greek letter, and the international language of denialism is English.<BR/><BR/>Correct these two errors and we can go on.<BR/><BR/>Consider yourselves audited.Marion Delgadohttps://www.blogger.com/profile/09493068399042656060noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-48029021679152088862008-02-17T13:58:00.000-05:002008-02-17T13:58:00.000-05:00Hello, the angle very important! Taking an angle o...Hello, <BR/>the angle very important! Taking an angle of 90° the emissivity of water is about 0,65. The earth radiates at right angle, thus I estimate that the earth has an emissivity of about 0,7 (the seas are covering about 70% of earths surface). Thus the greenhouse effect is much weaker than often thougt.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-19076021276145272612008-02-13T10:02:00.000-05:002008-02-13T10:02:00.000-05:00Looks like kramm may have copied right off the wik...Looks like kramm may have copied right off the <A HREF="http://en.wikipedia.org/wiki/Climate_model" REL="nofollow">wikipedia page for Climate Model</A><BR/><BR/>The problem is, he apparently does not understand what "effective emissivity" is -- ie, that it already includes the influence of the greenhouse effect due to atmosphere.<BR/><BR/>From wikipedia<BR/><I><BR/> * ε is the effective emissivity of earth, about 0.612<BR/><BR/>The constant πr2 can be factored out, giving<BR/><BR/> (1 − a)S = 4εσT4<BR/><BR/>This yields an average earth temperature of 288 K [3]. This is because the above equation represents the <B>effective radiative temperature</B> of the Earth (including the clouds and atmosphere). The use of <B>effective emissivity already accounts for the greenhouse effect.</B> (along with clouds and other stuff)<BR/><BR/></I><BR/><BR/>So, in effect, kramm is trying to "prove" that with no greenhouse effect, the earth would have the same temperature that it actually does by using an effective emissivity that already takes into account the greenhouse effect!<BR/><BR/><BR/><BR/>Also from wikipedia:<BR/><BR/><I>The average emissivity of the earth is readily estimated from available data. The emissivities of terrestrial surfaces are all in the range of 0.96 to 0.99 [4] [5] (except for some small desert areas which may be as low as 0.7). Clouds, however, which cover about half of the earth’s surface, have an average emissivity of about 0.5 [6] (which must be reduced by the fourth power of the ratio of cloud absolute temperature to average earth absolute temperature) and an average cloud temperature of about 258 K [7]. Taking all this properly into account results in an effective earth emissivity of about 0.64 (earth average temperature 285 K).<BR/><BR/></I>Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-86048369824096635852008-02-12T16:09:00.000-05:002008-02-12T16:09:00.000-05:00The G&T failed my sniff test because they spent to...The G&T failed my sniff test because they spent too much time ranting, and never actually put anything up evidence wise. There was plenty of symbol manipulation, but no real connection to the actual world. It is too long since I last did thermodynamics, and it wasn;t that kind anyway, so I do not know enough to critique it properly.guthriehttps://www.blogger.com/profile/17992984293423290387noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-39162338634071169222008-02-12T14:33:00.000-05:002008-02-12T14:33:00.000-05:00Then again, one could probably say the same thing ...Then again, one <I>could</I> probably say the same thing about the emissivity value given by real climate for that simple model: that is was chosen to make the temp come out right :)<BR/><BR/>I honestly don't know whether that was the case or whether the 0.769 was determined independently.<BR/><BR/>--TAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-59925203186341103642008-02-12T14:23:00.000-05:002008-02-12T14:23:00.000-05:00yes, it's no accident that the value kramm uses fo...yes, it's no accident that the value kramm uses for emissivity is 0.61<BR/><BR/>That <I>is</I> the value that makes the earth's surface temp work out to about 288K (288.6, actually) using <I>his</I> equation:(1 – a) S/4 = eps sigma T_e^4 .<BR/><BR/>where "eps" is emissivity<BR/> <BR/><BR/>But if you look at <A HREF="http://www.realclimate.org/index.php/archives/2007/04/learning-from-a-simple-model/" REL="nofollow">RealClimate's derivation for the simple model with an IR absorbing atmosphere</A>, you will note that their equation <BR/><BR/>G= S/ (1 - (.5)lamda )<BR/><BR/>where lamda is emissivity<BR/><BR/>has a [ 1 - .5(emissivity) ] factor instead of the "bare" "emissivity" factor that kramm has in his equation (since real climate considers the fact that there is emission and absorption in the IR by the atmosphere -- ie, greenhouse effect).<BR/><BR/>(Note that Kramm's "S" is actually equivalent to real Climates "TSI", so real Climate's "S" is equivalent to everything on the left hand side of kramm's equation: (1 – a) S/4 )<BR/><BR/>The value real climate gives for emissivity is 0.769, so <BR/><BR/>real climates factor <BR/><BR/>1 - 0.5*emissivity = 1 - 0.5 (0.769) = .616 (essentially, the value Kramm uses for his emissivity)<BR/><BR/><BR/>In other words, Kramm's emissivity value was CHOSEN to give the right answer for the earth's temp (assuming as he did that there was no greenhouse effect)<BR/><BR/>How convenient.<BR/><BR/>--TAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-5295484659469125722008-02-12T10:53:00.000-05:002008-02-12T10:53:00.000-05:00Errm yes. Haven't they simply calculated the value...Errm yes. Haven't they simply calculated the value of eps which gives you 288K given all the other parameters? Of course, in the real world, if you suddenly changed eps from 1 to 0.61 then the T would change too.William M. Connolleyhttps://www.blogger.com/profile/05836299130680534926noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-66962514883511946372008-02-12T08:57:00.000-05:002008-02-12T08:57:00.000-05:00True Griffin, but they have bundles several differ...True Griffin, but they have bundles several different things together in that eps (emissivity of the earth and oceans, albedo, etc), and their calculation makes it clear that they either don't know or are resisting using a realistic value. Instead they are playing the game, oh this could be anything, what if were something it could not be.<BR/><BR/>Their entire argument rests on picking a value of eps which is <BR/><BR/>a. Not within the bounds of possibility and<BR/>b. Supports the idea that there is no greenhouse effect.<BR/><BR/>So color my fur dubious. This is another one of those implausible but technically possible arguments.EliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-21991928884806160552008-02-12T01:47:00.000-05:002008-02-12T01:47:00.000-05:00>> And why do they call epslion “phenomenological”...>> And why do they call epslion “phenomenological”? <BR/><BR/>If they're using it the right way, they just mean that epsilon isn't derived exactly from some microscopic principle. Which is probably right, seeings as you just measure it. Not that there's anything wrong with that - thermodynamics is a phenomenological theory, and it's solid as.<BR/><BR/>The term is used a lot in the literature of non-equilibrium statistical mechanics (and almost nowhere else), usually to make distinctions between microscopic and macroscopic regimes.<BR/><BR/>I'm not sure their use of the word adds much meaning, but it's not a term of abuse - doesn't imply that there is dodgyness going on with epsilon.<BR/><BR/>-GriffinAnonymousnoreply@blogger.com