tag:blogger.com,1999:blog-2249983551893842827.post3082149752978757484..comments2023-10-26T23:39:36.158+01:00Comments on Climate and Stuff: Are Adiabatic Lapse Rates Controlling Temperaturesthefordprefecthttp://www.blogger.com/profile/07210786222021457913noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-2249983551893842827.post-36305493407148205652012-01-09T02:26:28.178+00:002012-01-09T02:26:28.178+00:00Nick
The easy bit first
I can find no definitive s...Nick<br />The easy bit first<br />I can find no definitive statement about black/grey body radiation from gases. All books say BB radiation occurs from all "stuff" above 0K temperature. Everyone scientific agrees with this. but what is the difference between solid and gaseous stuff. E.G. take solid CO2. I would assume this does BBradiation as the temp is above 0K. This heats a bit and sublimates to CO2 gas. Now all of a sudden it only radiates at certain frequencies - why?<br /><br />Liquid nitrogen is similar. I assume BBradiation when a liquid(?) but then on turning to gas NO radiation will be emitted. Just does not sound logical!<br /><br /><br />Lapse rates - I just have to think about!thefordprefecthttps://www.blogger.com/profile/07210786222021457913noreply@blogger.comtag:blogger.com,1999:blog-2249983551893842827.post-4775762132278585142012-01-08T04:40:12.803+00:002012-01-08T04:40:12.803+00:00TFP,
Here's how I think it works. The lapse ra...TFP,<br />Here's how <a href="http://moyhu.blogspot.com/2010/06/venus-models-and-adiabatic-pump.html" rel="nofollow">I think</a> it works. The lapse rate is the point of neutral convective stability. Below that, it's stable; above, it's unstable.<br /><br />At the dry lapse, a rising parcel of air heats at exactly the same rate as still air nearby. It neither gains nor loses buoyancy.<br /><br />But below the lapse rate it's stable. As it rises, it cools relative to air nearby. It takes energy to push it up. That energy comes from the KE of the atmosphere - eddies etc.<br /><br />And where does the energy go? It does work pumping heat against the temp gradient. The rising air carries "coolness" up. <br /><br />What about the displaced air? Same. Imagine 1kg rising, 1 kg coming down. The falling air now warms faster than nearby air. It takes work to force it down. And it is carrying heat against a thermal gradient. Again heat pumping. The rising air carries coolness up - falling brings warmth down.<br /><br />The effectiveness of this heat pump is proportional to deviation from lapse rate. And it pumps heat to maintain the lapse rate. It all comes from the KE of the air, which is driven by temp differentials (Hadley cells etc).<br /><br />Conversely, above the lapse rate, everything is the other way around. Rising air becomes warmer than the ambient, so rises even faster. It carries heat down the gradient and creates KE. It is a heat engine. And because of that, it tends to reduce the gradient - accelerated conduction. So just as the pump brought the gradient up to 10 K/km, the engine brings it down. Again the effectiveness is proportional to the deviation of the gradient from 10.<br /><br />As to non-GHG gases, all substances have an emissivity. With gases it is very selective (bands), and there's no such thing as a black body. They emit according to emissivity and mass. Monatomic and symmetric diatomic gases have very low emissivity.Nick Stokeshttps://www.blogger.com/profile/06377413236983002873noreply@blogger.comtag:blogger.com,1999:blog-2249983551893842827.post-12178910379794878742012-01-07T06:12:18.167+00:002012-01-07T06:12:18.167+00:00Thanks for that .... BUT!!
at 10k metres the temp ...Thanks for that .... BUT!!<br />at 10k metres the temp is set by the lapse rate and the temp at 0m<br />so a parcel of air moving from 0 to 10km will loose thermal energy and gain potential enregy ending up at the same temp as the other stuff at 10km<br /><br />an in reverse from 10km to 0m so unless you assume that the parcel is heated without heating the other parcels no heat will be transported..<br /><br />I assumed that if a 100% insulated row of air were suddenly turned to a column of air then the lower air would be compressed and heated and the upper rarified air would cool to maintain energy balance.( low air high T but low potential energy; high air low T but high potential energy) This would give the adiabatic lapse rate. But then will not the air mix to eventually give a uniform temperature? But then you have medium temp with high potential energy and medium temp with low potential energy. Thi9s seems wrong?<br /><br />Also I know you have said that N2 and O2 do not emit radiation but what is the difference between a gas and a solid when it comes tho blackbody radiation. - Most books talk about all matter above 0K emitting BBradiation. So why not non GHGs. I KNOW that no narrow emissions from non-GHGs will occur - non is captured and none is emitted. But non GHGs can be warm, they are matter, so do the not radiate over the usual BB spectrum?<br /><br />I just cannot find and definitive statement that says gasses do not have a black body radiation!<br /><br /> <br />of interest:<br />http://www.ssec.wisc.edu/library/coursefiles/03_abs_emiss_ref.pdf<br /><br />The physics of atmospheres By John Theodore Houghton<br />preview: <br />http://books.google.co.uk/books?id=K9wGHim2DXwC&printsec=frontcover&dq=%22The+physics+of+atmospheres+By+John+Theodore+Houghton%22&hl=en&sa=X&ei=eeEHT9LGMseo8QPrlayJCA&ved=0CDUQuwUwAA#v=onepage&q=%22The%20physics%20of%20atmospheres%20By%20John%20Theodore%20Houghton%22&f=falsethefordprefecthttps://www.blogger.com/profile/07210786222021457913noreply@blogger.comtag:blogger.com,1999:blog-2249983551893842827.post-60629754031114879592012-01-05T08:25:32.824+00:002012-01-05T08:25:32.824+00:00See my response to one part of your statement at S...See my response to one part of your statement at <a href="http://scienceofdoom.com/2012/01/03/kramm-dlugi-on-illuminating-the-confusion-of-the-unclear/#comment-14955" rel="nofollow">Science of Doom</a>, reproduced here for interest:<br /><br />You said:<br /><br /><i>"..Also, to maintain number of molecules at each altitude what goes up must come down! So energy transfer is minimal (zero).."</i><br /><br />If higher temperature molecules move up and lower temperature molecules move down you have conservation of mass. And you have conservation of energy. <br /><br />But you don't have constant energy vs height. <br /><br />In fact, what happens when convection takes place - say with a heated plate at the bottom of a water tank - is that warmer water moves up and colder water moves down. <br /><br />This redistributes energy.<br /><br /><a href="http://paoc.mit.edu/labweb/lab2/gfd_ii.htm" rel="nofollow">Here is a nice page with video link</a> showing an experiment on this topic. There are other great videos via links at the top of this page. It accompanies the excellent Marshall & Plumb (2008) textbook.Science of Doomhttp://scienceofdoom.comnoreply@blogger.com