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From: Bill Ward on 8 Dec 2008 04:55 On Mon, 08 Dec 2008 05:06:34 +0000, Don Klipstein wrote: > In article <pan.2008.11.30.20.54.34.361748(a)REMOVETHISix.netcom.com>, Bill > Ward wrote: >>On Sun, 30 Nov 2008 07:13:33 -0800, bill.sloman wrote: >> >>> On 29 nov, 06:43, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>> On Fri, 28 Nov 2008 19:25:22 -0800, bill.sloman wrote: >>>> > On 27 nov, 20:50, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: >>>> >> On Thu, 27 Nov 2008 07:50:47 -0800, bill.sloman wrote: >>>> >> > On 27 nov, 06:32, Bill Ward <bw...(a)REMOVETHISix.netcom.com> >>>> >> > wrote: >>>> >> >> On Wed, 26 Nov 2008 17:09:40 -0800, bill.sloman wrote: >>>> >> >> > On 26 nov, 22:17, Bill Ward <bw...(a)REMOVETHISix.netcom.com> >>>> >> >> > wrote: >>>> >> >> >> On Wed, 26 Nov 2008 07:53:11 -0800, bill.sloman wrote: >>>> >> >> >> > On 26 nov, 12:28, Whata Fool <wh...(a)fool.ami> wrote: >>>> >> >> >> >> Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> Â wrote: >>>> >>>> >> >> >> >> >bill.slo...(a)ieee.org wrote:> >>> >>> <big snip - Bill Ward does go in for mindless repetition> >>> >>>> > Since the effective radiating altitude is 6km above ground, right in >>>> > the middle of the troposphere, this seems to be exactly the right >>>> > place for a radiative transfer model to be effective. >>>> >>>> There's an excess of water vapor available to convect latent heat up >>>> to the effective radiating altitude. >>> >>> The air at the effective radiating altitude is well below the freezing >>> point of water - the earth radiates as if it is a black body at -14C, >>> and while this is an average over all wavelengths (for wavelengths >>> absorbed and re-radiated by CO2 the temperature has to be closer to >>> -55C) it makes sense that the radiation appears to come from a layer >>> where water vapour - the predominant greenhouse gas - has condensed >>> out. >>> >>> The partial pressure of water vapour above the cloud tops is too low to >>> convect any signficant latent heat higher >> >>You seem to be going to great lengths to repeat my points as though they >>were your own. I'll take that as a compliment. Once the cloud has >>condensed, its latent heat has radiated from the cloud tops, > > Radiation of the heat (latent or otherwise) does not occur the > instantly. The air may descend somewhere else before losing all its heat > to radiation. True enough. I misspoke. I should have said the cloud starts radiating as soon as it begins forming, and continues from that point on. >> and has a clear shot to space. Above the cloud tops, WV is gone, >>radiation is effective, convection isn't needed. > > What about when CO2 is present? What about when cloud tops are low? There's not much CO2, and when cloud tops are low, temperature is higher and radiation is greater. It's the integration over the area of the Earth that counts. A few very effective radiating spots could make a big difference. >>>>Â It's in the 10s of kW/m^2 compared to the 500W/m^2 max from >>>>surface radiation. Â >>> >>> It was at the surface, where the partial pressure of water vapour is >>> around 2300 Pa. The saturation vapour pressure has dropped to 603 Pa >>> by the time the temperature has dropped to zero Celcius. It drops off >>> even faster over ice, so it certainly isn't beating radiation at the >>> effective emitting altitude. >> >>Assume at the surface boundary layer we have a thermal with a given >>humidity and velocity. What do you think happens to a parcel of air, and >>the energy it contains, as it rises? Keep in mind that matter and >>energy are conserved. >> >>I can tell you, from direct observation, that it continues upward at a >>relatively constant velocity until it reaches either a change in the >>lapse rate, or the condensation altitude (cloud base). You need to >>rethink your position to include that easily verifiable fact. You also >>need to get out more. Try riding a sailplane in a thermal. > > Not that most of the world has thermals from surface to tropopause - > those are thunderstorms. > >>> http://www.engineeringtoolbox.com/water-vapor-saturation-pressure-air-d_689.html >>> >>> http://www.answers.com/topic/dewpoint-jpg-1 >>> >>> http://faculty.matcmadison.edu/slindstrom/VaporPressure.doc >> >>Thanks for the supporting links. I may have posted a couple of them >>before. >> >>>>The lower troposphere is translucent in the 15u band. Â How could >>>>CO2 play any significant part, compared to radiation? Above the >>>>clouds, it has a clear shot to >>>> space. >>> >>> CO2 has both 5u and 15u absorbtion bands > > I would like to add that the 15 um band is significant at surface > level temperatures. At 288 K, a blackbody has spectral power > distribution about 71-72% of peak. Sorry, I don't understand what that means. Can you explain? > >>Please. Are you now claiming that the surface is radiating >>significantly in the 5u band? You're the radiation expert, what BB >>temperature would that represent? My BOE guess is about 300C, which >>seems a bit unrealistic for Earth, > > At 288 K, a blackbody has spectral power distribution about 22% of > peak > at 5 um. There is some surface radiation in that band being absorbed by > CO2 overhead. What percent? It's a fairly narrow band, overlapping water. Can you explain, using this graph? It looks like less than 5% of the area under the spectrum to me. http://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png >> especially at the effective radiation altitude. Looks like you've >>reached the bottom of the barrel. >> >>> http://www.wag.caltech.edu/home/jang/genchem/infrared.htm >>> >>> What do you mean by "translucent"? >> >>Scattering rather than absorbing, like the frosted glass on a light >>bulb. I was humoring you. I suspect the lower troposphere is nearly >>opaque to the 15u band, and satellites are just seeing emission from the >>top layer. It doesn't matter either way to the argument. >> >>> CO2 absorbs and retransmits infra-red radiation at specific lines >>> within both bands, and this radiation won't have a "clear shot at >>> space" until it gets high in the stratosphere. >> >>How much? And how much difference does it make in view of the negative >>feedbacks involved in the convective transfer? Try considering the >>lower troposphere as a variable (temperature sensitive) thermal >>resistance > > The majority of the troposphere that is lacking convection has thermal > resistivity not collapsing until convection occurs. That portion of the > tropospher has upward mobility in lapse rate. Local convection should still be quite effective. >> and the region above the radiating layer as a relatively smaller, >>slightly CO2 sensitive resistance. >> >>> CO2 is also disproportionately effective at broadening water vapour >>> absorption lines, and this will be significant in the region close >>> above the cloud tops where there's still some partial pressure of >>> gaseous water to absorb and retransmit at water vapour's absorbtion >>> lines. >> >>OK. Now use your radiative transfer model to compare that to the effect >>of warming (lowering) the emitting layer a few degrees. Don't forget >>the T^4 term. > > Lowering of the emitting layer is what happens if GHGs are reduced. Why would GHGs necessarily be involved, since clouds radiate as black bodies? > Except the emitting layer will still have the temperature appropriate > for 1/4 of the solar constant times ratio of solar absorption to > emissivity of the radiating layer. Not if the surface temperature has increased. The lapse rate won't allow it. The temperature of the emitting layer will increase, radiating the heat necessary to cool the surface back down - negative feedback. >>Sorry about the repetition, but it was worth it, since you have now >>apparently caught on to what I was saying. I'm more pragmatic than >>polite, I guess. > > - Don Klipstein (don(a)misty.com)
From: Bill Ward on 8 Dec 2008 05:29 On Mon, 08 Dec 2008 01:32:30 -0800, John M. wrote: > On Dec 8, 10:21 am, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: > >> What would drive horizontal advection if not density differences and >> resulting vertical convection? > > Coriolis. I believe that just changes the apparent direction of an already existing horizontal movement. Nice try, though.
From: Martin Brown on 8 Dec 2008 07:24 On Dec 7, 7:55 am, Bill Ward <bw...(a)REMOVETHISix.netcom.com> wrote: > On Sun, 07 Dec 2008 05:45:26 +0000, Don Klipstein wrote: > > In article <pan.2008.11.29.05.49.04.133...(a)REMOVETHISix.netcom.com>, Bill > > Ward wrote: > >>On Fri, 28 Nov 2008 19:35:59 -0800, bill.sloman wrote: > > >>> On 28 nov, 14:20, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> > >>> wrote: > >>>> z wrote: > >>>> > and the fact that water vapor partial pressure rises with > >>>> > temperature, thereby making it an amplifier of other effects, such > >>>> > as CO2. > > >>>> An unproven hypothesis. i.e random noise. > > >>> There's nothing unproven about the "hypothesis" that the partial > >>> pressure of water vapour in contact with liquid water rises with > >>> temperature. It's up there with Newton's law of gravity as one of the > >>> fundamental theories of science. > > >>> And more water vapour does mean more pressure broadening in the carbon > >>> dioxide absorbtion spectrum. > > >>> Carbonic acid (H2CO3) may not be stable in the vapour phase at room > >>> temperature, but it is stable enough that any collision between a water > >>> molecule and a carbon dioxide molecule lasts qute a bit longer than > >>> you'd calculate from a billiard-ball model. > > >>> Eeyore's response isn't random noise either, though it's information > >>> content isn't any more useful - we already knew that Eeyore knows squat > >>> about physics, and he's long since made it clear than he doesn't > >>> realise how little he knows by posting loads of these over-confident > >>> and thoroughly absurd assertions. > > >>He may also be aware that increased water vapor lowers the condensation > >>altitude, > > > Cloud bases lower if relative humidity rises. Relative humidity stays > > about the same if water vapor concentration is only commensurate with > > temperature rise. > > Interesting concept. I'm assuming the surface temperature determines the > absolute humidity, and the condensation altitude would be determined by > the lapse rate downward from the cloud tops (radiation layer). It seems > to me the surface temperature varies a lot more than the higher altitudes.. > > Is there any actual data on the altitude of the radiation layer that > radiates the most power? From what I've seen, it's mid troposphere, not > the tropopause. Are there any credible models of the individual > mechanisms from cloud tops to the tropopause? > > >> raising the radiation temperature, and increasing the emitted IR > >>energy by the 4th power radiation law. IOW, it's a negative feedback, > >>not positive. > > > Radiation from cloud bases is toward Earth. > > I think that concept confuses people, at least me, when I first heard > it. It appears at first glance you are claiming the cloud bases are > warming the surface, which is clearly impossible by the second law. That depends on whether or not the cloud base is actually warmer than the surface. It isn't all that common unless thick low cloud moves in quickly after a previously clear still night sky where the ground has already become substantially colder than the cloudbase. Typically the effect of clouds at night is to prevent the ground from losing quite so much heat by radiation to the roughly -70C effective sky brightness temperature. > The clouds are colder than the surface, and energy can never radiate from > cold to hot. The lower levels of clouds can sometimes be warmer than the upward facing ground. At the bottom layer where water vapour is condensing to form liquid droplets there is latent heat being released. > > A little more thought reveals the actual mechanism must be that some of > the radiation that comes from the surface can be considered to be radiated > back to maintain the (Tsource^4 - Ttarget^4) term in the Stefan-Boltzmann > equation. That still requires that the net heat flow is outward, never > inward (unless the surface is cooler). The upper layers may reduce the > cooling rate of the surface, but they can never actually heat it. Depends if the surface has already got colder than the clouds first. I suggest you wait for a suitable winters night that starts clear with a frost and then has a warm front of cloud move in and watch the exterior thermometer. > > The _net_ radiation has to be from the surface to the clouds. Only if the clouds are cooler than the surface (which is usually the case). > > > Meanwhile, increasing GHGs cools the lower stratosphere and raises the > > tropopause - cloud tops around the tropopause will be cooler. > > I'm not clear why. Could you explain why a cooler stratosphere raises the > tropopause? Is it because the tropopause is the top of convection, so a > colder stratosphere allows convection to continue higher before the > UV-O2, O3 inversion takes over? Essentially yes. Warm air can rise higher before the boundary layer is reached. So long as the air above it is cooler it can keep on going up. Regards, Martin Brown
From: Martin Brown on 8 Dec 2008 07:32 On Dec 8, 1:20 am, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > Martin Brown wrote: > > Eeyore wrote: > > > z wrote: > > > >> and the fact that water vapor partial pressure rises with temperature, > > >> thereby making it an amplifier of other effects, such as CO2. > > > > An unproven hypothesis. i.e random noise. > > > You are clueless. That warmer air can carry more water vapour is a well > > known experimental fact. > > You fail to address the idea it's an *amplifier*. I would not use the word "amplifier" myself to describe what is actually a positive feedback mechanism. But his meaning is clear and the physics are baiscally correct more CO2 in the atmosphere makes it warmer and the extra warmth allows more water vapour into the air before it saturates. Warmer seas and warmer air over them will contain more water vapour as a result. Regards, Martin Brown
From: Martin Brown on 8 Dec 2008 07:41
On Dec 8, 8:52 am, Whata Fool <wh...(a)fool.ami> wrote: > d...(a)manx.misty.com (Don Klipstein) wrote: > > >In <pan.2008.12.03.05.51.11.802...(a)REMOVETHISix.netcom.com>,B. Ward wrote: > >>On Wed, 03 Dec 2008 04:14:23 +0000, Don Klipstein wrote: > > >>> In <pan.2008.11.26.21.52.54.243...(a)REMOVETHISix.netcom.com>, Bill Ward > >>> said: > >>>>On Wed, 26 Nov 2008 07:52:48 -0800, bill.sloman wrote: > > ><I snip to edit for space arbitrarily on level of quotation/citation, > >without snipping perfectly accurately on basis of degree of quotation> > > >>>>> Don't be silly. I was being rude about the phrase "water and water > >>>>> vapor IR radiation plus phase change _moderate_ the temperature" which > >>>>> is total nonsense, as the Venus example demonstrates. > > >>>>> You also need to apologse for not knowing what you are talking about. > > >>>>>> Just say how N2 and O2 could cool after daytime heating and > >>>>>> I will go away. > > >>>>> They emit and absorb in the infra-red just like water and carbon > >>>>> dioxide; because they are symmetrical molecules the transitions are > >>>>> forbidden, but pressure broadening/intermolecular collisions means that > >>>>> the transitions happen anyway, albeit much less often than with > >>>>> asymmetrical molecules. > > >>>>I think we need a link for that. It would mean N2 and O2 are GHGs. > > >>> I suspect to some extremely slight extent they actually are. > > >>Can you tell us why you suspect that? Perhaps a link to some data? > > > On that point, I am feeling challenged to find links supporting a > >contention that N2 and O2 have IR absorption spectrum features having any > >significance at "earthly temperatures". > > > Considering only global average surface temperature of 288-289 K, a > >blackbody has spectral power distribution over 1% of peak over > >wavelengths from about 3.4 um to about 66 um. > > > Going so far as .1% of peak spectral power distribution of a 288 K > >blackbody, the wavelength range is about 2.95 um to close to 100 um. > > > Source: The "blackbody formula". > > > I have strong doubt that the massive amounts of O2 and N2 in the > >atmosphere completely lack any infrared spectral features in or shortly > >outside such a range. > > ><SNIP from here on basis of low level of content to show as quoted less > >than twice> > > > - Don Klipstein (d...(a)misty.com) > > The N2 and O2 in the atmosphere are not dry. N2 would have very > little infr-red if dry, and O2 would probably have a little more, but not > worth mention, and definitely not enough to mean that the N2 and O2 in > the Earth's atmosphere could cool themselves without GHGs. > > (without getting a lot warmer than present).- Hide quoted text - Utter and unmitigated bullshit!! A pure N2 and O2 atmosphere would develop strong winds of the type seen on the gas giants driven by the temperature and pressure differentials on the night and daytime sides of the planet. The atmosphere would lose heat by winds blowing from the cold regions at the anti-solar point to the warm sunny side. Where the air would take heat from the hot surface and rise genrating a circulation pattern. The surface gets to radiate IR away easily at night since we have already established that to a very good approximation they are transparent to IR. Regards, Martin Brown |