Can you keep an open mind on the cause of winds? Climate science needs your help!
by Anastassia Makarieva
Many of us who have become researchers have been attracted by the dynamic and constructive debate that lies at the heart of scientific progress. Every theory is provisional waiting to be improved or replaced by a more thorough understanding. In this perspective new ideas are the life-blood of progress and are welcomed and examined eagerly by all concerned. That’s what we believed and were inspired by. Is climate science a dynamic field of research that welcomes new ideas? We hope so – though our faith is currently being tested.
Five months have not been enough to find two representatives of the climate science community who would be willing to act as referees and publicly evaluate a new theory of winds. Of the ten experts requested to act as referees only one accepted. This slow and uncertain progress has caused the Editors to become concerned: recently they “indefinitely extended” the public discussion of the submitted manuscript. The review process is perhaps becoming the story.
Here the authors share their views and request help.
Background
On August 06 2010 our paper “Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics” was submitted to the Atmospheric Chemistry and Physics Discussions (ACPD) journal of the European Geosciences Union. There we proposed a new mechanism for wind generation based on pressure gradients produced by the condensation of water vapor. ACPD ensures transparency during the review procedure: the submitted manuscripts and subsequent reviews are published online and available for public discussion. Authors can follow their submission through the process: they see when the Editor invites referees and whether they accept or decline.
Here are the standings as of 20 January 2011:
The Editor handling our paper has invited ten referees so far. Only one, Dr. Judith Curry, accepted. After 10 November 2010, in the record there have been no further attempts to find referees.
Normally ACPD’s discussion should take eight weeks. But in early January 2011, after twelve weeks in process, the status of the discussion of our manuscript was changed to “indefinitely extended”. In a recent letter to the authors, the Editor-in-Chief admitted that handling ‘a controversial paper’ is not easy, but assured us that the Journal is doing their best.
Discussion of our propositions secured over a thousand comments in the blogosphere within four weeks of publication indicating wide interest. Among the ACPD discussion participants two are active bloggers. Does blog culture outcompete formal peer review in evaluating novel concepts? It’s an open question. But let’s take a moment to focus on science.
Why condensation-induced dynamics is important
It would be generally useful to understand why the winds blow. It is sufficient to note that understanding the physical bases of atmospheric circulation is key for determining the climate sensitivity to changes in the amounts of atmospheric greenhouse substances, which is currently a highly controversial topic. The lack of current understanding may not be widely recognized outside the climate and meteorological community. But within the community moist processes in the atmosphere are admitted to be among the least understood and associated with greatest challenges. Not only theorists, but also modelers recognize their existence. For example, in a paper titled “The real holes in climate science” Schiermeier (2010) identified the inability to adequately explain precipitation patterns as one of such holes. In particular,
“a main weakness of the[ir] models is their limited ability to simulate vertical air movement, such as convection in the tropics that lifts humid air into the atmosphere.”
Any meteorological textbook will provide a discussion of buoyancy-based convection: how a warm air parcel ascends being lighter than the surrounding air. The convective instability of moist saturated air, so far neglected by the meteorological theory, is different. Any upward displacement of a saturated air volume, even a random fluctuation, leads to cooling. This causes the water vapour to condense. Condensation diminishes the total amount of gas and thus disrupts the hydrostatic distribution of moist air (if a hydrostatic equilibrium exists it is unstable to any such minor movements). The conclusion: moist saturated atmosphere in the gravitational field cannot be static.
Our analyses show that the current understanding of air movements being dominated by temperature and buoyancy is incomplete and flawed. Rather we find that the phase changes of water (condensation and evaporation) can play a much larger role than has previously been recognized. You can find out more if you see our paper. We would hope that a dynamic and advancing science would welcome new ideas.
Can the blogosphere help?
Perhaps we can help the Journal review our paper with your help. Are you an open minded climate scientist who would be ready and competent to discuss our ideas?
The ACP Chief-Executive Editor Dr. Ulrich Pöschl is aware that we are inviting your helps and asked that the following issues be noted (we quote):
1) ACPD is not a blog but a scientific discussion forum for the exchange of substantial scientific comments by scientific experts.
2) The open call for scientific experts who would be ready to act as potential referees would be a private initiative of the manuscript authors.
3) The list of potential referees compiled by the authors will be treated like the suggestions for potential referees regularly requested. The responsibility and authority for selecting and appointing referees rests exclusively with the editor.
If you have no conflict of interests and are willing to review our paper please contact the corresponding author (A. Makarieva) and we will forward your details to the Editor as a potential referee. For those who would like to remain anonymous please approach the ACP Chief-Executive Editor directly. We would be very grateful for your help – we have faith in you.
Anastassia Makarieva
on behalf of the authors:
A.M. Makarieva, V.G. Gorshkov, D. Sheil, A.D. Nobre, B.-L. Li
P.S. Thanks to Jeff for hosting our appeal on this blog. For a list of publications relevant to condensation-induced dynamics, please, see here.
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“”””” Kevan Hashemi says:
January 24, 2011 at 3:01 pm
Mr. Smith,
Your description of electrostatic force being able to support water droplets is fascinating. I will have to think about it more, because I don’t yet understand it, but it certainly adds a new dimension, because that means that the charge will keep building up where the water is condensing, as the air rises through the cloud-forming layer. “””””
Kevan, when I talked about “somebody” supporting the water droplets, I of course was assuming the non-precipitating case (it ain’t rainin yet), so I assumed that the water droplets were still small enough to be supported. Now Dr Makarieva pointed out that the droplets are supported by upward mass air flow. So that is a macro view, and as she said the droplets are actually falling through that upward air flow at the terminal velocity. So in the macro view you have to consider Reynold’s numbers and the like but for small enough drops I think it is safe to assume a non turbulent laminar flow around the droplet. Someone mentioned friction forces, and I suppose in a sense you could call the interface forces a friction. Eli points out that VdW forces are acting between molecules. Some of those result from the dipole nature of the water molecule; so even though the droplet may have a net charge of zero, so that it is not subject to any local electric fields perhaps due to charged clouds, there can still be local electric forces due to molecular dipoles. As I recall it is usual for molecules to repel each other somewhat, which is why you get the small pressure adder term (b) in the Van Der Waals equation of state.
All of these kinds of forces the surface “friction”, viscosity shear (in the atmosphere) as well as the microscopic molecular level collisions, are all acting in concert to suspend the water droplet or raise it through the air column, till it get heavy enough to precipitate.
My point is simply, that whatever forces of any nature (besides gravity) are acting to support the water droplets, those forces must result in a net downward force on the atmosphere that simply is the weight of the droplet (unless it is accelerating too) so the weight of the water must still provide a pressure adder; and it isn’t clear to me, why that would be different from that supporting the water as a vapor.
Now we can imagine a closed vessel containing air (even water) on the space station; so now we have removed gravity; and I doubt that anything much has changed inside that closed vessel. So of coursae the gas pressure remains as it was, due to the kinetic energy of the molecules, and that includes the partial pressure of the water vapor. Now in this case, if the water vapor condenses, then my gravitational factor doesn’t come into play.
Now I’m curious as to just what the Makarieva Effect would do in that case. So if we still have the good Doctor’s attention, she might comment, on what happens in zero g. Or is her result a consequence of gravity; so no show in zero g.
As to the suspension by electric fields; that of course is what Milliken did; but he used a low vapor pressure oil so he wouldn’t have his droplets evaporating. The droplets are sprayed into the gap between two capacitor plates, which can be viewed from the side through a long focus microscope. You let the droplets fall, with no electric field, and they reach terminal velocity which you can time over a trap distance; or today you could have more sophisticated speed reading. From the terminal velocity and the density of the oil, you can derive the mass and weight of the droplet. You then turn on the field, and if the droplet has collected any electrons, the electric field can support the droplet and hold it still. Uncharged droplets will simply drop out of the way. The experiemtn depends on the fact, that the droplets are so small, that you can find droplets with just a single electron extra. Of course Millikan obtained a number of different charge values based on the electric field strength necessary to levitate each droplet; and of course they turned out to be integer multiples of a single value. He did get droplets with a single electron charge; I did too when I did it in school. Lots of people tried refined versions of the experiment, hoping to find charges of -1/3 or -2/3 thinking they could detect a free quark. All of those experimenters are buried in the same cemetary, as the Optician who tried to polish out #80 grit pits with Jewellers rouge; old age it says on their death certificates.
Kevan Hashemi says:
January 24, 2011 at 6:51 pm
“Nice idea with the balloons. But I don’t think anyone is claiming that condensation reverses a pressure drop. The balloons in the refrigerator will not start to expand again.”
My misunderstanding. I thought that was your claim when you stated “There are two effects: contraction due to water vapor turning into liquid and heating due to water vapor giving up its latent heat of evaporation. The heat causes the air to expand. According to my calculation, the expansion due to heating is eight times greater than the contraction due to vapor becoming liquid.”
But I agree, I don’t think the balloons will expand when internal air hits the dew point. I think the “giving up of latent heat” is occurring the entire time, with heat leaving the edge of the balloon system (transferred into the surrounding refrigerator air) every second. Overall deflation will be slower, but there will not be an expansion event.
The atmospheric process of adiabatic condensation confuses me, though. Condensation with no transfer of latent heat? My understanding is that the act of expansion is work, and at some point when enough of this work is done the water vapor condenses into liquid water that has the same energy content of the original water vapor. No transfer of energy occurs between the water and surrounding air, yet there is condensation.
Dear Kevan
For some reason, I cannot see here your comment that has just arrived to my mail box. I reproduce it below:
Your conclusion that condensational mass removal is insignificant is based on consideration of the buoyancy of a given air parcel. Your point is that if we raise this parcel sufficiently high, it will be much warmer than the dry air parcel would have been — had we raised it to the same height. This is due to the well-known difference between the moist and dry adiabatic lapse rates.
Air density (kg/m^3) rho = NM = pM/RT, where N is molar density (mol/m^3), M (g/mol) is molar mass, p is air pressure, R = 8.3 J/mol/K, T is temperature. What you propose is that when you raise your air parcel to sufficient height h = 8 km, the difference between moist adiabatic lapse rate (about 4.5 K/km) and dry adiabatic lapse rate (9.8 K/km), will amount to over 40 K. At T ~ 250 K your point is that this makes a solid impact on density and, hence, buoyancy. If pressure is the same, a comparative increase in temperature of 40 K raises buoyancy by about 20%.
Now looking at rho = NM and recalling that the saturated Nv makes at best 4% of N at the surface, you conclude that the maximum impact of vapor removal on buoyancy can amount to a few per cent, which is much less than the dozens per cent that you calculated from temperature differences due to latent heat release.
These calculations of buoyancy are totally irrelevant though to condensation-induced dynamics. As I said above, in order that buoyancy effects to be significant, there must be a horizontal temperature gradient. There must be air with buoyancy smaller than that of moist air. If the vertical temperature gradient is spatially uniform, warm or cold, the air will not move.
So, let us forget about buoyancy and concentrate on the new physics: you raise moist air parcels over an infinite area: at any height the temperature, pressure and buoyancy are the same. But, due to condensation, partial pressure of vapor changes non-hydrostatically: dpv/dz = -pv/hv, where hv is much smaller than the hydrostatic equilibrium height h.
Hydrostatic equilibrium is disturbed. The pressure gradient force that arises is equal to -[dpv/dz – (1/pv)dp/dz] = pv (1/hv – 1/h). This force acts throughout the entire column where the moist saturated air ascends. It accelerates the air upwards. Due to the fact that the height is smaller than width, hydrostatic equilibrium is restored much quicker in the vertical plane — some air from the surface moves upwards to fill the gap left by condensed vapor. In the result, pressure is lowered at the surface where condensation takes place.
As I said above, the comparison of the maximum possible effect of latent heat release on pressure versus condensational mass removal effect on pressure is given in Fig. 1c of our paper. This figure grossly overestimates the effect of latent heat release, because it assumes that there is no heat exchange between the columns. In reality there is never such a huge difference between the areas where the air ascends and where it descends because of large turbulent mixing.
Eq. 1 does not and cannot say anything specific about condensation-induced dynamics, because it contains the amount of condensed vapor, dq, as an independent variable. This equation does not tell anything about buoyancy either. This is because it is the first law of thermodynamics. For a given dV, you are right, pressure will fall less when there is condensation. For a given dT, it is easy to see that the opposite is true. These thermodynamic considerations do not teach anything though about the dynamics: namely, the appearance of non-equilibrium pressure gradients that make the air move.
Anastassia Makarieva says:
January 25, 2011 at 10:22 am
“As I said above, the comparison of the maximum possible effect of latent heat release on pressure versus condensational mass removal effect on pressure is given in Fig. 1c of our paper. This figure grossly overestimates the effect of latent heat release, because it assumes that there is no heat exchange between the columns. In reality there is never such a huge difference between the areas where the air ascends and where it descends because of large turbulent mixing.”
By “maximum possible effect”, does the figure assume that 100% of atmospheric condensation is the result of latent heat release to the surrounding air? Wouldn’t the figure then be grossly, grossly overestimating the effect of latent heat release? I understand that convective and radiative heat transfer of some magnitute is always occuring, but isn’t the lion’s share of atmospheric condensation adiabatic?
Anastassia:
Thanks for your detailed response. I will read it a few times to make sure I understand it. Will answer in when I think I have something worth saying.
Steve:
You say, “No transfer of energy occurs between the water and surrounding air, yet there is condensation.” I think that’s incorrect. Whenever water condenses, we get back the heat we had to put in to make it vaporize. I think that’s why steam burns are so nasty when compared to hot-air burns. The steam, when it condenses, gives up 2 MJ/kg.
Kevan Hashemi says:
January 25, 2011 at 3:18 pm
“Steve: You say, “No transfer of energy occurs between the water and surrounding air, yet there is condensation.” I think that’s incorrect. Whenever water condenses, we get back the heat we had to put in to make it vaporize. I think that’s why steam burns are so nasty when compared to hot-air burns. The steam, when it condenses, gives up 2 MJ/kg.”
I’m getting there. I think there is some confusion because we are conflating “heat” and “energy”.
My understanding of adiabatic condensation is that the expanding water vapor does work on the environment. This work is energy transfer but not heat transfer (ideally, but some percentage of energy loss is always heat transfer). My statement, “No transfer of energy occurs between the water and surrounding air, yet there is condensation.” is incorrect, and should be, “Little to no transfer of heat occurs between the water and surrounding air, yet there is condensation.” Your statement, “Whenever water condenses, we get back the heat we had to put in to make it vaporize.” should read, “Whenever water condenses, we get back the energy we had to put in to make it vaporize.”
For example, if I lift and move a bowling ball 20 feet I’ve converted chemical energy into kinetic energy. Yes, the bowling ball will pick up some heat from the friction of being moved, but the temperature of the bowling ball will not increase to the extent had I simply held the bowling ball and transferred the same quantity of chemical energy entirely as heat.
Anastassia Makarieva says:
January 24, 2011 at 9:42 am
Steve
January 24, 2011 at 9:24 am
If a vapor condenses, doesn’t the resulting condensation exert less pressure on the surrounding system than the original vapor? I would think that the act of condensation would exert a negative pressure, actually, so for total pressure to remain approximately the same the remaining dry air would have to expand in order to make up for the pressure loss of water vapor condensation.
Exactly. This is why the cloud sucks in the surrounding air, as Jantar said above. Since condensation occurs as the air moves upwards and cools, the resulting pressure gradient force is also upward directed.
—
Anastassia, fine article. And Jantar, great to have another sailplane pilot here.
Jantar here gave a great description of that experience. Many times just below the cloud base your variometer needle will be pegged at 1200 ft/min upward and you start counting seconds compared to the spinning altimeter to try to gauge your rate of climb, sometimes 1800 to 2400 ft/min. You only have seconds to respond.
But the real experience of condensing water vapor is to stand on your own patio and watch a tornado form over your house. It’s always on very warm day with stifling humidity. You look up at the dark base and start to see some very thin angle hair white clouds some 500 feet lower, always white compared to the cloud above. You start to feel the warm moist wind at your back as these wisps appear and disappear and they look so innocent. As they to start to appear and stay longer you notice a very slow rotation, not fast, just 5 r.p.m. at best. Winds still getting stronger. This whole process is within a few minutes. You now see they are persistent with a definite rotation and its faster, more are now forming even lower, these what I call white whisps… Go get in the closet.
These angel hair clouds are condensation occurring lower and lower and closer to the ground and the suction is awesome. Just look at some pictures of the vortexes filmed during the California forest fires last year. Those are thermal, 1000 deg+, vortexes and though looking impressive with the fire they are but as tiny dust devils compared to tornadoes. It’s the moisture and condensation people, not the heat, heat has it’s effect and usually in the same direction but the force from condensation is much greater.
And I have to believe this same process happens over large regional areas also, frontals. So what is the cause and what is the effect when it comes to pressure variance? Seems this paper has it right.
Anastassia, keep up the work, I love science when it finally, over years of misinterpretation, ends up correct in the end. That is why I have always read so many scientific papers for many, many years.
wayne
January 25, 2011 at 6:56 pm
Thank you very much for this description of tornadoes. I would dream to see one one day (two years ago there was a tornado in Moscow, but I do not live there). The maximum wind speed recorded for tornado that we were able to find in scientific literature is 130 m/s (see here, Table 1, Wurman J, Weather & Forecasting 17 (2002) 473). We have estimated that the pressure gradient force associated with condensation is sufficient to produce such velocities, see here and here. This is a unified explanation for the formation of both tornado and hurricanes: based on release of potential energy accumulated in the atmosphere, not on heat extraction from the ocean.
That’s the point. Nobody questions the existence of thermally driven convection. But in order to yield velocities comparable to what is produced by condensational mass removal of vapor from the gaseous phase, both temperature and its gradient in the thermally driven cells should have been much, much larger than they are actually observed to be in most conspicuous atmospheric vortexes like tornadoes and hurricanes. In reality, as I several times commented, in the atmosphere the warm air very often descends rather than ascends.
An open-minded student of meteorology would be prevented from noticing this ‘odd’ air behavior. Instead of operating with absolute temperature, in meteorology people use the so-called potential temperature:
theta = T (p0/p)^(R/c_p)
As one can see, this “temperature” grows as pressure p decreases. So, even if the temperature in the region of ascent is lower than in the region of descent, but pressure p is lower as well (for unknown reasons), potential temperature can be higher in the region of ascent. And we all know from textbooks that when the temperature is higher (who cares: absolute or potential!), the air ascends. So it’s all right, the student is led to conclude, thermal convection works and forgets the issue. In reality it does not.
Anastassia
January 25, 2011 at 9:28 pm
Thank you for some good links. I’ll read them all. And i think you see that I really do understand your groups theory, I understand it not from the science and math side but because I have many times actually experienced it in the real world. That is where I say stay with it, it is real, whether science wants to currently listen or not. Thermal has been the standard answer for so long and it’s hard to change consensuses.
So you want to see a tornado huh, just come to Oklahoma in late spring for a week or two. I’ve even heard you can now get special storm-chaser tours, don’t wait for one to come to you, go chase one down!
However, there is one aspect I don’t understand yet and I haven’t been able to completely absorb the paper. In the summer here there are many days with clouds (condensation) floating across the sky, building and dissipating, day after day, never raining, and the moisture is just being recycled over and over. As I spoke of sailplanes there is tremendous convection happening under these large clouds always but that is all very local wind in nature. It seems just by intuitive logic that until it does actually rain and liquid water is removed from the system in large quantities that the effect stays local. But with heavy rain I can then see the horizontal aspect you spoke of, the paper thin atmosphere compared to the horizontal plane. Is that the only time when it then becomes regional (500-1000 km) in nature, when rain/ice/snow is removed?
Anastassia
January 25, 2011 at 9:28 pm
So you and et al. are M10 in JeffId’s post! I think after reading all of these links I will have the answer to my question above, as I read that thread is already getting into the regional and Hadley aspects that was central to my question. The details of the models is an area I have so far shied from so I best just be quiet and learn some.
Steve
January 25, 2011 at 11:47 am
When we speak of adiabatic condensation this means that the latent heat released upon condensation remains within the air parcel where condensaton occurred. Strictly speaking, liquid water should also remain there — when it is removed we have what one calls pseudoadiabatic process.
In our Fig. 1c two atmospheric columns are compared, both are in hydrostatic equilibrium. But in one column the lapse rate is moist adiabatic (column A), while in another one it is dry adiabatic (column B). Surface temperatures are the same, so at any given height the air in column A is always warmer than the air in column B.
The second difference is that the amount of vapor in column A is smaller than in column B by the amount that is necessary to make the lapse rate in A moist adiabatic (to do so, we do need to condense some vapor throughout the column). So surface pressure (and total amount of gas) in column A is smaller than in column B.
One can see from Fig. 1c that below the height zc where pA-pB = 0, the effect of mass removal dominates and the air pressure is lower in column A. Above zc, the temperature difference (the one Kevan was talking about) plays finally in, such that the warmer air in column A has higher pressure than in B above zc.
What is meant by ‘maximum effect’ of latent heat: this means that there is no heat conductivity between the column, such that the temperature difference between them amounts to over 40 K at a height of several kilometers. In reality this never happens: due to strong horizontal mixing, the ascent is not adiabatic. Latent heat is at least partially removed from the air parcel where condensation takes place. It is lost by radiation to space and by turbulent mixing to the descending column which is being warmed. Actually such circulation pumps the latent heat from the condensation area to the surface of the area where the air descends. This was happening for over two months this summer during the heat wave in Russia.
George E. Smith
January 25, 2011 at 10:11 am
George E. Smith
January 25, 2011 at 10:11 am
The difference lies in the fact that in order to support droplets the air must move upwards — if we are talking of a stationary pattern. In order for the air to move, there must be a non-equilibrium gradient of air pressure. Considering one dimensional motion, if the pressure gradient force is balanced by the downward force associated with droplet friction. That is, a microscopic pilot riding on the droplet will serve as a brake for the upward air flow in very much the same manner as windmills, for example, serve as a brake for the horizontal air flow. In its turn, the upwelling air will be pushing the droplets upward as the horizontal air flow is pushing the windmills.
In contrast, no air flow is needed to sustain vapor molecules in the atmosphere. The air is static.
I agree, it does not.
My colleagues and I very much value the readers’ attention. It is a pleasure to share our thoughts. Zero g is a very interesting case.
Condensation occurs because the temperature drops with height. When we have gravity, this happens any time when the air ascends because of expansion. Let us put g = 0 and consider an atmosphere in a closed container. A vertical temperature gradient can form due to the greenhouse effect. Also, we can just impose it externally on our atmosphere by some technological device. This will lead to the appearance of a non-hydrostatic pressure gradient and air motion.
The latter case is realized in practice in heat pipes. These are technological devices that employ the pressure gradient of the saturated vapour to effectively transfer heat. The rapid transport of heat along the pipe is due to the difference in partial pressures of saturated vapour within the pipe. One end of the pipe is warm (attached to the body that we have to cool), another is cold. Vapor pressure is high where it is warm and low where it is cold. This pressure gradient causes the vapour to flow very rapidly along the tube from the hot end to the cold. The theoretical limit of flow velocity is, obviously, the velocity of molecules. This makes heat pipes very efficient coolers.
However, in heat pipes one must artificially remove the latent heat from the colder end of the pipe (otherwise the temperature gradient responsible for the vapor motion will disappear). This is a limitation on the pipe performance. Likewise, in an atmosphere with g = 0 and a temperature gradient due to absorbers of thermal radiation, the limitation is that the released latent heat must be ultimately radiated to space. That is, if you want to have a larger air velocity, you must radiate more efficiently.
Atmosphere with gravity is unique in that there is an adiabatic temperature gradient that persists in the region of ascent irrespective of how large the vertical velocity is. There is no problem of disposing heat (the process is adiabatic yet the temperature drops) to maintain the temperature gradient that is needed to sustain condensation. This allows for a positive feedback between velocity and condensation: the larger the vertical velocity, the larger the condensation rate S, the larger the pressure gradients associated with condensation (see Eq. 37 in M10), and so on. Such a positive feedback would be absent at g = 0.
wayne
This is a very interesting question. Note also that it resonates with the comment of Dr. Judith Curry (the only reviewer so far of our work):
When vapor condenses, the air pressure is lowered. When moisture evaporates, air pressure rises. If we see a constant amount of cloud water but no rain, this means that this process is localized in the atmosphere on a small scale: condensation occurs in the region of ascent where the cloud resides, evaporation (of condensed droplets) occurs in the region of descent, where relative humidity is less than unity. This may result in the formation of regular patterns like cloud streets.
When is this possible? It should be possible when the droplets that are formed are sufficiently small (have high surface to volume ratio and low terminal velocity) and the circulation velocity is sufficiently low. Only in this case the droplets will have time to evaporate before reaching the surface. One can hypothesize that such a regime is unstable: if vertical velocity increases and/or droplets get larger, they are removed more quickly from the atmosphere across a larger area. The balance evaporation – condensation = 0 in the atmosphere is then broken in this area and it becomes a large scale area of low pressure.
But note also that persistent clouds without rain may also represent a non-stationary accumulation of liquid water in the atmosphere: in this case, the entire area with clouds gradually becomes the low pressure area despite there is no rainfall.
It would be great if climate scientists, many of whom do find time to do blogging and may even happen to read this thread, would join the discussion of condensation-induced dynamics. There is much to discuss here. It is beyond doubt that having got acquainted with the main propositions, people will be able to use them to explain many weather and climate patterns of which we may have little or no knowledge at all.
Anastassia Makarieva says:
January 26, 2011 at 6:28 am
“When we speak of adiabatic condensation this means that the latent heat released upon condensation remains within the air parcel where condensaton occurred….What is meant by ‘maximum effect’ of latent heat: this means that there is no heat conductivity between the column, such that the temperature difference between them amounts to over 40 K at a height of several kilometers. In reality this never happens: due to strong horizontal mixing, the ascent is not adiabatic. Latent heat is at least partially removed from the air parcel where condensation takes place. It is lost by radiation to space and by turbulent mixing to the descending column which is being warmed. Actually such circulation pumps the latent heat from the condensation area to the surface of the area where the air descends. This was happening for over two months this summer during the heat wave in Russia.”
In your statements I don’t see where you explain that at least some energy in latent heat is expressed as work, not heat, on the surrounding air during an adiabatic cooling process. The temperature of the ascending air mass goes down without any increase in temperature to adjacent air masses, just energy expressed as work, but at the moment of condensation suddenly there has to be a heat transfer between the water vapor and the surrounding air? Every joule (or most) ends up as released heat right then and there at the moment of condensation? If so, I don’t think that I am ever going to understand this adiabatic atmospheric process.
It seems like you are treating “latent heat” as a special kind of energy that, during adiabatic atmospheric cooling, acts differently from all of the other energy in the air mass. The temperature of the water vapor goes down without any heat exchange between the water vapor and surrounging air mass, just an energy exchange in the form of work. But this work is not an adequate energy exchange to allow water to condense without a significant heat exchange? I don’t understand why the energy exchange needed to achieve condensation cannot also be expressed as work on the surrounding air instead of heat.
Anastassia Makarieva says:
January 26, 2011 at 10:19 am
Thank you for spending so much time sharing your work on the web, open to all scientist and layman alike to appreciate and discuss. It is, in my view, the future happening now. I looked at your web site on land use issues and the effects of deforestation etc and find it intresting and informative. Have you been in communication with Dr Pielke Sr and Jr, http://pielkeclimatesci.wordpress.com/
http://rogerpielkejr.blogspot.com/ and are you familiar with their work on land use issues and climate?
Steve:
“The temperature of the ascending air mass goes down without any increase in temperature to adjacent air masses,”
That’s not true: the adjacent air masses warm up. The ascending gas compresses the descending gas. The descending gas heats up.
“just energy expressed as work”
The work done by the expanding gas turns into heat and pressure energy in the adjacent gas.
“but at the moment of condensation suddenly there has to be a heat transfer between the water vapor and the surrounding air?”
Absolutely, at that very moment.
“Every joule (or most) ends up as released heat right then and there at the moment of condensation?”
Yes, every Joule.
“If so, I don’t think that I am ever going to understand this adiabatic atmospheric process.”
Indeed: if what you said was true, nothing would make sense. But I hope that what I say holds together.
“I don’t understand why the energy exchange needed to achieve condensation cannot also be expressed as work on the surrounding air instead of heat.”
If you start thinking it through again, I hope you won’t get to this question. There are several answers. To start again, you could try this simple explanation of convection:
http://homeclimateanalysis.blogspot.com/2010/04/convection.html
To see why some gas has the energy to compress other gas, and thus cause circulation, see the p-V diagram here:
http://homeclimateanalysis.blogspot.com/2010/04/work-by-convection.html
And after that you will be able to explain to me how a jet engine works.
Yours, Kevan
PS. I still have not been able to understand Anastassia’s recent explanation of the condensation-suction process. I am still trying.
Steve: I noticed another comment above from you. You say that when water condenses, some of the energy we put in to vaporize it can manifest itself as work. No, it can’t. That would violate the Second Law of Thermodynamics, which says that you cannot make a machine that is 100% efficient at converting heat into work. All it takes to vaporize water is heat, so if I can get work out of the act of condensation, I’d be able to start again by adding heat, and so build a cyclic machine that creates work.
Anastassia Makarieva says:
January 26, 2011 at 10:19 am
wayne
This is a very interesting question. Note also that it resonates with the comment of Dr. Judith Curry (the only reviewer so far of our work):
When vapor condenses, the air pressure is lowered. When moisture evaporates, air pressure rises. If we see a constant amount of cloud water but no rain, this means that this process is localized in the atmosphere on a small scale: condensation occurs in the region of ascent where the cloud resides, evaporation (of condensed droplets) occurs in the region of descent, where relative humidity is less than unity. This may result in the formation of regular patterns like cloud streets.
When is this possible? It should be possible when the droplets that are formed are sufficiently small (have high surface to volume ratio and low terminal velocity) and the circulation velocity is sufficiently low. Only in this case the droplets will have time to evaporate before reaching the surface. One can hypothesize that such a regime is unstable: if vertical velocity increases and/or droplets get larger, they are removed more quickly from the atmosphere across a larger area. The balance evaporation – condensation = 0 in the atmosphere is then broken in this area and it becomes a large scale area of low pressure.
But note also that persistent clouds without rain may also represent a non-stationary accumulation of liquid water in the atmosphere: in this case, the entire area with clouds gradually becomes the low pressure area despite there is no rainfall.
It would be great if climate scientists, many of whom do find time to do blogging and may even happen to read this thread, would join the discussion of condensation-induced dynamics. There is much to discuss here. It is beyond doubt that having got acquainted with the main propositions, people will be able to use them to explain many weather and climate patterns of which we may have little or no knowledge at all.
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You know, after asking that question of you I had some secondary doubts on my own question.
If there is any condensation, this effect of lowered pressure is going to happen regionally whether there may also be local effects or not. Stratus clouds may not even have a local effect. Cumulus always do due to the clumps. But you know, both local and regional is always happening at the same time, it is never really just local. When clouds form, like after a clear night, that IS the condensation even though the droplets are not large enough to fall in participation. Thinking of that it doesn’t seem to matter if 1 cm3 of water has condensed to form 21 raindrops or 10,000 tiny particles forming the mist from which clouds are made.
The condensation has already occurred.
And if you imagine yourself raised up high in the atmosphere and look down (as in a plane) you see condensation has occurred everywhere, maybe enough to cover an entire state or more. That suction would then be horizontally. You would see individual clouds dissipate but there would always be another to take it’s place and the over all effect would be lower pressure compared to the cloudless night a few hours before. Most importantly, that would seem to make the atmosphere as a whole pulse every diurnal period as the clouds of that type normally disappear every night, reform the next day. There is something I had never thought of in that way.
That made me reconsider my whole question, what exactly was I asking you. Sure didn’t want to infer something that would lead to a thought that wasn’t real, like: If it doesn’t fall to the ground as rain there is no effect for now I see it does. Seems if it does participate that just adds permanency to the effect. Kind of like a closure of a single event. When precipitating, the effect is no longer a one-time event but a continuous force laterally as long as the water is falling out.
I see it now. (if not, please clarify) Don’t you love it when you are able to think in an entirely different direction that just yesterday you thought was so perfectly logical and in reality was so wrong. That’s exactly why I follow science as a hobby!
Darn that auto spell checker, try precipitation, NOT participation.
Pounding my head– always re-read before hitting ‘submit’!
Kevan Hashemi says:
January 26, 2011 at 11:49 am
“Steve – The temperature of the ascending air mass goes down without any increase in temperature to adjacent air masses…Kevan That’s not true: the adjacent air masses warm up. The ascending gas compresses the descending gas. The descending gas heats up.”
So because the expanding, rising volume is doing work on adjacent air volumes (moving them by applying pressure), those adjacent volumes must be heating up from the pressure increase? Well, if the pressure is applied to a gas that remains in the same volume, yes I can see how the temperature must increase (ideal gas law). But if the pressure is applied and the gas simply moves (wind)? Are you saying that in adiabatic processes there really is a heat transfer, it’s just in the form of work that is immediately translated into heat?! That would be confusing. Why don’t they just call it a heat transfer?
“The work done by the expanding gas turns into heat and pressure energy in the adjacent gas….If you start thinking it through again, I hope you won’t get to this question. There are several answers. To start again, you could try this simple explanation of convection: http://homeclimateanalysis.blogspot.com/2010/04/convection.html”
Hmmm, the explanation at that link doesn’t really help me. In it you state,”In short, we assume that any heat the Volume loses or gains on the way up is negligible. The expansion of the Volume will be adiabatic. As a gas expands adiabatically, it cools down, even though it loses no heat.” That statement doesn’t make sense to me. It cools down but it loses no heat? It most certainly does lose heat or it would be the same temperature! What it doesn’t do is transfer heat – it transfers energy. I understand that at some point somewhere all that energy will end up as heat, but that could end up being far away in time and space. For example, a helium balloon that rises to great altitude and lands on a mountain will have some portion of it’s original internal energy stored as potential energy as long as the mass of that balloon remains on that mountain. Adiabatic expansion is completely new to me, so I have no idea how long it takes for the work of moving an air mass to be expressed as heat, and how far away from the expanding air mass this work will be expressed as heat.
Kevan Hashemi says:
January 26, 2011 at 11:56 am
“Steve: I noticed another comment above from you. You say that when water condenses, some of the energy we put in to vaporize it can manifest itself as work. No, it can’t. That would violate the Second Law of Thermodynamics, which says that you cannot make a machine that is 100% efficient at converting heat into work. All it takes to vaporize water is heat, so if I can get work out of the act of condensation, I’d be able to start again by adding heat, and so build a cyclic machine that creates work.”
As I said to Anastassia, it seems like you are treating latent heat as a special kind of energy. Which may be true, I’m just looking for the “how”! Adiabatically, the energy of the rising water vapor can be transferred to the surroundings as work, except for the energy of it’s latent heat?
Hmmm. You don’t have a problem getting heat out of condensation, but if I say “work” (same units, joules) suddenly I’ve invented a perpetual motion machine? I don’t expect a 100% return in the form of work, which is pretty clear since you quote me as claiming “some of the energy we put in to vaporize it can manifest itself as work.” According to you, 0% of the latent heat can be transferred as work (“No, it can’t.”). How is that?
I’m doing a poor job of answering your questions. I apologize. It may be that you and I are saying exactly the same thing, and our effort to do so without mathematics is making us go around in circles.
When I say “It gains no heat” I mean “No heat enters or leaves.”
You say, “It cools down but it loses no heat? It most certainly does lose heat or it would be the same temperature!” Well, the word “loss” in thermodynamics means something irreversible. In adiabatic expansion, internal heat is turned into work and work only. No heat is “lost”. When heat is converted into work, it is not “lost”. We can convert it back into heat any time we want. Only when heat flows out of our system do we say it is “lost”. Or at least that’s how I was taught to use the word.
But you have pointed out that these words are making my answers confusing and useless. So I will try harder.
Work can always be turned into heat, but heat cannot always be turned into work. Condensation results immediately in faster-moving molecules, which is heat. After that you can see about turning some of that heat into work, but you need some other components in the operation, such as a cold reservoir. Adiabatic compression, on the other hand, is in itself reversible. The gas will expand out again for you with no other component required.
If we say that condensation energy is converted directly into work, we are glossing over the fact that some other component is required to cooperate with the conversion of heat into work. In this case, what is that component?
I’m saying that air with moisture will be warmer as it rises, so it will expand and be less dense. Now it will rise above the dry air, like your balloon to the top of a mountain. That’s work. But we needed the dry air to make the conversion possible.
Do you agree with all that?
Retired physicists who might help:
Hal Lewis
Freeman Dyson
@ur momisugly Steve says:
January 26, 2011 at 2:53 pm
As I said to Anastassia, it seems like you are treating latent heat as a special kind of energy.
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What you might do is ask yourself: Is latent heat warm, in fact, does latent heat have a temperature at all? Doesn’t temperature rely on kinetic energy and therefore able to perform work. That might be where your logic hits problems. That is: Can latent heat express itself at all except at condensation time?
To me it’s potential energy and right there you can get in trouble if kinetic and potential are mixed in equations. There .are. two forms of energy. Not trying to correct you but those seem good questions to ask yourself.
Kevan Hashemi says:
January 26, 2011 at 4:36 pm
“You say, “It cools down but it loses no heat? It most certainly does lose heat or it would be the same temperature!” Well, the word “loss” in thermodynamics means something irreversible. In adiabatic expansion, internal heat is turned into work and work only. No heat is “lost”. When heat is converted into work, it is not “lost”. We can convert it back into heat any time we want. Only when heat flows out of our system do we say it is “lost”. Or at least that’s how I was taught to use the word.”
Ahhhh, I didn’t know about “loss” terminology. An energy transfer within two components of the system is not referred to as a “loss” by either component of the system – got it.
“Condensation results immediately in faster-moving molecules, which is heat.”
As state changes from gas to liquid to solid, the molecules have less kinetic energy, not more. What are the faster moving molecules – the air adjacent to the condensation?
“If we say that condensation energy is converted directly into work, we are glossing over the fact that some other component is required to cooperate with the conversion of heat into work. In this case, what is that component?”
Again, I’m not following how the latent heat transfer (as work) is any different from all of the other energy transfer in an adiabatic process.
I’m a visual thinker, and I imagine a hornets nest of air molecules pushing out as their mass rises. This pushing, ascending in altitude, is work and lowers the kinetic energy of every molecule in the air mass (i.e., the temperature of the air mass drops). Considering that the potential energy of the mass is increasing as it lifts itself through the atmosphere, it isn’t surprising that something has to give. Those molecules can’t do work, get an increase in potential energy, and keep their original kinetic energy! Within this air mass are water molecules that are losing their kinetic energy while still colliding with each other. Eventually the collisions lack the energy necessary to overcome the attractive power between the water molecules and they stick together – we have atmospheric condensation. (That’s simple condensation – a cloud nuclei, such as a bit of dust, is more likely to serve as the condensation surface.)
I understand that some of the temperature drop in the air mass will be due to heat exchange with adjacent, colder air masses. Cooling will not be 100% adiabatic! But what adiabatic cooling there is, to my understanding, is work, not heat transfer. That air mass climbed a mountain! I don’t see how it can be assumed that condensation results in a temperature increase to adjacent air masses that is equivalent to 100% of the energy of latent heat.
“I’m saying that air with moisture will be warmer as it rises, so it will expand and be less dense. Now it will rise above the dry air, like your balloon to the top of a mountain. That’s work. But we needed the dry air to make the conversion possible.”
I understand that. My confusion commenced when you stated that the transfer of latent heat at condensation would cause expansion of adjacent air that was 8 times the magnitude of the compression experienced when the water vapor condenses. I took that to mean that as warm air rises you suddenly get a burst of positive pressure when the dewpoint is reached. That seemed off (I expected a negative pressure), so I had to research this adiabatic cooling process.