On the First Principles of Heat Transfer: A Note from Alan Siddons
Posted by jennifer, April 13th, 2009 - under Opinion.
Tags: Climate & Climate Change
CLIMATE concerns look surreal when you examine modern assumptions (“the settled science”) on the basis of first principles like conductive, convective and radiative heat transfer, specific heat (where water is king) and density. To me, they paint a picture 180° contrary to the greenhouse theory consensus.
In my view, the earth’s surface can do nothing except heat the air molecules that surround it, and thus be cooled in turn (convective transfer follows, of course, but the surface must heat the air first). Yet the prevalent gossip is all about how air molecules heat the surface. That alone is surreal.
Listed below is mostly a collection of what various academic and engineering sources say about heat transfer, i.e., the conditions by which Body A is able to raise Body B’s temperature. While they don’t explicitly refute the IPCC’s notion of back-radiation, they DO insist that if A is radiating 100 watts per square meter at B and B is radiating 50 at A, heat transfer follows a one-way path from A to B. That is, B alone gets hotter and no “mutual heating” occurs. By contrast, observe what the IPCC depicts: mutual heating.
One-way heat transfer renders null and void the repeated assertion that A (the earth’s surface) gets hotter by thermally exciting B (IR-reactive gases). The unalterably more-to-less flow of thermal energy is the very essence of the second law of thermodynamics and it prohibits “mutual heating,” meaning that “radiative forcing” by IR-reactive gases is entirely a product of the imagination, a complete reversal of cause and effect.
Moreover, if earth’s surface temperature then shifts focus to heat RETENTION rather than heat GAIN, the FIRST thing to investigate is a substance called water, which covers 70% of our planet, is 800 times denser than sea-level air, and is FAMOUS for retaining heat! Solids are roughly 2000 times more dense than air and must also be considered.
In any case, hinging the whole affair on trace gases that intercept a small portion of the earth’s IR spectrum is so outlandish a premise I’m amazed that anyone can offer it with a straight face. Gases are the runt of the litter, the least able to hold onto heat and the first in line to confront the vacuum of space. Light passes through air at 99.97% of its optimum speed and yet we propose that a few of the gases it contains CONTROL the earth’s emission to space? As I say: surreal.
1. Professor M. Quinn Brewster, University of Illinois: Thermal Radiative Transfer and Properties
Like conduction, thermal energy is in harmony with the second law of thermodynamics such that, in the absence of work, thermal energy is radiated spontaneously from higher temperature to lower temperature matter.
http://www.amazon.com/Thermal-Radiative-Transfer-Properties-Brewster/dp/0471539821/ref=sr_1_1?ie=UTF8&s=books&qid=1216732467&sr=1-1
2. Heat transfer
Thermal energy flows from higher temperature to lower temperature. This process is called heat transfer.
There are three ways heat flows:
heat conduction,
convection, and
thermal radiation.
http://dev.cpo.com/home/Portals/2/Media/post_sale_content/FPS%203rd/PresentationSlides/U4/FPS3Chpt11Heat.ppt
3. Department of Physics and Astronomy, Vrije University, The Netherlands
Radiation
If the two bodies are in thermodynamic equilibrium no net heat transport takes place and the two bodies are at equal temperature
http://www.nat.vu.nl/envphysexp/REAL%20Experiments/Heat%20radiation/Radiation_Theory.html
4. Pyrotechnic Chemistry, by Kurt Kosanke, I. von Maltitz, B. J. Kosanke, Ron A. Hancox, B. Sturman, R. J. (2004)There are three mechanisms by which energy can be transferred from reacting to pre-reacting layers: conduction, convection and radiation. [...] In radiation, thermal energy is passed from hotter to cooler regions as long wavelength light (infrared).
http://www.amazon.ca/Pyrotechnic-Chemistry-B-J-Kosanke/dp/1889526150
5. Heat Transfer
Heat will always be transferred from higher temperature to lower temperature independent of the mode.
http://www.energymanagertraining.com/GuideBooks/1Ch2.pdf
6. Heat is transferred from high temperature areas to low temperature areas by conduction, convection and radiation.
http://irc.nrc-cnrc.gc.ca/pubs/bsi/88-2_e.html
7. Heat transfer is the net change in energy as a result of temperature differences. This energy is transferred in the direction of decreasing temperature until thermal equilibrium (equality of temperatures) is achieved. The basic mechanisms involved in this process include radiation (the transfer of energy in the form of electromagnetic waves) and conduction (the transfer of kinetic energy).
http://science.jrank.org/pages/3269/Heat-Transfer.html
8. Radiation heat transfer takes place when bodies with temperature gradients are separate in space. All bodies emit radiant heat continuously, and the intensity of the emission depends on the temperature and the nature of the surface. Heat transfer by radiation becomes increasingly important as the temperature of an object increases.
http://dspace.mit.edu/bitstream/handle/1721.1/37806/36119103.pdf?sequence=1
9. Thermal radiation is electromagnetic radiation that consists of quanta and waves, to be precise, photons and waves, like light’s propagation. Thus, the radiative heat transfer can take place through vacuum. The energy always moves from a warm system to a colder system.
http://biocab.org/Heat_Transfer.html
10. Radiation heat transfer is concerned with the exchange of thermal radiation energy between two or more bodies. Thermal radiation is defined as electromagnetic radiation in the wavelength range of 0.1 to 100 microns (which encompasses the visible light regime), and arises as a result of a temperature difference between 2 bodies.
http://www.efunda.com/formulae/heat_transfer/radiation/overview_rad.cfm
11. Temperature is a measure of the amount of energy possessed by the molecules of a substance. It is a relative measure of how hot or cold a substance is and can be used to predict the direction of heat transfer.
What is Heat Transfer? “Energy in transit due to temperature difference.”
http://nptel.iitm.ac.in/courses/Webcourse-contents/IISc-BANG/Heat%20and%20Mass%0Transfer/pdf/M1/Student_Slides_M1.pdf
12. Heat transfer is a study of the exchange of thermal energy through a body or between bodies which occurs when there is a temperature difference. When two bodies are at different temperatures, thermal energy transfers from the one with higher temperature to the one with lower temperature. Heat always transfers from hot to cold.
http://www.tufts.edu/as/tampl/en43/lecture_notes/ch1.html
13. As a result of heat transfer, hotter objects tend to become cooler and cooler objects become hotter, approaching thermal equilibrium.
…There are three modes of heat transfer: conduction, convection, and radiation. All heat transfer processes occur by one or more of these three modes. Infrared thermography is based on the measurement of radiative heat flow and is therefore most closely related to the radiation mode of heat transfer.
…Radiative heat transfer is unlike the other two modes in several respects:
1. It can take place across a vacuum.
2. It occurs by electromagnetic emission and absorption.
3. It occurs at the speed of light.
4. The energy transferred is proportional to the fourth power of the temperature difference between the objects.
http://spie.org/samples/TT75.pdf
14. Heat is thermal energy that is transferred between two bodies due to a difference in temperature. Heat transfer is the process of increasing the kinetic energy of a material’s particles from a material of high temperature to one of lower temperature. It can also be thought of in the opposite direction of cooling an object by slowing down its particles. Heat can be transferred to other materials through conduction, convection and/or radiation.
http://www.school-for-champions.com/science/heat_transfer.htm
15. HEAT TRANSFER: form of energy transfer due to temperature difference
higher temperature —-> lower temperature
stops when two mediums reach the same temperature
Dr. Saziye Balku
http://mechatronics.atilim.edu.tr/courses/mece310/ch8mechatronics.ppt
16. Heat Transfer, in physics, process by which energy in the form of heat is exchanged between bodies or parts of the same body at different temperatures. Heat is generally transferred by convection, radiation, or conduction.
http://encarta.msn.com/encyclopedia_761567280/heat_transfer.html
17. Winthrop University, South Carolina
Heating methods
Temperature difference: Energy always moves from higher temperature regions to lower temperature regions
Energy-form conversion: Transfer of heat by doing work
Heat flow
Three mechanisms for heat transfer due to a temperature difference
• Conduction
• Convection
• Radiation
Natural flow is always from higher temperature regions to cooler ones
http://bohr.winthrop.edu/faculty/lipinski/link_to_webpages/courses/tillery/ch04.ppt
18. Heat Transfer: Transmission of energy from one region to another as a result of a temperature difference between them. Energy transfers from high temperature region to low temperature region. (2nd law).
http://ocw.kfupm.edu.sa/user/DADME315/ME305notes.doc
19. Heat transfer in engineering consists of the transfer of enthalpy because of a temperature difference. Enthalpy is the name for heat energy, to distinguish it from other sorts, such as kinetic energy, pressure energy, useful work. There has to be a temperature difference, or no heat transfer occurs. (If we insist on moving enthalpy from a cold body to a hotter one, we will have to do extra work, as in the case of a refrigerator. This invariably involves some other process, such as mechanical work, and cooling by expansion of gases, but within the overall activity heat transfer always goes from the hotter to the cooler.) The temperature difference is called the driving force. Other things being equal, a greater temperature difference will give a greater rate of heat transfer.
http://en.wikibooks.org/wiki/Heat_Transfer/Introduction
20. Heat is energy or more precisely transfer of thermal energy. As energy, heat is measured in watts (W) whilst temperature is measured in degrees Celsius (°C) or Kelvin (K). The words “hot” and “cold” only make sense on a relative basis. Thermal energy travels from hot material to cold material. Hot material heats up cold material, and cold material cools down hot material. It is really that simple. When you feel heat, what you are sensing is a transfer of thermal energy from something that’s hot to something that is cold. http://www.g9toengineering.com/resources/heattransfer.htm
21. Modes of Heat Transfer
Heat transfer can be defined as the transmission of energy from one region to another as a result of temperature difference. Heat conduction is due to the property of matter which causes heat energy to flow through the matter. Heat convection is due to the property of moving matter (naturally or under force) to carry heat energy from higher temperature region to low temperature region. Heat radiation is due to the property of matter to emit and absorb different kinds of electro-magnetic radiation.
http://www.ironwoodelectronics.com/articles/article4.html
22. Fundamentals of Heat Transfer
1st and 2nd Laws of Thermodynamics
The 1st Law of Thermodynamics involves the conservation of energy. It states that – within a closed system where no other energy material can enter or leave – energy can neither be created nor destroyed. Although energy cannot be created or destroyed, it can be transferred to work other forms of energy.
Transferring heat energy is subject to the 2nd Law of Thermodynamics. The 2nd Law (again applying to a closed system) says that – for a spontaneous process – there is a net increase in entropy (i.e., a measure of the disorder that exists in a system).
Three alternate but equivalent ways to describe the 2nd Law are:
1. Heat flows spontaneously from a hot body to a cool one. (Example: A hot microprocessor or laser diode is cooled by flow of heat into heat sink or cold plate.)
2. It is impossible to convert heat completely into useful work. (Example: In a combustion engine, a certain heat component must always be exhausted without performing work.)
3. Every isolated system becomes disordered in time. (Example: In conduction when hot and cold bodies first contact each other, the system is somewhat ordered. Hotter molecules move faster than cooler molecules. But, once the entire system attains a uniform temperature, this order is lost.)
Expressed in mathematical terms, any of the above statements imply the other two.
The 1st and 2nd Laws of Thermodynamics govern the various modes of heat transfer: conduction, convection and radiation.
Radiation
In radiation, heat flows from a higher temperature body to a lower temperature body when the bodies are separated in space, even across a vacuum.
http://www.lytron.com/tools_technical/notes/heat_transfer_fundamentals.aspx
23. University of Nebraska, Physics Department
When an object is in equilibrium with its surroundings, it radiates and absorbs at the same rate. Its temperature will not change.
http://www.physics.unomaha.edu/sowell/phys1110/Lectures/Chap11/HeatTransfer.pdf
24. Valdosta State University, Georgia
Heat is a form of energy whose magnitude depends on the total energy of motion of the molecules within a substance or object.
Temperature is a measure of the average energy of motion of the molecules within a substance or object. It is an indicator of the tendency of a substance to transfer heat energy since heat energy always moves from higher temperature to lower temperature.
http://www.valdosta.edu/~pbaskin/phys1111ch12notes.doc
25. Students will understand that, on its own, heat travels only from higher temperature object/region to lower temperature object or region. Heat will continue to flow in this manner until the objects reach the same temperature.
Heat energy is the disorderly motion of molecules. Heat can be transferred through materials by the collisions of atoms or across space by radiation. If the material is fluid, currents will be set up in it that aid the transfer of heat. To change something’s speed, to bend or stretch things, to heat or cool them, to push things together or tear them apart all require transfers (and some transformations) of energy. Heat lost by hot object equals the heat gained by cold object.
http://www.grayson.k12.ky.us/Teachers/EOP%20-%208th%20Science%20Curriculum/MG%20Science%20Unifying%20Ideas.doc
26. Boston University, Physics Department
Heat transfer in general
We’ve looked at the three types of heat transfer. Conduction and convection rely on temperature differences; radiation does, too, but with radiation the absolute temperature is important.
http://physics.bu.edu/~duffy/py105/Heattransfer.html
27. National Oceanography Centre, University of Southampton UK
Heat flows from a region of high temperature to a region of low temperature. Heat transfer occurs by three main methods: Conduction and convection, which require matter (atoms/molecules) to provide a pathway for heat transfer, and radiation, which does not.
http://www.noc.soton.ac.uk/JRD/SCHOOL/002/mt002a_2.php
28. California Institute of Technology, Infrared Processing and Analysis Center
How Does Heat Travel?
Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass. The method used to transfer heat is usually the one that is the most efficient. If there is a temperature difference in a system, heat will always move from higher to lower temperatures.
…Objects emit radiation when high energy electrons in a higher atomic level fall down to lower energy levels. The energy lost is emitted as light or electromagnetic radiation. Energy that is absorbed by an atom causes its electrons to “jump” up to higher energy levels. All objects absorb and emit radiation.
When the absorption of energy balances the emission of energy, the temperature of an object stays constant. If the absorption of energy is greater than the emission of energy, the temperature of an object rises. If the absorption of energy is less than the emission of energy, the temperature of an object falls.
http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/transfer.html
IN summary, I can no longersee how we got it into our heads that the earth’s surface temperature is due to the IR-response of a few trace gases, a response which immediately ceases when the stimulus is turned off! Via conduction and convection, an atmosphere merely makes a heated surface cooler than it would be otherwise. In addition, a planet’s liquids or solids lose heat over a 2-dimensional area, whereas a gas radiates in 3 dimensions. This geometrical factor alone handicaps the ability of a gas to conserve thermal energy, irrespective of how relatively massless it is.
Alan Siddons
Holden, Massachusetts
Detail of UN/IPCC illustration http://www.ilovemycarbondioxide.com/FAQ.html
The latter is just a demonstration on how AGWers invent ciphers and constants which diverge from real data. If RW thinks the value of ε for CO2 is higher than 0.001, it’s time he demonstrates it by simple algorithms based on observation and experimentation.
OTOH, is there a single post debating the nature of IR? No, so RW’s comment about what I’m measuring during a clear sky night is pathetic.
Nasif – you, like Gordon, are babbling. Do you understand what radiative transfer is? You can investigate the effects of CO2 on radiative transfer in the atmosphere using MODTRAN. Your belief that “its thermal properties are not enough for causing any disturbance on Earth’s climate” springs purely from ignorance.
Given that you believe that the atmosphere doesn’t radiate downwards, where does the IR that you can measure from a clear sky at night come from?
“The sunspots and cosmic rays have a 79 percent correlation with our thermometer record since 1860. Meanwhile the CO2 correlation is a mere 22 percent. I love repeating that comparison! The Intergovernmental Panel on Climate Change already admitted in 2001 that it’s modeled “scenarios” cannot accurately predict cloud impacts on temperatures.”
http://climaterealists.com/index.php?id=3285
And only 1 in 3 people in the USA now believe in the AGW disaster, despite the billions of dollars invested by NGOs in hype. Perhaps the environmental-extremists will at last be recognized for what they are: leaches on the ass of progress.
Comment from: RW April 21st, 2009 at 8:11 pm
Nasif – you, like Gordon, are babbling. Do you understand what radiative transfer is? You can investigate the effects of CO2 on radiative transfer in the atmosphere using MODTRAN. Your belief that “its thermal properties are not enough for causing any disturbance on Earth’s climate” springs purely from ignorance.
Given that you believe that the atmosphere doesn’t radiate downwards, where does the IR that you can measure from a clear sky at night come from?
Ha-ha-ha… The unique person here who doesn’t know on heat transfer science is you.
Science is not a matter of beliefs, but of real observed from nature phenomena. Please, good sir, show scientifically that the CO2 has a TE higher than 0.001 at its current Pp and that EIEC has no effect on thermal radiation. Thanks…
Keep on babbling, Nasif.
jae, I checked the correlation between hadcrut temperatures and sunspot numbers since 1860. R-squared = 0.03. Between CO2 and temperature since 1958 (when the Mauna Loa record started), the correlation is very good – R-squared = 0.71. ‘climaterealists.com’ is lying to you, and sadly you are much, much too stupid to realise it.
By the way, for the seventh time: simply calculate the “trend” in global temperatures over the past seven years, using your favourite data set. Calculate the error on the trend, using an appropriate model of the noise characteristics of the data. Tell us what you find.
Er, RW, you appear much, much too stupid to even read my post. It refers also to COSMIC RAYS, not just sunspots. So show your work, and we will see who is stupid. Also, show your work on the CO2 correlation.
I already showed you a calculation of the trend. I’m too rusty on statistics to analyse the noise characterisics. If you are so adamant about this, you would show your results. Again, show your work, instead of just arm-waving.
You appear to be just another angry liberal “believer,” who is being buried by opposing science (the only thing you CO2/AGW freaks have left to support your story are compter models, which have been falsified in many ways). SSTs are down, atmospheric temperatures are down, glaciers are growing, sea-levels have stabilized, Artic and Antartic ice is growing, and the Polar Bears are happy. Too bad.
You are also facing a public, where only 1 of 3 individuals now think AGW is even a serious problem and where the majority has placed “climate change” at the very bottom of their list of environmental concerns. And even environmental concerns are now down at 8th place, IIRC. Your “side” has over-hyped the issue to the point that the average Joe is laughing at the whole “hypothesis.” Only the little kids care, and they can’t vote. I would say that you have now completely lost the argument, LOL. It will be pure suicide for many Congressmen to enact any legislation that actually decreases CO2 emissions significantly. The best they can do is “pretend” to be cutting carbon emissions, without increasing costs (IOW, armwaving).
It’s the Sun, stupid!
Comment from: RW April 22nd, 2009 at 8:41 am
Keep on babbling, Nasif.
Incapable of demonstrating that ε of CO2 is higher than 0.001 and that Bul doesn’t exist just because you don’t even know what those 101 Physics terms mean?
ε = Total Emittancy
Bul = Einstein Induced Emissivity Coefficient.
Well, now you can google them and come again with a copy and paste and “your” explanation. Please, come with a real scientific dialogue, not ideas from your imagination.
Nasif:
“Well, now you can google them and come again with a copy and paste and “your” explanation. Please, come with a real scientific dialogue, not ideas from your imagination.”
Don’t hold your breath. It seems to me that RW is just waving his/her arms in the wind. Notice that there is never an equation, graph, citation, link, or any data. Just words, and most of them are ad-homs. It is laughable! I would guess 17 years old, based on the language and lack of substance.
Jae… Indeed, lol!
Many scientists have found errors on calculations of the proponents of the idea that carbon dioxide is the cause of global warming. One of the more grave errors resides on believing in a downwelling photon stream which, as AGW proponents say, warms the surface. However, when we analyze the issue of downwelling radiation emitted by the atmosphere, we find that such heating up of the surface by greenhouse gases doesn’t exist.
The problem with AGW idea is that AGWers think that the Earth is isolated and that the heat engine only works on the surface. They don’t take into account that heat incoming from the Sun is transferred by conduction from the surface to the subsurface layers, where it is stored until the sun declines and the incidence of direct solar radiation disappears, this is, during nighttime.
During nighttime, the heat stored in the subsurface is transferred by conduction towards the surface, which is colder than the materials not exposed at the surface of the ground. The heat transferred from the subsurface layers to the surface is then taken by the air through convection and it warms up. The upwelling photon stream affects the directionality of the radiation emitted by the atmosphere driving it upwards, i.e. towards the upper atmospheric layers and, from there, towards the deep space. This process is well described by the next formula:
Fsh = -ρ (Cp) (Ch) (v (z)) [T (z) – T (0)]
Where F is for Sensible Heat Flux, ρ is the density of air, Cp is specific heat capacity of air at constant pressure, Ch is the heat transfer coefficient (it’s 0.0013), v (z) is the horizontal wind speed across z, T (z) is the temperature of the surface, and T (0) is the temperature of air immediately above the surface.
The “minus” sign means that heat is absorbed by the air. For example, the sensible heat flux for a region where the temperature of the surface is 300.15 K, the temperature of air is 293.15 K and the horizontal wind speed is 40 m/s is 0.439 kJs/m^2.
I want to make clear that this formula applies for oceans and land, although on land it’s preferable to use Cd instead Ch. Anyway, Cd ≈ Ch ≈ 0.0013.
The sensible heat flux is, day and night, directed upwards, that is, from the surface to the atmosphere (Peixoto & Oort. 1992. Page 233).
Except for some small regions on Earth where the temperature of air is higher than the temperature of the surface, the heat is always transferred from the surface to the air because of the next effect which is enforced during daytime by solar photon stream:
Iav = h 1/4π [(Aul / Bul) / (gl *Blu / gu *Bul) e^hν/kT – 1 (Modest. Second Edition: Pp. 288-310).
And these are only the tip of the iceberg.
“The problem with AGW idea is that AGWers think that the Earth is isolated and that the heat engine only works on the surface… babble babble babble”
The problem with you, Nasif, is that you haven’t got the faintest idea about any science relevant to climate from the last 150 years.
jae:
“show your work on the CO2 correlation.”
1. Get data.
2. plot CO2 vs temperature
3. fit line, do statistics
“I’m too rusty on statistics to analyse the noise characterisics”
Finally, the admission of ignorance. If you were not ignorant and could do basic calculations, you’d find that for global temperatures over the last seven years, the error on the “trend” is larger than the magnitude. Therefore, there is no statistically significant trend.
Hahaha… You have no arguments against science. What kind of science is this?
RW “scientific” argument “The problem with you, Nasif, is that you haven’t got the faintest idea about any science relevant to climate from the last 150 years.” Get lost.
RW “…the error on the “trend” is larger than the magnitude. Therefore, there is no statistically significant trend”.
UAH said something similar. They said the average decadal trend since 1998 has been 0.04 C, an insignificant warming. Now we are in agreement.
RW “Nasif – you, like Gordon, are babbling. Do you understand what radiative transfer is?”
One thing is clear, you have no idea what it is, or anything else about physics.
Hi Gordon,
having a statistically non relevant trend over 10 years is not the same as having it over 30 years! Moreover, the satellite data are noisier than GISS or HADCRUT, so in a sense this is not too surprising.
Actually the Antarctic sea ice is also a highly fluctuating quantity, because it is not bounded by land. It’s quite difficult then to make some reliable trend even over a few decades. The Arctic, being surrounded, is much more deterministic.
Concerning the greenhouse effect, I can honestly tell you it’s not violating any principle of thermodynamics. I think actually nobody in its right mind (including the “skeptic” researchers) thinks the physical ground of the GE is not coherent with physics.
Comment from: Flanagan April 24th, 2009 at 4:17 pm:
Concerning the greenhouse effect, I can honestly tell you it’s not violating any principle of thermodynamics. I think actually nobody in its right mind (including the “skeptic” researchers) thinks the physical ground of the GE is not coherent with physics.
Perhaps the warming effect (WE, not GE) of the atmosphere is correct in the sense that even during nighttime the surface warms the atmosphere; however, AGW idea is violating principles of thermodynamics. Just consider the mythical downwelling radiation during nighttime, which is offered by AGWers without considering convection and conduction. I know what you could say because the tale is the same everywhere, so I ask you to consider the sensible heat flux, the conduction of heat from subsurface materials to the surface during nighttime and the photon streams.
Flanagan “having a statistically non relevant trend over 10 years is not the same as having it over 30 years…”
With all due respect, my interest is science, not statistics and noise. The UAH satellite data shows clearly that the average warming has not only leveled off, it is diminishing. Roy Spencer just noted on his site that March 2009 is the coolest March in the NH and the Tropics in the past 3 years. The temperatures are supposed to be going the other way, as CO2 density increases.
“Concerning the greenhouse effect, I can honestly tell you it’s not violating any principle of thermodynamics”.
I did not say the GHE was violating the laws of thermodynamics, I said the AGW theory that back-radiation is warming the surface to a higher temperature than it is heated by solar radiation is violating the 2nd Law. I don’t think the GHE is a viable theory at all. The notion that GHG’s accounting for about 1% of the atmosphere can act in some way to trap heat or back radiate an amount equivalent to solar radiation, as NASA maintains, is ludicrous.
I can buy into the theory that clouds are a significant absorber of heat because they contain enough water (not vapour) to contain and radiate heat. How they work in the overall scheme of things is not clear. My position is that no one knows to a high enough degree why the atmosphere is at an average temperature of +15 C.
Nasif “They don’t take into account that heat incoming from the Sun is transferred by conduction from the surface to the subsurface layers, where it is stored until the sun declines and the incidence of direct solar radiation disappears, this is, during nighttime”.
Nasif…what do you think of Stephen Wilde’s theory that N2 and O2 pick up surface heat through conduction?
http://climaterealists.com/index.php?id=1487&linkbox=true
That would make a lot more sense than GHG activity since N2 and O2 make up 97% of the atmosphere.
RW “Simply calculate the “trend” in global temperatures over the past seven years, using your favourite data set….”
Why? It’s been done by one of the premier data set providers in the world, Roy Spencer. Why do we need your crap? Spencer’s satellites cover 95% of the atmosphere whereas Hadcrut, Gisstemp, etc., use data sets with a far lower and more unreliable coverage.
““It was arguably hotter in the ’30’s than now” Not even remotely. ”
Rubbish!! The hottest year in US history is 1934 and several of their hottest years is in that era. I know, I know, you’ll whine that’s not global. I keep trying to get you to look at the temperature contour maps on the UAH site so you can see that globality is a myth. There is no global temperature, there is only a statistical average that involves as much cooling as warming. The hottest 1934 year in the US is as viable as any other part of the globe.
Why was 1934 the hottest year? Was it caused by CO2? No. Why was the Arctic as warm in the 1920′s as now? CO2? No. You AGW freaks don’t want to answer such inconvenient questions. You throw around statistics as if math makes a difference. Just remember Mark Twain’s observation, “There are three kinds of lies: lies, damned lies, and statistics”.
RW “Gordon, you’re babbling, again. You obviously have no idea what a black body is. The Sun would be a reasonable approximation to a black body whatever its temperature was. The atmosphere does not behave like a black body, and no-one thinks that it does”.
Are you a troll, or just another mathematician? I gave you the Planck formula that defines a blackbody and you tell me I have no idea what one is. Don’t talk to me, go talk to Planck. He’s dead, but he’d make infinitely more sense than you. The blackbody is based on his formula for radiative probability distribution.
If the atmosphere does not behave like a blackbody, then why are climate scientists applying Boltzmann, Planck and Kircheoff to it? Those formulae apply only to blackbody radiation.
Nick Stokes “Gordon, They don’t absorb IR, but they do warm, and any warm body gives off IR. RW is right, this is just babble. Have you not heard of Kirchhoff’s law, that for each frequency band, the emissivity and absorptivity are the same? If N2 and O2 aren’t absorbing, they aren’t emitting”.
Nick…you’re talking like a mathematician. Who said N2 and O2 are not absorbing? They are absorbing energy from the surface through conduction and a process that carries the warmer air aloft. Radiation is only one form of heat transfer. The satellites measure tropospheric temperatures from O2. How does it get it’s heat? Please don’t tell me it gets it from GHG’s, which account for 1% of the atmosphere.
What makes more sense: that gases accounting for 97% of the atmosphere are involved in heating it, or that gases accounting for 1%? I know where I’m putting my money.
When I was taught weather theory in high school, I was taught that warm ‘air’ rises. No one mentioned warm GHG’s rising. I understand the basic theory of precipitation, that water vapour rises, condenses, and forms rain or snow. However, WV is a part of air, not a separate entity. It rises with the N2 and O2 when heated by the surface by conduction in the boundary layer.
I don’t know why you consider that babble.
SJT “Eli Rabett organises a rebuttal to G&T…”
Talk about babbling. Just Rabett’s coverage of Clausius and the 2nd Law reveals neither he nor any of his contributors have the slightest idea what the 2nd Law means. Listing Peirrehumbert, a geophysicist, as an expert source, is pure humour.
Rabett just doesn’t get the obvious. Energy supplied by the surface to heat the atmosphere is a LOSS OF ENERGY at the surface. Rabett is describing a positive feedback where an essential source of amplification is missing. That’s why G&T refered to the process as a perpetual motion machine: the process is creating energy that is not there.
Roy Spencer has addressed that in his latest blog, but I have to respectively disagree with Roy. he has pointed out that climate scientists have re-defined positive feedback and it’s actually a negative feedback. At least Roy admits that. People like Rabbett have no idea what is involved in feedback.
The loss of energy at the surface has to be made up before the surface can heat beyond the temperture it was heated by solar radiation. You cannot add solar radiation a second time to a quantity that represents a loss of surface heat. The solar radiation was used to heat the surface and part of that heat was used to heat the atmospheric GHG’s. The heat represented by the GHG’s is not an independent source that can be added to solar radiation. If anything, the back-radiation is only making up the losses that created it.
Rabbett is obviously confusing the heat contained in the water of clouds with atmospheric WV and CO2. Besides that, the GHG’s are far too rare to make a difference. Also, they are warmed by a different frequency spectrum than they emit at.
I certainly hope Rabbett doesn’t consider submitting that nonsense to a physics journal. I can see it being accepted by the Journal of Climate, but not a serious physics journal.
Nick Stokes “And RW is right that the Sun is a BB emitter because of its optical thickness. It’s Kirchhoff’s Law again; if there is enough gas to absorb all the incident radiation at a given frequency, then it will emit as a black body – that’s where the “black” comes in. The only deviation for the Sun is that the temperature varies a bit through the region from which the radiation is emitted”.
Nick…I have tried being polite with you because you seem to be a decent guy. RW is a nincompoop (a silly, foolish, or stupid person) and you’re beginning to insult my intelligence. Although I place no value in ego, I wont sit around and be talked down to by a mathematician who is seriously confused about physics. I have watched you arguing feedback with Jan Pompe and I know you have no idea what it is. Now you’re lecturing me on blackbody radiation.
The Sun approximates a blackbody radiator because it emits a broad specturm of energy which satisfies Planck’s function. The radiated energy is due to vibrating atoms, not optical depth. Optical depth may be a function of the gas and temperature but it is not the source of the broad-range of radiative emission frequencies.
Comment from: Gordon Robertson April 25th, 2009 at 5:19 pm
Nasif “They don’t take into account that heat incoming from the Sun is transferred by conduction from the surface to the subsurface layers, where it is stored until the sun declines and the incidence of direct solar radiation disappears, this is, during nighttime”.
Nasif…what do you think of Stephen Wilde’s theory that N2 and O2 pick up surface heat through conduction?
http://climaterealists.com/index.php?id=1487&linkbox=true
That would make a lot more sense than GHG activity since N2 and O2 make up 97% of the atmosphere.
I agree with Stephen’s article, except for the name he gives to the process, but my disagreement on how he’s labeled the effect has nothing to do with science.
The next statement has lifted some doubts about Stephen’s thesis:
“There is always a net loss of heat on a daily basis from atmosphere to space regardless of any atmospheric greenhouse effect. ”
This is true because every region of Earth alternates day and night every day; for example, when in meridian W 90 is noontime, it is midnight in meridian E 90. However, one cannot say that the sensible heat flux towards the outer space during daytime in any meridian is higher than during nighttime because the solar photon stream on the illuminated side induces the photon emission towards the surface. Nevertheless, the amount of photons induced towards the surface from the atmosphere is sensibly small and it is far lesser than the emission induced by the surface photon stream from the atmosphere towards the outer space on the dark side of the Earth. Nevertheless, the net loss of heat is given regardless any atmospheric warming effect. Earth is not a thermo.
As for conduction as the main heat transfer mode from the surface to the atmosphere, the assertion is supported by observation and experimentation. The radiation meassured in the atmophere during nighttime is not “downwelling” radiation, but upwelling radiation from the surface (land and oceans) which is captured by atmospheric gases by convection. I have made many meassurements with radiometers and I have never meassured any “downwelling” radiation.
The real process happens when the surface transfers energy towards the atmosphere by conduction, i.e. the surface is a conductive donator of energy, while the atmosphere takes the energy by convection, i.e. the atmosphere is convective acceptor and conveyor of energy. The effect is more evident when the ground is saturated, i.e. when it doesn’t absorb any more water.
Regarding the assertion on N2 and O2 like the main conductive “acceptors” of photons in the atmosphere, it’s enough with seeing the thermal conductivity coefficients (k) of N2 and O2, which is 0.02583 W/m K for N2, and 0.02658 W/m K for oxygen. In comparison, carbon dioxide k is 0.017 W/m K, which is lower than k of N2 and O2. On the other hand, k of water is 0.6 W/m K. So, it’s clear that water thermal conductivity is 9x higher than k of CO2.
However, the prevalence of water is more evident if we consider the free thermal convective coefficient (h obtained from |∆Q|/|A (∆T) (∆t)|) because h for water is 20 to 100 W/m^2 K at 300 K, while h for the dry mixture of air, under the same conditions, is 0.5 to 2.5 W/m^2 K. Thus, the convective maximum potential of water overwhelms by 40 times the dry air convective maximum potential, yet if one forces air convection with a fan (up to 30 W/m^2 K).
Concluding, I agree with Stephen on his assertion that the warming effect of the atmosphere is due to water in its three phases, not to air.
Well concerning the temperature trend: statistics is science, I’m quite sure of that. Here is a paper that might interest some of you. It shows how a single realization of a globally coupled model looks like:
http://www.cdc.noaa.gov/csi/images/GRL2009_ClimateWarming.pdf
The model was created in 2003. The paper shows, in order to close that kind of discussions, that models do predict long periods of seemingly flat temperatures, even decreasing temperatures, which in any case does not prevent the long-term trend to be positive. This particular example for example predicts a flat temperature over the 2000-2010 period. It even predicts a 20-year long flat temperature period during the 21st century – but nevertheless the trend is there.
Just to say it doesn’t make sense to take a few years, or even a decade, to discuss the evolution over a century.
Comment from: Flanagan April 27th, 2009 at 10:39 pm
Just to say it doesn’t make sense to take a few years, or even a decade, to discuss the evolution over a century.
And it doesn’t make sense to take 34 years for discussing the evolution of climate on Earth over a millenia.
Where is this 34 years coming from? I can already count 150 years of direct temperature measurements. And if you thrust temperature reconstructions, yan can go back to several centuries before now…
Comment from: Flanagan April 28th, 2009 at 5:11 pm
Where is this 34 years coming from? I can already count 150 years of direct temperature measurements. And if you thrust temperature reconstructions, yan can go back to several centuries before now…
That’s a personal question. I trust science and scientific reconstructions, so I can go back to million years back. Don’t you?
The greenhouse theory as proposed by Arhenius 1896 was never proven theoretically and practically and was based on an incorrect understanding of how a actual greehouse worked, but is assumed correct by many contemporary climatologists, it remains an unverified hypothesis so criticism is valid. There are also many papers on MODERN greenhouse theory, particulary in easter europe, in this modern understanding the greenhouse effect is driven by atmospheric mass, convection with greenhouse gasses only playing a small role (around 10%) above the lower troposphere. This theory is based on know laws of physics and observation, and most important makes sense, it doesnt break the laws of thermodynamics. The IPCC greenhouse effect is a perpetuem mobile of the second kind, and proven wrong by observation i.e. no observable hot spot and increasing outgoing longwave energy.
Black ball equations to work out the temperature of the earth without a atmosphere are not appropraite for the earth and ignore the moderating effect of the sea, which effectively controls the throughput of energy and the overall energy balance.
Do not attack people who question current scientific concesus (or dogma even), this kind of open thought is encouraged in other fields of science as it enables the advancemet of science, even if proven wrong, it helps support the alternative hypothesis. Remember, concesus is the last hiding place of bad sciece. If we always assumed current scientific understanding is right, we would still think tectonic drift is impossible.
Hot objects are not “spatially aware” any more than a block of wood “knows” that it is supposed to move in the direction of greatest force when two opposing forces are applied
to the block of wood!
Heat Radiation is accomplished by propagating EM fields.
EM fields are Force fields, in fact the Electromagnetic Force is one of the four fundamental forces.
EM fields carry “Photon Energy”.
Photons have zero Mass.
Is it so surprising that opposing EM fields and corresponding Forces will only move the zero mass Photon energy in the direction of the larger force?
The “block of wood” analogy should be apparent except that, unlike a “block of wood”, a Photon has zero mass.
Hot objects produce a larger EM field (and force) than Cold objects so heat energy can only flow from Hot to Cold!….The direction of the larger force!
This is really what 2nd Law of Thermodynamics is fundamentally saying!
“Second Law of Thermodynamics: It is not possible for heat to flow from a colder body to a warmer body without any work having been done to accomplish this flow. Energy will not
flow spontaneously from a low temperature object to a higher temperature object.”
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html#c3
When you AGW’ers say that Heat can flow from Cold to Hot it’s like saying the “block of wood” will move in the direction of the weaker force!
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Electromagnetic Fields are Vector fields.
When opposing EM vector fields are summed, there can only be ONE resultant EM Vector Field.
The Magnitude will be (Larger Field – Smaller Field) and will always be in the direction of the Larger field.
——————
Measuring Back-Radiation:
1. Direct measurements require the detector to be cooled below the atmospheric temp.
2. Indirect measurements measure the loss of energy (eg.Thermistor) to the cooler atmosphere.
3. Solar Ovens (parabolic mirrors will concentrate solar and IR energy at a focal point) and should work at night if back radiation actually reached the Earth.
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