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Comments 128551 to 128600:

128551. Patrick 027 at 14:45 PM on 15 April 2009
        Why is Antarctic sea ice increasing?
        Very informative, Thanks! From the little bit I've pieced together, I would have thought that the ozone hole - via SAM - would also tend to make the storm tracks shift poleward ?? - but maybe only in winter ????
128552. Patrick 027 at 12:42 PM on 15 April 2009
        It's the sun
        It will help you a lot in understanding radiative energy transfer if you can visualize how things would look at different wavelengths.
128553. Patrick 027 at 12:42 PM on 15 April 2009
        It's the sun
        "LW glow of the atmosphere generally appears hotter near the horizon than straight upward when there are not clouds that are too close to the ground or the water vapor concentration is not too high, etc." Of course, this varies by wavelength. I think it would make the greatest difference generally between about 8 and 12 microns. It might not make any appreciable difference near 15 microns, or longer than ~ 20 microns, or around 6 to 7 microns, etc. - or at such wavelengths where the atmosphere is sufficiently opaque, a thin nighttime inversion would actually make the atmosphere glow brighter closer to the zenith.
128554. HealthySkeptic at 09:59 AM on 15 April 2009
        Did global warming cause Hurricane Katrina?
        Chris, Again you seem to be implying that Prof. Gray's scientific opinion is somehow diminished, simply by having it reported in a media article rather than a scientific journal. If that is indeed the case, then you are more naiive than I thought you were. I think you are just clutching at straws here in trying to explain away the fact that a respected atmospheric scientist simply does not agree with your apparently 'inerrant' scientific paradigm. This trend is growing stronger and stronger in scientific circles... get over it and move on. It's how science works.
128555. Patrick 027 at 09:52 AM on 15 April 2009
        It's the sun
        "It seems that your posts are really about trying to dis-prove the 2nd Law of Thermodynamics and the Law of Conservation of Energy." That's because you're confused. "I don't understand your logic." Then you probably won't understand any of this: ----- In the following and previously I have mentioned that radiant intensity is conserved along any path radiation propagates if there is no emission, absorption, scattering, or partial reflection along that path (perfect reflection without scattering - as with a perfect mirror surface - will conserve intensity, even if the mirror is curved on a macroscopic scale). There is an exception: when radiation propagates through materials, in the absence of reflection, scattering, absorption, or emission, the intensity is proportional to the square of the real component of the index of refraction. This can be proven with geometric optics. It is related to 'total internal reflection'. Assuming the second law of thermodynamics remains true, then it must be concluded that blackbody radiation intensity is also proportional to the square of the real component of the index of refraction of the medium in which the blackbody radiation is being considered. The index of refraction is of little importance to the macroscopic patterns of radiation transfer in the atmosphere when optical properties are stated as bulk properties of macroscopic parcels of air (obviously those properties arise in part from microscopic processes which may require taken into account the index of refraction - for example, in the evaluation of how cloud droplets scatter radiation). ----- "These objects [trees,buildings] have thermal radiation and will reduce the cooling effects." How could they? By your own logic, if the object being cooled just happened to be a slight bit warmer than those trees and buildings, the radiation from the trees and buildings must never ever ever reach the object that one is trying to cool. Isn't that a strange notion? ---- "If there really was a "refigerator in the sky"...The water at the focal point would NOT freeze, it would HEAT UP.....even MORE than it does with Solar Energy!" Are there refrigerators on airplanes? If an airplane with a refrigerator flew over, I don't think it's having a refrigerator would have much effect on radiation reaching the ground. There are heat engines in the atmosphere powered ultimately by the sun (via convection allowed by the distribution of solar heating and radiant cooling). If this were not true, there would not be much wind. Air accelerates when flowing from higher to lower pressure (horizontally - otherwise, gravity + pressure gradients affect acceleration), thus gaining kinetic energy - this process tends to be associated with warmer air rising and cooler air sinking - the warmer air's temperature drops more than the cooler air's temperature rises, so the average temperature drops, because heat energy has been converted to kinetic energy. Much kinetic energy is converted back to thermal energy by frictional dissipation, but at lower entropy so that it cannot be recycled very much into the atmospheric heat engine. But sometimes the reverse of the heat engine process does happen, and kinetic energy does work on the air, lifting cooler air up (and lowering its temperature) while warmer air sinks (and increases its temperature). This can be observed, most obviously in the global-scale overturning of the mesosphere, wherein the upper mesosphere over the summer polar region is refrigerated. All of which can adjust regional radiation patterns, but none of which is THE cause of backradiation from the atmosphere (the mesosphere in particular has very little effect on the radiant fluxes). The atmosphere radiates downward and upward because it is not perfectly transparent (emissivity is not 0) and it is not at absolute zero temperature - this would be qualitatively true even if there were no motions in the atmosphere. "Further, "a refigerator in the sky" still would need energy to operate and it would have to come from the SUN!" Yes, the vast majority of the energy does ultimately come from the sun. "All the energy radiated by the Earth and the atmosphere could still NEVER EXCEED the 342 w/m^2 Solar Energy!"" Then why is the Earth not frozen over? (think - how cold would the surface have to get to only radiate at the 168 W/m2 that it recieves directly from the sun?) Set aside the second law of thermodynamics for a moment; having radiant fluxes greater than 342 W/m2 does not violate the conservation of energy. If I started throwing balls to you, and you didn't start throwing them back until you had ten of them, mass is still conserved; you would just happen to have a reservoir of ten balls. Suppose three people, you, I and a third person (let's say Bob) have buckets of balls. Suppose every minute, I throw 10 balls into your bucket and 5 balls into Bob's bucket, and every minute, you throw 2 balls into the lake and Bob throws 13 balls into the lake. And every minute, you throw 20 balls into Bob's bucket and Bob throws 12 balls into your bucket. By how many does the number of balls in your bucket and Bob's bucket change in each minute? Answer: Zero. And that's true without needing either you or Bob to manufacture your own balls or destroy them. So you can throw 20 balls to Bob for every 10 balls I throw to you because Bob is throwing you 12 balls. How can Bob afford to throw you 12 balls when I only throw him 5? Because you are throwing him 20 balls. And in the back-and-forth of balls between you and Bob, you are not creating or destroying balls; nor are you constantly increasing your buckets' quantities of balls. -- "Any energy that would be absorbed by the Sun from the Earth would CAUSE the SUN TO INCREASE IN TEMPERATURE!"..."A very, very obvious violation of the Law of Conservation of Energy!"..."Further, if the Sun actually increased in temperature, the Earth would receive this energy and increase in temperature."..."The Earth would radiate MORE energy to the Sun, causing the Sun to increase in temperature, causing the Earth to heat up even more....etc."..."What you describes is a Perpetual Motion machine in a positive feed-back loop that will increase it's temperature to INFINITY!"..."An IMPOSSIBILITY." Have you forgotten what the law of conservation of energy is? It is actually separate from the second law of thermodynamics; the later could be violated without violated the first (though nothing I've suggested as being physically possible violates either one). The conservation of energy implies that if an object absorbs more energy than it emits, it will have a net energy gain. If it absorbs less than it emits, it will have a net energy loss. If it absorbs and emits the same amount, it neither gains nor loses energy (or gains and loses the same amount so that their is no net change in the total energy it has). In the buckets of balls illustration above, you and bob throwing balls to each other from those that you have does not create or destroy balls; you throw balls that you TAKE from your bucket. Likewise, if you picked up a ball from your bucket and bounced it off a wall and it landed in your bucket, your bucket will have only the same number of balls that it initially had. If you and I each had 100 dollars, and then I gave you ten dollars, and then you gave me ten dollars, and we repeated this all day long, by your logic, we'd be millionaires soon. But this is not what would happen; together we'd have the same total amount of money as when we started, because each time you get money from me, your gain is MY LOSS, and vice versa. If you have a heating element (the range on top of your oven - if you have an electric oven) that is glowing red (because it is hot), and you have a mirror, can you not see the heating element in the mirror if you angle the mirror just so? Do you not think that the heating element could 'see' itself in the mirror if you held the mirror up to it? ***And remember, it must be able to absorb the same photons that it could emit, or else you actually could construct a perpetual motion machine (as is the case if radiant intensity were not conserved in the absence of partial reflection, scattering, emission, and absorption). Therefore it could absorb photons from another object at the same temperature, or at any temperature sufficient to emit at least a few photons at the same wavelengths that the heating element is emitting.*** Mutual exchange of radiant energy could not be used to drive a perpetual motion machine by breaking the conservation of energy because it does not break that law. The radiant energy exchange between two objects at different temperatures cannot be used to construct a perpetual motion machine if the net heat flow is from hot to cold, and with radiant energy transfers behaving as I have described them, there is no way to get the net flow of heat to go from cold to hot spontaneously (without work input), so there is no way to run a perpetual motion machine that way. -- "A refigerator transfers heat from objects inside to the Radiating Tubes at the back. The Radiating Tubes are warmer than the surrounding air....so heat is transfered to the air. The atmosphere is, obviously, cooler than the Earth.....therefore...there IS NO REFIGERATOR IN THE SKY!"" That is like saying that your house is cooler than the outside air; therefore there is no refrigerator in your house. "There is no evidence, at all, of there being a "refigerator in the sky"."..."There is however, conclusive evidence that a "refigerator in the sky" does NOT EXIST!" On the contrary, it is known that there is such a refrigerator, most obviously in the summer high-latitude mesosphere; but that has little to do with the basic principles of the greenhouse effect, back radiation from the atmosphere, or how a solar oven works either as a oven or as a cooler. ------ "All radiation from the Spherical Earth and Spherical Atmosphere will occur normal to the surface."..."The Back Radiation from the Atmosphere will flow directly along lines to the center of the Earth."... What ever gave you that impression? Radiation emitted thermally is not a laser beam. It is not coherent (the phases of individual photons are not aligned). It is not all parallel rays. If all radiation from the surface were precisely vertical, then how could it be that radiation from trees and buildings could affect the radiative cooling of any object on the surface? If you take a flat surface and heat it up so it glows red hot, you can generally see that red glow even if you are looking at the surface obliquely; if the optical properties do not vary over angle - for example, if the surface is a perfect blackbody - then the intensity of the radiation will be the same as viewed in all directions that enter the surface from the front, whether head on or slantwise; the radiant flux per unit area normal to the direction of view will be proportional to the cosine of the angle from perpendicular to the surface, as is the projected area of that surface onto the plane perpendicular to the direction being considered. --- More precisely, that is the case for the radiant flux per unit area normal to the direction that comes from a particular unit area of the radiating surface, at a given distance from that unit surface. If the radiating surface covers a large area in comparison to the distance from the surface where the measurement is made, if one moves the measuring location around in any direction, the radiant fluxe per unit area in each direction from the measurement point will stay the same (assuming intervening space is transparent), because if one gets farther away from the emitting surface, the radiant flux per unit area from each unit area of the emitting surface decreases but the amount of emitting surface contained within a given range of directions (a solid angle) increases so that the total radiant flux per unit area for any direction stays the same; if one slides around parallel to the emitting surface, any particular area of emitting surface in some direction will shift to a different direction but will be replaced as another equal area of emitting surface comes into view along the same direction. Furthermore, if one is close enough to the emitting surface relative to the emitting surface's expanse, one will find same radiant flux per unit area for any direction that approaches the surface from any angle, because the more slanted angles will have a view of a greater amount of emitting surface per unit solid angle, in inverse proportion to the decrease in radiant flux per unit area from each unit area of emitting surface with more slanted angles, due to both the unit surfaces being farther away and to the cosine of the angle for the projection of a unit area at a given distance. --- A much simpler way to explain this is that contributions to total radiant flux per unit area of a surface with some set orientation come from each direction with nonzero radiant intensity, in proportion to the intensity, the cosing of the angle of the direction from the normal of the surface, and the solid angle that the intensity covers. A solid angle is analogous to a field of view. As seen from the center of a sphere with a radius of 1, the entire sphere encompasses a solid angle of 4*pi; a hemisphere (such a the sky as seen from a flat plain with no hills, buildings, etc., interfering) has a solid angle of 2*pi; the solid angle covered by any object is proportional to the portion of the surface area of that sphere covered by the object's projection onto that sphere (by rays emanating or going toward the sphere's center). An object will appear bigger when it is closer because it makes a larger projection onto such a sphere; it fills a larger solid angle - hence, if it is emitting radiation, it will make a larger contribution to radiant flux per unit area when it is closer, while it's radiant intensity (flux per unit solid angle) remains constant if the space between is transparent. This is closely related to inverse square laws. ..."The max effect will occur if the Solar Oven is pointed at the Zenith....straight up!....day or night!" That's because that's the direction in which backradiation is generally the least. It is the shortest distance through any layer of the atmosphere, so one can see farther into the atmosphere, less of the warmer lower air and more of the colder layers of the upper troposphere and lower stratosphere, and also more of space itself. If you look closer to the horizon, the atmosphere appears more opaque, and individual layers appear more opaque, because the line of sight goes over a longer distance to get through each layer at such an angle. (If you cut a slice of apple thin enough, you can almost see through it. You can see more of an object through a fog if it is closer to you. Imagine a fog that is glowing incandescently - this is how the atmosphere (and surface) appears in the LW portion of the spectrum. But using visible light to illustrate the point, imagine a fog that is glowing white hot. A very thin layer of it won't appear as bright as a sufficiently thick layer that blocks almost all radiation from behind it. The totality of what you see will appear hotter if you are looking through the fog toward a blue-hot object, more so if the blue-hot object is closer or the fog is optically thinner. It would appear cooler if you are looking in the direction of a red-hot object, more so through an optically-thinner white-hot object. This assuming the red-hot and blue-hot objects have nonzero emissivities.) "In fact, this is exactly what the The ACTUAL MEASUREMENTS conducted at the Physics Dept.of Brigham Young University, Utah clearly states:" ...""At night the solar cooker needs to also be aimed straight up towards the cold sky."..."During the day the solar cooker needs to be turned so that it does not face the Sun and also points towards the sky."" That makes perfect sense given everything I've said. ------------- "The only time I have heard of heat flowing from cold to hot is at the Quantum Level and was resticted to system masses of no more than a few "picograms"....obviously, not applicable to the Earth, Atmosphere and Sun system." The entire mass of the known universe consists of many quadrillions of quadrillions of quadrillions of quadrillions ... of picograms. The second law of thermodynamics arises from the statistics of microscopic processes. Keep that in mind when discussing the Poynting vector ... ------------- "This is clearly a subtraction of propogating Electromagnetic Fields." ... "Propogating Electomagnetic fields are Vector fields and obey Vector mathematics."... "P/A = e*BC*T^4 - e*BC*Tc^4 (Watts/m^2) is the Resultant Vector Electromagnetic Field after subtraction."..."There can ONLY be ONE Resultant Vector Electromagnetic Field, having only ONE magnitude and only ONE direction." From: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html "P = net radiated power" NET! NET! NET! PS: See also: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/raddens.html#c1 -- http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/radpow.html#c1 (the later mentions radiation from multiple directions). The vector that describes the energy transport by electromagnetic waves is called the Poynting vector: http://hyperphysics.phy-astr.gsu.edu/hbase/waves/emwavecon.html#c1 Yes, at any given time and place, the total poynting vector has a single vector value - but that value may be a vector sum of contributing sets of electromagnetic waves. And on a microscopic level, it will fluctuate as individual photons pass by in various directions and at various energies. The average over a surface parallel to the Earth's surface will tend to point up or down, in the direction of the resultant (if you prefer that term to net) energy transport. But this has contributing components. The radiation from the surface is a large upward component. The radiation downward from the atmosphere is a smaller downward component. The average of the resultant is upward. So if that's what you go by, use the resultant. That combined with convection will just balance the solar heat absorption by the surface, in agreement with what you've been insisting. Why not just accept that Kiehl and Trenberth's energy budget diagram was showing contributing components, not the total. From a climatologist's point of view, those contributing components are useful to know. Actually, though, if you insist on only considering the total, the average resultant from all electromagnetic waves, then you must also include solar radiation. In that case, the global average at the top of the atmosphere and in the stratosphere is nearly zero. In the troposphere it must be downward in order to balance the upward heat transport of convection. And do not think that just because the average of the resultant tends to be vertical, that photons are not going in many directions. For example, the resultant of solar radiation may be downward, but you can see blue sky all over the sky - in fact, it generally appears brighter near the horizon (for the same geometrical reasons that make the LW glow of the atmosphere generally appears hotter near the horizon than straight upward when there are not clouds that are too close to the ground or the water vapor concentration is not too high, etc.
128556. HealthySkeptic at 09:45 AM on 15 April 2009
        Misinterpreting a retraction of rising sea level predictions
        Like I said...talk about creative interpretation of the data!
128557. dchristie64 at 09:29 AM on 15 April 2009
        It's satellite microwave transmissions
        Dear sir, I worked as an electronic technician for goverment high-tech radar jamming systems back in the 80'. We tested these RF radar jamming sytems with typical RF generators at minimul power between .25 and 2 watts ranging from 2GHZ to 250 GHZ or so. If you left the generator on and pointing at you for a few days you's feel the effect on your heart and skin. It was reminded to us not to due that unless you want to have cancer. Since satelites have been put into space, the worlds cancer rate continues to climb. Do not try to deny people from real fact. Ever since we went into outer space, using the discovery, and sending rocketts and satelites remote areas in desserts and in the poles, polar caps have been effected, changes in our seasons, weather patterns and disease. So don't tell me that a dam aerisol can or a crushed styrophome cup is destroying the world. Wake up!..oh ..and find out a better calculation. To penetrate a 4 mile thick ozone layer takes more than 1.6 watts /m2...not to forget the refraction values as well to re-enter into the earth.
128558. Gord at 22:57 PM on 14 April 2009
        It's the sun
        Patrick - Re: Your Posts #282...etc --- Heat Radiation Radiation is heat transfer by the emission of electromagnetic waves which carry energy away from the emitting object. For ordinary temperatures (less than red hot"), the radiation is in the infrared region of the electromagnetic spectrum. The relationship governing radiation from hot objects is called the Stefan-Boltzmann law: P = e*BC*A(T^4 - Tc^4) Where P = net radiated power (Watts), e = emissivity, BC = Stefan's constant, A = area, T = temperature of radiator and Tc = temperature of the surroundings or another body. ..when rearranged gives P/A = e*BC*T^4 - e*BC*Tc^4 (Watts/m^2) This is clearly a subtraction of propogating Electromagnetic Fields. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html --- Propogating Electomagnetic fields are Vector fields and obey Vector mathematics. P/A = e*BC*T^4 - e*BC*Tc^4 (Watts/m^2) is the Resultant Vector Electromagnetic Field after subtraction. There can ONLY be ONE Resultant Vector Electromagnetic Field, having only ONE magnitude and only ONE direction. If T > Tc the direction is ONLY from T toward Tc and the magnitude is P/A. This complies with the 2nd Law of Thermodynamics. "Energy will not flow spontaneously from a low temperature object to a higher temperature object." If there were ANY flow from Tc to T (cold to hot) it would VIOLATE Electromagnetic Vector Field physics as well as the 2nd Law of Thermodynamics and Conservation of Energy. --------------- Regarding your discussion of emissivity and absorbtion being different, it does not apply to Trenberth's paper. He assumes that emissivity applies equally to absorbtion and emission. The only time I have heard of heat flowing from cold to hot is at the Quantum Level and was resticted to system masses of no more than a few "picograms"....obviously, not applicable to the Earth, Atmosphere and Sun system. --------------- You said.... "My pointing out that there is/are refrigerators in the sky was to correct your statement that their are none...." I have already posted a response to this before: --- My Post #264: The Trenberth Energy Budget shows that the Back Radiation flowing from the colder atmosphere and absorbed by the Earth's surface to be 324 Watts/m^2. (The Back Radiation ABSORBED by the Earth is, supposed, to Heat the Earth according to the AGW theory) Notice that the Back Radiation EXCEEDS the Solar Radiation (the only energy source)! Solar ovens (parabolic mirrors) have no problem concentrating the Solar radiation at it's focal point producing very high temperatures. Parabolic mirrors will concentrate IR energy (Back Radiation) the same way. Notice the authors of the paper state: "During both times, the solar cooker needs to be aimed away from buildings, and trees. These objects have thermal radiation and will reduce the cooling effects. At night the solar cooker needs to also be aimed straight up towards the cold sky. During the day the solar cooker needs to be turned so that it does not face the Sun and also points towards the sky." If there were a "refigerator in the sky" heat would flow from the colder atmosphere to the Solar Oven's focal point where this energy would be concentrated. In Fact, according to Trenberth, the Back Radiation exceeds the Solar Radiation and is 163% GREATER THAN THE SOLAR RADIATION. If there really was a "refigerator in the sky"...The water at the focal point would NOT freeze, it would HEAT UP.....even MORE than it does with Solar Energy! Further, "a refigerator in the sky" still would need energy to operate and it would have to come from the SUN! All the energy radiated by the Earth and the atmosphere could still NEVER EXCEED the 342 w/m^2 Solar Energy!" --- My Post #265 "If there were "a refigerator in the sky" the atmosphere would have to be warmer than the Earth. A refigerator transfers heat from objects inside to the Radiating Tubes at the back. The Radiating Tubes are warmer than the surrounding air....so heat is transfered to the air. The atmosphere is, obviously, cooler than the Earth.....therefore...there IS NO REFIGERATOR IN THE SKY!" --- The POINT being: There is no evidence, at all, of there being a "refigerator in the sky". There is however, conclusive evidence that a "refigerator in the sky" does NOT EXIST! --------------------- You said... "The solar oven works by concentrating sunlight to work as an oven, and by allowing radiative energy transfer between the sky and an object while blocking such heat transfers between the object and heat from trees, buildings, and perhaps also the sky near the horizon - which will tend to appear warmer because the rays in near horizontal directions pass through longer distances through the warmer lower atmosphere, so that it is nearly opaque in that direction, whereas, under clear skies (or only high clouds) with sufficiently low humidity, the warmer lower atmosphere exceeds some level of partial transparency over a greater range of wavelengths when looking more straight upwards. I mention this last point because it helps explain how the solar oven used as a radiant cooler (not a refrigerator) can achieve temperatures (in the object being cooled) lower than the surrounding surface temperature, which cools at night by radiation upward to space and the cooler atmosphere, but over all directions (radiant intensity weighted by the cosine of the zenith angle for a horizontal surface, for geometrical reasons)." --- All radiation from the Spherical Earth and Spherical Atmosphere will occur normal to the surface. The Back Radiation from the Atmosphere will flow directly along lines to the center of the Earth. The max effect will occur if the Solar Oven is pointed at the Zenith....straight up!....day or night! In fact, this is exactly what the The ACTUAL MEASUREMENTS conducted at the Physics Dept.of Brigham Young University, Utah clearly states: "At night the solar cooker needs to also be aimed straight up towards the cold sky. During the day the solar cooker needs to be turned so that it does not face the Sun and also points towards the sky." ----------------------- You said.... "When the sun radiates energy to the Earth it is losing that energy; if it got any back, it gains that energy. Nowhere in that statement is energy being created or destroyed; it is conserved all the way. The vast majority of what the sun loses will not come back, but the sun maintains its temperature because mass is being converted to energy in its core." --- Again, I strongly disagree! The Sun is a constant energy source. It provides all the Energy to the Earth. The Earth IS NOT AN ENERGY SOURCE! Any energy that would be absorbed by the Sun from the Earth would CAUSE the SUN TO INCREASE IN TEMPERATURE! A very, very obvious violation of the Law of Conservation of Energy! Further, if the Sun actually increased in temperature, the Earth would receive this energy and increase in temperature. The Earth would radiate MORE energy to the Sun, causing the Sun to increase in temperature, causing the Earth to heat up even more....etc. What you describes is a Perpetual Motion machine in a positive feed-back loop that will increase it's temperature to INFINITY! An IMPOSSIBILITY. ----------------------- You said.... "That analogy doesn't work very well; if it were truly the net law of gravity, some of the rest of the people who are not blasted into space would have to sink down into the Earth." --- You did not understand my point. I said... "It is equivalent to saying that the Universal Law of Gravitation is really the "NET Law of Gravitation" and that some people could be blasted into space by gravity as long as most people remained Earth bound!....Producing a violation of the Law of Conservation of Energy!" What I am referring to is the DIRECTION of Gravity changing. As long as the NET direction of Gravity was "downward" most people would remain Earth bound. Those few people who had Gravity spontaneously change direction to "up" would be blasted into space. This also would violate the Law of Conservation of Energy. The 2nd Law of Thermodynamics has everything to do with DIRECTION of energy flow.....warm to colder bodies. "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 In your case, you think that there can be a spontaneous change so that heat can flow cold to hot as long as the NET (most) of the energy flows from warm to cold. This also would violate the Law of Conservation of Energy. Both the 2nd Law of Thermodynamics and the Universal Law of Gravitation do NOT deal with NET effects....for a very good reason....the Law of Conservation of Energy! -------------------------- It seems that your posts are really about trying to dis-prove the 2nd Law of Thermodynamics and the Law of Conservation of Energy. I don't understand your logic.
128559. Timothy Chase at 15:27 PM on 14 April 2009
        Why is Antarctic sea ice increasing?
        Over at the thread on Real Climate that is devoted to the collapse of the ice bridge that helped support the Wilkins Ice Shelf, someone asked, "How does the collapse square with the latest NSIDC data which shows an increasing Antartic ice coverage?" Gavin responded, "Look in the region where this is happening." There is the warm West Wind Drift which is resulting in ice melt in along the West Antarctic Peninsula and in the nearby ocean, particularly the Bellingshausen Sea -- where sea ice is declining at -5.3% per decade. This is leading to additional fresh water at the surface which is no doubt leading to some of the stratification suggested in the model. However, if this fresh water gets caught up in the inner cold East Wind Drift, it will be carried to the West Pacific Ocean, where sea ice is growing at 1.2% per decade. That is essentially along the coast of continental West Antarctica. And some will be carried further east where the Ross Sea forms a harbor between West Antarctica and East Antarctica. This is where sea ice is growing at 4.8% per decade. No other place rivals it. In fact, the closest you get is the West Pacific Ocean at 1.2%. So part of what explains the growth in sea ice may be stratification due to fresh water, but also I would suggest the fresh water itself -- which freezes at a higher temperature than saltier seawater. However, with respect to the future, the ozone hole was increasing the strength of the Antarctic Polar Vortex, and now that the ozone hole is being repaired the Antarctic Polar Vortex is weakening, and the cold dry Antarctic climate is giving way to the moist maritime air of the north. Of course with global warming we would expect a poleward shift of storm tracks in any case, but in this case the effects would appear to be mutually reinforcing. In any case, here is a link to my comment where I followed up Gavin's suggestion -- by I would also recommend checking out the comment below it: 8 April 2009 at 8:19 PM http://www.realclimate.org/index.php?p=667#comment-119074
128560. Patrick 027 at 11:19 AM on 14 April 2009
        It's the sun
        2 more things: "Any, radiation absorbed by a body will increase it's temperature."..."The Sun cannot absorb (and increase in temperature)energy radiated from the Earth because the only energy that caused the Earth's radiation came from the SUN!"..."That is the same as saying that the SUN can heat itself....a violation of the Law of Conservation of Energy!" When the sun radiates energy to the Earth it is losing that energy; if it got any back, it gains that energy. Nowhere in that statement is energy being created or destroyed; it is conserved all the way. The vast majority of what the sun loses will not come back, but the sun maintains its temperature because mass is being converted to energy in its core. It does not violate the conservation of energy to wrap a hot brick in aluminum foil. If the sun were surrounded by mirrors, would not the sun get back it's light? If not, why can you see yourself in the mirror? How could a mirror even exist without breaking physical laws? --------- "It is equivalent to saying that the Universal Law of Gravitation is really the "NET Law of Gravitation" and that some people could be blasted into space by gravity as long as most people remained Earth bound!....Producing a violation of the Law of Conservation of Energy!" That analogy doesn't work very well; if it were truly the net law of gravity, some of the rest of the people who are not blasted into space would have to sink down into the Earth. For example, if one person were at the long end of a very lopsided teeter-totter and a whole crowd of other people jumped off a tall cliff and landed on the short end, then the first person could be expected to fly upward. The potential energy of some large mass would be converted into kinetic energy that would be converted into the kinetic energy of a much smaller mass moving at faster speed, which will ultimately change into potential energy as the person slows down, being accelerated toward the Earth by gravity; if the person has enough energy to never completely stop than s/he has reached escape velocity, etc. Hey, that's what would happen (setting aside air drag, etc.)! Of course, it is not a net law of gravitation, but simply the conservation of energy, work, energy = force times distance, and a lever, etc.
128561. Patrick 027 at 10:16 AM on 14 April 2009
        It's the sun
        It is obvious to me that the second law of thermodynamics and the conservation of energy do appear to be correct, no violation has yet been discovered and no one expects such a violation to be found (within this universe, etc.); provided that one considers mass to be a form of energy. It is also obvious to me that you have misinterpreted what these things mean. Since you take "hyperphysics" at it's word without qualification (PS that's no knock on the website; I think it's pretty good!), consider: ------------------------------ HEAT: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heat.html#c1 "Heat may be defined as energy in transit from a high temperature object to a lower temperature object. An object does not possess "heat"; the appropriate term for the microscopic energy in an object is internal energy. The internal energy may be increased by transferring energy to the object from a higher temperature (hotter) object - this is properly called heating. " If that is true, I've been a bit careless in terminology, but a few word substitutions would correct that in what I've written thus far - and in what I shall write, as I might slip up again... However, if it is the transfer of energy ... maybe the 390 W/m2 emission upward from the surface + 102 W/m2 convection and the 324 W/m2 downward from the atmosphere are not in themselves heat flows; it may just be the net flow of this energy that is the heat flow. Or maybe not... Anyway, consider this: ------------------------------ RADIATION: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html#c2 "The energy radiated by a blackbody radiator per second per unit area is proportional to the fourth power of the absolute temperature"... (see website for equation) "For hot objects other than ideal radiators, the law is expressed in the form:" ... (see website for equation) ... "where e is the emissivity of the object (e = 1 for ideal radiator). If the hot object is radiating energy to its cooler surroundings at temperature Tc, the net radiation loss rate takes the form" (see website for equation) I'll rewrite the equations here but replacing some variables and symbols with names: Ideal blackbody radiation: Power/area = sigma*T^4 where sigma = 5.6703*10^-8 W/(m^2 K^4) So that the radiant power is proportional to the fourth power of absolute temperature, and a 1000 K blackbody radiates with a power of 56,703 W/m2. And a 288 K blackbody (about the average surface temperature of the Earth) radiates with a power of about 390.1 W/m2. Sound familiar? For a nonideal radiator, the emission is a fraction of blackbody radiation is called emissivity, so that: Power/area = emissivity * sigma * T^4. And for a hot object at temperature T radiatively cooling to it's surroundings at temperature Tc, assuming the surroundings are effectively an ideal blackbody, the "net radiation loss" is Power/area = emissivity(of hot object) * sigma * (T^4 - Tc^4) A little math shows this is equal to: emissivity(of hot object) * (blackbody Power/area at T - blackbody Power/area at Tc) Nowhere does it say that the emissivity of the hot object must decrease to zero if it's surroundings are not at absolute zero. For clarification (you might find this if you follow links from http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/stefan.html#c2 ), emissivity is a material property that can vary as a function of wavelength and this wavelength dependent emissivity can vary as a function of temperature OF the emitting surface (but not simply as a function of it's surroundings). Because the temperature of surroundings affects the wavelength distribution of their emitted radiation, this can affect the effective absorptivity of a recieving surface - for example, clouds have higher absorptivity for the radiation as a whole emitted from the surface and atmosphere (including other clouds) than they do for the radiation from the sun - but this is because clouds have generally greater absorptivity in the wavelengths dominated by terrestrial emission (longer than about 4 microns) than those dominated by solar radiation (shorter than about 4 microns). BUT at any particular wavelength, the net radiative loss is from a hotter object to a colder object - for perfect blackbodies, power/area for any wavelength interval is greater at higher temperature; the emissivity is equal to absorptivity for each object (at local thermodynamic equilibrium) or layer or surface, etc, at each wavelength, and so when optical properties are varied, the absorption and emission change in proportion, so that a hot object cannot absorb more radiation emitted from a cold object than the same cold object can absorb from emission from the same hot object. Thus at every wavelength, the net radiation loss is from hot to cold. However, this can pass through a partially transparent layer of any temperature, as I explained previously. See: http://hyperphysics.phy-astr.gsu.edu/hbase/bbcon.html#c1 Blackbody radiation spectrum: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/radfrac.html#c1 Examples: http://hyperphysics.phy-astr.gsu.edu/hbase/bbrc.html#c1 AND for emissivity = absorptivity (why the surface does absorb radiation from the atmosphere, as they emit in some of the same wavelengths): "A Good Absorber is a Good Emitter" http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/absrad.html#c1 This section continues from the formula for net radiation loss, of a hot object at temperature T to surroundings at temperature Tc: QUOTE: "In this relationship the term with Tc represents the energy absorbed from the environment." Energy from the cooler environment is absorbed by the hot object! "This expression explicitly assumes that the same coefficient e [emissivity] applies to both the emission into the environment and the absorption from the environment. That is, a good emitter is a good absorber and vice versa; the same coefficient can be used to characterize both processes. Why is that true?" next paragraph - note the reference to the second law of thermodynamics: "Perhaps the most fundamental conceptual way to approach this question is to observe that a hot object placed in a room must ultimately come to thermal equilibrium with the room. The hot object will initially emit more energy into the room than it absorbs from the room, but that will cause the temperature of the room to rise and the temperature of the object to drop. But when they reach the same temperature, we can conclude that the amount of energy absorbed on average is exactly the same as the energy emitted. That is, the expression above for net energy radiated to the environment must give us zero when T=Tc." Their words, not mine. But I agree. "The above argument is based upon the Second Law of Thermodynamics in the form that states that heat will not spontaneously flow from a cold object to a hot object. If the absorption coefficient were higher than the emission coefficient for the object, then it could absorb net energy from the room even when its temperature were higher than the room." "But suppose you wanted to argue that a good absorber must be a good emitter based on the microscopic processes involving the atoms in the surface of an object. Then it becomes quantum question and involves the following ideas: " (see website for more). ---------------------------------------- I haven't found it in the "hyperphysics" website yet (but - please realize this - just because it is not explicitly mentioned in one website does not mean it is not true), but blackbody radiation is isotropic - the intensity (power per area per solid angle) does not vary over directions. Real materials can have direction-dependent optical properties. For an ideal blackbody at temperature T shaped as a thin plate with area A, the radiant energy flux per unit area from the plate's surface is the blackbody radiation at temperature T; the radiation has the same intensity in all directions but the projection of the area of the plate varies - just as one would recieve less radiant power per unit area from farther away, one would recieve less radiant power per unit area if viewing the plate slantwise instead of face-on. Either way, it is because the plate occupies a smaller solid angle from the viewing position. Conservation of radiant intensity in the absence of scattering, partial reflection, absorption, and emission is required by the second law of thermodynamics, because along every ray path in which object A can see object B, object B can also see object A, so both can exchange radiation along all such paths - at any wavelength and along any line of sight (even if bent at a perfect mirror or perfectly transparent lens), a hot object will have net radiation loss to a cold object if there is any thermally-emitted radiation exchanged. Hence, the highest temperature that can be achieved by focusing the sun's radiation on an object to heat it up is the temperature of the sun (if in space; othewise a bit less because of atmospheric scattering, even without clouds or much haze), in agreement with the second law of thermodynamics. Radiation at any wavelength and polarization (blackbody radiation is evenly distributed among polarizations) can be assigned a temperature based on the blackbody that would emit radiation at that wavelength and polarization with that intensity. This assigned temperature is reduced when radiation confined to nearly parallel rays are scattered (as sunlight is scattered to produce the blue sky and the light seen from clouds - sunlight is initially nearly parallel at great distances from the sun because the sun can only be seen within a small solid angle of directions) - this increase the radiation's entropy, and entropy = heat/temperature for heat flow. One other thing that can be mentioned, pertaining to lasers: entropy is reduced if some intensity of radiation is packed into a smaller interval of phase shifts relative to each other - coherent radiation has very low entropy, corresponding to the entropy of radiation from a blackbody at a sufficient temperature to produce such a concentrated radiant intensity per unit phase shift. Another reason to believe that some radiant energy can flow from colder to warmer: The blackbody radiation spectrums at different temperatures overlap - a white hot object emits more red light than a red-hot object of the same size and optical properties. Both red-hot objects and white-hot objects emit red photons. A red-hot object can even emit a few blue photons, though not many; a white hot object will emit many more blue photons. A violet-hot object emits even more blue photons, etc. The point is that, while temperature can be assigned to a population of photons (radiation intensity over a given wavelength interval, interval of polarizations, interval of phase shifts), a temperature cannot be assigned to an individual photon (just as it cannot be assinged to an individual molecule, atom, or electron, etc. - see: http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/ktcon.html#c1 ). So if a white hot object can absorb a yellow photon from a violet hot oject, why not absorb an identical photon from a red hot object. (PS for that matter, some optical manipulation could be used to make a white hot object appear to be a violet hot object with lower emissivity - by partially blocking lower-energy photons. This radiation could be absorbed by a blue hot object. However, this will not reverse the net radiation loss between the two objects; it will still be from blue-hot to white-hot. ------------------------------- "So, I take it that you now agree that there is no "refigerator in the sky" and Solar Ovens are not "heat engines" or "refrigerators in the sky"?" My pointing out that there is/are refrigerators in the sky was to correct your statement that their are none, but it has nothing to due with how the solar oven works. The solar oven itself is not a refrigerator or a heat engine; this has nothing to do with whether or not the atmosphere contains refrigerators and heat engines - it does; the heat engines are driven by the convective portion of heat flow from the surface to the various levels of the cooler troposphere, and the refrigerators-heat pumps are driven by a portion of the kinetic energy produced by those heat engines (but most, as I understand it, of the kinetic energy is lost to friction before it can drive any such refrigerator). The solar oven works by concentrating sunlight to work as an oven, and by allowing radiative energy transfer between the sky and an object while blocking such heat transfers between the object and heat from trees, buildings, and perhaps also the sky near the horizon - which will tend to appear warmer because the rays in near horizontal directions pass through longer distances through the warmer lower atmosphere, so that it is nearly opaque in that direction, whereas, under clear skies (or only high clouds) with sufficiently low humidity, the warmer lower atmosphere exceeds some level of partial transparency over a greater range of wavelengths when looking more straight upwards. I mention this last point because it helps explain how the solar oven used as a radiant cooler (not a refrigerator) can achieve temperatures (in the object being cooled) lower than the surrounding surface temperature, which cools at night by radiation upward to space and the cooler atmosphere, but over all directions (radiant intensity weighted by the cosine of the zenith angle for a horizontal surface, for geometrical reasons).
128562. Philippe Chantreau at 01:47 AM on 14 April 2009
        Arctic sea ice melt - natural or man-made?
        Quietman you're misunderestimating the skill of the conspirators. They're really really smart. Therefore, they know that the best way to destroy capitalism is to have capitalism destroy itself, by letting it go unchecked. The "green socialist threat" is nothing but a decoy. The real conspirators have been sitting in Wall Street and K Street (and the SEC?), encouraging always more deregulation, less regulation and weak enforcement of what little exists. Their plan is working like a (swiss) watch. It has already produced socialized banking. Not only the helicopters are black, after all, but they're also coporate...
128563. Philippe Chantreau at 01:34 AM on 14 April 2009
        Why is Antarctic sea ice increasing?
        Lee, I guess that's what David was asking in post #8 and I must say I have no idea. One would think that satellites are blind to the real origin of the ice. Hence, some glacial ice is bound to be part of the extent and area. I don't know how significant that is.
128564. Gord at 19:25 PM on 13 April 2009
        It's the sun
        Patrick - Re: Your Posts #273 etc. You said... "Gord - I know how a solar oven works. I don't disagree with your description of it. I looked over parts of http://solarcooking.org/research/McGuire-Jones.mht and do not see any errors there. It does not disagree with what I've been saying. That heat flows from hot to cold is just a useful simplication of the complete picture, which is that heat often flows in both directions but the net heat flow is from hot to cold." First, you have peviously stated that: Your Post #259 "THERE IS a refrigerator in the sky..." And, with reference to Solar Ovens: Your Post #267 "That's only true with some additional specifications. There are both heat engines and refrigerators in the sky." So, I take it that you now agree that there is no "refigerator in the sky" and Solar Ovens are not "heat engines" or "refrigerators in the sky"? --- With regard to: "That heat flows from hot to cold is just a useful simplication of the complete picture, which is that heat often flows in both directions but the net heat flow is from hot to cold." I TOTALLY DISAGREE as the 2nd Law of Thermodynamics is VERY CLEAR on this: "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 There is no mention of "net" anywhere! In fact, the 2nd Law specifically states that 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. This, OBVIOUSLY, does NOT allow ANY heat flow from cold to hot UNLESS work is done to accomplish this flow...and for a good reason!! The reason is that ANY HEAT flow from cold to hot objects without work being done to accomplish this flow will VIOLATE the Law of Conservation of Energy. Example: Your claim that the Earth's radiation can be absorbed by Sun. I repeat what I have already posted: "Any, radiation absorbed by a body will increase it's temperature. The Sun cannot absorb (and increase in temperature)energy radiated from the Earth because the only energy that caused the Earth's radiation came from the SUN! That is the same as saying that the SUN can heat itself....a violation of the Law of Conservation of Energy!" --- It should be obvious to you that both the 2nd Law of Thermodynamics and the Law of Conservation of Energy are BOTH correct and BOTH SUPPORT each other! Patrick, these are basic fundamental Laws of Science and saying that "it is the net heat flow that is being discussed" in 2nd Law is, obviously, not true. It is equivalent to saying that the Universal Law of Gravitation is really the "NET Law of Gravitation" and that some people could be blasted into space by gravity as long as most people remained Earth bound!....Producing a violation of the Law of Conservation of Energy! --- It seems that your posts are really about trying to dis-prove the 2nd Law of Thermodynamics and the Law of Conservation of Energy. In fact, your posts contain numerous examples of violations of these Laws of Science in an attempt to prove that these same violations comply with these Laws of Science. I don't understand your logic.
128565. Lee Grable at 07:00 AM on 13 April 2009
        Why is Antarctic sea ice increasing?
        Given the breaking away of several major ice shelves in the recent past, the Wilkens shelf being the latest, are'nt there more icebergs floating around the continent now?
128566. Chris G at 15:01 PM on 12 April 2009
        Water vapor is the most powerful greenhouse gas
        Don't know that anyone will come back to this discussion, but just in case... Let's pretend that about 2/3 of the earth is covered in water. If that were the case, shouldn't the atmosphere, in general, already be effectively saturated with respect to WV? What happens when the air becomes over saturated; the water precipitates out. True, if you irrigate a field in a dry region or exhaust WV from a hydrocarbon engine, you add to the WV downwind of that, but that doesn't change the thermodynamic properties of CO2. Nor does it change the fact that water evaporates more when it is warmer. With regard to #2, why would the sea surface temperature remain fixed when it is receiving more IR radiation?
128567. Patrick 027 at 13:51 PM on 12 April 2009
        It's the sun
        See also: http://www.realclimate.org/index.php/archives/2009/04/wilkins-ice-shelf-collapse/langswitch_lang/index.php?p=667#comment-119260
128568. Patrick 027 at 11:33 AM on 12 April 2009
        It's the sun
        To sum up: from an iterative viewpoint (which is applicable to following a parcel of energy through the system - for example, the amount of solar radiation absorbed in 1 second = 235 J: 168 J at the surface and 67 J in the atmosphere): The reason why there are fluxes greater than solar heating is that some of this heat is emitted or convected several times between the surface and atmosphere before actually escaping to space. Each time it goes back and forth between the surface and atmosphere, it adds to the total fluxes between them.
128569. Patrick 027 at 11:19 AM on 12 April 2009
        It's the sun
        ... to be more specific. Let's start with an Earth with surface and atmosphere at absolute zero, so that they do not radiate any energy. But for the sake of illustrating the concept, let's leave the optical properties as they are (no cloud, humidity, snow and ice, or temperature-dependent optical property feedbacks). We now turn the sun on. 235 W/m2 are absorbed; 67 in the atmosphere and 168 at the surface. But the atmosphere and surface are not radiating any energy and there is no convection. So is energy being destroyed? No. Energy is accumulating in the atmosphere and at the surface. This raises the temperatures of both. As the temperature is now nonzero, they start to radiate LW radiation, but very small amounts, so there is still energy accumulation. As they heat up, they radiate more, and so the rate of energy accumulation decreases - but it doesn't stop until outward energy fluxes equal inward energy fluxes. But what happens as the surface and atmosphere heat up? --- At wavelengths where the atmosphere is almost transparent but not perfectly so, so that it emits and absorbs some radiation, it will emit about the same amount of radiation to the surface and to space and the absorption of radiation from the surface will be nearly evenly distributed through the atmosphere if position is measured by optical thickness. Most of the radiation emited by the surface will reach space. However, at wavelengths where the atmosphere is moderately opaque, it will emit more radiation downward to the surface than upward to space; this is because there is enough opacity such that individual layers of the atmosphere can partially hide each other - for radiation going in any direction, a layer will absorb some fraction of radiation from behind and emit with the same fractional emissivity it's own radiation as a function of it's temperature. Because the upper half of the atmosphere is generally cooler than the lower half (both in terms of mass and optical thickness at most wavelengths) (there is not much opacity at most wavelengths in the upper stratosphere and points higher - these layers are very thin by mass and by optical thickness), the atmosphere looks warmer from the surface than it does from space. At wavelengths where the lower atmosphere is very opaque, the atmosphere will appear to the surface to have about the same temperature as the air just above the surface, and the troposphere will appear from above (the lower stratosphere) to be at the temperature of air near the tropopause, and the surface will be essentially hidden from the stratosphere and space; all surface radiation at such wavelengths will be absorbed in the atmosphere. The greater the opacity of the atmosphere, the more concentrated near the surface the absorption of radiation from the surface is. At some wavelengths, the warmer upper stratosphere is opaque enough to partly block the coldness of the upper troposphere and lower stratosphere from being seen from space. --- All details aside, the atmosphere absorbs some radiation from the surface, so only a fraction of that radiation reaches space. The radiation from the surface that is absorbed in the atmosphere is an additional source of heat for the atmosphere, but note this heat is coming ultimately from the sun - the surface had to warm up to be able to emit this radiation. Meanwhile, the atmosphere, being not completely transparent, radiates upward and downward. It must do both, because it's optical properties are not limited to one direction. ---(one could imagine replacing air molecules and cloud particles with one-sided mirrors that are perfect blackbodies on the other side - in which case, they would reflect radiation coming from one direction and absorb and emit radition from and to the other direction. It would still equally opaque and equally transparent in both directions. In fact, it would break the second law of thermodynamics to have a material that allows, at the same wavelength, radiation through one way but not the other - because that would make it possible to build a perpetural motion machine - it would also be possible to build a perpetual motion machine if absorptivity did not equal emissivity, for similar reasons. )--- . If warm enough and opaque enough, even if cooler than the surface, it can emit radiation in total (to the surface and to space) a greater amount than the surface emits upward. There is nothing particularly mysterious about this. The surface material actually emits downward into the Earth about the same amount it emits upward; the downward radiation is only inconsequential because below the surface material is more material that is also very opaque - photons can only travel very very short distances in such a material, and over very short distances, there are not significant variations in temperature to cause a net radiant heat flux. ---(This also applies to the atmosphere for air-to-air heat exchange: at wavelengths with large opacity; the general behavior is that a net radiant heat flux at a location is caused by temperature variations that are visible from that location; if opacity is too low, temperature variations nearby will be almost invisible (they are nearly transparent); if opacity is too high, temperature variations over moderate distances are hidden from each other.)--- And because at some wavelengths, the atmosphere has moderate to great opacity, the atmosphere radiates downward more than upward. Thus there is, in addition to radiation from the surface and atmosphere to space, downward radiation from the atmosphere to the surface and the upward radiation from the surface that is absorbed in the atmosphere. Energy is being both added to and removed from the atmosphere and the surface; because the surface is warmer than the atmosphere, it radiates more to the atmosphere than it absorbs from the atmosphere, so the net heat flow is from the surface to the atmosphere. As the surface and lowermost atmosphere heat up enough, the lower atmosphere becomes unstable to convection, and so convection will also transport heat from the surface to parts of the atmosphere. The entire system warms up until it can emit 235 W/m2 back to space, at which point, heat is no longer accumulating. Because solar absorption is shifted downwards relative to emission to space, there has to be an upward flow of heat between the solar absorption and emission to space. This requires some decrease in temperature over height. Thus: If the atmopshere were at the same temperature as a perfect blackbody that would emit 235 W/m2, then the surface would have to be warmer, and together they would emit more than 235 W/m2 to space because the atmosphere is not perfectly opaque (unless the surface has sufficiently low emissivity). So the atmosphere must be colder than that temperature. But if the surface were at the temperature at which it could emit 235 W/m2, the atmosphere, being colder overall, could not replace the amount it absorbs from the surface with the same amount to radiate to space - it radiates less to space than it absorbs from the surface, and thus the whole assemblage will radiate less than 235 W/m2. So if the surface's emissivity is not too far from 1, the surface temperature must be warmer than the temperature of a blackbody radiating 235 W/m2, and the atmosphere (or that part visible from space at the relevant wavelengths) will be colder than that same temperature. ---- The surface emits (using the blackbody approximation of perfect emissivity) 390 W/m2 and also cools by 102 W/m2 by convection because it is so warm. At equilibrium temperature, it has to be this warm in order to balance the 168 W/m2 of solar heating and the 324 W/m2 backradiation from the atmosphere - *** or else the conservation of energy could be violated ***(if more or less energy is flowing out than flowing in, then heat is being depleted or accumulated, and that tends to result in a decrease or increase in temperature, unless used up in latent heat, etc.)***. And why is the atmosphere so warm as to radiate 324 W/m2 downard? Convection still results in a general temperature decrease with height, and most of the mass (about 85 %) of the atmosphere is in the troposphere, so the atmosphere will emit more downward than upward, and it works out that it emits 324 W/m2 downard while emitting 195 W/m2 upward. If it is to have an equilibrium temperature, the atmosphere has to be warm enough to radiate these amounts in order to balance the 67 W/m2 of solar heating and the 350 W/m2 it absorbs from the surface and the 102 W/m2 it recieves from the surface by convection. And why do the surface and atmosphere together have to have the temperatures that they do? In order for the fraction of radiation emitted by the surface that is not absorbed by the atmosphere but instead goes to space (40 W/m2) and the radiation from the atmosphere to space (195 W/m2) to balance the 235 W/m2 of solar heating of the two. --- THIS does not violate any laws of physics. If you still do not see that, look at it using a recursive (or iterative) accounting method: Based on numbers from Kiehl and Trenberth (ignoring significant figures for the time being): Of total surface emission and convective cooling: 20.73 % is convection (entirely to atmosphere) 71.14 % is emission that is absorbed by the atmosphere 8.13 % is emitted to space. Of total atmospheric emission up and down: 62.43 % is downward to surface 37.57 % is upward to space. all in W/m2 (numbers will not add precisely due to rounding): STEP 1: 168 of solar radiation heats the surface and 67 heats the atmosphere - total is 235. 168 then leaves the surface to balance solar heating; of that: 13.7 goes directly to space. 119.5 is radiation absorbed by the atmosphere. 34.8 is convection to the atmosphere. 67 leaves the atmosphere to balance solar heating: 25.2 goes to space. 41.8 goes to the surface. Total to space: 25.2 from atmosphere + 13.7 from surface = 38.8. Notice that 38.8 is a lot less than 235 - there is 196.2 yet to radiate to space. Heat is accumulating. What is happening to it: STEP 2: From step 1: the surface transfered 154.3 to the atmosphere (119.5 by radiation, 34.8 by convection), and the atmosphere transfered 41.8 to the surface by radiation. Now, 41.8 leaves the surface to balance heating from the atmosphere: 3.4 directly to space 38.4 to the atmosphere (8.7 convection, 29.8 radiation absorbed by atmosphere). And 154.3 leaves the atmosphere to balance heating from the surface: 58.0 to space 96.4 to the surface Total to space from this step: 61.4. Still 134.8 yet to go to space. STEP 3. 96.4 leaves the surface to balance heating from step 2: 7.8 to space. 88.5 to the atmosphere (68.5 radiation, 20.0 convection) 38.4 leaves the atmosphere to balance heating from step 2: 14.4 to space 24.0 to surface Total to space from step 3: 22.3. 112.5 has yet to escape to space. STEP 4: 24.0 leaves the surface to balance heating from step 3: 2.0 to space 22.0 to the atmosphere (17.1 radiation, 5.0 convection) 88.5 leaves the atmosphere to balance heating from step 3: 33.3 to space 55.3 to surface Total to space from step 4: 35.2 Yet to escape to space: 77.3 STEP 5: 55.3 leaves the surface to balance heating from step 4: 4.5 to space 50.8 to atmosphere (39.3 radiation, 11.5 convection) 22.0 leaves the atmosphere to balance heating from step 4: 8.3 to space 13.8 to surface Total to space from step 5: 12.8 Yet to escape to space: 64.5 STEP 6 ... Do I need to continue? If you do steps until the amount yet to escape to space is very small, and then sum all the fluxes from all the steps, you'll find: -- surface emission + convection: 492 (102 convection + 390 radiation; of radiation, 350 to atmosphere + 40 to space; 350 radiation to atmosphere + 102 convection = 452 to atmosphere from surface) atmospheric emission to surface: 324 atmospheric emission to space: 195 total to space = 235 (195 from atmosphere + 40 from surface) -- With only steps 1 through 5, we had: surface emission + convection: 385.4 (79.9 convection + 305.5 radiation; of radiation, 274.2 to atmosphere + 31.3 to space; 274.2 radiation to atmosphere + 79.9 convection = 354.1 to atmosphere from surface) atmospheric emission to surface: 231.2 atmospheric emission to space: 139.1 total to space = 170.5 (139.1 from atmosphere + 31.3 from surface), with 64.5 yet to escape to space. ---- In reality, if we were not in a steady state or dealing with a climate change, the distribution of flux among cooling pathways as percentages of the heating from the previous step would not be constant among all steps.
128570. Patrick 027 at 05:08 AM on 12 April 2009
        It's the sun
        Gord - I know how a solar oven works. I don't disagree with your description of it. I looked over parts of http://solarcooking.org/research/McGuire-Jones.mht and do not see any errors there. It does not disagree with what I've been saying. That heat flows from hot to cold is just a useful simplication of the complete picture, which is that heat often flows in both directions but the net heat flow is from hot to cold. I had previously visited related portions of the hyperphysics site. There is nothing I saw that I disagree with here: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html#c3 ; but to clarify, the second law also applies to more than just heat flow and temperature variations, and can be expressed more generally in terms of entropy. Also, it is the net heat flow that is being discussed. To be clear, the second law does not allow heat flow from cold to hot along a second pathway even if the heat flow along a first pathway from hot to cold is greater; the net heat flow I've been refering to is along every possible channel of communication, every pathway of of heat flow (every direction, every wavelength and polarization of radiation, every time period - with one exception, which is if one tries counting individual quantized events as seperate pathways or defining groups of such events by the direction of heat transfer they can accomplish - alternatively, one would then need to take into account the actual energy distribution among individual particles in order to square this with the second law, although even that doesn't quite work - for example, in an elastic head on collision between two molecules of equal mass, if one is initially motionless (and thus not contributing thermal energy to the measure of thermal energy of the whole multimolecular assemblage) and a moving, energic molecule collides with it head on, and if none of the energy goes into rotational or vibrational or electronic energies of the individual molecules, than all the energy will be transferred from one molecule to the other in order to conserve momentum). You may want to explore some links from http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/seclaw.html#c1 ------ ENERGY CONSERVATION and SECOND LAW OF THERMODYNAMICS: "The Sun cannot absorb (and increase in temperature)energy radiated from the Earth because the only energy that caused the Earth's radiation came from the SUN!" You are suggesting that not one of any of the photons emitted by the Earth ever ever ever ever reaches the sun and is absorbed. That would be a miracle. The Earth emits radiation in all directions (not exactly evenly; the Earth appears colder from directly above either pole than from above the equator, and variations in temperature, humidity, ozone, cloud cover, etc, cause regional variations). The sun occupies a nonzero solid angle in the sky (PS an entire hemisphere - the sky seen from a flat plane at the surface - has a solid angle of 2*pi steradians; the entire sphere surrounding the Earth has a solid angle of 4*pi steradians). It is a very small fraction of all directions from Earth, but, except for the effects of spacial variations in emission over the Earth's surface, the sun will intercept that fraction of the total radiation emitted by Earth. The physical principles might be better illustrated by considering two infinite flat plates facing each other, and just considering the emission in the direction towards each other. Assume perfect blackbodies - emissivity = absorptivity = 1. One is in the range of temperatures found in most of the atmosphere or on most of the surface of the Earth (forget lightning bolts, the thermosphere, volcanic eruptions, welding arcs, meteors, etc.), the other has a temperature in the range of the photosphere of the sun. The second law implies that heat will not (in total effect - the net heat flux) spontaneous flow from the cooler plate to the hotter plate. Indeed, if we open up any channel of heat flow (have the space between them be at least somewhat transparent (radiation)- or somewhat thermally conductive, or a fluid that is allowed to move (convection), then the net heat flow will be nonzero and be from the hotter plate to the cooler plate. But does this mean that the cooler plate is not (in the case of radiation) radiating at all towards the hot plate? No. Think about that solar oven being used to cool; what was the temperature of the object being cooled? Was it hotter than the sun? No. Yet it was radiating heat. It will radiate heat as a function of it's temperature, no matter what it is radiating heat towards; it is only necessary to not aim it towards the sun to avoid heating it up because the sun is also radiating as a function of it's temperature and that temperature is hotter. "That is the same as saying that the SUN can heat itself....a violation of the Law of Conservation of Energy!" No it is not that at all. The energy came from the sun. A very very very very very small fraction of the sun's radiation is absorbed by the planets (aside from their albedos; most just escapes the solar system without intercepting any objects). A very very very very very very very very very very very very very very very very very very very very very very very small (but nonzero) amount of the energy radiated by the sun (a smaller fraction that intercepted by the planets) returns to the sun by emission from the planets and also by reflection from the planets. If the sun were completely surrounded by a perfect mirror, the sun would get back all the energy it radiates - it would be as if it saw another sun in all directions from itself. If the sun were completely surrounded by a perfect blackbody at absolute zero temperature, the sun would not get recieve any radiation. If the sun were surrounded by a blackbody with some nonzero temperature, the sun will get recieve some radiant energy. If that blackbody is at the same temperature as the sun, the sun (approximating it's visible surface as an isothermal blackbody) would recieve exactly the same amount of radiant energy that it radiates, and thus would not have a net gain or loss of radiant energy if it had no internal heat sink or source. If the blackbody were hotter than the sun, the sun would recieve more heat than it radiates and thus gain energy that way. Of course, the sun does have an internal heat source - nuclear fusion. This converts nuclear potential energy, measurable as an amount of mass that is lost - into heat energy. The Earth also has an internal heat source of a similar nature: radioactive decay. It also retains heat (from previous heat sources: radioactive decay, and energy from graviational potential energy that was present before the mass of the Earth came together and compacted and before the bulk of dense metallic iron sank to the center) at a higher temperature than the surface temperature within it's depths because the material it is made out of has only finite thermal conductivity and only convects at a finite rate. This geothermal heat is supplied to the surface of the Earth at a very small rate, a bit less than 0.1 W/m2, less than 1/2000 of the solar heating rate of the Earth and atmosphere. Most of this geothermal heat comes slowly and steadily through solid rock, not in singular episodic events. It can vary over geologic time, but even then, it's direct heating effects can generally be ignored in the study of climate change on the global and regional levels (except near the origin of the Earth, which was a bit over 4.5 billion years ago) (the indirect effects of geothermal heat - such as continental drift and mountain ranges, and the geological portion of the carbon cycle (very slow compared to recent anthropogenic CO2 emissions) - obviously have important climatic effects). --- In general, when other properties (optical properties of objects and the space between them, thermal conductivity, fluid viscosity, etc.) are held constant, a greater difference in temperature between a hot object and a cold object causes an increase in the net heat flow from the hot object to the cold object. In the case of radiation, this heat flow also increases if the average temperature of the two objects increases, because blackbody radiation intensity increases with increasing temperature in a nonlinear relationship with greater increases per unit temperature change at higher temperatures - especially at shorter wavelengths. The greater net radiant heat flux between objects with a greater temperature difference is due to the greater difference between the radiant flux in one direction and the radiant flux in the opposite direction. While some solar radiation is absorbed in the atmosphere, a majority is absorbed at the surface. However, a majority of radiation emitted to space is emitted from the atmosphere. Without some net heat flux from where solar radiation is absorbed to where radiation is emitted to space, heat will build up near the surface and be depleted at higher levels in the atmosphere. This causes an increasing temperature difference (if they are initially at similar temperatures) between the surface and near surface and the higher atmosphere. This increases the net upward heat flow from the surface and within the atmosphere to various levels within the atmosphere, by radiation and convection. This will tend to settle toward some equilibrium flux when the temperature difference is great enough to sustain a great enough flux of heat to connect the circuit between solar heating and radiant cooling to space. Thus the surface will be hotter than the Earth appears from space (from space, the part that radiates directly to space is visible - this is a distribution that includes a fraction of radiation from the surface, but overall is cooler than the surface). Thus the surface will emit more radiation upward than actually is emitted to space from the cooler atmosphere...etc.
128571. Gord at 23:10 PM on 11 April 2009
        It's the sun
        Patrick - Re: Your Posts #267 A Solar Oven is neither a "heat engine" or a "refigerator in the sky". It does no work, nor does it require work to be done for it's operation. It simply reflects Electromagnetic fields from a focal point or to a focal point. It is just a mirror that has a parabolic shape. The Solar oven is, in fact, a parabolic antenna similar to all Satellite Dish antennas. All antennas are reciprocal devices that can be used for transmitting or receiving. The Solar Oven "receives" energy from the "warmer" Sun to heat "cooler" objects placed at it's focal point. The Solar Oven will "transmit" energy from the "warmer" object (water in the Brigham Young University experiment) placed at it's focal point to the "cooler" atmosphere. The temperature of the Solar Oven itself does not affect this outcome, as is evident from the Brigham Young University experiment: "At night the solar cooker needs to also be aimed straight up towards the cold sky. During the day the solar cooker needs to be turned so that it does not face the Sun and also points towards the sky." During the day, the Solar Oven's temperature is is warmer than it would be at night and it still cools the water at the focal point! ---------------------------- Any, radiation absorbed by a body will increase it's temperature. The Sun cannot absorb (and increase in temperature)energy radiated from the Earth because the only energy that caused the Earth's radiation came from the SUN! That is the same as saying that the SUN can heat itself....a violation of the Law of Conservation of Energy! ----------- You said.... "Why would the Earth cool if energy sources were eliminated? Might it be because it would continue to radiate to space as a function of it's temperatures, rather than simply shut down such radiation as a result of the loss of the sun?" The Earth, especially the Oceans, store heat and would continue radiate heat if the Sun were shut down....but only for a short period of time. If the Earth's molten core energy were also removed, the Earth would rapidly cool to near absolute zero. ------------ You said.... "At no point in Kiehl and Trenberth's diagram is energy being created or destroyed (except the sun - but that's a conversion of energy, not creation ex nihilo) or is the second law of thermodynamics being broken." Again, I totally disagree! The Law of Conservation of Energy is very clear..."ENERGY CAN NEVER BE CREATED OR DESTROYED" The In-comming Solar radiation (in Trenberth's paper) is only 342 w/m^2 and it is the ONLY ENERGY SOURCE. Even if ALL this energy (342 w/m^2) reached the Earth's surface and was ABSORBED it is IMPOSSIBLE for the Earth or the Atmosphere to radiate more than 342 w/m^2! Trenberth's Energy Budget shows that the Earth's surface radiates 390 w/m^2! 390 w/m^2 is GREATER than 342 w/m^2. A very, very CLEAR AND UNDISPUTABLE VIOLATION OF THE LAW OF CONSERVATION OF ENERGY! --- The 2nd Law of Thermodynamics states: "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 1. The atmosphere is cooler than the Earth's surface and Trenberth's Energy budget CLEARLY shows Back Radiation from the cooler atmosphere being absorbed by warmer Earth! 2. The ACTUAL MEASUREMENTS conducted at the Physics Dept.of Brigham Young University, Utah clearly shows that the Back Radiation does not prevent water from freezing to ICE when the water is placed at the focal point of a parabolic mirror solar oven directed at the colder atmosphere. 3. The AUTHORS of the Physics Dept.of Brigham Young University, Utah paper attribute have concluded, correctly, that this result COMPLIES WITH THE 2ND LAW OF THERMODYNAMICS. 4. Both the 2nd Law of Thermodynamics AND actual measurements PROVE that the colder atmosphere cannot heat the warmer Earth. Trenberth's "Claim" that Back Radiation from the cooler atmosphere can be absorbed by warmer Earth IS A VIOLATION OF THE 2ND LAW OF THERMODYNAMICS.
128572. Quietman at 15:13 PM on 11 April 2009
        Volcanoes emit more CO2 than humans
        Patrick That is exactly what I am working to find. The oceans are still largely big unknowns. The benefit of this entire AGW argument is that now scientists in many unrelated fields are looking harder at the evidence and investigating deeper. That government site that posted a hypothesis for the volcanic nature for the root cause for ENSO led me to look into ocean floor research and I find it's all recent research. The nature of volcanic ejecta along subduction zones lends support for the hypothesis IMO. It's recycled seafloor.
128573. Patrick 027 at 14:46 PM on 11 April 2009
        It's the sun
        Gord - I also saw somewhere above that you mentioned backradiation from the atmosphere being the basis of AGW theory. A couple clarifications: First: what is a theory. Some others have explained it perhaps better than I could and I will provide links to those explanations at a later time. For now, I must point out that for a body of understanding to have the title of theory, it is generally necessary to be about a 'big, general topic'. For example: The theory of biological evolution, the theory of quantum mechanics, the theory of general relativity. The understanding of human evolution is part of the theory of evolution; there is not a seperate theory of human evolution, because that is a specific instance of something more general (that's not to say that human evolution is identical to all evolution, but variations in how different organisms have or are evolving will be a part of evolutionary theory). With regards to AGW, this is an instance of climate phenomena, that is encompassed by climate theory. Within climate theory is the understanding of the greenhouse effect. Perhaps that might be called a theory in itself (theory of the atmospheric greenhouse effect on planets) - however, anthropogenic global warming is a specific instance of this, and the full effects of global warming require other aspects of climate theory (fluid dynamics, etc.) to be understood. However, any understanding of cause and effect must be considered theoretical - without theory, all we have is patterns with no explanation of how and why (see Hume). In that sense, the understanding of AGW is the theory of AGW, but in this case, 'theory' is not part of a title of a specific body of understanding, but the name of a kind of thing - that kind of thing being 'understanding'. --- Second: Backradiation necessarily does occur as part of a greenhouse effect, and it does have important effects. However, the greater control of surface temperature and temperature in general within the troposphere comes from radiative forcing at the tropopause level. A change in radiative forcing at any level is a forced change in radiant flux at that level. A change in radiant flux causes an imbalance, so that heat must be accumulating or will be depleted below that level. A change in radiative forcing can be caused by a change in LW optical properties (as in changes in the greenhouse effect caused by increasing CO2), a change in SW optical properties (changes in albedo), or changes in SW absorption below that level caused by changing incident solar radiation. Equilibrium is restored when resulting temperature changes cause changes in radiant fluxes so as to restore balance. Radiant feedbacks are caused by changes in optical properties caused by climate change (in the shorter term: clouds, humidity, snow, ice, vegetation, dust, vertical and horizontal temperature distribution); these feedbacks amplify or reduce the climate change necessary to restore balance. Radiative forcing at the tropopause level is important to the surface because, however the resulting accumulation in heat below that level is initially distributed, changes in convection that respond to it tend to spread the heating effect vertically, so that the surface and all levels of the troposphere tend to warm or cool together. Changes in the moist convective lapse rate in the tropics (the temperature decrease with height that is of neutral stability to moist convection) are a feedback, reducing the surface temperature increase relative to that in the mid-to-upper troposphere. In polar regions, the air is generally stable to localized convection (especially/(particularly?) near the surface and especially in winter), as heat is transported sideways from lower latitudes, while strong positive feedbacks enhance heating at the surface, so the surface warming tends to be greater than warming higher in the atmosphere at higher latitudes in general. The stratosphere in general tends to cool off with an increased greenhouse forcing because the upper atmosphere radiates more strongly to space and recieves less heat from below when LW opacity is increased (when LW opacity increases, the cooler troposphere blocks more radiant heat coming from the warmer surface, and, depending on initial optical properties, the upper colder troposphere may also block more radiant heat coming from the lower troposphere).
128574. Patrick 027 at 14:10 PM on 11 April 2009
        It's the sun
        Gord - It might help to go over the budget line by line (and elimate any wasteful programs that don't work, and provide more funding where good necessary programs are underfunded :) ): From: Kiehl and Trenberth http://www.atmo.arizona.edu/students/courselinks/spring04/atmo451b/pdf/RadiationBudget.pdf (All in W/m2): (PS most solar radiation is SW (shortwave) radiation, with wavelengths shorter than about 4 microns. Essentially all terrestrial radiation - radiation emitted by most of the Earth and atmosphere at their typical temperatures (the thermosphere is very optically thin - nearly transparent in general at relevant wavelengths for emission - and absorbs a very tiny fraction of total SW absorption - and so does not contribute much to this energy budget) is longer than about 4 microns; this is called LW (longwave) radiation.) --- 1. Total climate system: energy fluxes at top of the atmosphere: Absorption of solar radiation: 342 (incident) - 107 (reflected) = 235 (67 absorbed in atmosphere + 168 absorbed at surface) Emission of LW (longwave) radiation to space: 235 (195 from the atmosphere + 40 from the surface) solar energy in = 235 = 235 = LW energy out at the top of the atmosphere 2. Energy budget of the atmosphere: LW emissions from atmosphere: to space: 165 + 30 = 195 to the surface (back radiation): 324 total LW cooling of atmosphere: 324 + 195 = 519 Atmospheric heating: by LW radiation from surface: 350 by convection from surface: 102 (78 latent heat + 24 sensible heat) solar heating: 67 total atmospheric heating: 350 + 102 + 67 = 519 total heating of atmosphere by surface and sun = 519 = 519 = total LW cooling of atmosphere. No energy generated or destroyed in the atmosphere when in equilibrium. 3. Energy buget of the surface: Surface cooling: LW emission: 390 (350 absorbed by atmosphere + 40 directly to space) convective cooling: 102 (78 latent heat (evaporation) + 24 sensible heat) total surface cooling: 390 + 102 = 492 Surface heating: LW absorbed from atmosphere (back radiation): 324 solar heating: 168 total surface heating: 324 + 168 = 492 total heating of surface by sun and atmosphere = 492 = 492 = total cooling of surface to atmosphere and space by convection and LW emission. No energy generated or destroyed at/in the surface when in equilibrium. --- If there were an imbalance anywhere (in reality there are always imbalances, but over time, either in the global average of vertical layers, or for each location - accounting for horizontal heat transfer by winds and currents, they tend to average to zero except for changes associated with longer-term climate changes), heat would be accumulated or depleted, tending to cause (in the absence of sufficient latent heat of phase changes, etc.) temperature changes, which change the LW emissions, tending to bring energy fluxes toward balance. Bear in mind that Kiehl and Trenberth's budget is an approximation, and they point out in the paper that there is some significant uncertainty regarding how solar heating is distributed between the atmosphere and surface; I think any corrections in solar heating distribution would be mainly balanced by corrections in the convective transfer of heat from the surface to the atmosphere (technically, the heat must be conducted/diffused first into the air immediately next to the surface (which allows for some relatively small difference between the surface temperature and the air temperature effectively at the surface, considering the scale of the atmosphere as a whole), but convection takes it from there). Although they also use an approximation of the surface having perfect emissivity in the LW portion of the spectrum; this is a good first approximation, but I think it is actually somewhere between 0.9 and 1, so the radiation emitted by the surface is a little less than 390 (but still in that range) - however, depending on how emissivity varies by wavelength, this also means that some backradiation is reflected from the surface, so the total upward LW radiation at the surface will not be reduced as much as the emission from the surface will be for a downward correction of emissivity. Also, they did these calculations for globally-representative conditions, which will not always be globally averaged conditions because some effects vary nonlinearly (this is not a critism of their work - they discuss this in the paper). On that point, some correction in the opposite direction as that for imperfect emissivity might be made for surface LW emission because - as I recall from what I read - they used a global average surface temperature. When emissivity does not vary much over wavelength, total emission over the spectrum of relevant wavelengths is proportional to the fourth power of temperature, so horizontal spatial variability at any level tends to increase LW emission from that level for a given area-averaged temperature. Interestingly, the general tendency is for spacial variability to be reduced at the surface in response to global warming (because the positive feedback are particularly strong where snow cover and ice cover are reduced), which means a (slightly?) greater surface temperature increase will be required to produce the same change in global average surface LW emission (but there is also convection: see below). In the mid-to-upper troposphere, however, the general trend is for the warmer areas to warm more (in association with changes in the latent heating of the air due to greater humidity supply, etc, due to higher temperatures.), so less warming at that level in the global average would be required to produce the same global average change in LW emissions from those levels. These are examples of feedbacks. (Do not make the mistake of assuming climatologists have ignored them - although something can be ignored if it is very small in comparison to some other things - for example, the exact size of Lake Champlaign (sp?) in New York may have an effect on local climate but global climate - at least for sufficiently long term climate states (which, more than just being averages, actually encompass patterns in shorter-term variability - chaotic, cyclical, or otherwise) - is not generally sensitive to such a detail).
128575. Patrick 027 at 10:27 AM on 11 April 2009
        It's the sun
        Forget the last two paragraphs; that was prep work to come up with an appropriate comparison.
128576. Patrick 027 at 10:26 AM on 11 April 2009
        It's the sun
        Quietman - remember comments 467,469: http://www.skepticalscience.com/Arctic-sea-ice-melt-natural-or-man-made.html What happens when you take 1 gram at 150,000 K and toss it into a pile of mass 30,000,000,000,000,000 g. What is the temperature change of the 30,000,000,000,000,000 g? Assuming similar specific heat values, it would be around 0.000000000005 K. 1/30,000 mol in 1 g; 1/30 mol in 1 L, 1000/30 +~ 30 mol / cubic m. 30 mol* 10,000 m /10,000 cm2/m2 = 30*6.02*10^23 / 6 = 30*10^23; 1000*10^23 by mass, 10^26 div by 30e6 s/yr = 10^20/30 = 100*10^18/30 = ~ 3e18 ratio 3e18 , 100 years, 3e16 = 30e15,
128577. Patrick 027 at 05:45 AM on 11 April 2009
        It's the sun
        Gord - Just to be absolutely clear: My point that there is a refrigerator in the sky (probably many at any given moment, actually) was really just an interesting aside; it has little to do with the overall energy budget as mapped out in Kiehl and Trenberth (a paper I have looked at more than once in the past; I'm glad you've had the chance to read it). "If there were a "refigerator in the sky" heat would flow from the colder atmosphere to the Solar Oven's focal point where this energy would be concentrated." That's only true with some additional specifications. There are both heat engines and refrigerators in the sky. Temperature variations produce pressure variations that cause air to accelerate so as to tend to lift warmer air and allow cooler air to sink. Kinetic energy can allow air to flow from low pressure to high pressure in some ocassions, having the opposite effect - this is when kinetic energy does work, is converted to heat energy, and drives a refrigerator. Meanwhile there is the coriolis effect which causes air to accelerate sideways in proportion to it's speed, depending on latitude, etc... -------- "For both time periods cooling should be possible because all bodies emit thermal radiation by virtue of their temperature. So the heat should be radiated outward." Ask yourself this: If the atmosphere above were hotter (And sufficiently opaque - let's say cloudy) than the solar cooker, the solar cooker would not cool off by radiating upward. But why? It is not because it stops radiating altogether, because: "all bodies [ with nonzero absorptivity and nonzero emissivity ] emit thermal radiation by virtue of their temperature.". Remember those trees and buildings continue to radiate as well, and that does not change if the temperature changes (unless material properties change as a result - the obvious example is that if the trees get to hot, they'll combust, etc.) The reason the solar cooker would not cool off in that case is NOT because it suddenly stops radiating thermal energy, but because the atmosphere is radiating a greater amount back. Now back to the more usual situation: The atmosphere does radiate some thermal energy back to the surface, because it is not 100% transparent at all relevant wavelengths, and it is not so cold as to be at absolute zero. If it were that cold, or if it were 100% transparent so as to reveal to the surface the entirety of the dark of space, that solar cooker would cool off much faster - not because it radiates more, but because it would now recieve essentially ZERO radiation from above. (PS It would actually be necessary to raise the atmospheric temperature (over all vertical levels) to somewhat above the surface temperature in order to balance the emitted radiation with back radiation, because at the same temperature, the atmosphere (at least in the absence of clouds or very high specific humidity) is partially transparent over a range of wavelengths from about 8 to 12 microns.) If you still don't believe me, consider this: Imagine the Earth's surface is a hot magma ocean (it may well have been that shortly after planetary formation). Suppose it is glowing red hot, as we would expect based on it's temperature. Suppose the atmosphere is such that some of this glow is visible from space. This is the thermal radiation emitted due to the Earth's surface's temperature. But it is only red hot - it cannot cool to the sun, which is about white hot. Does this mean that the Earth is not visible from the sun? Not easily, but you'll still see it with a good enough telescope - let's say you're a superhuman with a super telescope and both survive such conditions. Photons from the Earth are reaching the Sun. There is a flow of heat from the Earth to the Sun. It just happens to be less than the flow of heat from the Sun to the Earth. The Earth is cooler than red hot, but it does emit thermal radiation to space, and a small fraction reaches the sun - it is only small because the sun does not surround the Earth but only fills a small solid angle as seen from the Earth. --- ""There are only two significant energy sources that can directly affect the Earth's temp: 1. The Sun 2. The Earth's molten core." " ... "If these two energy sources were elliminated, the Earth would cool to near absolute zero." Why would the Earth cool if energy sources were eliminated? Might it be because it would continue to radiate to space as a function of it's temperatures, rather than simply shut down such radiation as a result of the loss of the sun? ---- "All the energy radiated by the Earth and the atmosphere could still NEVER EXCEED the 342 w/m^2 Solar Energy!" Using Kiehl and Trenberth's numbers, because only 235 W/m2 are absorbed by the Earth, only 235 W/m2 can be emitted by the Earth to space - if the temperature of the Earth is not changing (ie there is no net gain or loss of heat, or sufficient rearrangements of heat energy, etc...). But that is the radiant flux to and from the Earth as a whole, including the atmosphere. The entirety of the 390 W/m2 radiated by the surface does not go to space; the great majority is absorbed by the atmosphere. To a first approximation, none of the backradiation from the atmosphere goes to space, either. At no point in Kiehl and Trenberth's diagram is energy being created or destroyed (except the sun - but that's a conversion of energy, not creation ex nihilo) or is the second law of thermodynamics being broken.
128578. Patrick 027 at 04:54 AM on 11 April 2009
        Volcanoes emit more CO2 than humans
        But what evidence is there that this volcanic activity varies sufficiently on the relevant time scales to have any detectable climatic effect on the relevant time scales.
128579. Quietman at 03:05 AM on 11 April 2009
        Volcanoes emit more CO2 than humans
        Patrick The volcanic aerosol forcing is not what I am pointing out at all. That really does not apply to volcanism along the seafloor ridges at all. My use of terrestrial volcanos is only to show the increase in vulcanism overall. It is the underwater vulcanic activity that I am concerned with. The Earth is mostly covered by water and in that water are many more volcanos than at the surface as they run the length of the ridges that more than encircle the earth.
128580. Quietman at 02:58 AM on 11 April 2009
        It's the sun
        Patrick "Temperatures of the plasma at the earth are found to be about 150,000°K" Magnetic holes allow some of this heat in. Gord Interesting points.
128581. Gord at 23:18 PM on 10 April 2009
        It's the sun
        Patrick - I forgot to include this. If there were "a refigerator in the sky" the atmosphere would have to be warmer than the Earth. A refigerator transfers heat from objects inside to the Radiating Tubes at the back. The Radiating Tubes are warmer than the surrounding air....so heat is transfered to the air. The atmosphere is, obviously, cooler than the Earth.....therefore...there IS NO REFIGERATOR IN THE SKY!
128582. Gord at 19:58 PM on 10 April 2009
        It's the sun
        Patrick - Re: Your posts #259 and #260 You said that "THERE IS a refrigerator in the sky" and "Going just by the excerpt that you provide, there is no proof that radiant heat is not recieved by the surface from the atmosphere." I disagree with both your statements. This contradicts the actual measurements conducted at the Physics Dept.of Brigham Young University, Utah clearly which shows this: (Reposted from #248) ------------------------ Solar Cookers and Other Cooking Alternatives "The second area of solar cookers I looked at was their potential use for cooling. I tested to see how effective they are at cooling both at night and during the day. During both times, the solar cooker needs to be aimed away from buildings, and trees. These objects have thermal radiation and will reduce the cooling effects. At night the solar cooker needs to also be aimed straight up towards the cold sky. During the day the solar cooker needs to be turned so that it does not face the Sun and also points towards the sky. For both time periods cooling should be possible because all bodies emit thermal radiation by virtue of their temperature. So the heat should be radiated outward. Cooling should occur because of the second law of thermodynamics which states that heat will flow naturally from a hot object to a cold object. The sky and upper atmosphere will be at a lower temperature then the cooking vessel. The average high-atmosphere temperature is approximately -20 °C. So the heat should be radiated from the cooking vessel to the atmosphere." http://solarcooking.org/research/McGuire-Jones.mht This link shows that heating cannot occur from the atmosphere. In fact, the article shows how to COOL items placed in the Solar Oven at NIGHT AND DAY! All you have to do is point the Oven away from the Sun during the Day and the Oven will transfer heat from the WARM object in the Oven to the COOLER atmosphere! It can even be used to produce ICE when the ambient air temp is +6 deg C! "If at night the temperature was within 6 °C or 10°F of freezing, nighttime cooling could be used to create ice. Previous tests at BYU (in the autumn and with less water)achieved ice formation by 8 a.m. when the minimum ambient night-time temperature was about 48 °F." This confirms the validity of 2nd Law of Thermodynamics....heat energy CANNOT flow from Cold to Warm objects. And, there is no Refigerator in the sky to force energy flow from Cold to Warm. ------------------- The Trenberth Energy Budget shows that the Solar Radiation absorbed by the surface of the Earth is 168 Watts/m^2 and reflected by the surface is shown to be 30 Watts/m^2. Both these figures add up to 198 Watts/m^2 and would be available to any Solar Oven. The Trenberth Energy Budget shows that the Back Radiation flowing from the colder atmosphere and absorbed by the Earth's surface to be 324 Watts/m^2. (The Back Radiation ABSORBED by the Earth is, supposed, to Heat the Earth according to the AGW theory) Notice that the Back Radiation EXCEEDS the Solar Radiation (the only energy source)! Solar ovens (parabolic mirrors) have no problem concentrating the Solar radiation at it's focal point producing very high temperatures. Parabolic mirrors will concentrate IR energy (Back Radiation) the same way. Notice the authors of the paper state: "During both times, the solar cooker needs to be aimed away from buildings, and trees. These objects have thermal radiation and will reduce the cooling effects. At night the solar cooker needs to also be aimed straight up towards the cold sky. During the day the solar cooker needs to be turned so that it does not face the Sun and also points towards the sky." If there were a "refigerator in the sky" heat would flow from the colder atmosphere to the Solar Oven's focal point where this energy would be concentrated. In Fact, according to Trenberth, the Back Radiation exceeds the Solar Radiation and is 163% GREATER THAN THE SOLAR RADIATION. If there really was a "refigerator in the sky"...The water at the focal point would NOT freeze, it would HEAT UP.....even MORE than it does with Solar Energy! --- Further, the authors have correctly attributed the freezing of the water as complying with the 2nd Law of Thermodynamics: "For both time periods cooling should be possible because all bodies emit thermal radiation by virtue of their temperature. So the heat should be radiated outward. Cooling should occur because of the second law of thermodynamics which states that heat will flow naturally from a hot object to a cold object. The sky and upper atmosphere will be at a lower temperature then the cooking vessel. The average high-atmosphere temperature is approximately -20 °C. So the heat should be radiated from the cooking vessel to the atmosphere." --- There, clearly, is no "refigerator in the sky"....and the results of the actual measurements absolutely confirm the validity of the 2nd Law. "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 So, we have an actual measurement that complies with the 2nd Law....this is not a surprising result! ------------------------------- ---------------------------- Patrick...you said... "Just to be absolutely clear: "Unless the Earth "created" energy....It cannot radiate more energy than it receives." It IS NOT radiating more than it recieves. You insist the sun is the only source of energy here, which is essentially true (geothermal and tidal heating are minute in comparison), but you seem to be forgetting about it here. The surface gets heat from the sun and the atmosphere. The atmosphere gets heat from the sun and the surface." Again, I disagree with the logic of your statement: 1. Trenberth's Energy Budget does not include ANY other energy source other than the SUN! 2. The Earth and the atmosphere receive their energy from the SUN. 3. The Earth and the atmosphere ARE NOT ENERGY SOURCES. Like I have stated in my Post #243... -------------- "There are only two significant energy sources that can directly affect the Earth's temp: 1. The Sun 2. The Earth's molten core. If these two energy sources were elliminated, the Earth would cool to near absolute zero. The Earth's atmosphere is NOT an energy source. The AGW'ers have produced an Energy Budget Diagram (which excludes the Earth's molten core, so I will as well) The Sun is the ONLY energy source in the following diagram. Here is a link to Kevin Trenberth's paper: Earth’s Annual Global Mean Energy Budget http://www.atmo.arizona.edu/students/courselinks/spring04/atmo451b/pdf/RadiationBudget.pdf --------------- The Law of Conservation of Energy is very clear..."ENERGY CAN NEVER BE CREATED OR DESTROYED" The In-comming Solar radiation (in Trenberth's paper) is only 342 w/m^2 and it is the ONLY ENERGY SOURCE. Even if ALL this energy (342 w/m^2) reached the Earth's surface and was ABSORBED it is IMPOSSIBLE for the Earth or the Atmosphere to radiate more than 342 w/m^2! Your posts seem to dispute this fact, but as part of your logic you have also violated the 2nd Law of Thermodynamics. Adding fluxes that include "a refrigerator in the sky" to force the Back Radiation to be absorbed by the Earth is the Violation of the 2nd Law. The actual measurements conducted at the Physics Dept.of Brigham Young University, Utah prove this. Further, "a refigerator in the sky" still would need energy to operate and it would have to come from the SUN! All the energy radiated by the Earth and the atmosphere could still NEVER EXCEED the 342 w/m^2 Solar Energy!
128583. Patrick 027 at 14:48 PM on 10 April 2009
        It's the sun
        Because many common processes do not involve nuclear reactions, thermodynamic properties are often calculated without taken into account entropy and free energy associated with nuclear reactions. This essentially leaves those processes out of the defined system. Without changing the definition of the system, nuclear reactions would occur outside the system and potentially add to and/or take from the system mass, energy, and entropy; alternatively, one can evaluate the thermodynamics of nuclear reactions as part of a system.
128584. Patrick 027 at 14:41 PM on 10 April 2009
        It's the sun
        Gord - (continued): ... When that colder air comes into contact with the hot object, the greater thermal energy of the hot object's particles (molecules, etc.) is such that collisions on average transfer energy to the colder air molecules; however, at any given temperature, there is a distribution of energies of the particles, and occasionally, an energetic molecule in the cold air will collide with a less energic molecule of the hot object. Taken all such collisions as a subset of the whole process, one finds a transfer of energy from the cold air to the hot object. This is less than the reverse transfer by all other collisions. And so on with thermal diffusion through the air. Random particle motions tend to spread out particles from one area over time. Collisions are very important, but even without them, over time, heat will diffuse outward from a hot region and inward to a cold region; the same mechanism tends to result in mixing of substances, such as when the aroma of bread spreads out in the air (although convective transport - turbulent mixing, as opposed to molecular diffusion - is often important as well in that process). But this motion is random, which means that some particles with greater energy will occassionaly approach the hotter region, etc. Also, most molecules at any given time will have some thermal energy (or else they would not be moving and so diffusion would be impossible), so the less energetic molecules that diffuse into the hot region still carry some thermal energy with them; it just happens to be, on average, less than the energy which is being taken away. Notice that thermodynamics deals with temperature and thermal energy, which deals with the kinetic energy of a distribution of random particle motions, that approaches an equilbrium DISTRIBUTION as energy becomes 'thermalized' - maximizing the entropy for a given amount of energy and reducing the free energy so that the substance as a whole can be described with a single temperature (in the absence of collisions, seperate populations of particles could move through each other while retaining their initial temperatures). Thus, thermodynamics necessarily involves statistics and probability distributions; the net effects are the sums of many individual random events. The most succinct way to state the second law of thermodynamics is that the entropy of a closed isolated system never decreases; it can decrease if the system is not closed or not isolated and interactions occur such that the production of entropy elsewhere allows a reduction in entropy in the system. The flow of entropy is equal to the flow of heat energy divided by temperature. When heat energy flows from hot to cold, the entropy of the cold body increases more than the entropy of the hot object decreases because the same heat energy entering the cold body brings more entropy per unit energy into the cold body than it takes upon leaving the hot body. A heat engine works by converting some heat to work (free energy); this can be done when there is a temperature difference. Heat energy flows in at a high temperature (low entropy per unit energy), some of it is converted to work (essentially zero entropy per unit energy), and the remainder flows out at a cold temperature (high entropy per unit energy). Entropy tends to increase; the maximum possible efficiency of a heat engine - the ratio of work produced per unit heat inflow at the hot temperature - is determined by what would conserve entropy. A smaller amount of heat energy flowing out at a colder temperature can carry the same entropy as a larger amount of heat energy flowing at a higher temperature, and the difference in energies is the available free energy. (If a heat engine were run off of an isolated source of cold (ice cubes), then the efficiency could be defined instead as the work per unit heat outflow at the cold temperature. This will generally be a different value than the other efficiency.) A heat engine working in reverse is a heat pump - a refrigerator if the enhancement of cold is the purpose. The maximum coefficient of performance possible is determined by what would just conserve entropy; for the same difference in temperature, it involves the same ratio of free energy to heat flow at the high temperature and free energy to heat flow at the cold temperature as those for a heat engine, except the coefficients of performance are the reciprocals of those ratios. Entropy also increases when two substances are mixed, and variations in composition can be a source of free energy - for example, in reverse osmosis, work is done to remove salt from water. Osmosis could be used to generate usefual energy from the mixing of fresh water and salt. Of course, there are other complexities; entropy depends on temperature and mixing can produce a change in the thermal energy. In general, any process (physical, chemical, etc.) can happen spontaneously if, taking into account diffusion, changes of state, changes of heat energy and temperature, pressure, etc, the total entropy increases. Thermodynamic equilibrium occurs when entropy is maximized (for a system in isolation - no mass or heat inflow or outflow); a system that is not in thermodynamic equilibrium possesses some available free energy; rather than destroying the free energy approaching thermodynamic equilibrium, one could allow a much smaller increase in entropy while extracting work from the system, until a different equilibrium is reached (it won't be the same equilibrium because the system has exchanged at least energy with it's surroundings). Kinetic barriers may exist that prevent a system from spontaneously reaching thermodynamic equilibrium or slow that process; such barriers can be used to regulate processes to preserve free energy; in some chemical and physical reactions, catalysts can form a tunnel through such barriers, making the barrier much smaller. --- You refer to this website: http://solarcooking.org/research/McGuire-Jones.mht in your comment 248 above. Going just by the excerpt that you provide, there is no proof that radiant heat is not recieved by the surface from the atmosphere. What is demonstrated is that this radiant heat flux is less than that upward from the surface (and the solar cooker). The excerpt even contains a statement that substances (depending on optical properties) thermally emit radiation according to their temperature. This emission only goes all the way to zero when the temperature goes all the way to zero - or when the substance is perfectly transparent and/or reflective. At any given wavelength, a material will emit radiation as a function of temperature and the material's emissivity; at local thermodynamic equilibrium, emissivity = absorptivity, and emissivity cannot be less than 0 or greater than 1. A perfect blackbody has emissivity = absorptivity = 1. Blackbody radiation intensity (energy flux per unit area per unit solid angle - multiplying by the cosine of the angle from the perpendicular to a surface and integrating over all directions that pass through the surface from one side to another gives the radiant flux per unit area from or passing through the surface in that direction relative to the surface) at any given wavelength, per unit wavelength, increases at all wavelengths as temperature increases, but increases much more at shorter wavelengths.
128585. Steve L at 10:43 AM on 10 April 2009
        Why is Antarctic sea ice increasing?
        This is an interesting post, John. Your blogposts have been missed in my free time. Something that comes to my mind is: "Is this a strong negative feedback?"
128586. David Horton at 10:04 AM on 10 April 2009
        Why is Antarctic sea ice increasing?
        Ah, that explains it. Who can think like a "skeptic"?
128587. Patrick 027 at 06:33 AM on 10 April 2009
        It's the sun
        Another example of NET heat flow that you might have more familiarity with: If you have a hot object and a cold object in a room and turn a fan on to circulate the air, convection will tend to bring heat from the hot object and to the cold object. However, unless the air is ever at absolute zero, there will be some heat energy transported to the hot object; it will just be less than what is removed (air leaving the hot object will be hotter than air approaching it, but the air approaching it can have some non-zero temperature, and thus does have some heat energy, and when it comes into contact with the surface, heat energy can be exchanged in both directions as molecules bounce against each other, but the net effect is to transfer heat from the hotter object to the cooler air).
128588. Patrick 027 at 06:24 AM on 10 April 2009
        It's the sun
        Just to be absolutely clear: "Unless the Earth "created" energy....It cannot radiate more energy than it receives." It IS NOT radiating more than it recieves. You insist the sun is the only source of energy here, which is essentially true (geothermal and tidal heating are minute in comparison), but you seem to be forgetting about it here. The surface gets heat from the sun and the atmosphere. The atmosphere gets heat from the sun and the surface. Here's why: Start at absolute zero on Earth, so nothing is radiating any energy. Turn on the sun. The surface and atmosphere now recieve heat. Neither is radiating any heat. Thus they are gaining thermal energy. Temperatures increase. Temperatures increase until the surface and atmosphere combined radiate to space the same amount of energy per unit time that they together absorb from the sun. But within that system, there is additional radiation back and forth, because the atmosphere absorbs some of the radiation from the surface, and the atmosphere radiates some energy downwards (in fact, different parts of the atmosphere radiate energy to and from each other, and because the lower atmosphere is generally warmer than the upper atmosphere (the thermosphere, etc, is a very small fraction and doesn't have much direct effect on energy budgets of other layers), the atmosphere actually radiates more strongly downwards than upwards - it looks warmer from below than from above because the cooler upper atmosphere blocks some radiation from the warmer layers beneath, and vice versa in the other direction)). The surface temperature will rise (or fall) until it's combined heat loss from radiation and convection balances it's heat gain from the sun and atmosphere. Each layer of the atmosphere will also have changes in temperature until it's heat loss by convection and radiation balances it's heat gain from convection and radiation, including radiation from the sun.
128589. Patrick 027 at 06:08 AM on 10 April 2009
        It's the sun
        THERE IS a refrigerator in the sky - in which, above the tropopause, kinetic energy emanating from below does work, lifting colder air and pushing warmer air down. Because of changes in pressure, rising air cools adiabatically and sinking air warms up adiabatically - in this adiabatic process, there can be a net reduction or gain in thermal energy as some kinetic energy is either produced or consumed (does work). When warm air rises past sinking cold air, the average temperature decreases; the change in thermal energy corresponds to a gain in kinetic energy. The reverse can happen, and has importance particularly above the tropopause; it is most obvious in the mesosphere, where circulation driven by kinetic energy from below cools off the coldest air. But that involves a rather small amount of energy and can be ignored to a first approximation in accounting for the heat energy budget of the climate system. The radiant heat transfered from the atmosphere to the surface is less than that transferred from the surface to the atmosphere, and that does not violate any physical laws. -- "I don't see any mention of "NET" heat flow." Okay, but that's what they mean. The world doesn't make sense if otherwise - why? Consider this: if the sun were next to a blue-hot star, would the sun (that part of it facing the blue-hot star) go dark simply by being next to the other star? Does no light from the sun reach any star that is hotter? With a powerful enough telescope, I am quite sure you could see the sun from Sirius. What you are saying suggests otherwise, that the sun's light must not reach anywhere where temperatures are greater than the sun's photosphere. That when there is a lightning bolt, any photons from the sun must avoid it. --- Where is energy being created? Add up all the thermal fluxes into the surface, out of the surface, and you will see they are equal (for equilibrium conditions). Do the same for the atmosphere; you will find the same result. The atmsophere and surface both radiate in each other's directions and recieve some of each other's emissions. This happens because while one is colder than the other, niether is at absolutely zero, nor is either perfectly transparent at all relevant wavelengths. The atmosphere does thermally emit radiation, and some of it reaches the surface.
128590. Patrick 027 at 04:19 AM on 10 April 2009
        Volcanoes emit more CO2 than humans
        It is true that volcanic aerosol forcing has an effect on NAM and SAM. But you've been refering to alternative pathways... Of course there could be seafloor material in Alaskan volcanos - it's associated with subduction of the Pacific plate. A constant rate of subduction would give rise to episodic volcanic eruptions, because it is not in their nature to erupt slowly and continuously. If you take a jar of sand and pour it out at a constant rate to form a sandpile, there will be small avalanches and occasional large avalanches off the side of the sandpile as it grows. That's not to say that all variations in volcanic eruptions must be due to chance or that plate motions are constant. (though they cannot move faster or slower or change directions with any persistence over intermediate time scales.) But look at the graph at the top of this site. What was the climate doing between 1880 and 1940?
128591. MattJ at 02:46 AM on 10 April 2009
        Why is Antarctic sea ice increasing?
        I have an idea. Even better than "the warm satisfaction of guessing it" would be the even warmer satisfaction of seeing the article re-written to include the latest information. As it is, too many readers will not see the point of it. There is nothing to "sink your teeth into". Finally, I promise that this warmer satisfaction will not contribute to AGW;)
        Response: Agreed, will update the article. I'll give a clue - as I read the paper, my immediate thought was "this is the first question my skeptic readers will ask when I post this article" (Quietman, Wondering Aloud, I'm looking at you).
128592. Quietman at 01:03 AM on 10 April 2009
        Volcanoes emit more CO2 than humans
        Patrick Re: "But **what** is it that convinces you so? " Maps of the Arctic Ocean Floor. The Locations of the trenches. The increased volcanic activity. The seafloor material in the ejecta from Alaskan volcanos. Portions of Oceans cooling while anomalous areas are heating. ALL point to a very active tectonic spreading and subduction in the arctic and a severe change in ocean currents.
128593. Gord at 21:22 PM on 9 April 2009
        It's the sun
        Re: Post # 253 Patrick - Here is the 2nd Law of Thermodynamics: "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 I don't see any mention of "NET" heat flow. I do see the words "not possible" though.....unless work is done to accomplish this flow. Work would involve the natural creation of an equivalent "refrigerator in the sky" which does not exist. This is proven by actual measurements conducted at the Physics Dept.of Brigham Young University, Utah. (see my post #246) ------ Also, you have not addressed the fact that "the Sun is the ONLY energy source" in Trenberth's energy budget diagram. Unless the Earth "created" energy....It cannot radiate more energy than it receives. This the most basic fundamental physics. Clearly, the 390 w/m^2 that the surface of the Earth radiates exceeds the in-comming Solar radiation of 342 w/m^2. Unless you have a different "definition" of the Law of Conservation of Energy ("ENERGY CAN NEVER BE CREATED OR DESTROYED") then 390 is greater than 342 and therefore VIOLATES the Law of Conservation of Energy.
128594. David Horton at 19:41 PM on 9 April 2009
        Why is Antarctic sea ice increasing?
        Ah, I was expecting at least a tee shirt with "I guessed the right answer on Skeptical Science and all I got was this tee shirt" written on it.
128595. David Horton at 14:18 PM on 9 April 2009
        Why is Antarctic sea ice increasing?
        There is a prize John?
        Response: No prize other than the warm satisfaction of guessing it. But now I'm starting to feel the weight of expectation - it wasn't that big a question and I'm regretting talking it up (particularly as Phillipe Chantreau's questions in #15 were much more interesting than mine) :-)
128596. David Horton at 07:52 AM on 9 April 2009
        Why is Antarctic sea ice increasing?
        Oh well, I'll try for the prize. One obvious question is - how much sea ice build up since 2004? Another is - if less sea ice leads to "to a decrease in salt rejection from ice" then when sea ice builds up, this trend should be reversed. That is we should see an oscillation, not a trend.
128597. chris at 07:42 AM on 9 April 2009
        Misinterpreting a retraction of rising sea level predictions
        re #21

        Unless there is a clear and continuous upwards trend in a set of data, applying a linear trend to it means absolutely nothing

        Not really HS. A linear trend is a linear trend. The whole point of determining a linear trend over a significant time period (7 or 10 or 11 or whatever years), is to establish significant progression of a variable in the context of stochastic variability ("noise").

        If 1998 was such an "anomalous year" why do the values from 2002 to 2007 statistically differ very little from the 1998 value, and how does this fact support a "warming" trend?

        That's the point, HS. 1998 was anomalously warm; the strong El Nino raised the global temperature by around 0.2 oC above the trend. Now (2002 through 2007) the global temperature has reached the anomalously warm temperature of 1998 without the warming "pulse" of a strong El Nino... ..that's how the warmth of 2002-2007 supports a warming trend. It's about 0.2 oC warmer in this period than the equivalent period 10 years previously.
128598. tommybar at 00:39 AM on 9 April 2009
        Why is Antarctic sea ice increasing?
        For one thing--Antarctica is massive. Is the ice build up in one particular area, and not so much in another?
128599. Brendon Eishold at 20:55 PM on 8 April 2009
        Why is Antarctic sea ice increasing?
        From what I understood from the paper the warmer air and ocean temps means the sea ice forms more slowly which reduces the salt rejection which weakens convective overturning. This would suggest to me that autumnal ice formation would be slower than normal and that the spring thaw would come later. Thing is over the last couple of years, at least, the amount of ice in autumn has been well above the long term average. This last summer the ice went right back to around average levels but currently ice levels are again well above average, up near 1 millions sq km's above normal. This means there has been a rapid increase in new ice through the autumn. Am I missing something?
128600. Philippe Chantreau at 15:06 PM on 8 April 2009
        Why is Antarctic sea ice increasing?
        Paragraph d of the paper clearly shows that P is not nearly as much a factor as the increased stratification, although you're right in the sense that it is a factor. I don't know what you have in mind, John. I am nowhere close to your background in physics but questions I have would be the following: since the net increase is due more to less melt than more growth, there should be some seasonal variations corresponding to that, i.e. increased summer extent, and also decreased amplitude between summer and winter. Is it visible in the data? Since there is decreased convection from the deeper ocean, there should be a relative increase of heat content at greater depths, is it the case (not sure there are datasets for that)? Finally, this appears to be bound to change at some point. How much of an equilibrium is it really? What happens when the upper layer is disturbed? Shouldn't the underlying water at some point get warm enough to displace the lower salinity layer? Then what happens? Now are you going to tell us what your question was or keep us hanging :-)?

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