Yet More Corrections to Greenhouse Gas Theory Errors
Written by Dr Jerry Krause
The correction of intellectual error is often an arduous task. At the beginning of what is now known as science Galileo Galilei took on such a challenge and we are quite familiar with his story. It would seem that we should have learned to not place a great deal of confidence in human reason when the subject of our inquiry involves the natural world or universe. However, the most recent case involving continental drift and Alfred Wegener discloses that even modern scientists have a great tendency to cling to intellectual reasoning over empirical observation.
To anyone familiar with the history of science and the scientific hypothesis known as the greenhouse effect of certain atmospheric gases, it should be no surprise that I will likely face opposition similar to that faced by Galileo or Wegener as I attempted to disclose the fact that this popular hypothesis is based upon a fundamentally incorrect assumption.
This unstated assumption is that sensible heat can be transferred from a colder body to a warmer body, from a volume of the colder, generally upper, atmosphere to a volume of warmer, generally lower, atmosphere or from the colder atmosphere to the warmer earth’s surface that generally exists during midday.
While the condition—the atmosphere being colder than the earth’s surface—is that generally defined or assumed when the earth-atmosphere’s energy balance system is studied, the opposite condition—the surface inversion when the temperature of the surface is less than that of the base layer of the atmosphere—commonly exists during cloudless nights over land surfaces and in other common situations. In this case that assumed cycle cannot even begin or becomes quite confusing as the radiation emitted by the surface cannot be absorbed and converted to sensible heat in the warmer base layer of the atmosphere while at the same time it can be absorbed and warm the cooler layer which lies over the warmer atmospheric layer.
Isaac Newton, in formulating the Law of Gravity and this theory of gravity (which seem amazingly similar), stated that he did not know the cause of gravity and refused to speculate as to any possible cause. The reason for this, he stated, was that he knew of no observational evidence which suggested a cause. … In the present case an obvious and very fundamental question is: How can matter sometimes absorb radiation incident upon it and sometimes not absorb radiation incident upon it?
Fortunately for me, Albert Einstein answered this question long ago and Richard Feynman brought this answer to my attention in a simple way I could grasp. The fact is that matter always absorbs the radiation it is capable of absorbing according to the usual laws of absorption. However, Einstein assumed there were two types of emission—spontaneous and induced. According to absorbed radiation is not always converted into sensible or latent heat before it is emitted (strangely termed spontaneous emission) from the matter; instead a portion of the absorbed radiation can be directly emitted (induced emission) from the matter. From a consideration of Planck’s Distribution Law, Einstein concluded the absorption coefficient of certain wavelengths was equal to induced emission coefficient of radiation having the same wavelength. That induced emission if a real phenomena is confirmed by the common devices which we call lasers or masers.
It is clear that all theoretical reason which has been done concerning the greenhouse effect of certain atmospheric gases has ignored the possibility of induced emission and has assumed that all absorbed radiation must be converted to sensible heat before being spontaneously emitted by and from the absorbing matter.
Another important question is: Is all the past literature concerning the earth-atmosphere energy balance system wrong or misleading? I think not and I will use several basic situation to explain this conclusion.
MEASUREMENT OF LONGWAVE RADIATION
- E. Suomi [ ] stated that the presence of downward longwave radiation from a clear sky was positive evidence of the greenhouse effect. K. L. Coulson [ ] has reviewed the instruments which have been and are being used to measure terresteral and atmospheric emissions. Coulson likened the measurement of longwave radiation to the determination of the intensity of a light in a brightly lighted room with an instrument which is illuminated inside and out for which the detector itself is luminous. Suomi, S. O. Staley, and P. M. Kuhn [ ] designed a light and inexpensive net radiometer (Fig) which could be balloon-borne and gave its detailed theory, which is simply an analysis of the energy balance at the two absorbing-emitting (a-e) surfaces of the instrument. If this instrument is to detect only longwave emission its use must be limited to times when there is no solar radiation. The Eppley PIR pyrgeometer, whose use seems popular [ ], claims to measure longwave radiation during times when there is solar radiation and this possibility will be considered after considering the simpler case of night-time measurements.
It is clear that a major objective of radiometer design is to thermally isolate, except radiatively, as much as possible the detector (the a-e surface) from the remainder of the instrument and its environment. The actual performance of the Suomi-Staley-Kukn (S-S-K) net radiometer is easy to follow because the temperature (from the previous discussion a critical factor) of the a-e surface is measured and directly output (Fig). It can be seen that sometimes the temperature of the a-e surfaces are above the ambient temperature of the atmosphere and sometimes below. But it is clear that the temperature of the upward facing a-e surface, which detects the emission of the atmosphere above it, is always less than the ambient temperature.
If one studies the S-S-K net radiometer one fact should become evident. Its upper a-e surface is the equivalent of the earth’s surface; the principal difference between the artificial a-e surface and the natural a-e surface might be their thermal inertia. But when the natural surface is freshly fallen snow even this difference disappears. The difficulty in using the natural radiometer is measuring the actual temperature of the natural a-e surface [ ]. The previous comments might be incidental to the present topic of the measurement of longwave emission and even if they are, these issues will have to be considered later and now seemed an excellent time to introduce them.
The temperature of the upper a-e surface is seen (Fig) to be consistently 10oC, or more, less than the temperature of the atmosphere which is about 2 cm from the a-e surface. This temperature difference means when the atmospheric conditions are calm, the temperature of the natural surface and the temperature of the atmosphere 2 cm above the natural surface likely differ by 10oC or more. This temperature difference means when air temperatures measured 1.5 meters above the surface of the earth are used to calculate, when there is no actual measurement, the upward radiation emitted by the surface, there is likely considerable error. This temperature difference means the temperature of the a-e surface decreased below the temperature of the atmosphere to achieve an energy balance at the surface and the situation is that there is only on mechanism (radiation) by which this surface might lose energy. Calibration issue!!!
In view of the indicated performance of the S-S-K net radiometer, it would seem that the measurement (detection?) of longwave emission isn’t difficult and that very simple instruments can be reliably used.
Now, it is evident that , if the S-S-K net radiometer is set upon the earth’s surface, it must become an instrument capable of quantifying the downward longwave radiation emitted from a clear sky which is absorbed by its upward facing a-e surface. W. C. Swinbank [ ] modified a commercial (Funk) net radiometer so that he could measure and report such absolute values of emission from a clear sky under a variety of atmospheric conditions during the night-time.
Swinbanck’s report is notable because of its general absence from the referenced literature of the greenhouse effect which has been produced since its publication over thirty years ago. It is also notable because Swinbank did not detect any influence of the quite variable water vapor contents of the atmosphere which were present during some of the measurements when the atmospheric screen temperatures were similar. It is notable because Swinbank’s analysis of his empirical observations showed that values of the downward radiation measured were directly porportional to the sixth power of the atmosphere’s screen temperatures (K) with very good agreement. Not only were Swinbank’s empirical results not consistent with the greenhouse effect hypothesis, he also noted that they did not seem dependent upon atmosphere pressure since measurements made at significantly different elevations seemed to be consistent of his empirical relationship.
The commercial Funk’s net radiometer modified by Swinbank differed from an inexpensive net radiometer [ ] designed by the Suomi in that the absorbing-emitting surface of the Funk instrument was a thermopile whale that of the Suomi design was a blackened sheet of aluminum whose temperature was measured. Since the output output of the Funk instruments was only a voltage, it had to be calibrated by some laboratory procedure and this allowed Swinbank to modify the instrument and to obtain what he consider were values of the total downward emission from the atmosphere. From the earlier discussion, it is obvious that the temperature of the absorbing surface is important because this temperature defines the portion of the atmosphere whose emission can be detected.
The 10oC temperature difference makes a definite statement about the downward emission from the atmosphere. The statement is that it is always less than that emitted by the a-e surface when the upward facing a-e surface is the coldest portion of the radiometer which means that heat must be transferred to it from all other parts of the radiometer by all possible energy transfer mechanisms. The apparent simple solution to eliminate the complicated process of accounting for these heat flows within the instrument is to electrically heat the a-e surface to the ambient temperature of the instrument and atmosphere. In the case of the frequently used Eppley pyrgeometer, this is done. Thus, the problems of mearsuring longwave radiation alluded to by Coulson are simply solved and the energy balance at the a-e surface is the sum, of the absorbed downward radiation absorbed by the surface plus the electrical energy used to heat the surface, is balanced by the radiation emitted from the a-e surface.
However, this reasoning ignores the Second Law condition. As soon as the temperature of the a-e surface is increased, the portion of the downward radiation which the surface can absorb must decrease until it becomes zero when its temperature is equal to or greater than the temperature of the atmosphere from which the downward radiation is emitted. If this is the case, the energy balance at the a-e surface is that the electrical energy used to heat the surface is balanced by the radiation emitted from the a-e surface. Because all instruments have to be ‘calibrated’, the possible difference of energy balance might not have any influence upon their actual performance. Except surface temperature inversions often exist and when they do the ambient surface temperature is less than the maximum temperature of the atmosphere at some altitude above the surface.
Swinbank’s measurements over land surfaces were all made shortly after sunset and wind conditions during the period of the measurements are not reported. Initially, the period of measurement was quite long to establish the consistency of the measurements. In these cases it can be seen that sometimes the downward emission followed the ambient temperature and sometimes it didn’t. But these inconsistencies were small and did not really affect the over-al apparent quality of the measurements.
- C. King’s [ ] analysis of measurements of downward atmospheric emissions made at four Antarctic stations discloses the significance of the surface inversion which is a well known feature at these locations during the dark, winter season. The result of his analysis possibly explains why Swinbank’s relationship had been generally disregarded between 1963 and 1996. He found that if the ambient surface temperature is compared with the measured downward emissions, the Kelvin temperature was fourth power and not the sixth power which Swinbank found. However, when King compared the measured downward emissions with the maximum atmospheric temperatures found at the top of the surface inversions, he found the sixth power dependence reported by Swinbank. The data set analyzed by King was known to be contaminated by some measurements made during cloudy conditions; so it is readily understandable why the two sixth power relationships were not found to be exactly the same.
In the cases of the extreme surface inversion found over the high Antarctic Plateau, it is clear that the snow surface is acting as the a-e surface of a natural radiometer. The reason that the measured atmospheric emission was proportional to both the fourth power of the atmospheric temperature at the surface and the sixth power of the maximum atmospheric temperature is quite What are the radiative ones and that the conductive heat flow from the warmer subsurface and the conductive can convective heat flows from the warmer atmosphere at the top of the inversion are quite minor. Thus, the conditions of the natural radiometer confirm the performance of the radiometers used to measure the downward emission of the atmosphere. It is clear that if the radiometers used were of the Eppley design that very little heating of the a-e surface would be necessary to increase its temperature to the very cold ambient temperature so that the actual functioning of the radiometers of different design, those whose a-e surface can be heated and those whose surface cannot be, become nearly identical.
A BRIEF THEORETICAL CONSIDERATION
What are the implications of Swinbank’s relationship as corrected by King? If two planar and parallel solid surfaces faced each other in a vacuum so that only radiative energy transfer could take place, it is expected that two surfaces would come to both radiative and thermal equilibrium with each other regardless of any differences in composition or surface texture [ ]. From these studies of the Antarctic systems, it is clear that while near radiative equilibrium exists between the warmer atmosphere at the top of the inversion and the very cold snow surface, a thermal equilibrium does not exist. The evidence is overwhelming that condensed matter surfaces emit greater fluxes of energy than do isothermal layers of diffuse matter at the same temperature.
Thus, if the corrected Swinbank empirical relationship for the downward emission from a clear sky is compared with the Stefan-Boltzmann relationship for blackbody emission, the temperature relationship of the pseudo-thermal equilibrium at radiative equilibrium can be found.
REPORTS INVOLVING THE USE OF THE EPPLEY PYRGEOMETER
The Eppley Pyrgeometer is designed to not only electrically heat the a-e surface but the interior surface of the polished hemispheric window has also been coated with an interference film which primarily passes radiation with wavelengths between 3.5 and 50 µm. Hence, it is claimed that it can measure longwave atmospheric emission during the day as well as during night when shortwave solar radiation is absent. However, scientists [ ] who use this instrument have reported the need to correct daytime measurements for the heating of the window material which absorbs a portion of the atmospheric emission and thus is hotter than the ambient temperature. …
The empirical information of this latter report by E. A. Smith and L. Shi is very interesting and informative. There seems to be much gained by reviewing some of the basic circumstances at two sites and by considering the authors’ and other alternative explanations for the drastically different oscillations of the flux measured by the instrument at this one location.
The two sites differ in elevation (4.5 km vs. 3.65 km), topography (flat plateus vs. deep narrow valley), and humidity (dry vs. irrigated valley floor). The authors use the steep valley walls to explain the large magnitude of the daytime downward longwave flux which peaks shortly after 1200 hrs but the temperatures assumed (60oC) for these walls at this peak time is nearly 15oC greater than the maximum surface temperature at the same time at the flat, dry site. Obviously, the direct solar radiation strikes the flat surface more nearly perpendicularly than it can the steep valley walls at midday.
It has been shown [ ] that a cone is a good approximation for the theoretical blackbody cavity. A deep narrow valley approximates a cone. First, this means that the albedo of the valley is very likely greater than the albedo of any given surface. Second, by using the model shown (Fig) by Smith and Shi it is easy to see that the steep valley walls face each other in an approximately parallel fashion. It only seems reasonable to consider the possibility that the walls are close to a thermal equilibrium with each other. To consider this, I imagine moving the walls of the valley closer together until there is no flat valley floor. Would this change the thermal equilibrium of the walls? It could not if they were initially in equilibrium. From this reasoning and from what is observed, I conclude that the valley walls are likely near a thermal equilibrium with each other and with the valley floor regardless of the incident angle at which the direct solar radiation or the longwave radiation strikes and is absorbed by any given surface of this system.
The temperature of the a-e surface can be limited by two factors—the magnitude of the flux and the wavelength distribution of the flux. Smith and Shi focus on the magnitude factor and it does not explain the magnitude of the downward longwave radiation measured even when the temperature of the walls were assumed to be much greater than the greatest temperature of the valley floor. It might be too simple and without justification, but the minimum temperatature of the valley walls which could produce the maximum longwave flux measured by the pyrgeometer can be simply calculated in the same manner as the measured upward longwave flux from the valley floor can be used to calculate the floor’s minimum surface temperature (assuming that the surface emits as an ideal blackbody) at a given instant. The calculated minimum temperature of the valley walls is about 15oC when that of the valley floor is about 32oC. Certainly this more realistic than assuming the valley walls are at 60oC when the valley floor is about 32oC at midday.