Reply: Humidity increases nighttime temperatures
Dr. Sweger: I agree, and for the same reason that during the day high humidity slows the increase in temperature. The reason is that heat energy only flows in one direction: from a higher to a lower temperature. It is the same as in an electrical circuit. Electricity only flows from a higher potential to a lower one. During the day the energy from the sun is flowing from the sun towards the surface of the earth. The high specific heat of water impedes the flow of heat in the same way as a higher value of a resistor impedes the flow of electrons. At night the situation is reversed. Now the heat energy is flowing away from the earth into a very cold space, and the presence of water vapor impedes the flow of heat energy away from the earth’s surface. Thus the surface temperature decreases less on a humid night than a dry night.
The purpose of the paper was to demonstrate that any feedback loop between the effect of “greenhouse gases” and the earth’s surface must be negative, since it would result in an increase in water vapor, and thus an increase in the impedance of heat flow.
Reposts of two prior HS posts on Dr. Sweger's analysis:
Tuesday, March 13, 2012 [REPOST]
Water vapor, not CO2, controls climate and acts as a negative feedback
Physicist Daniel Sweger refutes the catastrophic AGW hypothesis in his paper The Climate Engine, showing that CO2 has a negligible effect upon climate and that water vapor acts as a negative feedback to global warming. Dr. Sweger uses data from 3 locales to show an inverse relationship between humidity and temperature. He notes,
"In the positive feedback mechanism as proposed by the global warming proponents this behavior would be reversed. Then the data would show a positive relationship between moisture content and temperature. But it does not. As suggested before, data is the language of science, not mathematical models."
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| The data clearly shows that the relationship between the amount of water vapor in the air and temperature is negative |
The role of water vapor in determining surface temperatures is ultimately a dominant one. During daylight hours it moderates the sun’s energy, at night it acts like a blanket to slow the loss of heat, and carries energy from the warm parts of the earth to the cold. Compared to that, if carbon dioxide has an effect, it must be negligible.
It is also clear from the data presented above that water vapor acts with a negative feedback. The data clearly shows that the relationship between the amount of water vapor in the air and temperature is negative; that is, the higher the amount of water vapor in the atmosphere the lower the surface temperature. In that regard, it almost acts as a thermostat.
As the air cools as a result of an increasing moisture content in the atmosphere, there is a decrease in the amount of water vapor produced by evaporation. Eventually this decrease of the level of water vapor being introduced into the atmosphere results in a decrease in moisture content. At this point more sunlight reaches the earth’s surface resulting in higher temperatures and increasing evaporation.
In the positive feedback mechanism as proposed by the global warming proponents this behavior would be reversed. Then the data would show a positive relationship between moisture content and temperature. But it does not.
As suggested before, data is the language of science, not mathematical models.
About the Author:
Dr. Daniel M. Sweger, AB (Physics, Duke University, 1965) and Ph.D. (Solid State Physics, American University, 1974) has been a research scientist at NIST, where he was active in a variety of research areas, including cryogenic thermometry, solid state and nuclear physics, and molecular spectroscopy. He also operated a computer software business and performed consulting for the US Army. He is now semi- retired and is an adjunct instructor at National College of Business and Technology (www.ncbt.edu), where, among other subjects, he teaches Environmental Science.
Saturday, April 2, 2011 [REPOST]
Physicist: Carbon dioxide has negligible effect on climate
Semi-retired physicist Dr. Daniel M. Sweger has been a research scientist at the National Institute of Standards and Technology, where he was active in a variety of research areas, including cryogenic thermometry, solid state and nuclear physics, and molecular spectroscopy.
Dr. Sweger's new paper, Earth’s Climate Engine (PDF), finds that if carbon dioxide has an effect on climate, it must be negligible. Instead, he finds on the basis of data and theory that water vapor is the dominant influence on climate, and its influence is the opposite of that assumed by the IPCC climate computer models.
From the Summary:
Dr. Sweger's new paper, Earth’s Climate Engine (PDF), finds that if carbon dioxide has an effect on climate, it must be negligible. Instead, he finds on the basis of data and theory that water vapor is the dominant influence on climate, and its influence is the opposite of that assumed by the IPCC climate computer models.
From the Summary:
… While models can be useful, the results must be compared to actual measurements, i.e. data. Data is the language of science, but little has been done in that regard with the climate change models.SOURCE
It is the premise of the author that water vapor is the dominant influence in determining and understanding global climate. Water vapor is much more abundant in the atmosphere than carbon dioxide, and its physical properties make it more important as well. During daylight hours it moderates the sun’s energy, at night it acts like a blanket to slow the loss of heat, and it carries energy from the warm parts of the earth to the cold. Compared to that, if carbon dioxide has any effect it must be negligible. Thus, the purpose of this paper is to explore the effect of water vapor on climate.
Detailed calculations and analysis of data from several locations clearly demonstrate that the effect of water vapor on temperature dominates any proposed effect of carbon dioxide. Furthermore, it is clear from the data presented that water vapor acts with a negative feedback on temperature, not a positive one. That is, the data demonstrate that increasing the level of water vapor in the atmosphere results in a decrease of temperature,not an increase as predicted by the climate models. In essence, atmospheric water vapor acts as a thermostat.
These results call into question the validity of using the results of the current general climate change models, particularly as the basis for policy decision making.
The high specific heat of water vapour is relevant but there is another mechanism involved as well.
ReplyDeleteBeing lighter than air water vapour rises higher and faster especially when the latent heat of condensation is released.
The higher it goes the more of its kinetic energy is converted to gravitational potential energy which is then available to be returned to kinetic energy in the descent of dry air.
So:
i) During the ascent the vapour cools the surface by taking kinetic energy upwards and converting it to gravitational potential energy. Only a portion of its energy is lost to space by radiation.
ii) During the descent the dry air warms the surface by converting gravitational potential energy back to kinetic energy.
It is the energy (kinetic energy and gravitational potential energy combined) locked into the convective cycle of uplift and descent which raises the surface temperature some 33C higher than the S-B expectation.
Not GHGs
In the paper Sweger says that the earths albedo is 30% therefore its emissivity is .7
ReplyDeleteHow on earth does he come to that conclusion?
Albedo is measured by satellites and is indeed ~30%
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