This adiabatic expansion/compression process of all atmospheric gases repeats ad infinitum to create the adiabatic lapse rate/temperature profile of the entire troposphere. Radiative forcing from IR active gases is a bit player completely dominated by the thermodynamics of convection, evaporation, and the ideal gas law which are the real causes of the real ~33C greenhouse effect, not radiative forcing from greenhouse gases.
As demonstrated by a paper in Nature by Robinson & Catling, convection/adiabatic lapse rate controls the radiative-convective equilibrium and tropospheric temperature profile of all planets in our solar system with thick atmospheres. The troposphere ends at about ~10,000 km where the pressure = 0.1 bar, at which point the atmosphere is too thin to sustain convection, and radiative forcing from greenhouse gases takes over to cause cooling of the stratosphere and beyond to space.
The greenhouse gas water vapor DOES have a profound effect upon climate, slowing of cooling at night and slowing of warming during the day. The wet adiabatic lapse rate is only one-half the dry adiabatic lapse rate, proving that water vapor has a large negative-feedback cooling effect, not warming effect, on climate.
Here's one of many such explanations recently published in the French magazine Contrepoints by French scientist Jacques Henry (Google translation from French):
To finish with the theory of greenhouse effect
By Jacques Henry
Since I sometimes get stolen green wood when I rise on the theory of the greenhouse effect, it is necessary to dot the "i". The greenhouse effect is now considered a "scientific fact" since millions of people adhere to this concept in particular "experts IPCC self-proclaimed climate" , a multitude of NGOs politicized and finally many ministers environmental or energy around the world and especially in Europe.
The hypothesis of global warming is based on two tenets, the greenhouse effect and the contribution of CO2 to the greenhouse effect. What is surprising, and disturbing, is that "scientific fact" is not based on sound science and compelling yet recognized as fundamental laws of thermodynamics or the gravitational equilibrium of the atmosphere. It is on this last point so I would insist in this post because the interpretation of gravitational equilibrium of the atmosphere has led to erroneous conclusions that have been misused to formulate the theory of the greenhouse effect and the intervention of CO2 in this theory.
I do not and will talk to the thermal radiative balance of the earth exposed to solar radiation is described by the equations of Planck and Stefan-Boltzmann black on the body, but only of the confusion has led to biased interpretation and erroneous atmospheric balance subject to the gravitational field of the Earth.
Unless deny gravitation and refute the observations of Galileo and Newton to the top of the Leaning Tower of Pisa, one must recognize certain facts. The atmosphere "weighs" on average ten tons per square meter at the sea. This is the first fact and the tiny gaps around the mean hold meteorologists because it is changes in atmospheric pressure anticyclones , depression and other phenomena related to just the fluctuating nature of the atmosphere of a field of high pressure to an area of low pressure variations on the whole of plus or minus 3%, which seems negligible but is not in Since huge air masses are involved. The density of the atmosphere and its temperature decrease with altitude, no one can deny these facts, ask any climber, it will confirm . Gravitational compression of the atmosphere therefore establishes a temperature distribution over the entire height of the troposphere, that is to say up to about 17 km altitude (at the equator) because beyond scarcity gas and ionization of molecules by the solar wind and cosmic rays are the laws concerning the behavior of gas no longer apply.
This correlation between altitude, air density and temperature is described by a simple law of physics called "adiabatic lapse rate", which has been verified and can not be disputed (see below). It indicates that the dry atmosphere cools to 9.8 degrees per kilometer and moist air only 6.5 degrees for one mile due to the very high thermal inertia of the water vapor.
As a reminder, the application of the laws of thermodynamics to Earth shows conclusively that the planet behaves like a black body at a temperature of - 18 degrees. The average altitude where you can find the temperature of -18 degrees is found to be 5000 meters. When the law describing the lapse rate of the atmosphere we find a mean surface temperature of 14.5 degrees (see below), which is fully consistent with all observations at the Earth is applied. Naturally, the closer you get to the poles, the higher the temperature decreases due to the impact of solar radiation decreases but the law describing the gravitational lapse rate of the atmosphere it still applies. And in deserts where the air is very dry, the average temperature is higher during the day and lower at night because there is not enough water vapor to absorb the difference of day and night.
Transposition of the comments on the atmosphere of Venus that led to the formulation of the theory of the greenhouse effect is wrong, for several reasons.
Venus is closer to the Sun and thus receives more radiant energy from the star, however its albedo (in a word can reflect solar radiation) is much higher than that of the Earth. The density of the atmosphere of Venus consists mainly of carbon dioxide (CO2) is about 92 times higher than that of the Earth with a ground pressure of 920 tonnes per m2 (basically as if we was at 1,000 meters under water on Earth) but the laws describing the lapse rate of the atmosphere are the same as those described for the Earth's atmosphere is a cooling of about 9 degrees per kilometer.
However, the density of the atmosphere of Venus (95 kg / m3 at the Venus ground) is such that the duct surface temperature according to the same laws of adiabatic compression to a temperature of 465 degrees. To find values similar to those of the Earth sea level atmospheric pressure must be at an altitude of 50 kilometers in the dense Venusian atmosphere where the temperature is so close to 0 degrees. We must not forget that the last day Venusian is 243 Earth days but trade between the bright side and the dark side of this planet are very active convection and if the illuminated face is "overheated" This explains why the face dark of the planet does not cool significantly because of strong winds continuously distributed heat around the planet.
For all these reasons, it can not be a greenhouse effect on Venus. The planet is indeed in radiative equilibrium with space but the parameters of this equilibrium are different from those existing for the Earth because of strong adiabatic lapse rate and due to the high density of its atmosphere. If there was a "greenhouse effect" on Venus because of its rich atmospheric CO2, there is a long time since the surface of this planet is molten gold that is not the case! There are indeed mountains and plains on this planet perfectly recognized by radar imagery and even volcanoes and perhaps the "sea" of liquid carbon dioxide supercritical ...
Confusion and transposition to Earth observations of Venus from the fact that the atmosphere of this planet is made up of more than 95% carbon dioxide, nitrogen for the rest and traces of sulfur oxides. He needed no more for the NASA engineers, including James Hansen, a former specialist in the atmosphere of Venus, incorrectly state that CO2 is a greenhouse because the surface of Venus is heated by this effect greenhouse at a temperature of 465 degrees: "There has to see what is happening on Venus! " , they said. But it is totally wrong and contrary to the laws describing the state of the gas! The theory of the greenhouse effect is therefore in violation of the fundamental laws of thermodynamics and also in violation of the laws describing the state of which are also associated gas, it's still much, much too much for n 'any critical thinking ...
For the curious here is the equation of the adiabatic equilibrium. The thermodynamic state of a column of air is described in a simplified manner as follows:
where U is the total energy, Cp the thermal capacity of the atmosphere (1004 J / kg / ° K for the dry air, wet air 1012 to a medium comprising 0.25% of water vapor), T the temperature of the portion of air column (in degrees Kelvin), g the acceleration due to gravity and h is the height or altitude. If this drift equation is obtained:
expressed in degrees K / km. We see the term g / Cp called "adiabatic lapse rate" which describes the balance between pressure and temperature of the atmosphere. This differential equation can be rearranged as follows:
Since g and Cp are positive physical quantities, we see immediately that the temperature distribution in the Earth's gravitational field, but it is valid for any planet equipped with a atmosphere decreases with altitude .
This equation can be solved well by introducing h "zero", the lower altitude at sea level or at the top of the Eiffel Tower for example T "zero", the temperature at this altitude:
And then there are easily ground temperature (h-zero = 0) by introducing into the calculation altitude 5 km to the isotherm at - 18 ° C corresponding to the radiative balance of the Earth system + atmosphere (as described by the Stefan-Boltzmann law):
t = - 6.5 (h - 5) - 18 = 32.5 to 18 = 14.5 degrees C, the 6.5 factor being the thermal capacity of the air loaded with water vapor. The average water vapor content of the atmosphere is of the order of 0.25%.
Note: These data are in any high school physics course and also there
There is a small detail to be to convince the skeptics who still have some courage to read this long post. If there were to be a greenhouse gas in our atmosphere, it would obviously steam for two reasons.
There has in the atmosphere more than 600 times more water vapor than carbon dioxide, it is still necessary factor 600 multiplied by 5, since the heat capacity of water is 4180 J / kg / ° K compared to that of CO2 is 840 joules / kg / ° K. We arrive at a factor of 3000 difference. So if there were to be a "greenhouse effect" on Earth due to water vapor, there is a long time since all the oceans would have evaporated into space [e.g. Hansen's "runaway-greenhouse" "tipping point" allegedly turning the Earth into Venus]... Carbon dioxide is wrongly accused!
Jacques Henry worked for many years as a researcher at the CNRS (Centre National de Recherche ScientifiqueI, the French. Partner of the Max Planck Society, and as a consultant for the nuclear division of Electricité de France (EdF) and is now retiredRelated:
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