Friday, 28 March 2014

Well here's a summary then WIlliam ...

A new comment on the post "A reader writes: Why are there people who seem hell-bent on denying anthropogenic global warming?" is waiting for your approval

Author :  D J Cotton

Well here's a summary then WIlliam ...

The Second Law of Thermodynamics never mentions thermal equilibrium or heat transfers from hot to cold. It is all about evolving towards thermodynamic equilibrium which is quite a different thing, involving mechanical equilibrium as well, and thus gravitational potential energy.

The Maxwell-Boltzmann distribution is derived theoretically for a non-gravitational field. Hence it is not strictly correct when a state of thermodynamic equilibrium (or close to such) exists and you are considering molecules at different altitudes, although it will apply in any horizontal plane.

It is a red herring to postulate a gas that does not absorb any solar radiation and re-emit it. If such an atmosphere did exist it would still exhibit a thermal gradient but, by the assumption made, it would be just as if it weren't there at all as far as radiation is concerned. Of course if it got too cold near the top, some would solidify and collapse.

It is energy from the Sun (mostly absorbed in the atmosphere) which heats the surface of Venus, for example, and actually raises its temperature from about 732K to 737K during the course of its 4-month-long daytime. But the whole temperature profile in the troposphere has to rise 5 degrees also for this surface warming to happen, and then indeed the surface is warmed by conduction from the base of the troposphere.

All planetary temperatures in tropospheres and even beneath any surface are determined by the gravito-thermal effect, and they have nothing to do with any greenhouse radiative forcing or sensitivity to carbon dioxide.

When they drilled the KTB borehole down to 9Km depth in Germany they were surprised at how much water they found underground. This then helps confirm that the gravito-thermal effect is also apparent in solids and liquids. At 9Km depth it was 270C, far hotter than they expected, with a thermal gradient in the outer crust at least 20 times as steep as the mean gradient to the centre of the core. That's because specific heat increases very significantly with the hotter temperatures in the mantle and core.

If you plotted just the temperatures between, say, 9Km and 4Km you would find that the near linear plot extrapolates quite well to the actual mean minimum daily temperatures at the surface.

Why is it so?


  1. A new comment on the post "New blog!" is waiting for your approval

    Author : D. Cotton

    That's good - then 30 to 40 people will learn the truth that the Radiative Greenhouse is smashed by radiation itself:

    There is no two-way radiation involved when a black metal disc just under the surface of water is receiving solar radiation from the Sun. Its temperature is raised by the hotter Sun. Its temperature is not raised by back radiation from a colder atmosphere, because that would violate the Second Law of Thermodynamics.

    Back radiation does not melt frost in the shade of a tree, but the Sun would if you cut down the tree. But the IPCC and NASA claim that the intensity of back radiation is greater than that of solar radiation reaching the surface.

    Every one-way transition of radiation is a completed, independent process which must (on its own) obey the Second Law. To claim that there is some net reverse process (such as the black disc warming the water which then evaporates and, days later, releases energy when it rains, is absurd. How can the first process of one-way radiation "know" that will happen in the future? What does happen is that the back radiation is pseudo scattered with each photon resonating and only ever temporarily raising electron energy (between quantum energy states) in the first molecule it strikes. That electron energy is not thermal energy which takes the form of kinetic energy mostly in the far heavier neutrons and protons. In other words, the energy never gets from the electrons to the nucleus.

    So here's how to get energy from back radiation:

    Build a model toy train. Place a black disc under water in the tender (coal car) and, at night, the back radiation will warm the black disc (being still as intense as solar radiation in the day) and the water will boil and thus be able to be used to drive a miniature steam engine that makes the train go around, and around, and around .. the track.

    You could make a fortune patenting this process scaled up to light up a city at night. /sarc

    But, until you do, I'll rest my case.

  2. A new comment on the post "New blog!" is waiting for your approval

    Author : D. Cotton

    It cannot be substantiated with standard physics that the surface of Venus is kept hot by radiation from the colder carbon dioxide atmosphere.

    In fact the surface temperature rises by about 5 degrees (from 732K to 737K) during the four-month-long day and so this requires an input of thermal energy, which cannot be coming from the colder atmosphere because, if it were, entropy would be decreasing.

    Venus cools by 5 degrees at night, and so it could easily have cooled right down over the life of the planet if the Sun provided no insolation. So we can deduce that it is energy from the Sun which is gradually raising the temperature of the Venus surface during those four months of Earth time. But less than 20 watts per square meter of solar radiation gets through to the surface because carbon dioxide actually absorbs incident solar radiation.

    If one tries to explain the 5 degree difference with Stefan-Boltzmann calculations for radiation, there is a difference of about 450 watts per square meter just between the two temperatures 732K and 737K, and so this is not supplied from the direct solar radiation which is only about one tenth of that which reaches Earth's surface.

    Hence there is no scientific basis for assuming that direct radiation to the surface is the cause of the high surface temperatures on Venus.