Water in a lake at the bottom of the landscape has no potential energy. It has no potential to flow anywhere. There is no energy that can be released as water falls because it is at it’s lowest potential.

Similarly with a column of air in hydrostatic equilibrium. What causes air to move are forces acting on it – Coriolis and buoyancy especially. A parcel of air will rise if it is less dense than the overlying air. Work is done is raising the air parcel against the force of gravity – hence the derivation of the dry adiabatic lapse rate. The air parcel will continue to rise and expand until it is as dense as the surrounding air. It is then stable – there is no tendency for the parcel to move – there is no longer a buoyancy force acting on it. Buoyancy is related to the temperature as higher temperature air parcels are less dense – but the rise is driven by displacement and not internal molecular energies that include kinetic temperature.

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html

Assuming for a moment that the process buoyant rising of an air parcel is quick enough that it is adiabatic – then all the kinetic temperature of the air parcel is retained in an expanded volume. The air is progressively cooler as it rises and expands – but it doesn’t lose energy.

There are basic physical relationships that are drummed relentlessly into young civil engineers. Doug’s inability to get even these basics correct is annoying and a distraction from far more interesting problems in climate.

“Assuming for a moment that the process buoyant rising of an air parcel is quick enough that it is adiabatic – then all the kinetic temperature of the air parcel is retained in an expanded volume. The air is progressively cooler as it rises and expands – but it doesn’t lose energy.”

Of course it loses energy. How could it cool and not lose any? As the volume of air expands, if performs work on the surrounding. This amount of work matches the amount of kinetic energy lost by the molecules in the now colder volume of air.

And still, 7 months after I first asked it, you Rob Ellison cannot explain how the necessary thermal energy gets into the surface of Venus in order to raise its temperature by 5 degrees over the course of its sunlit hours.

Sunlight provides the energy Dougie. Sunlight also warms the Earth’s troposphere by on average 75W/m2. It is well mixed by turbulent mixing and will rise buoyantly. There is no mystery.

I have also been thinking about the natural removal rate lately, and figure on a 50 year timescale with the natural level being the long-term average (currently near 280 ppm). The good news here is that the climate can be stabilized even with a non-zero steady emission rate, and the equilibrium CO2 level is a linear function of emission rate. For example if we can get emissions down to 10 GtCO2 per year, the stable level is near 350 ppm, and it would return to that over the next 100 years or so. If we continue at the current 36 GtCO2 per year we stabilize at 520 ppm. This means that policy is even more important because now a wider range of CO2 levels is available to us, and we can even leave some poorer countries (and perhaps the aviation business) with the ability to emit if they must, which has been a major concern for some. Relying on natural removal rates by the ocean may be controversial, but it is an area for hope.

He is integrating over all frequencies in order to obtain a “heating rate” but the facts of physics are that the radiation from a cooler source does zero heating in a warmer target because its frequencies are too low.

This is Dougie’s essential problem. Greenhouse gas molecules resonate at specific frequencies. They can vibrate – transferring energy to adjacent molecules. They absorb and emit photons at specific frequencies and the energy is related to the frequency by the quantum idea – E = hv

For some fun photon facts – http://judithcurry.com/2014/10/09/my-op-ed-in-the-wall-street-journal-is-now-online/#comment-636903

If they are scattered back towards the surface they will cause molecules at the surface to vibrate. And the balance of all absorbed and emitted, convected and conducted energy must approximately balance at the surface give or take non-equilibrium warming or cooling.

These are baby physics and it is egregiously annoying that we return to it again and again.

He is integrating over all frequencies in order to obtain a “heating rate” but the facts of physics are that the radiation from a cooler source does zero heating in a warmer target because its frequencies are too low.

This is Dougie’s essential problem. Greenhouse gas molecules resonate at specific frequencies. They can vibrate – transferring energy to adjacent molecules. They absorb and emit photons at specific frequencies and the energy is related to the frequency by the quantum idea – E = hv

For some fun photon facts – http://judithcurry.com/2014/10/09/my-op-ed-in-the-wall-street-journal-is-now-online/#comment-636903

If they are scattered back towards the surface they will cause molecules at the surface to vibrate. And the balance of all absorbed and emitted, convected and conducted energy must approximately balance at the surface give or take non-equilibrium warming or cooling.

These are baby physics and it is egregiously annoying that we return to it again and again.

Jim D, yes, and the fact that the skin layer doesn’t change by several tens of degrees every time a cloud blows over should also tell you something.

ME – “Assuming for a moment that the process buoyant rising of an air parcel is quick enough that it is adiabatic – then all the kinetic temperature of the air parcel is retained in an expanded volume. The air is progressively cooler as it rises and expands – but it doesn’t lose energy.”

P-N – ‘Of course it loses energy. How could it cool and not lose any? As the volume of air expands, if performs work on the surrounding. This amount of work matches the amount of kinetic energy lost by the molecules in the now colder volume of air.’

I was careful to assume an adiabatic process. No matter or energy is lost to or gained from the surroundings. From this assumption you can derive the 1st law and the dry adiabatic lapse rate – the drop in temperature with height as the parcel of air expands. The average kinetic temperature of the parcel falls.

In reality it does lose energy – hence the larger lapse rate in actuality.

But consider a rubber balloon filled with helium. There is a confining force of the surrounding atmosphere – outside the balloon – and internally a volume of gas that is warmer and thus less dense than the surrounding air. The buoyancy force is defined weight of the displaced air less the weight of the balloon itself and the weight of the helium inside the balloon. The balloon will rise and until the density inside the balloon approaches the density of the surrounding air. The work that is done is to raise the balloon against the force of gravity – this is equal to the potential energy arising from the density differences.

Hot air is less dense than the surrounding air and is free to expand as it rises and the surrounding pressures falls. As it expands the volume increases and – in the adiabatic assumption – average kinetic energy decreases.

– and internally a volume of gas that is warmer and thus less dense than the surrounding air.

The helium is not of course necessarily warmer but is less dense.

No Dougie? I guess he has gone off to remedial atmospherics. All those years and all that effort and it is back to the drawing board. Ces’t le vie – eh Dougie?

Rising air does no gain potential energy and lose internal energy as it does. It starts off with potential energy from density differences and work is done raising the mass of the air parcel.

Ya don’t gotta be a hydraulic engineer to understand this – but it might help.

I didn’t say energy doesn’t balance at the surface. It more or less does at any particular point over a 24 hour period. But there is net energy loss in the late afternoon and at night and net energy gain during the morning and early afternoon. What you can’t explain is the net energy gain and how it reaches the observed temperature. You probably don’t realise you can’t explain it because you are brainwashed with the climatology garbage about adding the back radiation flux to the solar flux and bunging the total into Stefan Boltzmann calculations. That’s why you think water vapour warms by about 30 degrees, whereas in fact empirical evidence proves the physics I present which explains why all the water vapour cools by about 10 to 12 degrees.

“I was careful to assume an adiabatic process. No matter or energy is lost to or gained from the surroundings.”

So you don’t know what adiabatic means. The process is adiabatic if it doesn’t involve a transfer of heat through the boundary of the systems involved. It doesn’t mean no work can be performed on the surrounding through a volume change. The second stage of the Carnot cycle is a paradigmatic example of a reversible, isentropic, adiabatic cooling process (expansion) that generates work on the surrounding at the expense of internal energy. It is exactly analogous to the case of a rising parcel of air in the atmosphere (quick enough so that heat transfer at the boundary can be neglected).

“From this assumption you can derive the 1st law and the dry adiabatic lapse rate – the drop in temperature with height as the parcel of air expands. The average kinetic temperature of the parcel falls.”

Yes, the temperature of the parcel falls, and hence so does its internal energy, which you had denied earlier. (Ellison: “The air is progressively cooler as it rises and expands – but it doesn’t lose energy.”) It certainly does.

You know I have described Bernoulli’s equation to you Dougie. This is based on the ideas of kinetic and potential energies of fluids. Water from a reservoir has the potential to flow downhill in a pipe and have a kinetic energy at the end of the pipe discharging into a well. The water in the well has no potential energy. It is at the bottom of the gravity well. The top of the water has the same potential energy as the bottom – zilch.

A parcel of air warmer than the surrounding air has a potential energy resulting from density differences and it rises until the work of raising the mass of the air equal the potential energy. It then stops and has no inclination to move anywhere – it is stable. There is no potential energy in a stable air column. It is like saying one end of a stick has more potential energy than the other. Well – if it falls over sideways – but how likely is that in a stable air column?

Pretending it has an inclination to flow somewhere is a violation of the condition of local thermodynamic equilibrium

Kinetic temperature involves the random movement of molecules in a volume. More kinetic energy and the gas is less dense. It rises. It expands. It cools. Until it is in local thermodynamic equilibrium and doesn’t want to rise anymore.

Here it is at hyperphysics – http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html

As it rises – the motions are still random just less concentrated. This is simple enough even for Dougie do you suppose?

You are about as right as webby Doug – don’t have a meltdown.

“Rising air does no gain potential energy and lose internal energy as it does.”

It certainly does. You are misdiagnosing DC’s confusion. The gravitational potential energy change is irrelevant and negligible compared with the internal energy change. It’s the internal energy change that’s responsible for the lapse rate. As for the gain in gravitational potential energy of a rising parcel, it’s compensated by the loss from a descending parcel of air of comparable mass. It would only have any relevance to kinetic energy if parcels of air were free falling in the gravitational field. But they aren’t. They are mutually balanced. Rising and descending parcels of air in the atmosphere are rather akin to pairs of identical masses tied together in an Atwood machine. As one rises, the other one descends and potential energies are directly exchanged between then with negligible effect on the kinetic energy of the parcels as a whole. It’s adiabatic contraction and expansion that accounts for the works performed by, and corresponding changes in internal energy of, the air parcels. The gravitational field only is relevant to constraining the vertical pressure profile without which no work would be performed at all.

At no stage is the electromagnetic energy (cum electron energy) ever converted to thermal (kinetic) energy in the warmer surface. That’s what you, Rob, and most climatologists need to learn, and that’s why the surface of the ocean absorbs and transmits photons from the Sun, but rejects (pseudo scatters) photons from the colder atmosphere.

‘The absorption of electromagnetic radiation by water spans a wide range of physical phenomena, characteristic of the general interaction of radiation with matter. It absorbs strongly in the microwave region by excitation of molecular rotations. In the infrared it exhibits strong absorptions from vibrations of the water molecule. As you go above the visible through the UV toward x-rays, it successively absorbs by photoelectric effect, Compton scattering and finally pair production.’ http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/watabs.html

IR photons cause molecules to vibrate – e.g. heat. Pseudo scattering is pseudo-science.

‘It certainly does. You are misdiagnosing DC’s confusion. The gravitational potential energy change is irrelevant and negligible compared with the internal energy change. It’s the internal energy change that’s responsible for the lapse rate.

Average internal energy changes as I said. Rising air carries latent high into the troposphere and beyond. Rising air will also radiatively cool in the real world. A parcel will rise to where it is stable – and only cooling or further warming will change that. Again – the potential to rise and fall has to do with buoyant potential energy.

As for the gain in gravitational potential energy of a rising parcel, it’s compensated by the loss from a descending parcel of air of comparable mass. It would only have any relevance to kinetic energy if parcels of air were free falling in the gravitational field. But they aren’t. They are mutually balanced. Rising and descending parcels of air in the atmosphere are rather akin to pairs of identical masses tied together in an Atwood machine. As one rises, the other one descends and potential energies are directly exchanged between then with negligible effect on the kinetic energy of the parcels as a whole.

Is this an idea from Hadley Cell formation?
Low pressure cells are divergent and high pressure convergent. Cyclones and anti-cyclones spinning in different direction in different hemispheres. In general hot air will rise near the equator move towards the poles losing heat and then fall. The vectors of Hadley and Walker Cells create the trade winds.

But the potentials exist because of density differences – both rising and falling. This is no necessity for rising and falling air masses to be equal. A warming surface will warm the troposphere – more warmth rising in the troposphere than cooling air falling.

It’s adiabatic contraction and expansion that accounts for the works performed by, and corresponding changes in internal energy of, the air parcels. The gravitational field only is relevant to constraining the vertical pressure profile without which no work would be performed at all.

The work is in raising the mass of air in the atmosphere against gravity. I can only suggest that you work through the derivation of the dry adiabatic lapse rate if you are capable. Sometime that I have seen little sign of I might add.

Let’s try that again.

It certainly does. You are misdiagnosing DC’s confusion. The gravitational potential energy change is irrelevant and negligible compared with the internal energy change. It’s the internal energy change that’s responsible for the lapse rate.

Average internal energy changes as I said. Rising air carries latent high into the troposphere and beyond. Rising air will also radiatively cool in the real world. A parcel will rise to where it is stable – and only cooling or further warming will change that. Again – the potential to rise and fall has to do with buoyant potential energy.

As for the gain in gravitational potential energy of a rising parcel, it’s compensated by the loss from a descending parcel of air of comparable mass. It would only have any relevance to kinetic energy if parcels of air were free falling in the gravitational field. But they aren’t. They are mutually balanced. Rising and descending parcels of air in the atmosphere are rather akin to pairs of identical masses tied together in an Atwood machine. As one rises, the other one descends and potential energies are directly exchanged between then with negligible effect on the kinetic energy of the parcels as a whole.

Is this an idea from Hadley Cell formation?
Low pressure cells are divergent and high pressure convergent. Cyclones and anti-cyclones spinning in different direction in different hemispheres. In general hot air will rise near the equator move towards the poles losing heat and then fall. The vectors of Hadley and Walker Cells create the trade winds.

But the potentials exist because of density differences – both rising and falling. This is no necessity for rising and falling air masses to be equal. A warming surface will warm the troposphere – more warmth rising in the troposphere than cooling air falling.

It’s adiabatic contraction and expansion that accounts for the works performed by, and corresponding changes in internal energy of, the air parcels. The gravitational field only is relevant to constraining the vertical pressure profile without which no work would be performed at all.

The work is in raising the mass of air in the atmosphere against gravity. I can only suggest that you work through the derivation of the dry adiabatic lapse rate if you are capable. Sometime that I have seen little sign of I might add.

“The work is in raising the mass of air in the atmosphere against gravity.”

I hadn’t realized you were agreeing with Doug C. on this. So you both are making the same mistake but phrasing it differently.

Are you really denying that through adiabatic expansion a rising parcel of air loses an amount of internal energy DE equal to W, where the work W is the product of the volume change by the pressure?

Thanks for the link, Walt Allensworth. What bothers me most about this article is the comparison between something a scientist says and something a politician says. Kerry is clearly parrotting someone else, since he is not a scientist. I take a scientist’s word more seriously because at least I know that they have worked in the field, even if their interpretation of the results is different. Yes, even if their statistics are flawed.
Rose