Backradiation argument rope a dope

Icefisher

Desert surfaces with no water vapour in the air are hot by day and relatively cold at night

Non-desert surfaces with water vapour in the air are hot by day and relatively warmer at night compared to a desert surface.

First, my experience in the desert and tropics would be modified by saying in the second sentence.

Non-desert surfaces with water vapour in the air are not has hot by day as deserts but warmer at night compared to a desert surface.

The different signs show clearly that something other than backradiation is needed to explain this observation because if backradiation was the only means the day time non-desert would be even more hotter than the desert surface than the nighttime difference.

One would think that if everything in the sky is radiating equal amounts in all directions at all times and that was the sole mechanism that it would be impossible to not see a far warmer daytime non-desert tropic thermometer than a desert one, clearly thats not the case.

So we need another mechanism! If so we need to ask if that other mechanism in need of help from backradiation?

Without the water returning heat leaving the earth, back to earth, the night time unheated surface would quickly become exstremely cold. Even day time shaded areas would have frost in places.

Careful here. The nighttime effect is NOT backradiation. Its just plain old radiation from an atmosphere warmer than the surface.

One of the primary ways the GHG theory and backradiation is sold is by confounding the difference between the surface and the climate. I will get more into that later. But briefly here is an example of how that confuses:

When the hotter atmosphere/climate is radiating to the ground at a higher rate because of water vapor the climate/atmosphere system is actually cooling at an accelerated rate by transferring stored heat from radiatively inefficient atmosphere to the radiatively efficient surface which in turn radiates it to the sky. Here radiation is aiding cooling.

For the other mechanism I will get to in another thread, water vapor is very important. It has 120% more heat content than CO2.

Its more conductive. It radiates at higher efficiency than CO2. In the tropics where water vapor content gets to around 4% it has more than 100 times the population of CO2 and 120% more heat per molecule. Making it a minimum of 220 times more important than CO2.


The Persians in warm dry areas used this principle, in wells or pits, during times when it was not particularly cold to make ice.

Yep! In a nice high dry desert it can get hot during the day and quite cold at night. But that can perhaps be explained by the unavailability of stored heat in the atmosphere to warm the ground by common radiation. This should be instructive to the relative impotence of CO2 whether it back radiates or not.

Thus what we need is a daytime example of backradiation warming the ground as it is only during the day where backradiation from a warmer atmosphere exist.

And I don't see it. In the non-desert tropics any backradiation to the extent it exists by virtue of up to 100 times the greenhouse gases than the desert is overwhelmed by evaporation and convection.

Icefisher,

The surface tends to have higher emissivity than the atmosphere because it is made of a different material. This is a physics, not a religious reason.

Steve, I believe completely the lesser emissivity of the atmosphere is the reason our climate is warmer than the SB temperature.

We are discussing the mechanism and its testable values. I do not believe backradiation warms anything nor insulates anything. I could be wrong on that but I need to see how it would be calculated in a consistent way with the surface molecules in the diagram above. If you want to create a differential opposing force between the two models, surface and atmosphere gases, I need some evidence of how its calculated instead of being inserted as a plug value.

We already discussed your equations and we noted what comes out of them is plugging in the 33 degree greenhouse effect as a given. Not good enough! We need to go beyond that. I will be demonstrating a non-radiative process for warming the atmosphere to greater than the calculated uniform radiation of the sun. So not assuming its all due to GHG and back radiation is going to be important.



If you make the surface of the earth into lots of very thin layers then the top layer would be radiating upwards at 342W/m^2 and radiating down at about the same rate.


How can it radiate in both directions a total radiation greater than it receives Steve?

You need to describe how the opposing force operates fundamentally differently in the surface from the gas. The simple surface model is just given a value of what it gets from the sun and the gas model is not but instead built on a notion of a process that prevents equilibrium as assumed for the surface.

For the actual major greenhouse effect I would propose an analogy.

The analogy I would use for the mechanism is how you can do the very identical thing in a passive solar water heating system using concepts of diurnal solar variability, an insulated place to store energy, conduction (alone) from the collectors to the water medium, the one-way process of convection. Result of this demonstrable system is done almost everyday in practical passive solar water heating system and it does not depend in any way on internal processes of radiation.

In such a system, the ability to radiate either from the storage system to space or internally from the storage system to the collectors reduces the efficiency of the system and would cause you to not have water of an average temperature greater than the ambient average temperature as great as you can achieve in these systems. But even this may be a non-issue as what the atmosphere radiates to space, in a consistent surface model, will cause the atmosphere to heat until what it is radiating to space what it receives from the surface. If it radiates back to the surface its cooling the atmosphere to enable more radiation from the surface. What climate science has to do is stop playing a shellgame and palming the pea and show exactly by demonstration what is going on.

The layer below it will be about the same temperature so will be radiating upwards at the same rate - so the 342W between top and second layer approx cancel out.

I get your math Steve. But the point I am making is why it is assumed to not equilibriate in the same way as the surface model and cancel out in the gas model.

The system operates like a heat pump. If you had uniform radiation it would not.

The pump depends upon 1) a source of energy greater than the uniform radiation, which it gets each day the sun comes up; 2) and insulation design that prevents an equal loss of that energy when the sun goes down (relatively non-radiative atmosphere and no conduction or convection to space; 3) gravity to make the heat in the system convect; 4) a storage medium (the gases in the atmosphere)

If you had uniform radiation on the collector coils of the hot water system (and this can be physically demonstrated) the water in the system could not exceed the average uniform SB temperature. Instead you would get what you get out of your tap now without a hot water system. (but the reasons would be different for the tap water as the tap water would lose the heat from solar pulses by not being remote from the surface and insulated but by not being insulated and losing what it gains by pulses of the sun at equal rates.)

But uniform radiation is not what we get in the real world.

So depending on how much you are willing to invest you can begin to approach the maximum SB temperature of the unobstructed shining sun which is in excess of the 1000 watts. That amount periodically shines on the surface and with a means to collect it (conduction and evaporation) and a means to transport it from the surface to storage (convection); and that storage is relatively insulated we can reduce heat loss in the whole system and the whole system heats.

If you comprehend the passive solar water heating system operates in a manner to potentially explain the entire GHE it mandates a lot more care in how you build a model and not to plug in assumptions of radiation doing it via some mysterious force.


Further this brings to light that maybe a better explanation for impotence of sun variability is we should not be dividing by 4 changes in solar wattage to spread it evenly across the surface though thats another topic and it might have different competitors like GCRs and such.

But it is very likely a more complicated calculation than going to the evenly distributed heat average and showing its impotent.

At the top you say:

Steve in one of the threads below assumes backradiation warming of the climate system to be a fact.

There is no evidence of warming resulting from backradiation

Do you mean it to read like that in such an absolute manner?

I guess one has to be careful of the concept of backradiation and clearly separate it from a warm atmosphere warming a cold ground which is not backradiation but plain old regular radiation.

In the G&T refutation blog a great deal of time was spent trying to show G&T claim that warming of the surface by a colder atmosphere was not a violation of the 2nd law of thermodynamics.

The discussion on it by the AGW scientists was hilarious. Oh it doesn't heat the surface it nets out surface radiation. "nets out"? The first law of thermodynamics says essentially energy cannot be destroyed.

So if so where is the energy? The AGW scientists admit its not warming the surface so what kind of energy is this? Its not netting as netting without explaining where the energy went is an incomplete explanation.

So where is it? I am saying look at the surface model above.

That energy is devoted to warming colder molecules below until they are as warm or warmer than the surface molecule.

Then net energy transfer down is zero and total energy in equal total energy out as in the surface model nothing is there for backradiation.

In the case of a gas the ground surface is already warmer than the sky temperature. So for the atmosphere is the intial condition is different we need to heat the gas molecule instead.

The downward flow is zero to start with.

OK all is well. What is left to explain is why the lower atmosphere can be warmer than the surface or warmer than the SB average calculation.

Here I invoke the passive solar system with differences in emissivity of the atmosphere vs the surface.

First I have to adjust the SB temperature of the surface and raise it just to radiate what it would as a black body. Here its a little confusing which figure to use as many processes are going on, clouds, heat pump, etc.

But lets keep it simple and use the 288K Trenberth uses.

Non-cloud emissivity has been measured from space at somewhere between .75 and .89. We will use the more conservative figure as one can also deduce that from Trenberth's figures by back calculating what the radiative nature of the planet surface would be if there were no clouds by measuring its reflectivity. With .89 emissivity at 288K you get 352 watts. So instantly we have accounted for 44 watts of the greenhouse effect. (trenberths calculation of 396 less what 288K would emit from a .89 emissive surface, trenberth use 1.0 which is that of a blackbody)

So Trenberth is wrong and his diagram should recognize the earth is not a blackbody and give us a figure. It could be more but I won't go there now. I want to know what some of the more solid pieces are.

So at this temperature 288K needed to radiate 352 watts from a surface with an albedo of .89 also has according to Trenberth 102 watts rising from it from convection.

Wow! We are now down to a needed 250 watts to balance our equation strictly from a surface perspective.

We will need to get to the issue of the convection watts as they cannot accumulate forever. But keep in mind here the atmosphere does radiate 199 watts directly to space so we have an avenue for it without needing to travel back to the surface.

So we know from NASA average insolation on the surface is 174 watts. But what would it be without clouds as we are working on a cloudless solution here? Kind of difficult to calculate. But we should note that we backfilled the 330 watt trenberth budget down to 250 watts minus 174 watts leaving only 76 watts to account for.




That 76 watts could come at night time from the atmosphere warming the ground using plain old regular radiation. Bottom line here is we know from the diagram above that the ground radiates 51 watts into the atmosphere, on the basis of equal in equal out used by some for radiative systems (see Tallblokes site for a discussion on flow diagrams for radiation) that only leaves 25 watts to account for.

It is also the equivalent of 4 degrees. Which is probably within error bars of UHI and non-random sampling, etc.

Warmists deny this by equating the temperature of the lower atmosphere to that of the surface. Certainly there is interaction occurring here but no requirement I can think of for equality in this system. It can be constantly seeking equilibrium but finding it only in passing as the system switches states with the diurnal cycle.

Change to uniform radiation often suggested for simplification then the system is completely different. . . . its an apples to oranges comparison. Thats because you ate the heart out of the heat pump principle.

Do that to the passive solar water heating system and it won't work either.

I never see this in the discussion. The inverse square law.

The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy (in the same time period).
More generally, the irradiance, i.e., the intensity (or power per unit area in the direction of propagation), of a spherical wavefront varies inversely with the square of the distance from the source (assuming there are no losses caused by absorption or scattering).
For example, the intensity of radiation from the Sun is 9126 watts per square meter at the distance of Mercury (0.387 AU); but only 1367 watts per square meter at the distance of Earth (1 AU)—an approximate threefold increase in distance results in an approximate ninefold decrease in intensity of radiation.

Hi icefisher, I think you need to hit the textbooks a bit because basic physics books have the answers you're looking for.



Hi Miescatter. I certainly can appreciate all the points you are making. But it seems you are missing the point I am making.

I am not caring about quantum mechanics I am at a far more basic level. Note the labels on the arrows. They are designated as watts. Watts is a term that denotes an energy flow. An energy flow is a reduction of the energy content of the sending mass and an increase in the receiving mass. Thus you can get readings various ways and even get an energy flow into properly designed device but if you are not measuring the energy change from one body to the other body you are in danger of getting false readings.

I have a lot of copper prongs floating around my house pointing a lot of volts into the space I live in, but energy only flows when I change the conductivity of the one prong to the other prong and my meter does not run unless I do. Further blocking the flow does not cause either prong to warm. I have various ways of measuring the energy potential there and in doing so I draw a bit of that energy into my device but my lamp on the table gets none of it. I can even then convert that calculation to fit any flow I want given other information about resistance and such.

Steve would like for us to believe that the subsoil should be the sum of its temperature plus half the surface radiation if consistent with his atmosphere model.

Climate science likes to use the diagram on the left as a description of how the surface warms the atmosphere then switch to the diagram on the right to explain how the atmosphere operates to warm the surface.

If I could get Steve to fill in the diagram on the right the same way he once described to me he believed the surface operated in a post in a previous thread on this topic I will have made the only point I am trying to make.

The fact that you can take an active IR device or a cryogenically-cooled passive device and measure the temperature of the atmosphere doesn't impress me.

The issue here is energy flow not a measure of potential flow The first reply deals with the issue of partial spectrum absorption.

My theory is via changes in emissivity the atmosphere can warm the surface via conduction and radiation using a heat pump principle as the cause of the warming of the atmosphere akin to a well insulated passive solar water heater.

The elements of an atmospheric heat pump to achieve a higher than average temperature is 1) gravity; 2) low emissivity atmosphere to store non-radiatively acquired warming (radiative equilibrates with it self as it does in the surface diagram, but convection does not as it needs a radiative or conductive mechanism to reverse it); 3) non-uniform input. The degree of non-uniformity is important as it is the peak input that establishes a limit for a substance with an extremely low conduction rate but this operates even with highly conductive substances like liquids but conduction losses will be greater so the limit will be lower.

The source of the heat would be via convection storing additional heat (from the noon equatorial sun) into an effectively insulated atmosphere (an atmosphere with a lower emissivity compared to the surface). Thus increasing GHG would effectively lower the ability of the atmosphere to store heat.

If convection did not accelerate conduction (a fact that Steve and Iceskater have difficulty wrapping their mind around as described in the "CO2 and heating the atmosphere" thread). Then the heat pump principle would not operate and the passive solar water heater would not work either. The fact it does work and can be demonstrated establishes that convection does accelerate conduction by replacing warmed equilibrated medium (atmosphere or water) molecules with cooler ones.

Another device used by CAGW advocates is "uniform radiation" to simplify their explanations (incorporated in "averaged" radiation figures) but the heat pump would not operate without higher than average pulses of energy. So a uniform radiation would also kill the heat pumps operation.

The question of course if you did kill this heat pump would the surface be warmer due to the effect of GHG? I see no reason to believe so because to do so a perturb something from an equilibrium state you need an energy flow "like a real flow of watts".

The first diagram on the left side of the head post explains how the surface maintains that equilibrium without an atmosphere while losing heat to the subsurface.

So taking these comments carefully review the diagrams above again.

So I come up with an obvious conclusion. We don't measure the actual radiative temperature of the surface film, we instead measure the atmosphere at the Stevenson screen level or measure the bulk water a meter or so under the surface. Imperfect conduction (radiation is alleged to be perfect) restricts the flow of energy through water to the radiating/evaporating surface that is probably effectively at the radiating temperature of freezing saltwater triple point cooling there at that micro inch level (almost impossible to measure as you are instead measuring the latent heat in the water vapor (steam) just above the surface, or you are measuring an equilibrium state of the bulk upper layer ocean below the surface whose conductivity rate creates a cooling gradient to the surface.

That would put the radiating temperature of 90% or so of the surface of the planet that is wetted by oceans, lakes, rivers, and precipitation somewhere around 0 degC. That won't be the sensible temperature however.

To make the sensible temperature equal to the radiating temperature you would have to momentarily turn of radiation for a moment and allow for an equilibrium to develop.

So inefficient conduction greatly lowers the radiating temperature and inefficient radiation from the atmosphere is unable to fill the gap. As you increase radiation efficiency in the atmosphere you give more ability to the surface to radiate but what this does is cool the stevenson screen while it provides a flow of energy to the surface.

So the bottom line here I fail to see where my viewpoint crosses the line into the absurdity of energy flows from cold to hot in the maps of that he has drawn here before (the incomplete diagram on the right). He needs to complete the diagram. The diagram in the first reply demonstrates how multi-tomic molecules could absorb specific frequencies and reemit at least in part via full spectrum thermal radiation, create a notch in the spectra as viewed from space, and do it all without backradiation sending an energy flow back to the surface while avoiding warming itself to spray it all upwardsly towards cold space.

I get the conundrum. But Steve's inability to see how convection accelerates conduction is his whole problem. The radiating surface of the planet is lower than its surrounding soil and air because of the restrictions imposed on it by slower conduction from the mass of stored energy in the soil and the atmosphere.

Thus the only time the surface can actually emit at a rate close to the surrounding temperature of the soil and/or the atmosphere is when energy input is at least as high as the output. To get output radiation equal to input radiation you have to have a sufficiently warm soil and water and/or sufficiently wet and warm atmosphere to shut down conduction in both directions (an equilibrium) As the solar input daily rises above this level conduction turns on and energy starts flowing into the storage reservoirs the surface does not just raise its radiation level to that of the incoming energy.

Backradiation is simply an invention to cover budget discrepancies. One can only expose it by showing inconsistency between surface and atmosphere radiation processes. Steve sees his inconsistency so he runs away from this grasping at straws instead. Like the suggest of your post suggesting one just does not understand what is going on and hiding among the trees in the forest.

One way for there to be a flow from the atmosphere is via a one way acceleration of energy into the atmosphere via a heat pump design. Convection operates like this and accelerates conduction like a fanned air cooled CPU has accelerated cooling. Folks like to try to deny this easily demonstrated fact also.

The problem for CAGW proponents is convection doesn't care if the gases are GHG or not.

Sure!

These are data taken at 5 minute time resolution using a pretty standard pyranometer. The field site was inside the Arctic circle in March, and these are the raw data (no quality control etc applied)



And measured 2 metre air temperatures using a portable Vaisala met station:




The average we measured was somewhere around 250 W m^-2, but generally higher on warmer days. A typical average in a tropical atmosphere is more like 350 W m^-2