Questions.....RE: The Greenhouse Effect

[SSDD]

The Greenhouse Effect


The treatment in the textbook (box on page 43) illustrates the greenhouse
effect by assuming an isothermal atmosphere-- (an atmosphere that is
all at the same temperature) that is perfectly transparent to solar
radiation, but acts like a blackbody in the infrared part of the
electromagnetic spectrum, where the planet emits radiation. It
absorbs all the radiation emitted from the surface of the planet, and
re-emits it: half in the upward direction to space, and half in the
downward direction, back to the surface of the planet. The problem is
solved by means of simultaneous equations: one is the radiation (or
energy) balance for the surface of the planet and one is for the radiation
balance of the atmosphere. Here is one alternative approach, which doesn't require solving simultaneous equations.

A simple approach

We can get the above results directly by recognizing that the top
layer of the atmosphere must emit 239.7 W/m2 of infrared radiation
to space (same amount of solar radiation that enters the atmosphere:
what goes in must go out). The bottom layer of the atmosphere
will emit an equal amount downward to the surface of the planet.
Hence, for thermal equilibrium, the surface of the planet must emit
enough radiation to balance not only the amount it receives from the
sun (239.7 W/m2), but also what it receives in the form of downward
infrared radiation from the atmosphere 239.7 W/m2). Hence, its emission
must match 239.7+239.7 = 479.4 W/m2. Applying the Stefan-Boltzmann
law: constant x T 4 = 479.4 W/m2. We thus calculate T = 303 K.
The figure below illustrates this calculation. Contrast it to the figure
above where we assumed no atmosphere, and you will see where
the greenhouse effect comes in.

The effective temperature we calculate in this manner is much warmer than the actual temperature of the Earth (288 K), because we made a number of simplifying assumptions.

Limitations of this calculation

1) It's assumed that the atmosphere is isothermal. The layer of the
real atmosphere that's most important in terms of the greenhouse
effect is the troposphere, where temperature decreases with height.
Because of this height dependence, the real atmosphere emits more
radiation in the downward direction than in the upward direction (88
units vs. 70 units in Fig. 3-19).

2) It's assumed that the atmosphere absorbs all the outgoing
radiation at all wavelengths in the infrared part of the
electromagnetic spectrum. In reality, the absorption of radiation by
the atmosphere is highly wavelength dependent. At some wavelengths
there's very little absorption and the radiation emitted by the
earth's surface escapes to space, while at other wavelengths it gets
absorbed, reemitted, absorbed and reemitted many times before it
finally escapes. To carry out this calculation accurately it has to
be done wavelength-by wavelength... to capture the fine scale detail
in the spectrum requires literally thousands of calculations
analogous to the one we did in class.

3) Radiative transfer isn't the only process by which energy escapes
from the earth's surface. Conduction of heat and evaporation of water
transfer about twice as much energy from the earth's surface to the
atmosphere as the net upward flux of infrared radiation from the
radiation does. If the temperature distribution on earth were
determined only by radiative transfer (as in this example) the Earth
would be so hot as to be uninhabitable. In this sense the true
'greenhouse effect' on Earth is much larger than the 33 K difference
between the observed surface temperature (288 K) and the effective
radiating temperature (255 K) ascribed to it in your text.

ATM S 211 - Notes

So the scientists at the University of Washington have a far different view of what is happening than you do, SSDD. Seems that most would go with the scientists at the U of W.

All I am asking is if that graph depicts the basic mechanism of the greenhouse effect...I have never seen such equivocation over such a simple question...either the graphic depicts the basic mechanism and the information is useful...or it doesn't and the university is publishing shit...which is it?

 

[SSDD]

The diagrams you show are quite oversimplified, where they pretend there is some thin layer of atmosphere somewhere above the earth that captures the entire physics. This is almost useless in understanding what is happening.

I got a lot of my atmospheric information from a long article by the American Institute of Physics.
Simple Models of Climate
They go through what happens layer by layer. The more valuable information starts with Fourier. Search his name in the article. The radiation flow has to be integrated (calculus) by a pile of infinitesimally thin layers.

So the universities in question are promoting falsehood...or at least the information they are providing is useless...is that what you are saying?

And again...my question/observations were limited to the basic mechanism...if the data provided in those graphs is not depicting the basic mechanism, then it is good to know that the universities are promoting fake/useless info...if the graphics do depict the basic mechanism, then they are sufficient for my questions/observations.

LOL No, the Universities in question stated exactly what they meant. That AGW is real, and here is how it works. It is dumb asses like you that seem to think that you can lie about what they say and get away with it.

What lie have I told rocks...I am trying to get to a starting point for a discussion...but there is no point in starting if we aren't on the same page...either we agree that the graphic in question depicts the basic mechanism for the greenhouse effect, or we don't...if we do, then I am willing to proceed even with a vulgar old whore such as yourself...if we don't, then there is no point in proceeding.

 

[Wuwei]

The diagrams you show are quite oversimplified, where they pretend there is some thin layer of atmosphere somewhere above the earth that captures the entire physics. This is almost useless in understanding what is happening.

I got a lot of my atmospheric information from a long article by the American Institute of Physics.
Simple Models of Climate
They go through what happens layer by layer. The more valuable information starts with Fourier. Search his name in the article. The radiation flow has to be integrated (calculus) by a pile of infinitesimally thin layers.

So the universities in question are promoting falsehood...or at least the information they are providing is useless...is that what you are saying?

And again...my question/observations were limited to the basic mechanism...if the data provided in those graphs is not depicting the basic mechanism, then it is good to know that the universities are promoting fake/useless info...if the graphics do depict the basic mechanism, then they are sufficient for my questions/observations.

I did not say falsehood. I said oversimplification. Their explanation is not at the level of a graduate course or science journal. It is compressing many pages and equations into a simplified picture for beginning students. Is that the level you want?

 

[Wuwei]

I am trying to get to a starting point for a discussion...but there is no point in starting if we aren't on the same page

A better starting point would be Trenberth's cartoon.

 

[SSDD]

I did not say falsehood. I said oversimplification. Their explanation is not at the level of a graduate course or science journal. It is compressing many pages and equations into a simplified picture for beginning students. Is that the level you want?

I don't have a graduate level question...my questions/comments are pretty much restricted to the graphics and what they say...either the information is accurate at a basic level or it isn't...if its, then we are on the same page and can proceed...if it isn't then there is really no point....

 

[SSDD]

I am trying to get to a starting point for a discussion...but there is no point in starting if we aren't on the same page

A better starting point would be Trenberth's cartoon.

Trenberths cartoon is shit and everyone knows it....the graphics above are far more straight forward and I don't want to get side tracked by trivialities and tangents...

 

[Wuwei]

I am trying to get to a starting point for a discussion...but there is no point in starting if we aren't on the same page

A better starting point would be Trenberth's cartoon.

Trenberths cartoon is shit and everyone knows it....the graphics above are far more straight forward....

You are exaggerating. There is one point that is shit and that is when he subtracts large uncertain numbers and gets a small result that is meaningless. Otherwise the diagrams you show are a simplification of what Trenberth shows.

 

[SSDD]

I am trying to get to a starting point for a discussion...but there is no point in starting if we aren't on the same page

A better starting point would be Trenberth's cartoon.

Trenberths cartoon is shit and everyone knows it....the graphics above are far more straight forward....

You are exaggerating. There is one point that is shit and that is when he subtracts large uncertain numbers and gets a small result that is meaningless. Otherwise the diagrams you show are a simplification of what Trenberth shows.

So since my questions/observations are basic in nature, can we proceed with the graphics above assuming that they depict the bare fundamentals and describe the most basic mechanism of the greenhouse effect

 

[Old Rocks]

This is a lower division course, and not a course that goes deeply into the mechanics of AGW. And the authors of the course definately state that the warming is real. Apparently you just looked at the graphs and were stupid enough not to read the text that went along with it. What one would expect of someone with no education beyond grade school.

 

[Billy_Bob]

The diagrams you show are quite oversimplified, where they pretend there is some thin layer of atmosphere somewhere above the earth that captures the entire physics. This is almost useless in understanding what is happening.

I got a lot of my atmospheric information from a long article by the American Institute of Physics.
Simple Models of Climate
They go through what happens layer by layer. The more valuable information starts with Fourier. Search his name in the article. The radiation flow has to be integrated (calculus) by a pile of infinitesimally thin layers.

So the universities in question are promoting falsehood...or at least the information they are providing is useless...is that what you are saying?

And again...my question/observations were limited to the basic mechanism...if the data provided in those graphs is not depicting the basic mechanism, then it is good to know that the universities are promoting fake/useless info...if the graphics do depict the basic mechanism, then they are sufficient for my questions/observations.

LOL No, the Universities in question stated exactly what they meant. That AGW is real, and here is how it works. It is dumb asses like you that seem to think that you can lie about what they say and get away with it.

Their calculations fail every time. They are incapable of ANY predictive value. Thus they are not reflective of reality.

 

[SSDD]

This is a lower division course, and not a course that goes deeply into the mechanics of AGW. And the authors of the course definately state that the warming is real. Apparently you just looked at the graphs and were stupid enough not to read the text that went along with it. What one would expect of someone with no education beyond grade school.

My questions/observations go to the fundamentals...it is at the bare bones foundation that I want to start...either you can discuss the topic at that level...or you can't...I deliberately chose the most fundamental description of the greenhouse effect that I could find. Like I said...I don't want to get diverted by trivialities and tangents...

 

[SSDD]

got to say...I am surprised and not surprised at the unwillingness of you warmers to engage in even a basic conversation even when we are using your materials...33 posts in and still not apparently willing to confirm that the graphics from respected universities are true...at even a basic level.

 

[SSDD]

This unwillingness to engage in a simple conversation...even using your materials exposes a pretty big issue if you ask me..despite all the confidence you exude on the topic...your unwillingness to discuss the basics speaks a different story.

 

[Billy_Bob]

This unwillingness to engage in a simple conversation...even using your materials exposes a pretty big issue if you ask me..despite all the confidence you exude on the topic...your unwillingness to discuss the basics speaks a different story.

They are either unwilling to defend an indefensible position or they are incapable of defending their position.

In either case, it stems from a lack of understanding of the science and the inability to articulate their position from verifiable facts. Just throwing up a link, without highlighting the relevant point area within it, tells me they don't have a F-ing clue.

 

[Old Rocks]

Why argue with a dumb ass lying brick wall. The OP was a lie. The class notes did not indicate that AGW was false. In fact, it was a simplified explanation of how AGW works. That the notes were supporting the science involved in AGW is evident in #13 and #18.

 

[SSDD]

Why argue with a dumb ass lying brick wall. The OP was a lie. The class notes did not indicate that AGW was false. In fact, it was a simplified explanation of how AGW works. That the notes were supporting the science involved in AGW is evident in #13 and #18.

Paranoid much rocks....in the first place, I haven't even mentioned AGW, and had no intention of mentioning it...I had questions about the fundamental mechanism of the greenhouse effect...I went out and got the most basic material I could find from supposedly respected sources...The OP was the truth and I haven't said a single thing that would lead a rational person to think otherwise....

Either you can discuss the fundamentals of the greenhouse effect or you can't...if you can't, then kindly buzz off and make room for someone who can...if there are any warmers here who can....that is.

 

[SSDD]

This unwillingness to engage in a simple conversation...even using your materials exposes a pretty big issue if you ask me..despite all the confidence you exude on the topic...your unwillingness to discuss the basics speaks a different story.

They are either unwilling to defend an indefensible position or they are incapable of defending their position.

In either case, it stems from a lack of understanding of the science and the inability to articulate their position from verifiable facts. Just throwing up a link, without highlighting the relevant point area within it, tells me they don't have a F-ing clue.

Interesting to watch...isn't it? Someone wanting to discuss the bare bones fundamentals of the greenhouse effect, and they aren't even willing to confirm that the materials published by respected universities on the topic are, in their opinion...true..

Genuine fear of engaging on the topic...hell of a thing...

 

[Billy_Bob]

This unwillingness to engage in a simple conversation...even using your materials exposes a pretty big issue if you ask me..despite all the confidence you exude on the topic...your unwillingness to discuss the basics speaks a different story.

They are either unwilling to defend an indefensible position or they are incapable of defending their position.

In either case, it stems from a lack of understanding of the science and the inability to articulate their position from verifiable facts. Just throwing up a link, without highlighting the relevant point area within it, tells me they don't have a F-ing clue.

Interesting to watch...isn't it? Someone wanting to discuss the bare bones fundamentals of the greenhouse effect, and they aren't even willing to confirm that the materials published by respected universities on the topic are, in their opinion...true..

Genuine fear of engaging on the topic...hell of a thing...

If they agree to the basic premises then they can not him and haw when that premise is shown false. IF they agree then they must also agree that premise is false when it is shown.

This they must avoid at all costs..

 

[SSDD]

This unwillingness to engage in a simple conversation...even using your materials exposes a pretty big issue if you ask me..despite all the confidence you exude on the topic...your unwillingness to discuss the basics speaks a different story.

They are either unwilling to defend an indefensible position or they are incapable of defending their position.

In either case, it stems from a lack of understanding of the science and the inability to articulate their position from verifiable facts. Just throwing up a link, without highlighting the relevant point area within it, tells me they don't have a F-ing clue.

Interesting to watch...isn't it? Someone wanting to discuss the bare bones fundamentals of the greenhouse effect, and they aren't even willing to confirm that the materials published by respected universities on the topic are, in their opinion...true..

Genuine fear of engaging on the topic...hell of a thing...

If they agree to the basic premises then they can not him and haw when that premise is shown false. IF they agree then they must also agree that premise is false when it is shown.

This they must avoid at all costs..

Guess so....doesn't say much for the "settledness" of the science though if they are afraid to even discuss the basics using their own materials...it isn't as if I had brought some "denier" material here to try and trick them with it...it is their own materials...I just have a couple of questions regarding them...

I have to tell you, I didn't expect this degree of fear...for all their bluster on varying topics to exhibit this degree of timidity when it comes to discussing the basics is just a bit surprising....Doesn't do much to support the swaggering bluster they exhibit on the rest of the board when they are tiptoeing as quiet as church mice around this topic.

 

[Wuwei]

Sorry, I had to leave in a hurry. The references you quoted are pretty much the same. I read the following reference in more detail
ATM S 211 - Notes

The author makes two simplifying assumptions:

1) It's assumed that the atmosphere is isothermal.

2) It's assumed that the atmosphere absorbs all the outgoing radiation at all wavelengths in the infrared part of the electromagnetic spectrum.

Of course the atmosphere is far from being all at the same temperature, and not all IR is absorbed, but it simplifies everything.

Using those assumptions he explains how you can make a back-of-the-envelope calculation of the temperature of the earth given the input radiation from the sun. The explanation starts at the heading, A simple approach

He does the calculation only by assuming an energy balance and the S-B equation. The input energy from the sun must equal the output IR out of the top of the atmosphere. From that and the S-B equation you can calculate the surface temperature.

It should be understood that this approach does not discuss the exact mechanism of the green house effect. The only aspect of the GH effect he uses is that the atmosphere radiates equally up and down. That's quite a simplification and is only a short cut to estimating the surface temperature, and why the earth does not freeze.

Where do you want to go from here?