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What is a Watt???
#1
Hi All,
Over on this thread Richard T Fowler kindly took the time to correct me in my understanding of what a Watt means.
I doubt I am the only one to have had, or am still having problems getting to grips with what a Watt actually is.

I have attached to this post a pdf copy of the discussion as it happened, and I hope it helps others.

Please feel free to ask any questions arising, you won't look any sillier than I already have..
Am I embarrassed? Should I be embarrassed?
Well, no, it is not that I was wrong, it is that I have learnt from it.

I may even be able to answer some (simple) questions,
but more likely others will be able to answer them.




Attached Files
.pdf   Richard T Fowler & Derek - What is a Watt discussion_Final..pdf (Size: 349.45 KB / Downloads: 535)
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#2
Hello Derek,

I appreciate your acknowledgment, and I'm glad to have been of service to you and your readers.

Watts are easy. Just remember, a watt is not a watt-second. Watts are power, watt-seconds are energy. A watt-second = 1 joule. And a joule does NOT equal a watt.

If anyone is still confused, it may perhaps be that they haven't understood the difference between power and energy. I think you, Derek, have understood it. But you sometimes get tripped up in considering that a watt = a joule-per-second, and you seem to have sometimes thought that this somehow makes watts interchangable with joules. But they are not interchangable. They are both SI units, which measure different things. On one level, you have always understood that. On another level, the practical level, you have sometimes confused them, which in turn led to the confusion over whether seconds should be included in the measurement of total incoming radiation.

An additional source of confusion is when we speak of "radiation", it is possible to mean EITHER power OR energy, and one has to use the context of the discussion to discern what we're talking about. I think that those who have worked such problems in the past tend to assume that others automatically know whether the discussion is about power or energy. (In this case, it was about power, but even if one knew that, one could still be confused by the fact that, since we are speaking of an *average* power for a period of time, the average power varies directly with total energy.)

Happy thinking, then! On to the next question ....

RTF

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#3
(01-12-2011, 06:29 AM)Richard T. Fowler Wrote: An additional source of confusion is when we speak of "radiation", it is possible to mean EITHER power OR energy, and
one has to use the context of the discussion to discern what we're talking about.


I think that those who have worked such problems in the past tend to assume that
others automatically know whether the discussion is about power or energy.
(In this case, it was about power, but even if one knew that, one could still be confused by the fact that,
since we are speaking of an *average* power for a period of time, the average power varies directly with total energy.)

Happy thinking, then! On to the next question ....

RTF

I wonder if another penny has just dropped.
I thought "We" had been talking about "radiation" in relation to the Global Energy Flow W m-2 K&T type plots,
as commonly referred to as Global energy budgets. I assumed we were talking about energy flows.
ie, "Watt-seconds"

In the case of the P equation, I would assume now Watts is used in the context of power.
ie, Watts.

A seemingly small but actually quite important difference.


Attached Files
.pdf   How NOT to discuss in context...pdf (Size: 318.92 KB / Downloads: 431)
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#4
A FEW EQUATIONS

RTF

Richard, my genuine apologies, in that I deleted the content of this post completely unintentionally.
Now restored as Post 7 below - Thank you SST.

Thanks in advance
Derek.
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#5
Phew! A hard lesson. I am a novice with the physics and the practical meaning of the different terms used in the subject of climatology (if that is the correct term?).

My attempt to understand energy can be seen in this Post in the thread MELTING GLACIERS.

There I attempt to calculate the energy needed to melt enough landborne ice in ten years to raise global sea levels by 1 metre. I don't believe it is possible but then my understanding and calculations are newly aquired and may lack understanding of some critical point.

Meanwhile, for those of us still way down in the learning curve may I offer:

Heat Transfer, Conduction, Convection and Radiation by Nasif Nahle.
Environmentalism is based on lies and the lies reflect an agenda that regards humanity as the enemy of the Earth. - Alan Caruba
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#6
An Excerpt:

Quote:Confusion of watts, watt-hours, and watts per hourThe terms power and energy are frequently confused. Power is the rate at which energy is generated and consumed.For example, when a light bulb with a power rating of 100W is turned on for one hour, the energy used is 100 watt-hours (W•h), 0.1 kilowatt-hour, or 360 kJ. This same amount of energy would light a 40-watt bulb for 2.5 hours, or a 50-watt bulb for 2 hours. A power station would be rated in multiples of watts, but its annual energy sales would be in multiples of watt-hours. A kilowatt-hour is the amount of energy equivalent to a steady power of 1 kilowatt running for 1 hour, or 3.6 MJ.

Terms such as watts per hour are often misused.[15] Watts per hour properly refers to the change of power per hour. Watts per hour (W/h) might be useful to characterize the ramp-up behavior of power plants. For example, a power plant that reaches a power output of 1 MW from 0 MW in 15 minutes has a ramp-up rate of 4 MW/h. Hydroelectric power plants have a very high ramp-up rate, which makes them particularly useful in peak load and emergency situations.

Major energy production or consumption is often expressed as terawatt-hours for a given period that is often a calendar year or financial year. One terawatt-hour is equal to a sustained power of approximately 114 megawatts for a period of one year.

Red bolding mine
Wikipedia LINK
It is our attitude toward free thought and free expression that will determine our fate. There must be no limit on the range of temperate discussion, no limits on thought. No subject must be taboo. No censor must preside at our assemblies.

–William O. Douglas, U.S. Supreme Court Justice, 1952
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#7
Derek,

Thought you might want to know, you've just been accused of what amounts to scientific fraud over at the Air Vent page where we met.

The question is over a matter that is in the Johnson work, Computational Blackbody Radiation. Johnson allegedly claims that he is using the diameter of the Earth to compute the disc-equivalent surface area, but he is plugging in "diameter" in the value where radius is supposed to go.

ScienceofDoom is claiming that you were just joshing everyone by pretending to believe that this was correct. He is implicitly saying that you knew it wasn't, all along.

I thought I saw a link to a copy of that here on your forum somewhere. I'll have to go look for it now.

RTF
Reply
#8
A FEW EQUATIONS


Equation #1. Watts = "joules per second" = "power".

This is a rate of INTRODUCTION of energy into a certain defined volume of space. (Or, conversely, a rate of its REMOVAL from such a volume.)

To introduce energy into a defined volume of space from outside that defined volume, the energy has to EITHER pass through the boundary of the volume, OR be created within that volume.

For problems that involve only the transport of existing energy, the only introduction of energy is by its passing through the boundary of the volume from outside the volume.

Since the boundary consists of a finite, positive number of planes, the entire boundary has an outer surface area S[a] that can be likened to a single plane of the same area S[a] on ONE of its sides.




Equation #2.

"Watts per square meter" = ["joules per second" per square meter] = "density of power".



Equation #3.

Joules = "energy".



Equation #4.

"Joules per CUBIC meter" = "density of energy".



THOUGHTS ABOUT THESE EQUATIONS

"Density of energy" contains a reference to "Cubic" rather than "Square" because ... why??

Because a joule has a nonzero volume and thus cannot exist within/on a planar surface.

"Density of power" contains a reference to "Square" rather than "Cubic" because when we are not considering newly created energy, power (for example, a watt) has a ZERO volume and thus cannot exist OUTSIDE of a planar surface.


Question: Based on the above truths, can one introduce "energy" into a defined volume of space, from outside that defined volume, in 0 (zero) seconds of time? No, it takes time, because ... why??

Because the energy (joules, or joule, or fraction of a joule) has to be moved through space in order to introduce it into a defined volume of space.

If it could happen instantaneously, then by definition, there would be no space between the starting point and the ending point of the energy. Consequently, the starting point would by definition be part of the defined volume, a reality which we have already specified by definition NOT to be true. Therefore, the answer to the question is "No."



CONCLUSIONS TO BE DRAWN FROM THE ABOVE

Conclusion #1:

A plane (whether flat or curved) can constitute a defined volume of space, but it cannot constitute a NONZERO defined volume. The volume of a plane must, by definition, be zero. Saying it has a volume but the volume is "zero" has the same effect as saying it has "no volume"; thus, we can see that a plane can simultaneously have "a volume" and "no volume", because the word "volume" can mean two different things simultaneously. But at no time can a plane have a nonzero volume.



Conclusion #2:

Units of "Energy" (i.e. just joules, without any spatial reference) are a measurement of a specific amount of energy which exists in a NONSPECIFIC, NONZERO volume of space, such that, by "nonspecific", we mean that the expression of the amount of space containing the specified energy is capable of variation, without affecting the total amount of energy being specified.



Conclusion #3:

Units of "density of energy" are a measurement of a specific amount OR AN AVERAGE AMOUNT of energy which exists in a SPECIFIC nonzero volume of space, such that, by "specific . . . volume of space" we mean "not capable of variation in its volume".



Conclusion #4:

Based on Conclusion #3,

-- If a specific amount of energy A[e] exists within an UNFIXED, nonzero space named N, and
-- if A[e] constitutes the entire energy within N at any time, and
-- if N is redefined to include a larger volume than it did before the redefinition, and
-- if N is thereby enlarged without allowing any of the energy A[e] to exit N either before or after the redefinition, and
-- if the space that is added to N by the redefinition contained no energy prior to the instant of the redefinition, and
-- if no energy crosses into N from outside of N at any time,

THEN: the value of A[e] (the total amount of energy within N at any time) is unchanged during the redefinition, and the expression of the density of energy of N DECREASES at the time of redefinition.



Conclusion #5:

A given rate of power can EXIST for a NONZERO volume of 3-dimensional space, but only for a ZERO length of time.



Conclusion #6:

A given rate of power can PERSIST for a NONZERO length of time, but only where the power is CONSTANT throughout that entire length of time.

Such an expression of persistent power could (but does not necessarily HAVE to) constitute an AVERAGE power, i.e. an AVERAGE rate of energy INTRODUCTION per unit of time, OVER a certain TOTAL period of time.

(Such total period for which the average is expressed can be of KNOWN or UNKNOWN length, and need not be equal to 1 of the specified unit of time in the denominator of the rate.)



Conclusion #7:

Within 3-dimensional space, a quantity of energy can only exist along ALL THREE dimensions of space, AND either 1) the dimension of time AND a timeless dimension of intensity ("density of power"); OR 2) a time-containing dimension of intensity ("density of energy").



Conclusion #8:

Density of energy for a given region of space can be calculated using only the energy that exists within the defined space at the start of the time for which energy is measured; OR just the energy that is introduced/removed DURING the time for which energy is measured; OR the combination of the first two quantities.



Conclusion #9:

Based on Conclusion #7, for a given, fixed, nonzero volume of space AND a given density of power, energy varies directly with time.



Conclusion #10:

Based on Conclusion #7, for a given, fixed nonzero volume of space AND a given OVERALL power, energy varies directly with time.



Conclusion #11:

Based on Conclusion #7, for a given, fixed, nonzero volume of space, a given OVERALL power, AND a given density of ENERGY, overall energy varies directly with time. QUESTION: "RTF, how can density of energy be constant, while overall energy is variable?" Aha, the answer is ........ when your "density of energy" is an AVERAGE density of energy OVER a period of time!



RTF
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#9
Richard T Fowlers A FEW EQUATIONS post is going to take some digesting.
I will also whilst doing so refer in greater depth to,
http://physics.nist.gov/cuu/Units/units.html
where, interestingly,
" Table 4. Examples of SI derived units whose names and symbols include SI derived units with special names and symbols "

" heat flux density, irradiance.....watt per square meter.....W/m2 "


Attached Files
.pdf   SIDiagramColorAnnot.pdf (Size: 84.19 KB / Downloads: 379)
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#10
I have now had a second read through RTF's A FEW EQUATIONS post it has cleared (at least part of) the subject (area) up for me.
However I will add "I think" as Richard111 did.
So, "we" now have (a unique approach and actually quite clear) description of a W/m2 as a unit of power, thank you RTF.

I will not revisit the SI links above just yet, because as RTF as I (think I) now "get" states,
"A watt is power. Not energy, power.
It is power because it does NOT contain time.
The time has been removed by dividing the joule a/k/a the watt-second (which DOES contain 1 second worth of time) by 1 second.
Because the amount of time in the numerator is of equal value to the amount of time in the denominator, ALL time is removed, and
we are left with a timeless unit of power.

Although a W/m2 is a "derived" unit of a Watt, I have no issue with the above also applying to the W/m2 unit.

My seemingly stubborn "reluctance" to understand RTF's correct descriptions of what a W/m2 is,
is because I have been looking at this from an "in context" point of view.
The context being with regard to computer climate modeling, and the K&T type plots.
Until recently very few have actually used the word power when referring to W/m2 in this context,
and the K&T plots are confusingly titled as "Energy Flows".
Power and energy seem to have been used (or misunderstood as used) interchangeably and incorrectly by many a lot of the time,
or / and my understanding of what was being said was incorrect.
I very much doubt I was alone in this (but I will be one of the very few to admit it openly).

However many that do understand that a Watt is a unit of power,
may have been coming at "the problem" with computer climate modeling and of the K&T type plots from this angle.
RTF wrote,
" I think that the key difference is that the models are all assuming that the entire system is in equilibrium.
As long as that is the case, power is all you need to compare incoming radiation.

But as soon as you assume that equilibrium is not the only state (and possibly never realized),
then you have to deal with energy in order to compare different geometries.
"

RTF I have deliberately highlighted part of the above quote in red, is it possible for you to expand upon / explain this more please.
I think this is a main / major point many have missed the importance and subtly of.

The NASA plot does seem to "assume" an equilibrium, so does seem to be describing using W/m2 as power.
[Image: global_energy_budget_components.png]

At so many levels (in context of computer climate modeling and the K&T type plots specifically) any assumption of "equilibrium" to my mind is a misnomer,
it simply can not and does not happen.
This is a whole "different" subject area as such (there is no "equilibrium" as depicted / assumed), but
I think it reasonable and have been taking it as read that there is no "equilibrium". It is a silly notion.
So, I have been looking at these K&T type plots as energy flows, that is the "source" of my "reluctance" regarding what is a W/m2 actually describing.
The plots should be describing Joules because there is no equilibrium,
and
the only way the figures quoted make sense at present (realizing there is no "equilibrium) is that
they must be actually W/m2 per second figures, ie, Joules.
Hence I have used the below plot as an "opposite" of the NASA version.
[Image: radiation_budget_kiehl_trenberth_20.jpg]

I knowingly chose the above two plots because of their confusing depictions in regard to the K&T types of plots in respect to this discussion of what is a W/m2 because
they can not show an "equilibrium" as such,
because then there would be no man made "global warming" would there. ?
For the depicted "net absorbed" to have an effect, and there be warming (or cooling), it must also be released at a later time (at no doubt varying rates)
- this I assume must introduce time into the plot. Hence I describe this plot as "opposite" to the NASA plot, which "avoids" this issue.

Do the the above types of plots depict a "second" energy version, of the first, never given, "natural equilibrium" power version,
that man by his activities has supposedly unbalanced, so resulting in the "second" energy versions we see depicted above.

NB - Claes Johnson may be suggesting (as I superficially understand his works) the power figures are wrong within the K&T type plots because
they must first (but do not) take the "temperature" (energy level) differences between emitter and receiver into account, and so
the powers will be quite different to those currently depicted.
Below is a slightly altered by Claes Johnson version of one of the K&T type plots
in which he illustrates the above point I have tried to make regarding his approach.
[Image: divineClaesJohnson.gif]

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#11
I have spotted this posted by SST elsewhere in the forum,
which must apply at so many levels to the computer climate models and K&T "types" of plots, and also
any (possibly persisting) notions of a depicted "equilibrium",
incorrectly employing the W/m2 unit of power.

Most notably,
" You can not average an intensive property and have it mean anything. "

Sunsettommy posted in,

E.M.Smith comment

From HERE

Quote:E.M.Smith says:
January 28, 2011 at 11:27 am

Dr. Lurtz says: The radical shift in temperature anomaly points to the issue of temperature measurement. It would be a violation of Physical laws for that much heat to be radiated into space that quickly without a massive change in Global temperature; therefore, either the heat must be going somewhere, or, the temperature measurements do no represent the Global temperature!!

You’ve got it! THE basic problem, one that folks on all sides regularly ignore, is that a Global Average Temperature simply does not exist. It is at best a massive confusion and at worst a deception.

The reasons for this are, unfortunately, founded in 2 rather arcane bits of understanding, so I suspect that just about everyone (including Ph.D. “Climate Scientists” at NASA) just ignore them rather than take the time to think about it.

They are:

1) You can not average an intensive property and have it mean anything. Temperature is an intensive property.

2) Temperatures are driven by processes, such as land form (mountains) that are fractal in nature. Every single ‘surface’ has it’s own temperature. I assert temperatures are fractal in that the size of a fractal varies with the size of ruler you use to measure it (and we are constantly changing our rulers / thermometers).

Because of these two things, the idea of a Global Average Temperature is simply wrong.

Note that this is different from measuring the infrared signature for an entire planet from a single view of the whole place. Then you have fixed your ‘ruler size’ at ‘one planet’ and so #2 drops out. Further, you are not averaging temperatures, you are counting total photons of IR. That count is then DEEMED to be the same as certain black body temperature, but it is not saying the surface IS that temperature (as it is not). It is a leap of assumption, then, to say that the “average of surface temperatures” would be the same as that hypothetical black body. So you can get an IR measurement from space that is useful; you just can’t say that is the average of surface temperatures (only that it is the same IR as a Black Body of a certain temp would have emitted). You can see this pretty clearly if you assume a BB of 100 pixels all at 100 K, then ask “What if I raised ONE to 200 K?”. You now get 2^4 more IR from that one pixel. But ((99*100)+(1*200))/100 will not give you the same ‘temperaure’ as that IR image… If we assume the IR count at 100 K is “1″ for our counter, then we would have 16 + 99 = 115 IR Count and map that to 115 K; where the former temp average gave 101. So which is it, 101 K (average of temperatures) or 115 K (count of increased IR photons)?

Now say only 1/2 of that pixel was actually doing the radiation. Increase the pixels count to 200. We’ve now got ((199*100)+(1*200))/200 = 100.5 for our “Average of temperatures”. Yet our IR count stays the same…

(There are two variations on that last ‘change’. One is to say that the hot pixel was made of one hot and one cold, so the x16 was really x32 from 1/2 of the pixel… that is, it was not a 200K pixel, it was one at 100k and one a bit hotter. 2^1/4 hotter, or about 238 K if I’ve done the math right. That gives ((199*100)+238)/200 = 100.69 K “average of surface temperatures”. The other variation is to say that the half pixel was in fact 200 K, and you need to redo your IR photon count. That would give (199 x 1 + 16)/2 or 107.5 K for our hypothetical ‘temperature’. In both cases (which ever set of assumptions you want to make) you get divergence between the IR Count as temperature proxy and the “average of temperatures”. 100.69 K vs 107.5 K in the last case or 101 K vs 115 K.)

And yes, I ‘left out some bits’ in this example to make it more useful for illustration. The basic point is that IR rises as a 4th power of temp. But an average of temperatures flattens everything linearly. To assume the IR count is an average linear increase in temperatures requires that the IR be evenly distributed, but we know it is not.

Back on Intensive Properties:

Here’s the wiki on intensive vs extensive properties:

http://en.wikipedia.org/wiki/Intensive_a...properties

OK, a simple example. Two pots of water, one at 10 C the other at 20 C. Mix them. What is the final temperature? You can’t know.

It depends on how big the pots were. Relative mass. We assume the masses being heated and cooled are constant and of the same average specific heat for the planet to change temperatures, but that isn’t true. Oceans overturn and different water comes to the surface. Snow falls in the mountains, now we’re not heating rocks with the sun but heating snow.

If those pots of water were 0 C and 100 C the problem is much much worse. Is that 0 C water in the form of ICE or not? Is that 100 C water vapor, or not? Heat of fusion and heat of vaporization. No temperature change, lots of heat flow.

So are we measuring, on average, the change of vaporization from the ocean? The change of condensation from the air? The rate of melting of snow and ice (that consumes heat) or the rate of snow fall (that liberates heat)? And in what masses?

As a simple example, a acre of mountain desert drops from 1 C to 0 C. In the first case, it is just bare sand. It stays that way for one week. An “average of temperatures” would say nothing happened in days 2-6. Yet cold soaked into the sand to some depth. Some heat flowed. It was, in fact, constantly cooling (heat flowed out of the sand and into the air but the air did not warm, as the heat was leaving on to space, cooling).

Now put 1 inch of snow on that ground. Still 0 C. Yet that snow has a much higher heat content than the inch of air it replaced. Have it snow each day. Now, each day, you have taken 1 inch of snow worth of ‘heat of fusion’ and dumped it to space. That is one heck of a lot more “cooling” than the dry example. Yet the thermometer says “nothing happened”… You did not account for mass and heat of fusion.

OK, that’s the ‘nickle tour’ of intensive vs extensive variables and why you can’t average them and have any meaning left.

The “fractals” one is a bit harder. (Please, don’t groan like that… I’ll try to make it easy). This is related to an interesting issue of measuring coastlines. If you measure the coastline for California from Mexico to Oregon by taking a speed boat straight up the line off shore, you get a short number. If you follow each in / out of every major bay, it’s a longer ride. Follow every little estuary in, even longer. Get down to measuring the distance around each grain of sand on the beach it becomes gigantic. About 1000 miles to 80,000 miles. Your choice. As you make the ruler shorter, you measure more curves on more things and get a longer total.

For temperatures, we know that it varies down to the size of a single pebble. An IR image shows that. We assume that a white box about 3 feet off the ground sort of averages them all out to something usable. So far so good. We are fixing our ‘ruler’ size at whatever area of scope a single Stevenson Screen averages. BUT, then we scatter them all over the place with random distances between them and change the number of them by a factor of 10 (or more) over the period of time we are measuring. We are changing the area each of these is expected to measure, changing our ruler length. We have a very dynamic “rubber ruler” measuring a fractal surface.

No wonder the numbers keep wandering around!

http://chiefio.wordpress.com/2010/11/22/...peratures/

http://chiefio.wordpress.com/2010/07/17/...os-is-agw/

And these properties are Not Negotiable. They are fundamental properties of nature. Yet all of “Climate Science” is predicated on strictly ignoring them and in fact on abusing them in ways that are non-physical.

So yes. “the temperature measurements do not represent the Global temperature!!”


Where could the heat be going??

Must it? Was it ever there? Since our method of measuring in broken fundamentally, we don’t really know where the heat went, or if it was there to begin with. All we have are temperatures and IR counts. Those are NOT heat.

IMHO, the heat leaves each day. We warm during the day, and cool at night. The net change in temperatures over the seasons are not “accumulating” heat, they are changes in heat applied as our axial tilt changes an wind blows in from somewhere else. There is no heat stored other than what gets trapped under a cloud layer waiting for the next cold clear night. Then it is gone.

http://wattsupwiththat.com/2011/01/23/frostbite-falls/

http://chiefio.wordpress.com/2010/12/28/...our-peril/

My thoughts are that the oceans can not absorb heat that fast; therefore, the sudden change in temperature anomaly is due to the inability to correctly measure the Earth’s Global Temperature.

In this sentence we can see the impact of decades of “Climate Science” at work confounding things. I’m not picking on you, Dr. Lurtz, the same sentence will be made by millions of folks for the same reasons.

First, we have “oceans absorb heat” then we have “change of temperature”. We treat these as fungible goods. They are not. Heat is a flow of energy. Temperature is a pressure to flow, but may or may not have a flow, and certainly does not have a size of flow. We can have massive heat flow with no temperature change. Happens every day and all the time in weather. Tons of snow falls, at 0 C. Then it melts and flows away as water, at 0 C. Air rises and water condenses as rain, the heat movement showing as a phase change again. Winds blow down a mountain range, getting hotter as they go, but not from the sun warming them nor from their velocity; then they blow across a valley and rise up the opposing moutains, cooling as they go. Lots of temperature changes, heat not so much…

Then we come back to “measure the Earth’s Gobal Temperature”. Yet there is no such thing to measure. It is a fantasy of arithmetic. And a broken one at that.

We can measure the total IR Emissions from a point in space. But that is NOT the “Global Average Temperature”.

We can measure a sample of temperatures on the surface, but averaging them has no meaning. None. Not a scrap.

And then we desire to mix these broken things together into a conceptual model of how the earth is changing… and where the heat is “stored” and “going”. Every day you can see this same broken parade wandering down these same streets, again and again and again….

What we ought to do? Put a single satellite in orbit with the whole disk of the planet in view and just do a gross energy out measure. IR photons and visible. Have a similar count of solar flux. Compare the two over about 120 years. THEN we would have a clue how our energy balance shifts over time.

But measuring airport tarmac today and comparing it to cow fields in 1850 with no attention to how many spots are measured, where they are, and how they changed, then averaging them; that has no relationship to heat flow at all, and precious little to reality in general.


Reply
#12
Whilst looking into the subtle and confusing differences between heat flow density and intensity that it occurs to me is happening in
the SI and Wiki definitions / explanations of the physics that are associated with the term W/m2 as applied to the K&T type plots, and
therefore by default the computer climate models I have come across the following Wikipedia page and figure.

http://en.wikipedia.org/wiki/File:Greenhouse_Effect.svg

Excerpt,

[Image: 750px-Greenhouse_Effect.jpg]

" This figure is a simplified, schematic representation of the flows of energy between space, the atmosphere, and the Earth's surface, and shows how these flows combine to trap heat near the surface and create the greenhouse effect. Energy exchanges are expressed in watts per square meter (W/m2) and derived from Kiehl & Trenberth (1997).

The sun is responsible for virtually all energy that reaches the Earth's surface. Direct overhead sunlight at the top of the atmosphere provides 1366 W/m2; however, geometric effects and reflective surfaces limit the light which is absorbed at the typical location to an annual average of ~235 W/m2. If this were the total heat received at the surface, then, neglecting changes in albedo, the Earth's surface would be expected to have an average temperature of -18 °C (Lashof 1989). Instead, the Earth's atmosphere recycles heat coming from the surface and delivers an additional 324 W/m2, which results in an average surface temperature of roughly +14 °C [1].

Of the surface heat captured by the atmosphere, more than 75% can be attributed to the action of greenhouse gases that absorb thermal radiation emitted by the Earth's surface. The atmosphere in turn transfers the energy it receives both into space (38%) and back to the Earth's surface (62%), where the amount transferred in each direction depends on the thermal and density structure of the atmosphere.

This process by which energy is recycled in the atmosphere to warm the Earth's surface is known as the greenhouse effect and is an essential piece of Earth's climate. Under stable conditions, the total amount of energy entering the system from solar radiation will exactly balance the amount being radiated into space, thus allowing the Earth to maintain a constant average temperature over time. However, recent measurements indicate that the Earth is presently absorbing 0.85 ± 0.15 W/m2 more than it emits into space (Hansen et al. 2005). An overwhelming majority of climate scientists believe that this asymmetry in the flow of energy has been significantly increased by human emissions of greenhouse gases [2].
"

I also came across this figure, on this Wikipedia page, which "says" much the same thing.

[Image: 800px-The_green_house_effect.jpg]

Given the subject of this thread, when taken IN CONTEXT,
the confused and confusing use of the term W/m2, the incorrect use of the unit of power, and the incorrect use / apparent "interchangeability" of power and energy,
as well as now mentioning / adding density and intensity,
then the source of the confusion seems rather clear to me.
The K&T type plots, the "greenhouse effect" they depict, and computer climate modeling. ie, Anthropogenic (man made - literally) Global Warming pseudo science.


AND, finally for this week,
Sunsettommy has posted the below in the charts thread, post 145.
Alan Siddons has produced the plots from the view point of accepting that W/m2 is correctly used as a unit of power in the K&T type plots,
and then proceeds to show how ridiculous (and unphysical) they actually are.

Given my approach has been to show that the W/m2 unit of power is used incorrectly, then this is a nice contrary approach / view,
to the problems of computer climate modeling and the K&T type plots, as well as the "greenhouse effect" I have been trying to expand upon.
This I have been trying to do by asking the question what is meant and described by the use of W/m2 in the context of the K&T type plots, computer climate modeling, and
the as explained by AGW (that it is wholely dependent upon) so called greenhouse effect "theory"..

Sunsettommy posted,
These were from Alan Siddons:

This one converts W/m² to temperatures (in Celsius) to show how stupid the whole budget is.


[Image: ASSlide11.jpg]

Notice how radiation from the 1.8 degree atmosphere raises the surface, which was initially at minus 39.8, to 14.8 degrees! That's impossible.

The next one is meant to illustrate that you cannot send light of a certain intensity through
a series of reflections, absorptions and re-emissions and expect that it will end up BRIGHTER than it started.
Again, K-T violates all known laws of physics.


[Image: ASSlide2.jpg]
End of quote.

Reply
#13
From this thread,
(02-01-2011, 02:39 AM)Richard111 Wrote:
(01-17-2011, 03:37 PM)Sunsettommy Wrote: People who are truly into discussing the topic will be able to talk about what is known and what needs to be better understood.No need to prove who is more correct since the objective is to learn.To better understand what is being postulated.The presentation under discussion may be incorrect or has room for improvement.But talking about it will benefit all parties to the discussion.

Well put, SST.

Herewith my understanding of watts and joules.

I have a 1 cubic metre plastic tank filled with rainwater outside the house.
For this thought exercise assume the plastic is not there. (magic if you want) I can measure the temperature of the water by dangling a thermometer in the middle.
From this I can calculate the number of joules of energy the 1 cubic meter of water contains. I can also calculate the radiation from the six sides of the water cube in watts per square metre. THIS IS NOW. Time T1 if you like.

1 second later, now time T2, I know the water has lost that number of joules of energy equivalent to the number of WATTS radiated from all six sides for a period of just 1 second.

Remember you must use degrees Kelvin. I subtract the radiated energy in joules from the initial energy state in joules and arrive at my new current energy content from which I calculate a new temperature. From that I calculate the new radiation level in watts per square meter.

We know the precise mass of the water and we know the total radiative surface area (making the assumption it is a blackbody as well) thus we can calculate total energy loss.

But if we can only see one square metre of the surface of that water we cannot calculate the total energy lost by radiation in proportion to the mass under that one square metre. This is why I believe "energy budgets" have no real value.

I will try to do all the above calculations and post my results later.

I replied there,
(02-01-2011, 01:33 PM)Derek Wrote: Richard111, I will have to use your quote of Sunsettomy's comment regarding discussion above in the small explanatory piece I have yet to write.

Regarding Watts, I may well move that part of your post to the What is a Watt thread, if that is OK with you.
I will also have to add to the first post / explanation of that thread because it is now obvious to me,
because of the investigation I have been embarking upon that there are a number of questions that the thread tries to address, and
they need stating to clear up what the thread is actually about.
Firstly the thread is not actually about the interpreted (and strict) physics definition of a Watt (as most seem to understand it). But that is the correct starting point as such.
The thread is more about how the W/m2 derived unit from a Watt is used in the K&T types of plots (and climate models, and greenhouse effect "theory"),
ie, have you seen the Wiki page / article linked to and copied there yet. Talk about confusing....energy mentioned 6 times, heat flow a couple of times, power, NOT MENTIONED AT ALL.
I also will have to follow up the SI definition of a W/m2, "heat flow density" is a bit vague to me at present. Then a comma, and then "irradiance".
Not at all clear to me, what is meant by "density" in this specific use, and why two descriptions???
At present I am wondering if I will end up with 3 different definitions / actual uses of what a W/m2 is, and how it is used.

But this is all as I hope you understand for the What is a Watt thread not this one,
so I'll tidy it all up next week.
Please feel free to comment here or there, and I will tidy up as appropriate probably next week.

"the small explanatory piece I have yet to write." is not so small now, and as yet unfinished.
I hope you all understand that the " small explanatory piece " comes first for me at present.
Then I will tidy up these threads.

As a "reminder" does anyone have a copy of RTF's "A FEW EQUATIONS" post please.
The whole aim of practical politics is to keep the populace alarmed
(and hence clamorous to be led to safety)
by menacing it with an endless series of hobgoblins, all of them imaginary.

H. L. Mencken.  

The hobgoblins have to be imaginary so that
"they" can offer their solutions, not THE solutions.
Reply
#14
Hi All,
Elsewhere I have been following discussions in regards of whether it is correct or not to divide solar input received at the top of the atmosphere by 2 or 4.
I think this is an absolutely central issue, that must be understood.

On this thread so far, the casual reader can not have failed to notice the "pain" I have suffered in trying to understand what a W/m2 actually is.
My confusion is because of the way W/m2 is used in the K&T plots.
I hope that may have become apparent to at least some whilst reading the thread.

I shall try to explain what has been confusing me in regards to the way W/m2 has been used in K&T.

As far as physics is concerned, W/m2 is a power figure, derived from a Watt AND
as such it is a timeless figure. ie, it must apply across all time scales.
This later point has, I think, been missed by many.

So, when using W/m2 figures the physics of what is being described must be taken into account in determining what maths can be used.
ie, the physics determines the maths.

If W/m2 is used in a way that is not physically correct, then it is the maths determining the physics, which will not work in reality.
The maths may be wonderful, but if it ain't physical, it is worthless maths.

My maths is particularly weak, I have no issue admitting that, but, I do remember vividly one maths lesson.
My maths teacher at school went purple with rage trying to explain to a classroom of not particularly interested teenage boys,
with regards to algebra, that you can not compare lions and zebras..
They have to be the same, you must use a common denominator.
With regard to W/m2, the only "common denominator" is that the figure must describe the physics in such a way as to be a timeless figure.
Otherwise comparison is not correct or possible.

The sun permanently illuminates half of the sphere that is planet earth.
So, as a hemisphere is twice the area of a disc, then dividing the power of solar input received by 2 over a lit hemisphere is correct.
The physics of dividing solar P received by 2 for planet earth is found in reality.

If however we divide solar P received by 4 then we have to assume that the planet has rotated fully once, or "x" number of times, (or the planet is disc shaped...)
because the solar input has been spread over the entire sphere's surface.
(A sphere has 4 times the area of a disc, and twice that of a hemisphere.)
This has introduced a time element to W/m2, in this case 24 hours, or multiples thereof.
P/2 = lion.
P/4 = zebra.

When P/2 and P/4 are used we are not using the same "thing", infact according to the definition of what a W/m2 actually is,
then because P/4 introduces a time element to a timeless figure, then,
whatever the figure is, it is not a W/m2.

The K&T plots start off with 342 W/m2 solar input, which is a P/4 figure.
From there on in, almost all the figures used in the plots are of different time scales,
some are timeless, as they should be, figures, some are not.
We are comparing lions, zebras, monkeys, giraffes, and goodness knows what other animals all together on one plot.

My maths teacher would probably of exploded, if he had ever looked at a K&T plot.....

When physically incorrect figures are used, or net figures are used, then the physics are mangled and any resemblance to reality is lost completely.
Maths does not determine the physics,
maths can ONLY describe the physics when applied in the correct physical manner to a given situation.

In K&t, and computer climate models the maths determines (mangles) the physics...

Net figures are a major problem also because, there could be, let us say,
16 arrows / reasons in one direction, and 6 or 7 arrows / reasons in the other direction.
Using a net figure would just mangle the physics, and any relationships within the physics.
Furthermore the net arrows will probably give the wrong impression of how it might change due to other factors changing.

In short, there are so many ways that the physics have to be described correctly by the maths, that,
the "sum" overall is probably impossible.
On thing is for certain though, calculating physics determined by maths is not the right way to go about things,
infact, it is a crassly stupid approach doomed to failure.
The best example of which is dividing solar input power to planet earth by 4.





The whole aim of practical politics is to keep the populace alarmed
(and hence clamorous to be led to safety)
by menacing it with an endless series of hobgoblins, all of them imaginary.

H. L. Mencken.  

The hobgoblins have to be imaginary so that
"they" can offer their solutions, not THE solutions.
Reply
#15
Sympathise with the math Derek. All I had at school were four figure log tables and a slide rule. It was embarrassing how long it took me to work out how to do antilogs on my on board computer.

I am trying to follow the excellent maths explanations by Joseph E. Postma at this site here.

You can download Understanding the Thermodynamic Atmosphere Effect in pdf format.

If it wasn't for the atmosphere and all the stuff in it we would be living on a rather overheated desert type world. Hmm.. have you read Dune? No sky dragon but he had sand dragons.
Environmentalism is based on lies and the lies reflect an agenda that regards humanity as the enemy of the Earth. - Alan Caruba
Reply
#16
Hi All,
A quick post holiday "update".

A W/m2 is a power figure, or if you prefer a "pressure" figure,
it is a temperature signal.

Years ago an Uncle of mine whilst explaining electricity to me, used a water pipe simile.
He said, imagine pipes carrying water rather than electricity.
Volts is the pressure, and amps is the pipe diameter.
You can not work much out about the flow of water or electricity without knowing the pressure (voltage) and the diameter of the pipe (amps).
This all makes sense to me as a simple analogy to "visualise" electricity flows.

W/m2 is a pressure figure, therefore it assumes the objects being compared are the same size / mass, etc, if they are not,
then another figure for "diameter" is needed.
How can so many have missed "diameter" of the pipes involved is missing from K&T and "greenhouse" ???????

"Greenhouse" is taught as,
1) Solar input received at earth's surface = 239W/m2.
2) 239 W/m2 is radiated by the earth's surface.
3) The atmosphere is heated up to the same temperature and thus radiates up and down 239W./m2.
So, the earth radiates from the atmosphere 239 W/m2 as it should to space, ie, earth appears to be -18C when viewed from space, as it should be,
AND,
the earth's surface is 239W/m2 from the sun, AND 239W/m2 from the atmosphere, 478W/m2 = +15C*.

So, "greenhouse" is taught as "pressure" only, but, if one includes amount of energy, or "diameter",
then earth's surface only receives 1 (directly from the sun) at 239 W/m2 + 1/2 ("back radiated" from the atmosphere) at 239 W/m2,
which is too little for earth's surface, according to "GH" to be 15C.
AND,
Earth should only radiate half the amount of energy it receives, at 239 W/m2 from the sun to space...
According to "GH" "theory".

* = 15C is a very questionable and often quoted supposed "Global Mean Temperature" (GMT),
That IS NOT the earth's surface temperature.
The 15C as quoted so frequently, is infact a near surface air temperature, as measured (usually at about 6 foot above the actual surface), and statistically produced by dubious methods.
Which is a different thing completely to earth's actual surface temperature.
The actual surface temperature, or any attempt at a meaningful global mean of it,
is infact completely absent from such descriptions.
Reply
#17
Yes! Very good point. Me, being a simple trusting soul, assume they always meant the "blackbody" equivalent of 1 square metre for each level of radiation defined in watts per square metre.

I have several times asked the question how to you define the radiation from a VOLUME of the atmosphere? I am currently trying to learn about infrared detectors as used in the satelites. So far it is not encouraging. The best I've read about so far only record IR from 4 microns to 20 microns. Big deal! There is still IR radiation down to 1,000 microns! It also appears they "average" all the readings. For example they will see high intensity narrow band (8 to 12 microns) through the 10 micron atmospheric window. They will also see low intensity wide band radiation from the cloud tops (most of which will be missed due to cutoff at 20 microns in the measuring instrument) and then there will be the very low intensity 15 micron radiation from CO2 in the cold upper troposphere where water vapour does not exist in any great quantity.

All of that is somehow added together to show -18C (255K) radiation from the whole earth from a source claimed to be radiating at 240 watts per square metre.

I know all the sums add up but verifying the input parameters seems fraught.
Environmentalism is based on lies and the lies reflect an agenda that regards humanity as the enemy of the Earth. - Alan Caruba
Reply
#18
(05-29-2011, 06:20 AM)Richard111 Wrote: Yes! Very good point. Me, being a simple trusting soul, assume they always meant the "blackbody" equivalent of 1 square metre for each level of radiation defined in watts per square metre.

The use of the W/m2 figure / unit ASSUMES
the same mass, "size", emissivity, specific heat value, etc, etc, etc,
between emitter and receiver..
Which in K&T, and "greenhouse" means,
Quack, quack, oooops.

Reply
#19
(01-13-2011, 07:17 AM)Richard T. Fowler Wrote: A FEW EQUATIONS

RTF

Richard, my genuine apologies, in that I deleted the content of this post completely unintentionally.
I hope you, or someone else has a copy of it, as I would dearly like to repost it here.
If anyone has a copy, please send it to me by PM and I will repost it ASAP.

Thanks in advance
Derek.

Sunsettommy:

It is restored and found at post #7.
It is our attitude toward free thought and free expression that will determine our fate. There must be no limit on the range of temperate discussion, no limits on thought. No subject must be taboo. No censor must preside at our assemblies.

–William O. Douglas, U.S. Supreme Court Justice, 1952
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#20
Thank you SST.
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