Guest Post by Willis Eschenbach
Once again, the crazy idea that downwelling longwave radiation (DLR, also called infra-red or IR, or “greenhouse radiation”) can’t heat the ocean has raised its ugly head on one of my threads.
Figure 1. The question in question.
There are lots of good arguments against the AGW consensus, but this one is just silly. Here are four entirely separate and distinct lines of reasoning showing that DLR does in fact heat the oceans.
Argument 1. People claim that because the DLR is absorbed in the first mm of water, it can’t heat the mass of the ocean. But the same is true of the land. DLR is absorbed in the first mm of rock or soil. Yet the same people who claim that DLR can’t heat the ocean (because it’s absorbed in the first mm) still believe that DLR can heat the land (despite the fact that it’s absorbed in the first mm).
And this is in spite of the fact that the ocean can circulate the heat downwards through turbulence, while there is no such circulation in the land … but still people claim the ocean can’t heat from DLR but the land can. Logical contradiction, no cookies.
Argument 2. If the DLR isn’t heating the water, where is it going? It can’t be heating the air, because the atmosphere has far too little thermal mass. If DLR were heating the air we’d all be on fire.
Nor can it be going to evaporation as many claim, because the numbers are way too large. Evaporation is known to be on the order of 70 w/m2, while average downwelling longwave radiation is more than four times that amount … and some of the evaporation is surely coming from the heating from the visible light.
So if the DLR is not heating the ocean, and we know that a maximum of less than a quarter of the energy of the DLR might be going into evaporation, and the DLR is not heating the air … then where is it going?
Rumor has it that energy can’t be created or destroyed, so where is the energy from the DLR going after it is absorbed by the ocean, and what is it heating?
Argument 3. The claim is often made that warming the top millimetre can’t affect the heat of the bulk ocean. But in addition to the wind-driven turbulence of the topmost layer mixing the DLR energy downwards into lower layers, heating the surface affects the entire upper bulk temperature of the ocean every night when the ocean is overturning. At night the top layer of the ocean naturally overturns, driven by the temperature differences between surface and deeper waters (see the diagrams here). DLR heating of the top mm of the ocean reduces those differences and thus delays the onset of that oceanic overturning by slowing the night-time cooling of the topmost layer, and it also slows the speed of the overturning once it is established. This reduces the heat flow from the body of the upper ocean, and leaves the entire mass warmer than it would have been had the DLR not slowed the overturning.
Argument 4. Without the heating from the DLR, there’s not enough heating to explain the current liquid state of the ocean. The DLR is about two-thirds of the total downwelling radiation (solar plus DLR). Given the known heat losses of the ocean, it would be an ice-cube if it weren’t being warmed by the DLR. We know the radiative losses of the ocean, which depend only on its temperature, and are about 390 w/m2. In addition there are losses of sensible heat (~ 30 w/m2) and evaporative losses (~ 70 w/m2). That’s a total loss of 390 + 30 + 70 = 490 w/m2.
But the average solar input to the surface is only about 170 watts/square metre.
So if the DLR isn’t heating the ocean, with heat gains of only the solar 170 w/m2 and losses of 390 w/m2 … then why isn’t the ocean an ice-cube?
Note that each of these arguments against the idea that DLR can’t warm the ocean stands on its own. None of them depends on any of the others to be valid. So if you still think DLR can’t warm the ocean, you have to refute not one, but all four of those arguments.
Look, folks, there’s lot’s of good, valid scientific objections against the AGW claims, but the idea that DLR can’t heat the ocean is nonsense. Go buy an infrared lamp, put it over a pan of water, and see what happens. It only hurts the general skeptical arguments when people believe and espouse impossible things …
w.
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Matt G says:
August 16, 2011 at 6:34 am
Matt, you have missed 1/2 the experiment. Now try allowing ONLY sunlight in, but removing (or at least significantly reducing) the incoming IR. The details would be a bit of a challenge, since you would have to maintain the air temperature over the water, but otherwise have the top of the tank surrounded by something very cold. The surface of the water will still be radiating ~ 400 W/m^2, but the incoming sunlight will only be providing ~ 170 W/m^2. This will ALSO cause the water to cool.
The obvious conclusion is that the SUM of the energy coming in affects the water temperature (along with the sum of the energy out). You can’t logically say that only one source of energy is keeping the water warm.
Come to think of it, a related experiment is performed all the time. On clear nights, the air (and ground and the surface of bodies of water) cool rather effectively. On cloudy nights, every thing stays warmer. The difference is that the clouds are very good emitters of thermal IR across the entire thermal IR spectrum, sending copious amounts of DLR to the surface where it gets absorbed. On clear nights, only GHG’s emit DLR — they only emit in particular bands of the spectrum, so they cannot radiate as much IR downward as the clouds do, so they cannot slow the cooing as effectively.
So the DLR is clearly responsible for slowing the rate of cooling at night. During the day, they ALSO slow the rate of cooling, which is clear if you think about it a little.
Bystander,
“Willis says “Please stop the condescending snarkiness, it just makes you look ugly.”
Ah – so condescending snarkiness is only OK when attacking real scientists then….”
In this case Willis was attempting to point a certain a[***]ole to a better way of interacting. Please do not throw this at him.
[Language. Robt]
Willis: Thanks for increasing the credibility of the skeptical community by taking on this issue.
Many people instinctively assume that when about 330 W/m2 of DLR is deposited in the top 1 mm of the ocean, that massive amount of energy can’t fit in thin layer of water and must be somehow be returned to the atmosphere (possibly by evaporation). After all, that energy can’t penetrate the ocean by convection or conduction. Unfortunately, some of these people don’t recognize that the upward 390 W/m2 of upward LWR emitted by the ocean originates in exactly the same top 1 mm of the ocean that absorbs DLR. Since most DLR originates at altitudes that are colder than the surface of the ocean, the net flux of long wavelength energy must be from the ocean to the atmosphere. Evaporation also removes about 80 W/m2 of energy from the top 1 mm. Only about 80% of solar radiation (SWR), penetrates the top 1 mm of the ocean. Therefore the top 1 mm of the ocean is running an energy deficit despite the large amount of energy that is deposited there by DLR. And measurements show that the top 1 mm is usually colder than the water immediately below.
In the tropics at noon on a sunny day, solar radiation might reach 500-1000 W/m2. If 20% of that much radiation were absorbed by the top 1 mm, the temperature of the top 1 mm might rise – thereby increasing upward radiation and evaporation without “warming” the bulk of the ocean. However, this situation persists for only a small fraction of each day.
One might say that the bulk of the ocean is warmed by the >80% of SWR that penetrates the top 1 mm of the ocean; not the DLR that is absorbed in the top 1 mm. Neither LWR nor evaporation cool the water below the top 1 mm. The surplus energy from SWR that is deposited below the top 1 mm is eventually returned to the cooler top 1 mm by convection and conduction. From the top 1 mm, that energy is eventually returned to the atmosphere and space.
Kadaka, point taken again.
richard verney says:
August 16, 2011 at 9:37 am
[…]
Good comment. The LW radiation comprises a flux which isn’t separable into individual ‘up’ and ‘down’ components in any meaningful way. This is what I was trying to get at with the badly thought out and badly worded comment Kadaka rightly criticised.
By the way Richard, this paper looks like good reading in the context of your ocean freezing question to Willis:
http://www.fisica.edu.uy/~barreiro/papers/BarreiroCherchiMasina2011.pdf
It’s under discussion here:
http://judithcurry.com/2011/08/16/climate-sensitivity-to-ocean-heat-transport/
I think a systems approach needs to be taken with respect to the ocean.
From the point of the greenhouse effect it does not matter if a solar photon is absorbed 30ft down and LWIR photons are being absorbed or emitted in the top millimeter. One might say it is the ocean’s business how it arranges its own temperature structure. All that really matters is that heat *energy* is being lost or gained by the ocean as a whole.
Evaporation-condensation is another energy exchange process altogether. At any one moment in time, energy is being exchanged but the temperature is constant. This sort of harkens back to the discussion of Local Thermodynamic Equilibrium (LTE) some months back.
“OK, if gross flows are important than why hasn’t anyone computed the gross energy flows of kinetic energy? …. So, why would anyone think the gross flows are important for the case of radiation? Maybe Willis or someone can explain to me the difference.”
Because for radiation, the flow in one direction is due to the object on one side. If I know the temperature and emissivity of one object (such as the surface of the ocean), then I can say how much IR energy it is emitting, INDEPENDENT of the temperature or emissivity or other objects around. So it makes perfect sense to discuss the energy being radiated, not simply the net radiation. (Of course, in the end it is the NET energy that determines the change in temperature, so eventually you need to know about the other objects around).
For conduction you need to know the temperature of BOTH objects and the conditions in between them. This means that knowing the conditions of he ocean surface will not suffice to know the conduction. So in a sense you are already looking at the net flow of energy, and the details about how much goes each direction is not important.
(But such details are indeed considered when looking at microscopic details of the kinetic theory of gas http://en.wikipedia.org/wiki/Kinetic_theory or details of phonons http://en.wikipedia.org/wiki/Phonon)
George says:
August 16, 2011 at 9:40 am
You got that backwards, George. The critical angle would apply to light heading UP to the surface at a 48 degree angle and then reflecting back down into the water.
There is, however, a different effect that does come into play for water, making it more reflective as the light hits at a more glancing angle. Look toward the bottom of this link: http://en.wikipedia.org/wiki/Reflectivity
How come everybody is talking about AVERAGE radiation levels resulting in AVERAGE temps using the Stefan-Boltzmann formula when there is a fourth power in this formula?
Earth has ONE sun, that radiates on half the earth. Average radiation on this half is 1364/2 = 682 W/m^2 resulting in an average temp of 303K after deduction for albedo.. Directly under the sun the temps could be much higher. These possible temps aren’t seen because the heat is taken up by the oceans and continents. Taking these high temps to the nightside of our earth makes it possible to start talking about reduced cooling by “greenhouse” gasses.http://wattsupwiththat.wordpress.com/wp-admin/edit-comments.php?comment_status=all#comments-form
All we need to do is calculate a temperature budget for earth to see if we’re loosing or gaining 😉
Hasn’t been done afaik
“”””” Alexander Duranko says:
August 16, 2011 at 7:32 am
Some interesting analysis of ocean heating recently.. Regarding CO2 and H2O specific ‘DLR’, you must realise that because Kirchhoff’s Law requires that emissivity and absorptivity are the same at equilibrium, ….. “””””
Too bad your statement needs those two words “at equilibrium” in order to be correct.
The Earth’s atmosphere is never in (thermal) equilibrium; not even vaguely, so forget Kirchoff’s Law.
While we are considering the validity of “Eschenbach’s Axiom” (Willis to us); that “Downwelling Long Wave Radiation (DLWR) can’t not heat the deep ocean”; we should not forget that fundamental Axiom of Climatism; “Gases cannot radiate thermal (continuum) EM radiation” so therefore Earth’s atmosphere cannot radiate a thermal (Planckian) EM radiation spectrum. And the reason for this fundamental truth, is simply that gases (well at least mono-atomic and homo-diatomic) gases can’t because they have a zero electric dipole moment; and Maxwell’s equations tell us we can’t radiate EM waves without an antenna, so in order to radiate an EM thermal spectrum, based on Temperature of the radiating substance, the atoms/molecules have to have an electric dipole moment that is not zero.
So the molecules must be assymmetrical like H2O for example; they can’t be symmetrical like CO2 or CH4 for example; neither of which has a non-zero electric dipole moment, at any ordinary Temperature. In particular N2, O2, and Ar, the principle gases of earth’s atmosphere all have zero electric dipole moments, at ordinary Temperatures, so they cannot radiate a thermal continuum EM spectrum.
Well that’s the belief anyhow; just like Eschenbach’s Axiom.
tallbloke says:
August 16, 2011 at 10:33 am
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Thanks for the heads up. When I have a little time, later this week, I shall consider the paper and the post about it on Claimate etc. Looks interesting.
Tim Folkerts says:
August 16, 2011 at 10:22 am
It would be better to complete this using only solar sources and no DLW, but would also have to be done outside to keep the same solar radiation 170w/m2 input sources. Changing the percentage radiation source will also change how much penetrates the water. The variable outside atmospheric day temperatures makes very little difference to the volume of water, so leaving it outside would be more accurate. Don’t know how this would cause it to cool compared with a 20c rise in one day, way above the highest atmospheric temperature that day. Also demonstrated with solar ponds, the water can warm much more via the sun, it is latent heat and convection that keeps the ocean surface stable.
“The obvious conclusion is that the SUM of the energy coming in affects the water temperature (along with the sum of the energy out). You can’t logically say that only one source of energy is keeping the water warm.”
I can when this is only demonstrated to do so, but remember this was only for one day. My main point it that for just one day the difference is huge and for over a period a massive change has to occur for this to be even noticeable from the solar source.
On clear nights the atmospheric temperatures can cool quickly, but the ocean SST’s hardly change at all. Only the top 1mm is shown to be a little cooler at night over the ocean, but it makes no difference to SST’s over one full day. Clouds do have an affect on atmospheric temperatures and warm during night and cool during the day. Simply because the clouds cool during the day shows that the suns affect on atmospheric temperatures is greater than any DLR. (despite the 170 and 390 values shown) I agree the DLR is clearly responsible for slowing energy through the atmosphere, but for ocean the changes are very small or make no difference because it always has a high concentration of water vapour above it’s immediate surface.
Folks, and particularly Tallbloke, you are arguing that radiatively heating a liquid from above the surface causes overturning.
Heating a liquid from above the surface causes stratification, not overturning. You can experience this in the ocean or a lake on a calm sunny day. This is because the heating decreases with depth, no matter what the type of radiation is. As a result, the warmest layers are always on top. In that condition, heat is transferred downwards by conduction.
w.
Tom Folkert,
“The difference is that the clouds are very good emitters of thermal IR across the entire thermal IR spectrum, sending copious amounts of DLR to the surface where it gets absorbed.”
And where does the energy come from for the clouds to emit energy all night Tom? The amount of thermal mass in them simply is not enough. You have to give up this idea of components of a system functioning the same in isolation.
steven mosher says:
August 16, 2011 at 1:52 am
Hmm Tallbloke. Rather than trust a magazine about how reflective insulation works or does not work I think I trust the stuff I built for DOD. And I’ll use my thermos to keep my coffee from cooling faster than it would. And If I have to go near a wacking hot fire i’ll also wear a reflective suit
here have some fun. there’s plenty more
http://www.insul.net/howto.php
And yes, if you use a space blanket too long you get hoarfrost in the inside.. cause its working. but eventually get to the fire
—————————————————————-
Steven,
Does adding more of this highly reflective aluminium increase the thermal reflectivity?
For instance would you prefer to be in an armour suit like in the days of other dreamy notions of how the world worked… Would it’s greater concentration of molecules even tho reflective of IR enable heat transfer. Or is the real key to not transferring a lot of heat the tiny mass of the aluminium actually being heated. So would adding more co2 make the layer more dense and transfer heat faster?
This post has nothing to do with how the world works…
How did this thread get so long so fast? I haven’t had time to read them all, so hopefully this isn’t repetitive. Willis, do you know what you are talking about? Infrared doesn’t penetrate a whole millimeter, but mere microns. The point is not that it cannot heat the ocean, it can, but the point is it is coupled to the ocean quite differently from solar, while models generally couple them both to the whole mixing layer as if they were equivalent. Solar can penetrate 10s of meters, there has even been Kelp forests at 100 meters depth.
Radiation that penetrates mere microns is more likely to be involved in surface latent heat effects, is more likely to be reradiated quickly and more likely to be less coupled to the ocean by foam or spray or surface biofilms, etc. Your argument amounts to “A watt is a watt”. In a complex nonlinear system a watt isn’t just a watt. It does matter where that watt is. Vertical and horizontal distribution make a difference. The albedo of the ocean is likely to be different in the IR range than in the visible range, just as it is different for snow and other surfaces. You wouldn’t claim a watt absorbed in the desert where it is far more likely to be radiated that night is the same as a watt deposited in a humid climate where it will stick around for longer. What makes you think in a complex nonlinear system you are entitled to the assumption that a watt in the first microns of the ocean surface is the same as one 50 meters down? That is the assumption the modelers are making.
Willis Eschenbach says:
August 16, 2011 at 12:57 pm
Folks, and particularly Tallbloke, you are arguing that radiatively heating a liquid from above the surface causes overturning.
Heating a liquid from above the surface causes stratification, not overturning. You can experience this in the ocean or a lake on a calm sunny day. This is because the heating decreases with depth, no matter what the type of radiation is. As a result, the warmest layers are always on top. In that condition, heat is transferred downwards by conduction.
The air doesn’t heat the water. Period. It doesn’t contain enough energy to do so. Period. Never happens. As you said a cold body never warms a warm one… So the atmosphere except the last few hundred meters are colder than the ocean surface. The top 33 feet of the ocean contains the same mass as the entire atmosphere above it. Being that the last few feet are in actual contact. That is all that can affect change.
If your going with the insulation model…
1. You have diminishing returns with every layer added. So adding more co2 only adds a small portion of actual “benefit”. It’s non-linear and dilative.
2. What gives you the idea that adding heat next to the surface wouldn’t cause other mechanisms to operate faster… IE a higher flame boils water faster. Do you suggest water can only evaporate in a static fashion linearly?
Richard Verney says:
There is no double accounting. If my household receives $170/day and spends $170/day, there is absolutely nothing that prevents my wife and me from handing thousands of dollars back and forth each day. This does not violate and “conservation of money” nor does it require any double accounting to make the budget balance. Same for the earth’s energy budget.
I would challenge you to find any part of the system where the energy in is not equal to the energy out.
A better way to think about this is from one day to the next. At the moment, a column of air 1 m^2 from the ground to the top of the atmosphere has a total thermal energy of about
1000 J/kg*K * 10,000 kg * 250 K = 2.5 billion J.
(These are all only a rough estimate, but it makes the point.) This is energy the atmosphere already has — not energy it needs to get every second from the sun or some place else. This column of atmosphere can easily loose ~ 325 J each second to the earth and 200 J each second to outer space for quite some time without cooling too much. During the day, that column of air will absorb ~ 2*70 = 140 J each second from the sun and a little over 350 + 24 + 78 J from the ground (since evaporation and radiation and convection will be greater during the day then during the night) for a net gain of ~ 75 J each second during the day (ie the atmosphere warms up during the day). At night, it will not get any energy from the sun, but it will still get energy from the ground (via radiation convection and conduction), for a net loss of ~ 75 J each second (ie the atmosphere cools at night). Over the course of a day, the net change is ~ 0.
No double accounting. No violation of conservation of energy. No violation of the 2nd law of thermodynamics.
The details of loses and gains at specific locations and specific times and specific seasons obviously would require much more work, but the “back of the envelope” calculation shows everything is in accordance with the laws of physics.
This post is clearly a rebuttal. Less clear is a rebuttal to what?
For those of us who are less well connected to the debate, could we get a little context next time, please? Who believes this and where are they saying it? Then tear into why they’re wrong. Just a little context would go a long way. Thanks.
kuhnkat askes:
August 16, 2011 at 1:14 pm
“And where does the energy come from for the clouds to emit energy all night Tom? The amount of thermal mass in them simply is not enough. ”
See the previous post. There is a surprising amount of thermal mass in the atmosphere.
Besides, the clouds are also ABSORBING energy from the ground very effectively, which means that most of the energy is simply going back and forth continuously. One second, a square meter of cloud emits ~ 325 W thermal IR downward that the ground absorbs. That same second, a square meter of ground emits ~ 390 W thermal IR upward that the clouds absorb ( the exact numbers are not important; I am simply taking representative numbers where the clouds are cooler than the surface). The clouds are actually GAINING energy in the exchange, which would tend to warm them (although there are also many other energy exchanges that will affect the overall energy and temperature of the clouds).
Mike Rossander says:
August 16, 2011 at 1:49 pm
As you can see from the comments there are lots of folks out there who claim that DLR can’t heat the body of the ocean.
The context is that another of my threads was devolving into a discussion of this issue.
As a result I wrote the arguments list above, and tallbloke and the folks who think DLR can’t warm the ocean started answering (although none have explained why, if the DLR isn’t warming the ocean, it hasn’t frozen yet.
w.
Mike Rossander says:
August 16, 2011 at 1:49 pm
This post is clearly a rebuttal. Less clear is a rebuttal to what?
For those of us who are less well connected to the debate, could we get a little context next time, please? Who believes this and where are they saying it? Then tear into why they’re wrong. Just a little context would go a long way. Thanks.
Hi Mike,
take a look at this post I wrote and Willis’ contributions to it.
http://tallbloke.wordpress.com/2011/03/03/tallbloke-back-radiation-oceans-and-energy-exchange/
Willis Eschenbach says:
August 16, 2011 at 2:12 pm
As a result I wrote the arguments list above, and tallbloke and the folks who think DLR can’t warm the ocean started answering (although none have explained why, if the DLR isn’t warming the ocean, it hasn’t frozen yet.
tallbloke says:
August 15, 2011 at 1:46 pm
Hi Willis,
Argument one asks what the difference is between rock and water. Warm water molecules rise to the top. Warm rock molecules conduct heat to their neighbours, which can’t go anywhere.
Argument two asks where the energy goes. The answer is:
space.
Argument three is not an argument that DLR can warm the ocean, it’s an argument that it can slow its rate of cooling.
Argument four is a numerical misunderstanding. The ocean surface very efficiently absorbs 95% of DLR, and promptly re-emits half of that (the other 5% being reflected). The other half makes it another couple of molecules deeper and then the molecules it warms become more buoyant than their neighbours and rise to the top, losing another half upwards. Now we’re down to ~72W/m^2. Lets remember the net flux is 66W/m^2 upwards at this point. So your ice cube argument fails. The ocean absorbs and re-emits the long wave radiation coming downwards from the atmosphere, the sums balance. In fact it emits 66W/m^2 more long wave radiation than it absorbs. It always has, and the oceans don’t freeze, because solar shortwave warms them to really significant depths of 100 metres and more as internal tides and currents mix its energy downwards. Some of that solar short wave energy is re-emitted as long wave from the surface along with some of the long wave which came from the atmosphere. The rest causes evaporation and thermals or is conducted upwards. The difference is, the solar derived energy can remain deep in the ocean for a long time, controlling it’s bulk temperature.
The question is, do DLR heated water molecules make it downwards far enough for long enough to warm the ocean bulk. I think the answer is no, because warmer water molecules are naturally buoyant, and because the vortices which mix solar energy so efficiently are below the wave troughs, several thousands of times deeper down than the depth DLR penetrates water to. For experimental evidence on this matter I’ve tried putting small soaked pieces of loo paper just under the surface out in the rolling waves away from the shore where they break. They don’t get sucked downwards. So that’s turbulent convection gone, what’s left? Conduction is a non-starter, because water thermally stratifies and anyway is a relatively poor heat conductor unless the heat source is underneath rather than above.
But this isn’t about absolutes. I’m sure the increased DLR warmed the ocean a little bit, or at least slowed its rate of cooling a little bit. I think the increased insolation due to (empirically measured) reduced cloud cover in the tropics 1980-1998 did a lot more to increase ocean heat content. To turn your question back to you, where else could that energy have gone?
Cheers
TB
richard verney says:
August 16, 2011 at 9:37 am
I did not make a “bald statement”. I said that we know (from Stefan-Boltzmann) that the ocean is radiating about 400 w/m2. We know (see the Trenberth document specified earlier) that the sun hitting the surface is on the order of 170 w/m2. Obviously, if the ocean were losing 400 w/m2 and only receiving 170 w/m2, it would soon be frozen. That is not a “bald statement” as you claim, it is all observation-based. Things that lose energy faster than they gain it cool until they equilibrate, which at only 170 w/m2 warming the ocean (in your scenario) is well below freezing.
I say that the DLR is what makes up the difference, it is the energy source that keeps the ocean from freezing.
You say the ocean doesn’t warm from DLR … so what keeps it from freezing?
You have to understand, richard, that simple questions like this need answers. I have nothing to prove here, I’ve asked a question. You can go through all the gyrations you want, you can try to make it look like I’m the one with something to prove … but all I’m doing is asking a question:
In your explanation, what keeps the ocean from freezing?
You have made no attempt to dispute the facts as I’ve stated them about solar input to the ocean (about 170 w/m2) and S/B radiation losses from the ocean (about 400 w/ms). Given the huge energy imbalance between losses and gains in your explanation of how the world works, not my explanation (which is energetically balanced) but your explanation, what in your theory keeps the oceans from freezing?
w.
Tim Folkerts says:
August 16, 2011 at 1:47 pm
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If the income that you receive from your employer is $170 per day, as you say there is nothing preventing you and your wife handling 1000s of dollar notes per day but this does not mean that your income is any more than $170 per day.
I accept that you can receive $170 and give your wife $165 she then gives you back $164 and you then give her back $163 and she then gives you back $162 etc etc but the fact that so much money is passing through your hands does not mean that your daily income is anyting more than $170 and you could not obatin a mortgage on the basis that you were in receipt of $1000s per day. You are simply counting the same notes more than once.
The 390 w per sqm is a factor of the 170 w per sqm received from the sun. It is created by the solar energy received by the earth. If the sun had never fired up, the 390 w per sq m would not exist. You cannot create something from nothing and whatever is downwelling from the atmosphere it cannot be more than we have received from the sun.
Going back to Trenberth, of course I could go around adding amounts to both sides of the equation without disturbing the balance. But to do so is false. It is net flux that we need to consider when addressing the issues raised by Willis.
Richard M says:
August 16, 2011 at 7:14 am
We can analyze the system using either individual flows or net flows. However, in the real world there are no “net flows”. There are only individual flows. The “net” flow is a mathematical construct, a useful one to be sure, but a construct that has no real-world counterpart.
In fact, contrary to your claim, we do discuss the individual flows (what you call the “gross” flows) all the time, they are a major topic of discussion in climate science. See the Trenberth paper cited above for a host of examples, there are many more. The reason we discuss individual flows is that individual flows, because they are accurate representations of reality, can reveal more than looking at the net flows which are not.
Curiously, among other reasons this is true for a mathematical reason – net flows are not invertible to deduce the individual underlying flows. “Not invertible” means if we know the flow is 400 w/m2 out and 380 w/m2 in, we can calculate that the net flow is – 20 w/m2. But we can’t invert the process, because knowing the net flow tells us nothing about the individual flows.
This means that information has been thrown away to get to the “net flow” number, and I prefer not to throw away information when I don’t have to.
w.